Preparation of Nano-silver Artemisia Argyi and Anti-bacterial Finishing to Silk Fabric

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A Systematic Study of the Synthesis of Silver Nanoplates_ Is Citrate a “Magic” Reagent_ sup

SUPPORTING INFORMATIONA Systematic Study of the Synthesis of Silver Nanoplates: Is Citrate a"Magic" Reagent?Qiao Zhang,† Na Li,†,‡ James Goebl,† Zhenda Lu,† Yadong Yin*,††Department of Chemistry, University of California, Riverside California 92521 USA‡ School of Chemical Engineering & Technology, Harbin Institute of Technology, Harbin, Heilongjiang 150001 P. R. China* To whom correspondence should be addressed, yadong.yin@ Experimental SectionsChemicals. Hydrogen peroxide (H2O2, 30 wt-%), acetic acid (glacial), sodium hydroxide, and sodium potassium tartrate were purchased from Fisher Scientific. Silver nitrate (AgNO3, 99+%), sodium borohydride (NaBH4, 99%), ethylene glycol (EG), sodium citrate tribasic dihydrate (TSC, 99%), tricarballylic acid (99%), and L-ascorbic acid were obtained from Sigma-Aldrich. Polyvinylpyrrolidone (PVP, M w ~ 29,000) was purchased from Fluka. Malonic acid disodium salt monohydrate (99%), succinic acid disodium anhydrous (99%), glutaric acid (99%), oxalic acid (98%), DL-isocitric acid trisodium hydrate (98%), 1,3,5-benzenetricarboxyllic acid (98%), pimelic acid (98%) and polyethylene glycol (PEG, Mw ~ 3500) were purchased from Acros Organics. Adipic acid disodium salt was purchased from TCI America. Diethylene glycol (DEG) was purchased from Alfa Aesar. All chemicals were used as received without further treatment. Synthesis of Ag nanoplates Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.14 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), and H2O2 (30 wt %, 60 µL) were combined and vigorously stirred atS1room temperature in air. Sodium borohydride (NaBH4, 100 mM, 250 µL) is rapidly injected into this mixture to get the nanoplates. After ~3 min, the colloid turns to a deep-yellow color, due to the formation of small silver nanoparticles. Within the next several minutes, the morphology continues to change from particles to nanoplates accompanied by the solution color changing from yellow to blue. For the other specific conditions, e.g., different surfactants or concentrations, the synthetic strategies are described in the Caption of each figure in Supporting Information. Synthesis of Ag nanowires. Ag nanowires are prepared by a modified polyol process developed by Xia and co-workers (Y. Sun, B. Mayers, T. Herricks, Y. Xia, Nano Letters 2003, 3, 955.), in which AgNO3 was reduced by EG in the presence of Pt seeds and PVP. In a typical process, 15 mL of EG was heated at 170 o C for 2 hours under magnetic stirring. 4.5 mL EG solution of 0.1 mM K2PtCl6 was then rapidly injected into the EG solution, which became light brown in several seconds, confirming the formation of Pt seeds. 5 min later, 18 mL EG solution of a mixture of AgNO3 (0.05 M) and PVP (Mw ~ 40,000, 0.1 M) was added dropwise to the seeds solution through a syringe pump at a rate of 0.5 mL/min. This reaction mixture was then heated at 170 o C for another 40 min to ensure the complete reduction of AgNO3. The as-obtained product is then washed with ethanol for three times and D.I. H2O for twice, and finally dispersed in 40 mL of D.I. H2O.Synthesis of Ag nanoplates from Ag nanowires Typically, 0.1 mL of Ag nanowires (out of 40 mL) was dispersed in 24.25 mL of H2O first, followed by mixing trisodium citrate (75 mM, 0.3 mL), and hydrogen peroxide (30 wt. %, 100 µL) were combined and vigorously stirred at room temperature in air. 10 min later, sodium borohydride (NaBH4, 100 mM, 250 µL) is rapidly injected into this mixture, generating a pale yellow colloidal solution. After ~3 min, the colloid turns to a deep-yellow color, due to the formation of small silver nanoparticles. Within the nextS2several seconds, the morphology continues to change from particles to nanoplates accompanied by the solution color changing from yellow to blue.Synthesis of Ag nanoparticles In 24.1 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH4, 100 mM, 250 µL) is rapidly injected into this mixture to get the nanoparticles.Synthesis of Ag plates from Ag nanoparticles To the as-obtained yellow Ag sol, hydrogen peroxide (30 wt. %, 60 µL) is rapidly injected. Sodium borohydride (NaBH4, 100 mM, 250 µL) was then quickly injected to get the final product.Characterization The morphology of Ag nanoparticles was characterized by using a Tecnai T12 transmission electron microscope (TEM). The measurement of optical property was conducted by using a Varian Cary 50 UV/Vis spectrophotometer (190 nm – 1100 nm). A probe-type Ocean Optics HR2000CG-UV-NIR spectrometer was used to measure the UV-Vis spectra of the reaction system to get the real-time spectra change during the synthesis of silver nanoplates. Computational method The molecules were built by using GaussView 4.1. The geometries were then optimized at the Hartree-Fork level with 6-31G(d) basis set by Gaussian 03W.S3S4Name Structure Distance betweentwo nearestcarboxylic groups (Å) Yield of platesAcetic acidN/A ~ 0%Oxalic acid 2.69 ~ 0%Malonic acid 2.68 ~80%Succinic acid2.78 ~100%Citramalic acid3.82~100%Tartaric acid3.26 ~80%Glutaric acid3.26 ~50%Adipic acid 2.87~20%醋酸草酸丙二酸琥珀酸，丁二酸甲苹果酸，柠苹酸酒石酸戊二酸，胶酸己二酸，肥酸S5Pimelic acid 6.62~ 0%Citric acid 3.12~100%Isocitric acid3.09 ~90%cis ‐Aconitic acid 2.82~90%Tricarballylic acid3.18~85%Trimesic Acid4.76 ~ 0%Table S1. The 3D structures of carboxyl compounds with different numbers of carboxylic groups and chain lengths that have been used as the capping agent to prepare silver nanoplates.庚二酸柠檬酸异柠檬酸丙三酸均苯三甲酸顺乌头酸，顺丙烯三甲酸the spectra obtained in the absence (red) and in the presence (black) of H2O2, respectively.S6S7Figure S2 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting ammonium persulfate ((NH 4)2S 2O 8, APS) for NaBH 4.Synthesis of silver nanoplates by using APS. Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and APS (0.5 M, 1 mL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 50 µL) is rapidly injected into this mixture to get the nanoplates.S8Figure S3 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting sodium acetate for trisodium citrate.Synthesis of silver nanoplates by using acetate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), sodium acetate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 100 µL) is rapidly injected into this mixture to get the final product.Figure S4 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium oxalate for trisodium citrate.Synthesis of silver nanoplates by using oxalate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium oxalate (75 mM, 0.5 mL), poly (vinyl pyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH4, 100 mM, 100 µL) is rapidly injected into this mixture to get the finalproduct.S9Figure S5 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium malonate for trisodium citrate.Synthesis of silver nanoplates by using malonate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium malonate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH4, 100 mM, 50 µL) is rapidly injected into this mixture to get the nanoplates.S10Figure S6 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium succinate for trisodium citrate.Synthesis of silver nanoplates by using succinate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium succinate(75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 30 µL) were combined and vigorously stirred at room temperature in air. Sodiumborohydride (NaBH4, 100 mM, 50 µL) is rapidly injected into this mixture to get the nanoplates.S11S12Figure S7 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium citramalate for trisodium citrate.Synthesis of silver nanoplates by using citramalate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium citramalate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 50 µL) is rapidly injected into this mixture to get the nanoplates.Figure S8 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium tartrate for trisodium citrate.Synthesis of silver nanoplates by using tartrate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), sodium potassium tartrate(75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 30 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH4, 100 mM, 50 µL) is rapidly injected into this mixture to get thenanoplates.S13S14Figure S9 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium glutarate for trisodium citrate.Synthesis of silver nanoplates by using glutarate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium glutarate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 100 µL) is rapidly injected into this mixture to get the nanoplates.S15Figure S10 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting disodium adipate for trisodium citrate.Synthesis of silver nanoplates by using adipate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.24 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), disodium adipate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 50 µL) is rapidly injected into this mixture to get the nanoplates.S16Figure S11 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting trisodium isocitrate for trisodium citrate.Synthesis of silver nanoplates by using isocitrate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium isocitrate (75 mM, 0.5 mL), and hydrogen peroxide (30 wt. %, 30 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 100 µL) is rapidly injected into this mixture to get the nanoplates.S17Figure S12 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting trisodium cis-aconitate for trisodium citrate.Synthesis of silver nanoplates by using cis-aconitate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium cis-aconitate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 30 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 100 µL) is rapidly injected into this mixture to get the nanoplates.Figure S13 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting trisodium tricarballylate for trisodium citrate.Synthesis of silver nanoplates by using tricarballylate Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.14 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium tricarballylate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH4, 100 mM, 150 µL) is rapidly injected into this mixture to get thenanoplates.S18S19Figure S14 TEM image (a) and the histogram (b) of thickness when the concentration of NaBH 4 is 0.4 mM while the other conditions keep the same.S20Figure S15 TEM image (a) and the histogram (b) of thickness when the concentration of NaBH 4 is 0.6 mM while the other conditions keep the same.S21Figure S16 TEM image (a) and the histogram (b) of thickness when the concentration of NaBH 4 is 0.8 mM while the other conditions keep the same.S22Figure S17 TEM image (a) and the histogram (b) of thickness when the concentration of NaBH 4 is 1.0 mM while the other conditions keep the same.Figure S18 The position of the surface plasmon band as a function of the concentration of NaBH4.S23S24Figure S19 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting ethanol for PVP.Synthesis of silver nanoplates by using ethanol Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.14 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), ethanol (17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 150 µL) is rapidly injected into this mixture to get the nanoplates.S25Figure S20 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting polyvinyl alcohol (PVA) (Mw ~ 88,000) for PVP.Synthesis of silver nanoplates by using PVA Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.14 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), polyvinyl alcohol (PVA, Mw ~ 88,000, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 150 µL) is rapidly injected into this mixture to get the nanoplates.S26Figure S 21 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting polyethylene glycol (PEG) (Mw ~ 3,500) for PVP.Synthesis of silver nanoplates by using PEG Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.14 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), polyethylene glycol (PEG, Mw ~ 3,500, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 150 µL) is rapidly injected into this mixture to get the nanoplates.S27Figure S22 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting ethylene glycol (EG) for PVP.Synthesis of silver nanoplates by using ethylene glycol Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.04 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), ethylene glycol (EG, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 250 µL) is rapidly injected into this mixture to get the nanoplates.S28Figure S23 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting diethylene glycol (DEG) for PVP.Synthesis of silver nanoplates by using diethylene glycol Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.04 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), diethylene glycol (DEG, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 250 µL) is rapidly injected into this mixture to get the nanoplates.S29Figure S24 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting glycerol for PVP.Synthesis of silver nanoplates by using glycerol Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.04 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), glycerol (17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodium borohydride (NaBH 4, 100 mM, 250 µL) is rapidly injected into this mixture to get the nanoplates.Figure S25 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting ascorbic acid for NaBH4.Synthesis of silver nanoplates by using ascorbic acid Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.04 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Sodiumascorbate (100 mM, 250 µL) is rapidly injected into this mixture to get the nanoplates.S30S31Figure S26 The UV-vis spectrum (a) and TEM image (b) of a typical sample prepared by substituting hydrazine for NaBH 4.Synthesis of silver nanoplates by using hydrazine Typically, the total volume of the reaction solution is fixed at 25.00 mL. In 24.19 mL of pure water, an aqueous solution of silver nitrate (0.05 M, 50 µL), trisodium citrate (75 mM, 0.5 mL), poly (vinylpyrrolidone) (PVP, weight-average molecular weight Mw ~ 29, 000 g/mol, 17.5 mM, 0.1 mL), and hydrogen peroxide (30 wt. %, 60 µL) were combined and vigorously stirred at room temperature in air. Hydrazine hydrate (hydrazine 64%, 100 µL) is rapidly injected into this mixture to get the nanoplates.。

纳米银粒子_二氧化硅复合颗粒溶胶_凝胶的制备与表征_马少华

文章编号:1672-4291(2008)01-0030-04收稿日期:2007-05-16基金项目:国家自然科学基金资助项目(60678005);陕西省自然科学基础研究计划资助项目(2006F 39)作者简介:马少华,男,硕士研究生,研究方向为光学材料的制备及性能.*通讯作者:李贵安,男,副教授,博士.E -mail:liguian66@163.co m纳米银粒子-二氧化硅复合颗粒溶胶-凝胶的制备与表征马少华, 李贵安*, 张玉荣(陕西师范大学物理学与信息技术学院,陕西西安710062)摘要:采用溶胶-凝胶法,成功制备出不同浓度的银-二氧化硅复合颗粒.采用透射电子显微镜、X 射线衍射仪、紫外可见近红外光谱仪对其形貌、结构及光学吸收特性进行了表征和分析.结果表明,纳米银粒子(15~20nm)具有良好的面心立方结构,且均匀分散于二氧化硅颗粒表面.银粒子等离子共振吸收峰位于410nm,吸收强度随银粒子浓度增加而加强.关键词:纳米银粒子;二氧化硅;溶胶-凝胶法中图分类号:O437 1 文献标识码:APreparation and characterization of silver nanoparticles -silicacomposite grain by so-l gel technologyMA Shao -hua,LI Gu-i an *,ZHANG Yu -rong (College of Physics and Information Technology,Shaanx i Normal U niversity,Xi an 710062,Shaanxi,China)Abstract :The sliver -silica composite grains w ith different concentrations w ere prepared by so-l g el technology.The feature,structure,and optical absorption properties of silver nanoparticles w ere characterized by transmission electron microscope (TEM ),X -ray diffraction (XRD),and ultraviolet v isible near infrared (U V -Vis -NIR)absorption spectrometer.T he results indicate that the silver nanoparticles (15~20nm )have face -centered cubic crystal structure and are homogenously distributed on the surface of silica.It w as found that the peak of plasma resonant absorption locates at about 410nm for silver nanoparticles,and the intensity of absorption increases w ith that of the silver concentration.Key words:silver nanoparticles;silica;so-l gel technolog y 纳米尺度颗粒因其具有颗粒尺寸小、比表面积大、表面原子数多、表面能与表面张力随颗粒尺寸下降急剧增大等特性而表现出量子尺寸等效应.金属纳米颗粒所具有的不同于常规固体的新奇特性(如光学与电磁学特性),使其在催化、传感器、非线性光学以及信息存储等领域展现出非常广阔的应用前景,并已成为当今热点研究课题之一[1-4].近年来,纳米银颗粒的制备技术发展迅速,方法多样,但由于纳米尺度的金属颗粒具有较高的表面能,因而在制备中易发生团聚,致使其纳米效应减弱或失去.因此,解决纳米尺度颗粒的分散性及稳定性问题一直是人们研究追求的目标之一.在纳米银粒子掺杂的功能复合材料研究中,制备银-二氧化硅复合颗粒主要采用光照[5]和吸附[6]等方法.这些方法操作工艺复杂,且对设备要求较高.为克服上述制备工艺的不足,作者采用溶胶-凝胶法在二氧化硅颗粒第36卷第1期陕西师范大学学报(自然科学版)Vol.36 No.1 2008年1月Journal of Shaanxi Normal U niversity (Natural Science Edition)Jan.2008表面合成纳米银粒子,成功制备出不同浓度的银-二氧化硅无机复合颗粒,并对其结构和光学特性进行表征.结果表明,采用这种方法制备银-二氧化硅复合颗粒,可有效控制纳米颗粒的团聚.1 实验试剂为正硅酸乙酯(分析纯,西安化学试剂厂)、硝酸银(分析纯,西安稀有金属新材料股份有限公司)、乙醇(分析纯,西安三浦精细化工厂)、硝酸(分析纯,西安三浦精细化工厂)、去离子水等.所有试剂实验前未经处理.样品采用溶胶-凝胶法制备.将一定量的硅酸乙酯置于反应容器中,加入适量乙醇强力搅拌,再加入适量硝酸酸化的去离子水,使混合液保持恒温50 ,反应3h (硅酸乙酯、乙醇、水的摩尔比为1 4 6);然后分别将所需量的硝酸银溶于适量硝酸酸化的去离子水中混合均匀,并将其滴加于上述反应混合物中,保持恒温50 ,再避光反应3h 得均匀透明溶胶.将所得溶胶避光恒温静置直到形成凝胶,然后将凝胶分别在80 、120 下恒温干燥12h,部分样品分别在300 、500 各保温热处理2h,升温速率为2 /min.采用日本日立公司H 600透射电子显微镜(TEM ,加速电压为30 104V )观察形貌、颗粒大小;用日本理学公司D/M ax 2550型X 衍射仪(XRD,Cu ,40kV/50mA)对样品进行晶型检测;采用美国Perkin -Elmer 公司的Lambda 950型紫外可见近红外光谱仪(UV -Vis -NIR,以空气作为参比物)在300~800nm 的波长范围内对样品进行光谱测量.2 结果与讨论2.1 Ag 粒子形成机理实验中二氧化硅来自硅酸乙酯的水解与聚合反应,而银粒子来自硝酸银的还原.按照本实验试剂加入顺序,首先是正硅酸乙酯水解聚合生成二氧化硅的反应.然后是硝酸银还原反应.由于二氧化硅颗粒在硝酸银加入之前已基本形成,且二氧化硅表面带一定量负电荷,因而,随着硝酸银的加入,带正电的Ag +被吸附在表面带负电的二氧化硅颗粒上.因为在正硅酸乙酯水解、聚合的过程中生成有大量的乙醇自由基,于是在二氧化硅与乙醇的共同作用下,乙醇自由基把吸附在二氧化硅颗粒表面的Ag +逐渐还原为银原子Ag 0,进而大量的银原子在二氧化硅表面聚集形成纳米量级的Ag 粒子.其反应为[7]Ag n +Ag ++CH 3CH 2OH Ag n +1+H ++CH 3CH 2O.值得注意的是,反应中自由基CH 3CH 2O 并不还原Ag +,而是由乙醇自由基CH 3CH 2O 和Ag +共同作用,Ag +吸收了一个电子,于是Ag +被还原为Ag 0,并沉积在二氧化硅表面形成银粒子[8].2.2 复合颗粒形貌分析为分析样品中银粒子的形貌与分布情况,对样品的显微结构进行了观测.将研磨很细的粉末样品于乙醇中超声分散均匀,投于电镜铜网上,待样品自然干燥后于电镜内进行测量.图1是样品500 热图1 5%Ag 样品的TEM 照片(500 )Fig.1 TEM im age of 5Ag%sample heat treated at 500处理后的透射电子显微镜照片.从照片中可以看出,纳米银粒子分布于二氧化硅颗粒表面,形状近似为球形,银粒子尺寸约在15~20nm 之间.照片显示,纳米银粒子分布在二氧化硅颗粒表面,这主要是因为在硝酸银加入之前,二氧化硅颗粒已基本形成.在这种情况下,生成二氧化硅的反应已基本完成,因而,Ag +只能沉积在二氧化硅颗粒表面而被还原,最终导致纳米量级的银粒子分散在二氧化硅表面.2.3 Ag 粒子X 射线分析为检验样品中银粒子是否以纳米尺度存在以及估算银粒子的尺寸,实验对样品进行了XRD 测量.图2是500 热处理下具有不同浓度银复合颗粒样品的X 射线衍射图样.无银二氧化硅也给出其衍射图样.在所有图样中,作为基质的二氧化硅处于非晶态,XRD 图样显示出明显的非晶衍射包络.随着银浓度的逐渐增加,在二氧化硅非晶衍射包络的背景上逐渐出现银的多个衍射峰,强度随银的浓度相应增加.经过与XRD 标准图谱对照,它们分别对应于面心立方金属银的(111)、(200)、(220)、(311)四个晶面的衍射峰.至于在衍射图样b 中没有发现明显第1期马少华等:纳米银粒子-二氧化硅复合颗粒的溶胶-凝胶制备与表征31的银的衍射峰,这主要是因为相比非晶态的二氧化硅而言,样品b 中银的浓度太低,仪器无法检出.图2 样品X 衍射图样(500 )Fig.2 X -ray diffraction patterns ofsamples heat treated (500 )a.未加A g;b.1%Ag;c.5%Ag ;d.10%Ag根据XRD 图样信息,我们采用Scherrer 方程估算银颗粒的平均尺寸[9],有D =0.89 cos ,其中,D 为垂直于晶面方向晶粒大小的平均尺寸(nm), 为X 射线波长(nm).XRD 表征中采用Cu 靶辐射,X 射线波长为0.1541nm, 是衍射峰半高宽(rad.), 是衍射角.表1为选取5%Ag (500 )表1 根据Scherrer 方程计算的银粒子颗粒尺寸(5%Ag)Tab.1 Silver particle size estimated from X -ray line by using Scherrer s equation for (5%Ag)samples heat treated at 500 晶面2 /( ) /( )D /nm 11138 040 323120044 220 4425并用Scherrer 方程估算银颗粒尺寸的结果.值得注意的是,用不同衍射峰所对应晶面进行计算,结果稍有差别,这主要是因为样品中晶粒形状不规则以及晶粒尺寸不一致所造成的.另外,使用Scherrer 方程来估算颗粒尺寸时应尽量选取低角度(2 50 )衍射峰,再求平均值.本文用Scherrer 方程估算出的银粒子平均粒径约为28nm,这与TEM 观察的颗粒大小分布(15~20nm )相比偏大.主要原因是当用于X 射线测量的颗粒粒径很小时(如纳米量级),被测量的颗粒表面张力增大,这会导致颗粒内部晶格发生畸变,导致估算结果比实际颗粒偏大.图3为500 时5%Ag (111)面衍射峰图.图3 5%Ag(111)面衍射峰(500 )Fig.3 Diffraction peak of 5%Ag (111)plane heat treated (500 )2.4 Ag 粒子光吸收分析为研究纳米银粒子的光吸收特性,实验对样品的光吸收进行了分析.图4是样品在300 热处理下不同浓度银复合颗粒紫外可见近红外吸收光谱以图4 样品的UV -Vis -NIR 吸收光谱(300 )Fig.4 UV -Vis -NIR absorption spectra ofsamples heat treated (300 )a.未加A g; b.0.1%Ag; c.1%Ag及二氧化硅的吸收光谱.可以看出,二氧化硅在可见光波段(400~800nm)无明显吸收峰,曲线平滑.但随着银的加入,曲线在410nm 附近出现银等离子共振吸收峰,且强度随银浓度的增加而增大,吸收峰也存在宽化现象.与纳米银在溶液中狭窄的吸收峰相比,在固态中银粒子的吸收峰加宽.这是因为随着银浓度的增加,单位体积内形成了更多的纳米银颗粒,从而对等离子共振吸收峰的贡献增加.至于相对于其在溶液中的吸收峰加宽现象,除了由于高浓度银的加入使形成的纳米银颗粒尺寸有所增加外,纳米银颗粒形状的不规则以及尺寸的不一致(由Scherrer 方程的计算结果所证实)等因素,也是引起吸收峰宽化现象的重要原因[10].另外,从图4还可看出,随银浓度的增加样品的吸收呈现整体加强.这与测试样品的颜色随银浓度变化规律一致.图5反映了不同热处理温度对银粒子等离子共振吸收的影响.从图可看出,样品在120 热处理后,吸收曲线在410nm 附近为一个较宽的吸收包32 陕西师范大学学报(自然科学版)第36卷图5 不同热处理温度下样品的UV-Vis-NIR吸收光谱(5%Ag)Fig.5 UV-Vis-NIR absorption spectra of(5%Ag) samples at different heat treated temperaturea.120 ;b.500络.但当温度升高到500 时,曲线出现明显的吸收峰.该吸收峰是银纳米粒子的等离子共振吸收峰.这是因为当样品的热处理温度升高时,部分吸附在二氧化硅表面未被还原的Ag+在高温条件下可与二氧化硅相互作用,进而被还原成银原子[11],并在二氧化硅表面聚集形成纳米银粒子,从而使二氧化硅表面的纳米银粒子浓度增加,最终导致银纳米粒子等离子共振吸收的强度加强.3 结论应用溶胶-凝胶法,制备出不同浓度的银-二氧化硅复合颗粒,并对其结构和光学特性进行表征.结果表明,纳米银粒子(15~20nm)具有良好的面心立方结构,且均匀分布于二氧化硅颗粒表面;银粒子等离子共振吸收峰位于410nm,其吸收强度随样品中银粒子浓度的增加而增加.参考文献:[1]李贵安,宋建平,李貅,等.纳米金属-偶氮染料共掺杂复合膜的制备与吸收蓝移现象[J].化学学报,2005,63(8):777-782.[2]L i Guian,So ng Jianping,Li X iu,et al.Prepar atio n andfluorescence properties of co-doped nanoco mposite film based on supr a molecular str ucture[J].Chinese Journal of Chemical Physics,2006,19(2):183-186.[3]李贵安,宋建平,李貅,等.金属-染料包覆共掺杂复合物的制备与热学特性[J].西安交通大学学报:自然科学版,2005,39(4):433-436.[4]李贵安.纳米粒子与染料超分子结构复合材料的设计及其吸收红移机理[J].陕西师范大学学报:自然科学版, 2006,34(1):32-35.[5]姚素薇,曹艳蕊,张卫国.光还原法制备不同形貌银纳米粒子及其形成机理[J].应用化学,2006,23(4): 438-440.[6]王果,戴静,毛从文,等.Ag/SiO2纳米复合材料的制备及其导电性能研究[J].材料科学与工程学报,2006, 24(5):761-765.[7]Wu P W,Dunn B,Doan V,et al.Controlling thespontaneous precipitation of silver nanoparticles in so-l g el materials[J].Journal of So-l Gel Science and T echnolo gy, 2000,19(2):249-252.[8]Ameen K B,Rajasekhar an T,Rajasekhar an M V.Grainsize dependence of physico-o ptical properties of nanometallic silver in silica aer ogel matrix[J].Jour nal of Non-Crystalline Solids,2006,352(8):737-746.[9]丛秋滋.多晶二维X射线衍射[M].北京:科学出版社,1997:220-232.[10]Zhu M W,Qian G D,Ding G J.Plasma resonance ofsilver nano particles deposited on the surface of submicron silica spheres[J].M aterials Chemistr y and Physics,2006, 96(2):489-493.[11]Epifani M,Giannini C,T apfer L,et al.So-l gel synthesisand characterization of A g and A u nano particles in SiO2,T iO2and ZrO2thin films[J].Jour nal of the A merican Ceramic So ciety,2000,83(10):2385-2393.责任编辑强志军第1期马少华等:纳米银粒子-二氧化硅复合颗粒的溶胶-凝胶制备与表征33。

10 International Conference on Nanotechnology and Biosensors 2010巯基水杨酸+三乙胺+pvp 纳米银

Preparation of Silver Nanoparticle with Different Particle Sizes for Low-Temperature SinteringSteve Lien-Chung Hsu, Rong-Tarng WuDepartment of Materials Science & Engineering, National Cheng-Kung UniversityTainan, 701-01, Taiwan, R.O.C.E-mail address: lchsu@.twAbstract—In this study, silver nanoparticles were synthesized by chemical reduction from silver nitrate using different organic compounds as the protecting agent and organic bases as the reaction promoter. The average sizes of the resulting silver nanoparticles were between 3 to 15 nm depending on the type of the protecting agent, which allowed low-temperature sintering of the metal. These suspensions of silver nanoparticles prepared by this method are free from any metal ion contamination and are suitable for use in semiconductor industry. The suspensions will be used to make micro-interconnects in integrated circuits (IC) devices by inkjet printing.Keywords-Silver; Nanoparticles; SuspensionsI.I NTRODUCTIONIn recent years, metallic nanoparticles have drawn a lot of attention due to their unusual physical and chemical properties, which largely differ from their bulk properties [1, 2]. They shows unique properties such as excellent conductivity, chemical stability, and catalytic activity, etc. which are dependent on the particle size, size distribution and shape [3-5]. Among all metals, silver has the highest electrical and thermal conductivity. Silver materials with zero-, one-, or two-dimensional nanostructures such as nanoparticles, nanowires, and nanocubes are believed to have great potential for applications in optics, catalysis, and other fields [6-9]. In the characteristic of silver material, the low sintering temperature of silver nanoparticles is important in flexible electronic applications [10,11].In previous literature, to prepare silver nanoparticles suspensions by the chemical reduction method, a protecting agent needs to be added, such as long-chain thiol, long-chain amines, carboxylic compounds, poly(vinyl pyrrolidone) [12-14], etc. In addition, reagents such as formaldehyde, glycol ethylene, NaBH4 etc., are usually needed to be the reducing agent [15-17]. In this research, we use different organic compounds as the protecting agent and organic bases as the reaction promoter to prepare contamination-free suspensions of silver nanoparticles with different particle sizes for ink jet printing application.II.E XPERIMENTALA.MaterialsSilver nitrate (AgNO3) was obtained from Showa Chemical Co. Triethylamine (TEA) were purchased from Tedia Company Inc. Alpha-Terpineol was obtained from J. T. Baker.Formaldehyde (HCHO, 37 wt. % in water) was purchased from Tedia Company Inc. Thiosalicylic acid (TSA) was obtained from Acros Organic.Poly(N-vinyl-2-pyrrolidone (PVP) (molecular weight ~10,000) was obtained frrom ICN Biomedical Inc.B.Preparation of silver nanoparticles suspensionsThe AgNO3 was dissolved in de-ionized water in a beaker. To this solution, a protecting agent 〔poly(N-vinyl-2-pyrrolidone or thiosalicylic acid or triethylamine〕was added. After being stirred, HCHO solution was then added to the solution. Subsequently, a promoter (triethylamine or pyridine) was added drop wise. The color of the solution turned from clear to black. After being stirred for 200 min at room temperature, the precipitates were washed several times with ethanol, followed by centrifugation (6000 rpm, 10 min), to remove unbounded TEA. The particles were then dried at room temperature under vacuum for 24 h. The silver nanoparticles suspensions were prepared from the dried silver nanoparticles by re-dispersing them into alpha-terpineol.C.CharacterizationThe transmission electron microscopy (TEM) images of silver nanoparticles were obtained with a JEOL JEM-1200EX transmission electron microscope operating at 120 KV with an Energy Dispersive Spectrometer (EDS). The X-ray diffraction (XRD) experiment was conducted on a Rigaku D/MAX-IIIV X-ray Diffractometer using Ni-filtered Cu-Kα radiation with a scanning rate of 4° min−1 at 30 kV and 20 mA. The weight loss of the silver films was analyzed using a TA Instrument Thermogravimetric Analyzer (TGA) 2050 at a heating rate of 10 o C/min under air. The UV-visible spectra of the silver nanoparticle suspensions were obtained on a Hitachi U-2001 UV-VIS spectrophotometer.2010 International Conference on Nanotechnology and Biosensors IPCBEE vol.2 (2011) © (2011)IACSIT Press, SingaporeIII.R ESULTS AND D ISCUSSIONA.Poly(N-vinyl-2-pyrrolidone) stabilized silvernanoparticlesAccording to literature, the reduction reaction of AgNO3 by formaldehyde is slow without the addition of basic catalysts. A higher pH is favored for higher reducing power. In order to avoid the use of inorganic bases as the reaction promoter, which usually contains other unwanted metal ions, we chose organic bases, triethylamine or pyridine as the reaction promoter. These bases are easy to be washed out after reaction and will not contaminate the resulting silver nanoparticles. In our process, all reagents are organic materials except the AgNO3 precursor. The final product is only pure silver nanoparticles without other metal ion impurities, so the silver nanoparticles product is suitable to use in IC devices. As shown in Fig. 1(a) shows the silver nanoparticles prepared from pyridine. The viscosity of the dispersion was 1.25 cps and the particles sizes were around 10-20 nm. Fig. 1(b) is the EDS pattern of the silver particles. Fig. 1(c) show the UV-Vis absorption spectra of silver nanoparticles prepared from pyridine with different concentrations of AgNO3. They have the characteristic absorption bands with maxima at 420-430 nm. That could be due to the increase of polydispersity of particle sizes in higher concentration of the reagents.The X-ray diffraction patterns of the silver nanoparticles, presented in Fig. 1(d), show the peak characteristics of metallic silver. The reflection peaks are indexed as the fcc (111), (200), (220), and (311) planes, indicating that the silver is well crystallized.Figure 1. (a) TEM micrographs of silver nanoparticles prepared from PVP(b) EDS pattern (c) UV pattern (d) XRD pattern.B.Thiosalicylic acid stabilized silver nanoparticlesThe low molecular weight organic compound, thiosalicylic acid (TSA), was also used as a protecting agent to prepare the nanoparticles in order to reduce the sintering temperature. As shown in Figure 2(a), when we used triethylamine as the reaction promoter and TSA as the protecting agent, the silver nanoparticles were successfully reduced from the AgNO3 precursor. The EDS analysis shown in Figure 2(b) confirms that the particles are silver. Figure 2(c) presents the particle size distribution of silver nanoparticles. The average size of the particles is 7.99 nm with a standard deviation of 2.24 nm, which was calculatedby Matrox Inspector 4.1 software from Figure 2 (a).Figure 2. (a) TEM micrographs of silver nanoparticles prepared from TSA (b) EDS pattern (c) Particle size distribution of silver nanoparticlesFig. 3 shows the thermograms of pure TSA, TSA protected silver nanoparticles and PVP protected silver nanoparticles. From the TGA thermogram, we can see the decomposition temperature of pure TSA is at 150 o C. When the TSA is bounded to silver nanoparticles, its decomposition temperature increased to 280 o C. Although its decomposition temperature increases, it is much lower than PVP (at 450 o C), which was used in our previous experiment. We anticipated that TSA-protected silver nanoparticles could be sintered at lower temperatures than PVP-protected silver nanoparticles.Weight(%)Temperature ( o C )Figure 3. TGA thermograms of pure TSA, silver nanoparticles prepared from TSA , and silver nanoparticles prepared from PVP .C.triethylamine stabilized silver nanoparticlesDuring the preparation of Ag nanoparticle suspensions, the individual particles had a tendency to form large agglomerates through the van der Waals force or Coulomb’sforce. In order to prevent the agglomeration of small particles, we added TEA to the suspensions as the stabilizer. The amine group can form a protective monolayer on the particle’s surface through the Ag-N bonding. The TEA has a dual function in the experiment. It can be served as a protecting agent and also a reducing agent.When we used the TEA as the reducing and protecting agent, the silver nanoparticles were successfully reduced from the AgNO 3 precursor. For TEA-protected silver nanoparticles, the agglomeration of small particles increased with the increasing TEA concentrations.Fig. 4 shows a typical TEM image of the silver nanoparticles, the histogram of diameters, and EDS. The silver diffraction pattern is shown at right corner in Fig. 4(a). The EDS analysis (in Fig. 4(c)) confirms that the nanoparticles are silver. We were able to control the particle size and the size distribution of silver nanoparticles from the AgNO 3/TEA molar ratio, and produce silver nanoparticlesless than 5 nm in diameter.Figure 4. (a) TEM micrographs of silver nanoparticles prepared from TEA (b) Particle size distribution of silver nanoparticles (c) EDS pattern .The UV–Vis absorption spectra of silver nanoparticles prepared from TEA with different molar ratios are shown in Fig. 5. For Fig. 5(a), the absorption peak with the maxima at 402 nm is due to the presence of silver nanoparticles. The X-ray diffraction patterns of the silver films, presented in Fig. 5(b), show the peak characteristics of metallic silver. The reflection peaks are indexed as the fcc (111), (200), (220), and (311) planes, indicating that the silver is well crystallized. From the TGA thermogram, we can see that the decomposition temperature of the TEA-protected silver nanoparticles is at 150 o C (as shown in Fig. 5(c)). In addition, TGA was used to analyze the amount of TEA bounded on the particles. The as-made silver nanoparticles contain about 10 % TEA. From the result, we are sure that the silver nanoparticles can be sintered and converted to the silver film at a low processing temperature and low protecting agent content.Figure 5. (a)UV-Vis absorption spectra of silver nanoparticles suspensionprepared from different AgNO3/TEA ratios (b) XRD (c) TGAIV. C ONCLUSIONSUsing PVP, TSA and TEA as the protecting agents, we successfully prepared stable silver nanoparticles suspensions. The average diameters of the nanoparticles were 15 nm, 7.99 nm, and 2.74 nm, when the protect agents were PVP, TSA and TEA, respectively. The resulting silver nanoparticles showed high crystallinity. The silver nanoparticle can be used to fabricate flexible electronics by ink-jet printing, because they have relatively low sintering temperatures. A CKNOWLEDGMENTThe financial support provided by the National Science Council (Taiwan, ROC) through project NSC-95-2120-M-006-003 .is greatly appreciated.R EFERENCES[1] J. M.Kohlera, L. Abahmanea, J. Wagnera, J. Albertb and G. Mayerb,“Preparation of metal nanoparticles with varied composition for catalytical applications in microreactors”Chemical Engineering Science vol. 63, 2008, pp. 5048-5055.[2] J. Perelaer, A. W. M. de Laat, C. E. Hendriks and U. S. Schubert,“Inkjet-printed silver tracks: low temperature curing and thermal stability investigation” J. Mater. Chem. Vol 18, 2008, pp. 3209-3215. [3] D. Kim, S. Jeong and J. Moon, “Synthesis of silver nanoparticlesusing the polyol process and the influence of precursor injection” Nanotechnology vol 17, 2006, pp.4019-4024.[4] R. Zhang, K. S. Moon, W. Lin and C. P. Wong, “Preparation ofhighly conductive polymer nanocomposites by low temperature sintering of silver nanoparticles” J. Mater. Chem. vol 20, 2010, pp.2018-2023.[5] Y. Xiong, A. R. Siekkinen, J. Wang, Y. Yin, M. J. Kimb and Y. Xia,“Synthesis of silver nanoplates at high yields by slowing down the polyol reduction of silver nitrate with polyacrylamide” J. Mater. Chem. vol 17, 2007, pp.2600-2602.[6] D. G. Thompson, R. J. Stokes, R. W. Martin, P. J. Lundahl, K. Fauldsand D. Graham, “Synthesis of Unique Nanostructures with Novel Optical Properties Using Oligonucleotide Mixed–Metal Nanoparticle Conjugates” small vol 4, 2008, pp. 1054-1057.[7]N. Pradhan, A. Pal and T. Pal, “Silver nanoparticle catalyzedreduction of aromatic nitro compounds” Colloids and Surfaces A: Physicochemical and Engineering Aspects vol 196, 2002, pp.247-257. [8] B. Y. Ahn, E. B. Duoss, M. J. Motala, X. Guo,S. I. Park, Y. Xiong, J.Yoon, R. G. Nuzzo, J. A. Rogers and J. A. Lewis “3OmnidirectionalPrinting of Flexible, Stretchable, and Spanning Silver Microelectrodes” Science vol 23, 2009, pp.1590-1593.[9]T. Takenobu, N. Miura, S. Y. Lu, H. Okimoto, T. Asano, M. Shiraishiand Y. Iwasa, “Ink-Jet Printing of Carbon Nanotube Thin-Film Transistors on Flexible Plastic Substrates” Applied Physics Expressvol 2, 2009, pp.0250051-.0250053.[10]J. Perelaer, C. E. Hendriks, A. W. M. de Laat and U. S. Schubert,“One-step inkjet printing of conductive silver tracks on polymer substrates” Nanotechnology vol 20, 2009, 1653031-1653035.[11]T. H. J. van Osch, J. Perelaer, A. W. M. de Laat and U. S. Schubert,“Inkjet Printing of Narrow Conductive Tracks on Untreated Polymeric Substrates”Adv. Mater. vol 20, 2008, pp.343-345.[12] C. Jiang, D. J. Cardin and S. C. Tsang, “Conductive Three-Dimensional Material Assembled from Silver Nanoparticles Using aConjugated Dithiol Linker” Chem. Mater. vol 20, 2008, pp.14-16. [13]I. K. Shim, Y. I. Lee, K. J. Lee and J. Joung, “An organometallicroute to highly monodispersed silver nanoparticles and their application to ink-jet printing” Materials Chemistry and Physics vol 110, 2008, pp.316-321.[14]X. Wang, S. Zhang and Z. Zhang, “Synthesis of hexagonal nanosizedsilver sulfide at room temperature” Materials Chemistry and Physics vol 107, 2008, pp.9-12.[15] A. Wang, H. Yin, M. Ren, Y. Liu and T. Jiang, “Synergistic effect ofsilver seeds and organic modifiers on the morphology evolution mechanism of silver nanoparticles” Applied Surface Science vol 254, 2008, pp.6527-6536.[16]M. Tsuji, P. Jiang, S. Hikino, S. Lima, R. Yano, S. M. Jang, S. H.Yoon, N. Ishigami, X. Tang and K. S. Nor Kamarudin, “Toward to branched platinum nanoparticles by polyol reduction: A role of poly(vinylpyrrolidone) molecules” Colloids and Surfaces A: Physicochem. Eng. Aspects vol 317, 2008, pp.23-31.[17]L. Li, Y. J. Zhu, Journal of Colloid and Interface Science vol 303,2006, pp.415-418.。

化学沉淀法制备纳米二氧化硅

第29卷第3期硅酸盐通报Vo.l 29 No .3 2010年6月 BULLETI N OF T HE C H INESE CERA M IC S OC IET Y June ,2010 化学沉淀法制备纳米二氧化硅韩静香,佘利娟,翟立新,刘宝春(南京工业大学理学院,南京 210009)摘要:采用硅酸钠为硅源,氯化铵为沉淀剂制备纳米二氧化硅。

研究了硅酸钠的浓度、乙醇与水的体积比以及p H值对纳米二氧化硅粉末比表面积的影响,并用红外、X 射线衍射和透射电镜对二氧化硅粉末进行了表征。

研究结果表明在硅酸钠浓度为0.4mol/L ,乙醇与水体积比为1B 8,p H 值为8.5时可制备出粒径为5~8n m 分散性好的无定形态纳米二氧化硅。

关键词:沉淀法;纳米S i O 2;制备中图分类号:TQ127.2 文献标识码:A 文章编号:100121625(2010)0320681205Preparation of Nano m eter Si O 2by Che m ica l P reci p ita ti onHA N J ing 2xiang,S HE Li 2j u an,Z HAI Li 2xin,LIU Bao 2c hun(Coll ege of Science ,Nan ji ng U n i vers it y ofTechnol ogy ,Nan ji ng 210009,Ch i na)Abstr act :Sod i u m silicane and a mmonium chlori d e were used to prepare nano meter Si O 2.The eff ects ofconcentration of sodiu m silicane ,vol u me rati o of ethanol to water and pH value on spec ific surf ace area ofSi O 2powder were investigated .The nano meter Si O 2was characteriz ed by FT 2I R,XRD and TE M .Theresu lts i n d icated that the opti m um conditi o ns of synthesizi n g nano meter Si O 2were as f ollo ws :theconcentration of sod i u m silicane was 0.4mol/L ,vol u me rati o of ethanol to water was 1B 8,p H val u e was8.5.The a morphous nano meter Si O 2is well dispersed and the average size is abou t 528nm in tha tcondition .K ey w ord s :che m ical prec i p itati o n ;nano m eter Si O 2;preparati o n作者简介:韩静香(19842),女,硕士在读.主要从事纳米材料的研究.通讯作者:刘宝春.E 2m ai:l b cli u @n j u t .edu .cn 1 引言纳米二氧化硅为无定型白色粉末,是一种无毒、无味、无污染的材料,其颗粒尺寸小,比表面积大,是纳米材料中的重要一员。

水溶性银纳米颗粒的制备及抗菌性能

水溶性银纳米颗粒的制备及抗菌性能孙磊1,*刘爱心1黄红莹2陶小军1赵彦保1张治军1(1河南大学特种功能材料教育部重点实验室,河南开封475004;2河南大学医学院,河南开封475004)摘要:采用液相还原法,以单宁酸为还原剂,聚乙烯吡咯烷酮(PVP)为修饰剂制备出了水溶性的表面修饰Ag纳米颗粒.通过X 射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、紫外-可见吸收分光光度计(UV-Vis)、傅里叶变换红外(FTIR)光谱仪等对所得样品的形貌和结构进行了表征.采用肉汤稀释法测试了样品的抗菌性能,考察了样品在水相中的分散稳定性,提出了PVP 修饰Ag 纳米颗粒的形成机理.结果表明所制备的样品具有Ag 的面心立方晶体结构,平均粒径为15-17nm.样品在水相中能长时间稳定分散;对埃希氏大肠杆菌(E.coli )、金黄色葡萄球菌(S.aureus )具有明显的抗菌作用.操作简便、条件温和的制备方法易于在工业规模上放大;试剂无毒,使得所制备的PVP 修饰Ag 纳米颗粒作为抗菌剂具有良好的应用前景.关键词:银纳米颗粒;水溶性;表面修饰;绿色无毒;抗菌性中图分类号:O648Preparation and Antibacterial Properties of Water-SolubleAg NanoparticlesSUN Lei 1,*LIU Ai-Xin 1HUANG Hong-Ying 2TAO Xiao-Jun 1ZHAO Yan-Bao 1ZHANG Zhi-Jun 1(1Key Laboratory for Special Functional Materials of Ministry of Education,Henan University,Kaifeng 475004,Henan Province,P .R.China ;2Medical College of Henan University,Kaifeng 475004,Henan Province,P .R.China )Abstract:Water-soluble surface modified silver nanoparticles were synthesized by liquid phase reduction with tannic acid as the reductant and polyvinyl pyrrolidone (PVP)as the surface modification agent.The structure and morphology of the as-synthesized powders were investigated by X-ray powder diffraction (XRD),transmission electron microscopy (TEM),ultraviolet-visible (UV-Vis)absorption spectroscopy,and Fourier-transform infrared (FTIR)spectrometry.The antibacterial activity of the water-soluble Ag nanoparticles against Escherichia coli (E.coli )and Staphylococcus aureus (S.aureus )was investigated by broth dilution.The stable dispersion duration of the as-synthesized Ag nanoparticles in water was also determined.A mechanism for PVP modified Ag nanoparticle formation is proposed.The results show that the as-synthesized PVP modified Ag nanoparticles have a face-centered cubic crystalline structure.The average diameter of the Ag nanoparticles ranges from 15to 17nm.The as-synthesized powders have good solubility in water over a long period of time.PVP modified Ag nanoparticles exhibit good antibacterial properties against E.coli and S.aureus .This simple and mild preparation method can be easily increased to an industrial scale process and,therefore,PVP modified Ag nanoparticles are potentially a new type of antibacterial.Key Words:Ag nanoparticles;Water-soluble;Surface modification;“Green ”and nontoxic;Antibacterial property[Article]物理化学学报(Wuli Huaxue Xuebao )Acta Phys.⁃Chim.Sin .2011,27(3),722-728MarchReceived:August 24,2010;Revised:November 1,2010;Published on Web:January 12,2011.∗Corresponding author.Email:sunlei@;Tel:+86-378-3881358.The project was supported by the National Natural Science Foundation of China (50701016)and Natural Science Foundation of Education Department of Henan Province,China (2007150008,2008B150003).国家自然科学基金(50701016)和河南省教育厅自然科学基金(2007150008,2008B150003)资助项目ⒸEditorial office of Acta Physico ⁃Chimica Sinica722No.3孙磊等1引言银纳米材料由于兼具本身固有的物理化学性质和纳米尺度的特殊效应,使其在电学、1,2光学、3-5催化、6,7摩擦学、8生物材料9,10等诸多领域都具有十分广泛的应用.近年来,随着数次大规模传染性疾病的爆发和细菌对传统抗菌剂耐药性的增强,开发新型抗菌剂和抗菌材料已成为科研工作者所关注的一个热点.纳米材料因具有大的比表面积和独特的物理化学性质,在抗菌性能方面的应用前景引起了人们的广泛兴趣.具有抗菌性能的无机纳米材料主要包括Cu、Ag、Au、ZnO、TiO2和藻酸盐等,相关研究已表明其中纳米Ag对于细菌、病毒和真核微生物具有最好的杀灭效果.11-15银离子、金属银或银纳米颗粒作为抗菌药物可用于烧伤治疗、牙科材料、不锈钢涂层、织物、水处理、防晒液等,它们具有对人体细胞的低毒性、高的稳定性和低挥发性等优点.16Leaper17对用于伤口愈合的含银纳米颗粒敷料进行了综述报道,总结了Ag纳米颗粒的抗菌作用机理、人体毒性、临床应用等研究结果.Kumar等18报道了在植物油中制备的银纳米颗粒作为涂料添加剂的抗菌性,其对革兰氏阳性菌和阴性菌均有杀灭作用.尽管银纳米颗粒具有优异的抗菌性,但由于其本身的非水溶性,使其作为抗菌材料在生物、医药方面的应用受到了一些限制;因而有必要对其进行表面改性,使其具有亲水性而便于实际应用.目前,水溶性银纳米材料的制备已有不少报道,19-25但这些研究中的多数并不以生物医用材料的应用为目的,在制备过程中通常没有考虑所用试剂的毒性和合成方法的经济性,往往实验条件苛刻,操作过程繁琐且试剂毒性大,不利于水溶性Ag纳米颗粒作为抗菌材料的应用和制备方法在工业化规模上的放大.因而以经济简便、易于实现工业化生产的方法制备出“绿色”无毒且具有良好抗菌性能的水溶性Ag纳米颗粒已成极为重要的一项课题.本文采用液相化学还原结合原位表面修饰的方法,以单宁酸为还原剂,聚乙烯吡咯烷酮(PVP)为修饰剂,制备了具有良好水溶性的Ag纳米颗粒,解决了产物的分离、提纯和水相中的再分散问题,方法操作简便,反应条件温和,易于工业化生产.制备过程所用还原剂单宁酸、修饰剂PVP均为食品医药领域常用的添加剂,与人体生物相容性好.这使得所制备的Ag纳米颗粒作为活性成分,在抗菌消毒药水等方面具有良好的应用前景.2实验部分2.1试剂与仪器硝酸银(AgNO3)购于国药集团化学试剂有限公司;单宁酸购于郑州市德众化学试剂厂;PVP(K30, M W=40000)为进口分装,德国BASF公司生产;丙酮购于天津市精细化工有限公司;氨水(25%-28%)购于洛阳市化学试剂厂,以上试剂均为分析纯,使用前均未经纯化处理.实验用水为蒸馏水.X射线粉末衍射分析(XRD)采用荷兰Philips公司制造的X′Pert Pro型粉末衍射仪(Cu靶Kα)测定;样品形貌及选区电子衍射(SAED)采用日本电子株式会社(JEOL Ltd)制造的JEM-100CX型透射电子显微镜(TEM)进行观察;采用英国UNICAM公司制造的Unicam UV540型紫外-可见(UV-Vis)吸收分光光度计测定样品的表面等离子体共振(SPR)吸收特性;采用美国Nicolet公司制造的A V ATAR360型傅里叶变换红外(FTIR)光谱仪测定样品的表面化学键合状态.2.2PVP修饰Ag纳米颗粒的制备为了得到粒径小而且分布均匀、水溶性好的PVP修饰Ag纳米颗粒,考察了不同反应物浓度、化学计量比等实验条件对产物的影响,制备了一系列样品.得到最佳实验条件下的制备过程如下:称取PVP0.1359g溶于45mL蒸馏水,移入250mL三颈烧瓶中.室温电磁搅拌下,取50mL2.4mmol·L-1单宁酸溶液加入烧瓶中,随后加入5mL0.5mol·L-1氨水,此时溶液为橙黄色透明液,测得pH约为9.取20mL120mmol·L-1AgNO3溶液,用恒压滴液漏斗将之缓慢逐滴加到上述三颈烧瓶中,溶液中很快出现许多黑色细小颗粒,且溶液由橙黄色透明液变为红黑色悬浮液.AgNO3溶液滴加完毕后,继续搅拌1 h,旋转蒸发浓缩样品溶液,然后加入适量丙酮使沉淀析出、抽滤,用丙酮洗涤数次,真空干燥24h.得到深红棕色粉末样品即为所要制备的PVP修饰Ag纳米颗粒.出于应用目的,采用与上述制备过程同样的反应物计量比和实验条件，在1000mL烧瓶中将反应物和溶剂的量均扩大为4倍进行了实验室的初步放大实验(反应液体积由120mL扩大为480mL).2.3PVP修饰Ag纳米颗粒的抗菌性能测试通过检测最小抑菌浓度(MIC)和最小杀菌浓度(MBC)评价所制备PVP修饰Ag纳米颗粒的抗菌性Vol.27 Acta Phys.⁃Chim.Sin.2011能.实验用菌株大肠杆菌(E.coli)、金黄色葡萄球菌(S.aureus)均购于中国普通微生物菌种保藏管理中心(CGMCC),细菌培养采用牛肉膏蛋白胨培养基和营养琼脂培养基,使用前灭菌保存.2.3.1菌悬液的制备26取4°C保存的菌种接种于牛肉膏蛋白胨培养基,放入37°C孵箱中培养18h;然后取该增菌培养物,再接种于牛肉膏蛋白胨培养基中,仍置于37°C 孵箱中培养6h,即制成含有一定菌落浓度的培养物.将一定量培养物加到无菌试管中,用无菌生理盐水调配成含菌量约为107colony-forming units(cfu)/ mL的菌悬液,菌落计数采用显微镜直接计数法.2.3.2MIC值测试采用不连续分步对倍稀释法配制样品溶液测定MIC值.27,28具体方法如下:配制1000.0μg·mL-1PVP 修饰Ag纳米颗水溶液10mL,以细菌过滤器过滤除菌备用.排列具透气胶塞的无菌试管,一列10管.量取2.0mL Ag纳米颗粒水溶液加到第1支试管中,接着加入2.0mL灭菌的牛肉膏蛋白胨培养基,混合均匀,配制成Ag纳米颗粒浓度为500.0μg·mL-1的样品.从第1支试管中取出2.0mL溶液,滴加到第2支试管中,接着加入2.0mL灭菌牛肉膏蛋白胨培养基,混合均匀后配成浓度为250.0μg·mL-1的样品.依此类推,浓度依次减半一直稀释到第9管,并从第9支试管中吸取混合后的溶液2.0mL弃去.第10支试管为仅含2.0mL灭菌牛肉膏蛋白胨培养基的无样品对照管.得到浓度分别为500.0、250.0、125.0、62.5、31.3、15.6、7.8、3.9、2.0、0μg·mL-1的梯度样品.采用微量加样器向各试管均加入制备好的菌悬液0.2μL,摇匀后放入孵箱中37°C培养24h.取出观察细菌生长情况.先观察对照管中细菌生长情况,在对照管中细菌呈混浊状生长;然后观察含有不同浓度Ag纳米颗粒的各试管中溶液的混浊度,溶液开始出现澄清的最低浓度确定为样品的MIC值.本实验重复三次,结果取平均值或重复值.2.3.3MBC值测试从样品浓度高于MIC值(包括MIC浓度)的试管中各吸取100μL分别滴到灭菌的琼脂平板上,涂布均匀,在孵箱中37°C培养24h.肉眼观察实验结果,菌落数小于5个或无菌落生长的最低样品浓度确定为MBC值.29实验重复三次,结果取平均值或重复值.3结果与讨论3.1PVP修饰Ag纳米颗粒的XRD分析图1(a,b)为在250mL和1000mL烧瓶中制备出的PVP修饰Ag纳米颗粒的XRD图谱.从图1可以看出2个样品在衍射角2θ为38.2°、44.3°、64.5°、77.5°和81.6°的位置均出现了多重衍射峰,这些衍射峰位分别归属于面心立方(fcc)晶型银的(111)、(200)、(220)、(311)和(222)晶面的衍射(JCPDS, No.87-0720),说明所制备样品为单质银.除了图1(b)在2θ约23°附近出现的修饰层PVP的非晶态衍射峰外,样品的XRD图谱中没有出现杂质的衍射峰,说明所合成的样品纯度较高.从图1还可看到,样品XRD衍射峰宽化较为明显,利用谢乐公式对(111)晶面的衍射数据进行计算可知,图1(a)样品的晶粒度约为6.3nm,图1(b)样品的约为7.4nm.除了晶粒度稍有增大外,图1(b)的相对衍射强度比图1(a)的略为减弱,这说明放大实验的样品结晶度稍差,推测其原因,可能是由于在1000mL烧瓶中制备样品,反应液体积比在250mL中的大,虽然反应物浓度、反应物化学计量比等实验条件均相同,但反应过程受到的搅拌力和传热传质速率会有一定区别,因而导致2个样品晶粒度和晶体缺陷程度略有不同.3.2PVP修饰Ag纳米颗粒的形貌分析图2为在250mL和1000mL烧瓶中制备出的PVP修饰Ag纳米颗粒的TEM照片,SAED图谱和用scion image软件对TEM照片进行粒径统计分析得到的粒径分布柱状图.30从TEM图中可以看出所合成的银纳米微粒形貌均为球形、分散较好,无明显聚集现象,粒径大小比较均一.由粒径分布图可以明显看出,在250mL和1000mL烧瓶中合成出的样品图1不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒的XRD图谱Fig.1XRD patterns of PVP modified Ag nanoparticles synthesized in flasks with different volumes(a)250mL;(b)1000mL724No.3孙磊等:水溶性银纳米颗粒的制备及抗菌性能平均粒径分别约为15和17nm,此结果与XRD估算的值有所不同,原因是XRD给出的是样品的晶粒度,而TEM图片给出的是颗粒的表观粒径.TEM观察到的一个纳米颗粒由2-3个银微晶所构成的.31由TEM图中插入的对应样品的SAED图可以看出,衍射斑点呈明显的环状,进一步证实了纳米颗粒由多晶构成.利用透射电镜电子衍射公式可计算出靠近中心斑点的三个电子衍射环分别归属于(fcc)晶型Ag的(111)、(200)、(220)晶面衍射.由TEM和粒径分布图分析可知，放大实验所制备出的样品颗粒平均粒径稍有增大,且粒径大小分布更宽.其原因可归结为反应液体积放大后,影响到了搅拌受力和传质传热的速率,纳米颗粒的成核生长过程受到影响.从而导致了粒径大小和分布的不同.3.3PVP修饰Ag纳米颗粒的UV-Vis分析将所得到的粉末样品重新溶于蒸馏水后进行UV-Vis测试,图3为在250mL和1000mL烧瓶中制备出的PVP修饰Ag纳米颗粒的UV-Vis图谱.从图3可以看出,样品分别在408和413nm附近出现了Ag 纳米颗粒的SPR特征吸收峰.与在250mL烧瓶中合成出的Ag纳米颗粒相比,放大实验后样品(曲线b)的吸收峰红移了约5nm,表明颗粒的平均粒径有所增大;吸收峰宽化也更为明显,表明其粒径分布更宽,这均与TEM分析的结果相一致.3.4PVP修饰Ag纳米颗粒的FT-IR分析图4所示为在250、1000mL烧瓶中制备出的图2不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒的TEM图(a,b)、SAED(插图)和粒径分布图(a′,b′)Fig.2TEM images(a,b),SAED patterns(inset)and particles sizes distributions(a′,b′)of PVP modified Ag nanoparticlessynthesized in flasks with different volumes(a,a′)250mL,(b,b′)1000mL;SAED:selected area electron diffraction3不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒的UV-Vis图谱Fig.3UV-Vis spectra of PVP modified Ag nanoparticlessynthesized in flasks with different volumes(a)250mL;(b)1000mL725Vol.27 Acta Phys.⁃Chim.Sin.2011PVP修饰Ag纳米颗粒和修饰剂PVP的红外光谱图.在图4(c)中,3428cm-1处的吸收峰为―OH的反对称及对称伸缩振动峰,它来自于PVP聚合链端的―OH;2950cm-1处的吸收峰对应于亚甲基中C―H 的伸缩振动;1663cm-1处的吸收峰归属于C＝O的伸缩振动;1440cm-1处的吸收峰为C―H键的面内摇摆振动峰;1290cm-1处的吸收峰对应于C―N键的反对称及对称伸缩振动;656cm-1处的吸收峰为C―H键的面外摇摆振动峰.以上各吸收峰都可归属于修饰剂PVP的不同基团化学键的振动吸收.图4(a,b)吸收峰位及透过率大致相同,表明在不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒表面化学键合性质基本一致.而从它们与修饰剂PVP红外图谱的对比可以看出,表面修饰Ag纳米颗粒在1440 cm-1处出现PVP中C―H键的面内摇摆振动峰,在1290cm-1处出现PVP中C―N键的反对称及对称伸缩振动峰,这说明Ag纳米颗粒表面确实存在PVP 修饰层.而C＝O的伸缩振动峰,则从PVP的1663 cm-1向短波数方向移到了1645cm-1.C＝O振动的减弱,是因为PVP中的O原子提供电子对填充纳米颗粒表面Ag原子的空轨道,换言之,PVP通过化学作用修饰到了Ag纳米颗粒表面.32从图4还可看出, (a)、(b)在2950和656cm-1处C―H键的振动峰与(c)相比消失了.这是由于反应物PVP与AgNO3的质量比只有1:3,在反应过程中也不能完全修饰到Ag纳米颗粒表面,即样品中修饰剂的含量较低,而且由于所制备PVP修饰Ag纳米颗粒的粉末颜色为深红棕色,与KBr粉末压片制成薄膜后,其对红外入射光的吸收仍较PVP样品的强,一定程度上掩盖了修饰剂PVP振动峰的信息,从而导致样品中某些振动峰强度减弱以致消失.而图4(a,b)中3416cm-1附近振动峰强度减弱与图4(c)相比并不明显的原因是―OH 除了来自PVP以外,也有可能是由样品中吸附水所引起的.3.5PVP修饰Ag纳米颗粒的抗菌性能虽然银纳米材料抗菌剂的具体作用机理目前仍不很清楚,但Ag纳米颗粒与体相材料相比具有更优异抗菌性能的原因普遍被认为来自纳米材料具有大的比表面积这一特性.15表1所示分别为250和1000 mL烧瓶中合成的PVP修饰Ag纳米颗粒对E.coli和S.aureus这两类菌种的MIC及MBC值.由表1可见,所制备的PVP修饰Ag纳米颗粒最小抑菌浓度分别只有3.9和7.8μg·mL-1,与商品抗菌剂的值(约800μg·mL-1)相比均要低得多,33这表明PVP修饰Ag纳米颗粒在很低浓度下就表现出抑菌性能.最低杀菌浓度也比文献报道的水溶性Ag纳米颗粒的MBC值(120μg·mL-1)小,34表明其杀菌性能较好.S. aureus和E.coli分属于革兰氏阳性菌和革兰氏阴性菌,所制备的PVP修饰Ag纳米颗粒对它们均有较好的抑菌和杀菌性能,这说明样品具有一定的广谱抗菌性.在1000mL烧瓶中制备出的PVP修饰Ag纳米颗粒,其MIC和MBC值普遍要比在250mL烧瓶中制备出的样品偏高,原因可能是放大实验后Ag纳米颗粒的粒径有所增大,比表面积减小,从而影响了其抗菌性能.3.6PVP修饰Ag纳米颗粒形成机理及分散稳定性PVP是一种水溶性非离子型表面活性剂,常用于制备纳米材料的修饰(包覆)剂.PVP作为修饰剂在还原AgNO3制备Ag纳米颗粒的过程中起到了重要的作用,主要体现在三个方面:首先,PVP中的N 和O原子提供电子对给Ag+的sp轨道,形成配合物;其次,在还原的过程中,由于PVP-Ag+的存在,使Ag+图4不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒和修饰剂PVP的FTIR图谱Fig.4FTIR spectra of PVP modified Ag nanoparticlessynthesized in flasks with different volumes andmodification agent of PVP(a)250mL;(b)1000mL;(c)PVP1不同容积烧瓶中制备出的PVP修饰Ag纳米颗粒的抗菌性能Table1Antibacterial properties of PVP modified Agnanoparticles synthesized in flasks with different volumesStrainE.coli S.aureusMIC/(μg·mL-1)250mL3.93.91000mL7.87.8MBC/(μg·mL-1)250mL31.315.61000mL31.362.5 MIC:minimum inhibitory concentration;MBC:minimum bacterical concentration726No.3孙磊等:水溶性银纳米颗粒的制备及抗菌性能更容易被还原,Ag 纳米晶核更易形成;最后,由于PVP 以化学作用修饰到了新生成的Ag 纳米颗粒表面,PVP 的空间位阻作用限制了颗粒之间的团聚,起到了控制粒径大小的作用.以上PVP 修饰Ag 纳米颗粒形成机理的推测在TEM 、FTIR 分析中都得到了证实,图5是其示意图.Ag 纳米颗粒在水相中的分散稳定性是影响其抗菌性能的重要因素之一.图6(a)是不同实验条件下(具体条件如表2所示，图中数字对应表格中的样品编号)制备的PVP 修饰Ag 纳米颗粒粉末以0.5g ·L -1的浓度溶解于水的照片,可以看到这些样品的水溶液均澄清透明,分散性很好,由于颗粒粒径不同而呈现出的颜色则稍有差别.对于本文实验部分详细描述的最佳实验条件下制备出的样品(表2中1号样品),测得其在水中的最大溶解浓度约为2.0g ·L -1,由抗菌性能测试结果可知,这个浓度完全能满足作为抗菌剂配制溶液的需要.图6(b)是该样品以最大含量分散于水中的照片.由于水溶性的PVP 修饰到了Ag 纳米颗粒表面,且颗粒粒径均比较小,上述样品在水中都有很好的分散稳定性,放置12个月仍6PVP 修饰Ag 纳米颗粒在水相中分散稳定性的照片Fig.6Photos of PVP modified Ag nanoparticles dispersed stably in water(a)samples (1-6)synthesized in different conditions (shown in Table 2)with the same concentration of 0.5g ·L -1;(b)sample synthesized in the optimum condition with the largest concentration of 2.0g ·L -1表2制备PVP 修饰Ag 纳米颗粒的不同实验条件图5PVP 修饰Ag 纳米颗粒形成机理示意图Fig.5Schematic illustration of the formation mechanism of PVP modified Ag nanoparticles727Vol.27 Acta Phys.⁃Chim.Sin.2011无聚沉.4结论采用液相化学还原的方法,制备了PVP修饰Ag 纳米颗粒.所得颗粒平均粒径为15-17nm,粒径大小分布均匀.PVP通过化学作用修饰在Ag纳米颗粒表面,使得所制备的样品在水中具有良好的分散稳定性.抗菌性能测试表明PVP修饰Ag纳米颗粒对于埃希氏大肠杆菌和金黄色葡萄球菌都具有优异的抑菌杀菌效果.该方法操作过程简便、所用试剂无毒、反应条件温和,所制备的PVP修饰Ag纳米颗粒作为新型抗菌剂具有良好的应用前景.References(1)Endrino,J.L.;Horwat,D.;Gago,R.;Andersson,J.;Liu,Y.S.;Guo,J.;Anders,A.Solid State Sci.2009,11,1742.(2)Sun,J.;Zhang,J.;Liu,W.;Liu,S.;Sun,H.;Jiang,K.;Li,Q.;Guo,J.Nanotechnology2005,16,2412.(3)Cobley,C.M.;Rycenga,M.;Zhou,F.;Li,Z.Y.;Xia,Y.J.Phys.Chem.C2009,113,16975.(4)Dong,X.;Ji,X.;Wu,H.;Zhao,L.;Li,J.;Yang,W.J.Phys.Chem.C2009,113,6573.(5)Wani,I.A.;Khatoon,S.;Ganguly,A.;Ahmed,J.;Ganguli,A.K.;Ahmad,T.Mater.Res.Bull.2010,45,1033.(6)Yao,W.;Guo,Y.L.;Lu,G.Z.;Guo,Y.;Wang,Y.Q.;Zhang,Z.G.;He,D.N.Acta 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(英文)针对棉织物滋生的真菌,纳米银的抗菌性能研究

Antimicrobial effect of silver nanoparticles produced by fungal process on cotton fabricsM.H.El-Raﬁe a,*,A.A.Mohamed b ,Th.I.Shaheen a ,A.Hebeish aa Textile Research Division,National Research Centre,Dokii,Cairo,Egypt bMicrobiology Department,National Research Centre,Dokii,Cairo,Egypta r t i c l e i n f o Article history:Received 17November 2009Received in revised form 13December 2009Accepted 15December 2009Available online 22December 2009Keywords:Nanotechnology Silver nanoparticles FungiAntimicrobial Cotton fabricsa b s t r a c tNanobiotechnology was used for the preparation of the silver nanoparticles colloid by making use of bio-mass ﬁltrate of fungus Fusarium solani .Finishing formulation containing as low as 54ppm nanosilver par-ticles were prepared and applied to cotton fabrics with and without binder.The ﬁnished fabrics were characterized by Scanning Electron Microscopy.The efﬁciency and durability of the nanosilver parti-cles-based antibacterial ﬁnish were determined.The ﬁnish appears as deposits on the surface of the ﬁbrils/ﬁber of the treated cotton.Efﬁciency of the antibacterial ﬁnish on the cotton fabric,expressed as bacterial reduction %,amounts to 97%and 91%for Staphylococcus aureus and Escherichia coli ,respectively.These values are reduced to 53%and 48.7%upon exposing to laundering for 20cycles.This problem was overcome by incorporation of a binder in the ﬁnishing formulation:Under this condition antibacterial cotton fabrics having bacterial reduction of 94%and 85%after 20washing cycles could be prepared.Ó2009Elsevier Ltd.All rights reserved.1.IntroductionHuman beings are often infected by microorganisms such as bacterium,mold,yeast,virus,etc.,in living environment (Lee,Yeo,&Jeong,2003).In recent years,antimicrobial agents that have been used industrially have included quaternary ammonium salts,metal salts solutions,and antibiotics.Unfortunately,some of these agents are toxic or poorly effective,which makes them not suitable for application in health foods,ﬁlters,and textiles,and for the exclusions of pollution.In contrast,silver is a non-toxic,non-toler-ant disinfectant that can reduce many bacterial infections signiﬁ-cantly (Jeong,Hwang,&Yi,2005).Research has been intensive in antibacterial material containing different inorganic substances with various nature.Among them,silver or silver ions have long been known to have strong inhibitory and bactericidal effect as well as a broad spectrum of antimicrobial activities.It is expected that the high speciﬁc surface area and high fraction of surface atoms of silver nanoparticles will lead to high antimicrobial activity compared to bulk silver metal (Lee et al.,2003).Furthermore,silver metal and silver dressings,when used in reasonable amounts,has no negative effects on the human body and it has a natural antimicrobial activity toward many pathogens such as bacteria,viruses,fungi,yeast,etc.(Panyala,Pena-Mendez,&Havel,2008).These particles can be incorporated in several kinds of materials such as clothes.These clothes with silver nanoparti-cles are sterile and can be used to prevent or to minimize infectionwith pathogenic bacteria.Nowadays,silver-based topical dressings have been widely used as a treatment for infections in burns,open wounds,and chronic ulcers (Lansdown,2002).In this study,we have prepared silver nanoparticles solution as per the fungi-based technique (Shaheen,2009),which an environ-mentally safe technique.The so prepared nano-sized silver colloids were applied to cotton fabrics at silver nanoparticles concentra-tions of 54ppm and 108ppm.The bactericidal efﬁcacy of the trea-ted samples was evaluated prior and after repeated washing cycles.2.Experiments 2.1.Materials2.1.1.Test fungiThe used fungus Fusarium solani strain was provided from The Regional Center for Mycology and Biotechnology,AL-Azher Univer-sity,Nasr city,Cairo.The fungus was maintained on potato–dex-trose agar (PDA)slants.2.1.2.ChemicalsSilver nitrate (AgNO 3),sodium nitrate (NaNO 3),magnesium sul-fate penta hydrate (MgSO 4Á5H 2O),potassium chloride (KCl),potassium dihydrogen phosphate (KH 2PO 4),ferrous sulfate (FeSO 4),sucrose and agar were all of laboratory grade chemicals. Bleached cotton fabrics and binder (Printoﬁx Binder MTB EG liq.)were kindly provided from El-Nasr Company for Spinning,Weaving and Dyeing –El-Mahalla El-Kubra,Egypt.0144-8617/$-see front matter Ó2009Elsevier Ltd.All rights reserved.doi:10.1016/j.carbpol.2009.12.028*Corresponding author.E-mail address:mh_elraﬁe@ (M.H.El-Raﬁe).Carbohydrate Polymers 80(2010)779–782Contents lists available at ScienceDirectCarbohydrate Polymersj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /c a r b p ol2.2.Methods2.2.1.Preparation of silver nanoparticles using biomassﬁltrate ofF.solaniFungus F.solani was inoculated in250ml Erlenmeyer conical ﬂasks containing50ml of fermentation medium which including 2g/l sodium nitrate,0.5g/l magnesium sulfate penta hydrate, 0.5g/l potassium chloride,1g/l potassium dihydrogen phosphate, trace amount of ferrous sulfate,20g/l sucrose,and pH was adjusted at6.5–7.Then incubated on an incubator at30–32°C under static conditions.The biomass was harvested after72h of growth byﬁltra-tion followed by extensive washing with distilled water to remove any medium component from the biomass.The washed biomass was taken in250ml Erlenmeyer conicalﬂask containing100ml of distilled water then the conicalﬂask was kept for72h at30–32°C and thereafter the aqueous solution components were separated byﬁltration.This solution(namely,biomassﬁltrate)was used for synthesis of silver nanoparticles by addition of AgNO3and kept for 48h under ambient condition($25°C).The optimum conditions for preparation of silver colloids with concentration of540ppm, excellent size and size distribution ranged from3to8nm could be produced using10g biomass of fungus F.solani;0.085g AgNO3; pH12;temperature,$25°C and duration,48h.The reduction of sil-ver ions to silver nanoparticles was routinely monitored by visual inspection of the solution,as well as,by UV–vis spectra and TEM.2.2.2.Silver nanoparticles loading on cotton fabricsBefore being used,cotton fabrics were washed and dried.Exper-iments were performed on samples with maximum dimension of 30cmÂ15cm.Cotton fabrics were padded with silver nanoparti-cles solutions at concentrations of54ppm and108ppm;both con-centrations were achieved through diluting the original solution of 2160ppm silver nanoparticles with distilled water.For the succes-sive treatment of fabrics with colloidal silver,the solution was agi-tated continuously.All samples were immersed in such colloid bath for1min then squeezed to100%wet pick up with laboratory padder at constant pressure.Samples were dried at70°C for3min, followed by curing at150°C for2min.Schematic representation of thisﬁnding treatment is shown in Fig.1.The antibacterial efﬁcacy were evaluated quantitatively of the following fabrics:(1)untreated fabrics,(2)fabrics treated with silver nanoparticles solution,and(3)silver nanoparticles treated fabrics after being subjected to repeated washing cycles(5,10and20wash-ing cycles).Laundering was affected with a machine set for warm water containing,2%sodium carbonate and soap.After each laun-dering(45min),the fabrics were tumble dried in a dryer at70°C.2.3.Characterization of silver treated fabrics2.3.1.Scanning Electron MicroscopyThe particles morphology of nano-sized silver incorporated into cotton fabrics were studied with Scanning Electron Microscopy (SEM)after gold coating.2.3.2.Antimicrobial activityThe antimicrobial behavior of fabrics was evaluated against two bacterial strains;Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.In order to study the antimicrobial activity of the fabrics, squares of1cm of each fabric were prepared in aseptic manner. Each square was placed in a sterile vial and the fabrics were sub-jected to pretreatment with800l l distilled water for10min.Tryp-tone soy broth(2.2ml)was then added to each vial to make up to a total volume of3ml.An aliquot(10l l)of S.aureus suspension was added to each vial(1.6Â103/ml)containing the fabrics.Control broths with and without bacterial inoculation were also included. The vials were then incubated with agitation at35°C,220rpm.Ali-quots of10l l broth were sampled at24h and serial dilutions for the aliquots were prepared in broth.Duplicate aliquots(50l l)of the serially diluted samples were spread onto plates.The plates were incubated at35°C and bacterial counts were performed. The bacteriostatic activity was evaluated after24h and calculated percent reduction of bacteria using the following equation:Rð%Þ¼½ðAÀBÞ=A Â100where R is the reduction rate,A is the number of bacterial colonies from untreated fabrics,and B is the number of bacterial colonies from treated fabrics(Duran,Marcato,De Souza,Alves,&Esposito, 2007).3.Results and discussionThe development of new clothing products based on the immobi-lization of nanophased materials on textileﬁbers has recently been of increasing interest to both the academic and industrial sector.Today, a wide range of nanoparticles with various structures can be immo-bilized on theﬁbers,bringing new properties to theﬁnal textile prod-uct.Silver ions,which have been used throughout history as an antimicrobial agent,have recently received renewed interest.The reason for this is because some bacterial strains have demonstrated an increasing resistance toward antibiotics.At the same time,the powerful antimicrobial activity of silver is known to be effective against nearly650types of bacteria(Perelshtein et al.,2008).3.1.Preparation of silver nanoparticlesSilver nanoparticles solution was synthesized using the biomass ﬁltrate of fungus F.solani at the optimum conditions mentioned above(Shaheen,2009).3.1.1.UV–vis spectroscopyFig.2shows the UV–vis spectra of silver nanoparticles prepared by using0.085g AgNO3/100ml to produce silver nanoparticles with concentrations of540ppm in100ml biomassﬁltrate of fun-gus F.solani.Fig.2shows that strong surface plasmon resonance occur at k max ca420nm which is considered in the range of ideal wavelength for Ag0nanoparticles colloidal solution.3.1.2.Transmission Electron Microscopy(TEM)Figs.3a and b show the TEM micrograph and the particle size and particle size distribution,respectively,when the silver nano-particles were prepared using0.085g silver nitrate in100ml bio-massﬁltrate.Considering the UV–vis intensity,wavelength,TEM and particle size distribution the most promising results obtained indicate that, the optimum conditions for preparation of silver nanoparticles col-loids with excellent size and size distribution ranged from3to 8nm could be produced using10g biomass of fungus F.solani;0.085g AgNO3;pH12;temperature,$25°C and duration,48h.Fig.1.Antibacterialﬁnishing of textile fabrics.780M.H.El-Raﬁe et al./Carbohydrate Polymers80(2010)779–7823.2.Mechanism of antimicrobial activity of silver nanoparticles Several investigations have been carried out on the mechanism of bactericidal activity of silver nanoparticles.It is generally be-lieved that heavy metals react with proteins by combining the thiol (–SH)groups,which leads to the inactivation of the proteins.Re-cent research has demonstrated that the antimicrobial activities of silver nanoparticles depend on chemisorbed Ag +,which readily formed on the surface of silver nanoparticles due to their extreme sensitivity to oxygen.However,the mechanism of the delivery of silver ions from silver nanoclusters to the bacteria needs further investigation.It was also proposed that silver ions released from silver nanoparticles can interact with phosphorous moieties in DNA,resulting in inactivation of DNA replication leads to the inhi-bition of enzymes functions (Gupta,Bajpai,&Bajpai,2008).3.3.Structure and morphology of the silver–fabric composite Silver nanoparticles were prepared using biomass ﬁltrate of fungus F.solani to obtain silver nanoparticles with concentration of 2160ppm and size range 3–8nm.The resultant product ob-tained was diluted to 54ppm and 108ppm with distilled water.The bleached cotton fabrics were padded through silver colloidal bath for 1min and squeezed to 100%wet pick up with laboratory padder at constant pressure.Samples were dried at 70°C for 3min followed by curing at 150°C for 2min.The SEM micrograph of cotton fabrics before (untreated)and after (treated)immersion in silver colloidal solution are shown in Figs.4a–c .The SEM image in Fig.4a demonstrates the smooth structure of the cotton fabrics before coating with silver nanoparticles.After pad-ding,the homogeneous deposition of silver nanoparticles (54ppm and 108ppm)on the cotton fabrics was shown in Figs.4b and c ,respectively.It is also observed that,the amount of silver nanoparti-cles deposited on cotton fabrics surface is greater the higher the con-centration of the silver nanoparticles colloids solution.3.4.Efﬁciency and durability of the nanosilver particles-based antibacterial ﬁnishTable 1lists the antibacterial properties (%bacterial reduction)of fabric treated with nano-sized silver colloids.This evaluation includes the untreated fabric,treated fabrics and treatedfabricsFig.3a.TEM micrograph of silver nanoparticles with a concentration of 540ppm.Fig.4a.SEM picture of untreated cotton fabric.M.H.El-Raﬁe et al./Carbohydrate Polymers 80(2010)779–782781after being subjected to repeated washing.It is evident from the data Table1that,regardless of the concentration of silver nanopar-ticles used for treatment,the reduction of bacterial colonies was al-ways higher than90%against both S.aureus and E.coli for silver nanoparticles treated samples without washing.Subjecting the treated cotton fabrics toﬁve washing cycles leads to a decrement in the reduction of the bacterial colonies to values slightly higher than70%.Subjecting the treated cotton fab-rics to more washing cycles10and20leads to marginal reduction in the antibacterial properties.Based on the above,it may be concluded that treatment of cot-ton fabrics with small sized silver nanoparticles3–8nm have excellent antibacterial effect which could be ascribed to deposition of silver nanoparticles onto the molecular structure of cotton cellu-lose of the fabric and theirﬁxation therein via chemical and phys-ical bonding.Results of Table1make it evident that54ppm of silver nano-particles is enough to induce antibacterial properties to cotton fab-ric.However,almost50%of the imparted antibacterial properties is lost under the inﬂuence of20washing cycles.This stimulates incorporation of1%binder in theﬁnishing bath formulation as shown under:Silver nanoparticles54ppmBinder1%Padding pick up100%Drying70°C/3min Curing150°C/2minIt is seen(Table2)that incorporation of the binder in theﬁnishing bath formulation enhances the antibacterial properties of the cotton fabric even after20washing cycles.Fabricsﬁnished using nanosil-ver particles solution at concentration of54ppm in presence of bin-der exhibit bacterial reduction values of94%and85%for S.aureus and E.coli,respectively.This is against values of53%and48.7% when theﬁnishing treatment was carried out without binder.In short,cotton fabrics having excellent antibacterial properties and can withstand repeated washing could be obtained by treating the fabrics with a bath of silver colloid having particle size of3–5nm in presence of a binder as described in this work. ReferencesDuran,N.,Marcato,P.D.,De Souza,G.I.H.,Alves,O.L.,&Esposito,E.(2007).Antibacterial effect of silver nanoparticles produced by fungal process on textile fabrics and their efﬂuent treatment fabric.Journal of Biomedical Nanotechnology, 3(2),203–207.Gupta,P.,Bajpai,M.,&Bajpai,S.K.(2008).Investigation of antibacterial properties of silver nanoparticle-loaded poly(acrylamide-co-itaconic acid)-grafted cotton fabric.Journal of Cotton Science,12,280–286.Jeong,S.H.,Hwang,Y.H.,&Yi,S.C.(2005).Antibacterial properties of padded PP/PE nonwovens incorporating nano-sized silver colloids.Journal of Materials Science, 40,5413–5418.Lansdown,A.B.(2002).Silver2:Toxicity in mammals and how its products aid wound repair.Journal of Wound Care,11(5),173–177.Lee,H.J.,Yeo,S.Y.,&Jeong,S.H.(2003).Antibacterial effect of nanosized silver colloidal solution on textiles fabrics.Journal of Materials Science,38,2199–2204. Panyala,N.R.,Pena-Mendez,E.M.,&Havel,J.(2008).Silver or silver nanoparticles:A hazardous threat to the environment and human health?Journal of AppliedBiomedicine,6(3),117–129.Perelshtein,I.,Applerot,G.,Perkas,N.,Guibert,G.,Mikhailov,S.,&Gedanken,A.(2008).Sonochemical coating of silver nanoparticles on textile fabrics(nylon, polyester and cotton)and their antibacterial activity.Nanotechnology,19, 245705.Shaheen,Th.I.(2009).Utilization of nanobiotechnology for synthesis of metallic nanoparticles and harnessing them in antimicrobialﬁnishing of cellulose based textile.M.Sc.Al-Azher University.Table2Effect of incorporation of the binder in theﬁnishing bath formulation on the antibacterial properties(%bacterial reduction)of cotton treated fabrics before and after being subjected to repeated washing cycles.Number of washing Bacterial reduction(%)S.aureus E.coli Before washing9791After5cycles96.888.4After10cycles9687.4After20cycles9485 Fig.4b.SEM picture of silver nanoparticles on cotton using54ppm.Fig.4c.SEM picture of silver nanoparticles on cotton using108ppm.Table1Effect of repeated washing on the antibacterial properties of silver nanoparticlestreated cotton fabrics.Number of washing cycles Bacterial reduction(%)Nano-sized silver colloids concentration54ppm108ppmS.aureus E.coli S.aureus E.coliBefore washing97919896After5cycles7671.476.773After10cycles62.551.664.556After20cycles5348.75955782M.H.El-Raﬁe et al./Carbohydrate Polymers80(2010)779–782。

鱼腥草雾化吸入的作用与功效

鱼腥草雾化吸入的作用与功效鱼腥草（Artemisia annua）是一种常见的中药植物，历来被用于治疗感冒、疟疾等疾病。

最近几年，鱼腥草的雾化吸入疗法作为一种新的治疗方式逐渐受到关注。

本文将详细介绍鱼腥草雾化吸入的作用与功效。

1. 鱼腥草的雾化吸入原理鱼腥草雾化吸入是将鱼腥草制成草本粉末后，通过雾化器将粉末转化为微细颗粒，然后通过呼吸道吸入进入人体。

这种吸入方式可以使药物直接进入呼吸道的上部和下部，并趋于周围肺组织，提高治疗效果。

2. 鱼腥草雾化吸入的作用2.1 抗炎作用研究发现，鱼腥草中含有一种称为青蒿素的活性成分，具有明显的抗炎作用。

青蒿素通过抑制炎症介质的产生，调节免疫反应，减轻炎症反应及相关症状。

雾化吸入可以使青蒿素直接作用于呼吸道黏膜，发挥更好的抗炎作用。

2.2 改善气道通畅鱼腥草雾化吸入可以有效改善气道通畅，减轻哮喘、慢性阻塞性肺病等疾病引起的呼吸困难。

鱼腥草中的活性成分能够扩张气道，减少支气管痉挛，缓解气道狭窄等症状。

2.3 抗菌作用鱼腥草中的活性成分具有显著的抗菌作用，可以抑制多种细菌、病毒和真菌的生长。

雾化吸入可以使药物直接作用于感染病灶，起到更好的抗菌效果。

尤其对于呼吸道感染引起的咳嗽、喉咙痛等症状，鱼腥草雾化吸入具有较好的治疗效果。

2.4 免疫调节作用鱼腥草中的一些活性成分可以调节人体免疫系统的功能，提高机体的抵抗力。

雾化吸入可以使这些活性成分直接作用于呼吸道黏膜和肺部组织，增强呼吸系统的免疫功能，减少感染的发生。

2.5 抗癌作用鱼腥草中的活性成分青蒿素被广泛应用于治疗疟疾，同时也具有一定的抗癌作用。

雾化吸入可以使青蒿素直接作用于肺部组织，对肺癌等呼吸道肿瘤有一定的治疗效果。

3. 鱼腥草雾化吸入的功效3.1 缓解呼吸系统疾病症状鱼腥草雾化吸入可以减轻咳嗽、喉咙痛、气短、胸闷等呼吸系统疾病引起的症状，改善呼吸困难，提高患者的生活质量。

3.2 防止感染和复发鱼腥草雾化吸入具有较好的抗菌作用，可以预防呼吸道感染的发生，同时对已经感染的疾病也能起到治疗作用。

光化学法合成银纳米线及其形成机理的研究_邹凯

2004年第62卷第18期,1771~1774化学学报ACTA CHI M ICA SINICAVol.62,2004No.18,1771~1774光化学法合成银纳米线及其形成机理的研究邹凯a,b 张晓宏X ,a 吴世康X ,a 段晓峰b(a 中国科学院理化技术研究所北京100101)(b 中国科学院物理研究所北京电子显微镜实验室北京100080)摘要结合晶种法和光化学还原法,在聚乙烯吡咯烷酮(PVP)的诱导下成功地制备出直径为50~120n m,长度约为50L m 的银纳米线以及银的树枝状纳米结构.实验表明各种反应条件如聚乙烯吡咯烷酮和硝酸银的摩尔比、晶种的加入量及反应时间等对纳米产物的形貌有影响.根据实验结果提出了一种新的银纳米线的形成机理.关键词银纳米线,银的树状纳米结构,UV 幅照,晶种法,PVPSynthesis of Silver Nanowires by the Photochemical Methodand Their Formation MechanismZOU,Kaia,bZHANG,Xiao -HongX ,aW U,Sh-i KangX ,aDUAN,Xiao -Fengb(a T echnical I nstitute o f Ph ysics an d Chemistry ,Chinese Academy o f Sciences ,Bei j ing 100101)(b Bei j ing Laboratory of Electron Microscopy ,Institute o f Physics ,Chinese Academy o f Sciences ,Bei j ing 100080)Abstract Using seed -mediated and photochemical reduction approach in the presence of poly (vinyl pyrrolidone)(PVP),Ag nano wires with dia meters of 50~120nm and lengths up to ~50L m and elegant silver dendrites wereprepared at room te mperature.It was found that experimental c onditions including the molar ratio of P VP to AgNO 3,the volume of silver seeds,and the reaction time all play influential roles in the formation of silver nanostructures.The mechanisms of formation of those silver nanostruc tures were discussed preliminarily.Keywords silver nanowire,silver nanodendrite,UV irradiation,seed -mediated,PVP金属纳米线因其在电子、光学器件和传感器上的潜在应用而成为近几年来纳米材料研究的热点课题.其中对金属银纳米线的研究更引起人们广泛的关注.目前合成金属纳米线最主要的方法是模板法.已经用于合成金属银纳米线的模板包括:多孔氧化铝板(AAO)和聚碳酸酯膜(PC)[1],多孔氧化硅[2]以及碳纳米管[3]等.模板法能够很好调控最终产物的形貌,并很容易得到取向一致的纳米材料阵列,但其后处理比较烦琐.因此人们还不断探索其它不用物理模板的方法来合成金属纳米线.Xia 等[4]曾报道了在聚乙烯吡咯烷酮(P VP)存在下,用乙二醇还原硝酸银的方法可大量合成直径可控的银纳米线.Murphy 等[5]也用晶种法在室温下成功制备金属纳米线,他们通过改变晶种银粒子和金属前驱体的比例,可以方便地控制银纳米线的直径和长-宽比.本文结合晶种法,在有聚乙烯吡咯烷酮(P VP)存在的情况下,用紫外光还原硝酸银,制备金属银纳米线和银的树状纳米结构,得到了很好的结果,并根据对不同反应时间产物透射电子显微镜的观察,提出了一种新的银纳米线形成机制.1 实验部分1.1 仪器和试剂工作中所用的电镜为Phillips C M12透射电子显微镜,以及附有GATAN 图像过滤系统的Phillips FEG -CM200透射电子显微镜等.聚乙烯吡咯烷酮(PVP)(M w =58000)为Aldric h 公司产品;Ag NO 3,三水合柠檬酸钠和NaBH 4均为分析纯试剂(韦斯化学试剂公司).使用前未作进一步纯化处理.X E -mail:shi kangwu@;zhangxh8@Received December 24,2003;revised March 16,2004;accepted May 21,2004.国家973(No.2001CB610502)和中国科学院资助项目.1.2 银纳米线的制备用作晶种的银纳米颗粒的合成:将10mL 的015mmol/L AgNO 3水溶液加到10mL 的015mmol/L 柠檬酸钠水溶液中,剧烈搅拌,快速加入016mL 的10mmol/L NaB H 4溶液,30s 后停止搅拌.所得样品用透射电镜观察,表明合成的银纳米颗粒直径为(4?2)nm.银纳米线的制备:取011mL 上述银纳米颗粒(晶种)悬浮液加入到3mL 的1mmol/L 硝酸银和2mmol/L 聚乙烯吡咯烷酮(M w =58000)(PVP 浓度按单体分子量计算)水溶液中,然后置于15W 低压汞灯(K =25317nm)下照射48h.将所得产物置于转速为6000r/min 离心机内离心分离20min,弃去上层溶液后,将沉淀分散在丙酮中.2 结果与讨论2.1 反应条件对产物形貌的影响对体系在具不同聚乙烯吡咯烷酮和硝酸银的摩尔比下进行对照试验,发现反应物的摩尔比对产物的形貌和直径有很大的影响.随着聚乙烯吡咯烷酮和硝酸银二者摩尔比(PVP/AgNO 3)的增大,所得银纳米线的直径和长度不断减小,当摩尔比继续增大到PVP/Ag NO 3m 10时,所得产物为直径约60nm 的银纳米颗粒,而很少观察到有银纳米线的存在.相反,当减小聚乙烯吡咯烷酮和硝酸银的摩尔比时,产物中的银纳米线直径和长度都有所增大.当摩尔比减小到PVP/AgNO 3n 018时,最终得到的产物为大量的无规团聚物.图1(A)为硝酸银和聚乙烯吡咯烷酮的浓度分别为1mmol/L 和2mmol/L 时紫外光照射48h 后产物的透射电镜图.从图中可以看出,所制得的银纳米线直径为80~100nm,长度约为35L m.图1(B)是银纳米线的高分辨透射电镜照片(HRTEM),箭头所示方向为银(111)晶面方向,其面间距为01235nm,与银(111)理论面间距相符(01234nm).产物的EDS 谱图[图1(C)]也证明银纳米线不含其它杂质(图中铜的峰来自承载样品的铜网).实验发现,所加晶种对最终产物的形貌也有较大影响.我们在其它实验条件不变的情况下改变加入晶种的数量作对比实验,结果表明:减少晶种用量使所得银纳米线更粗更长,而增加晶种含量则容易得到较细、较短的银纳米线.其原因可能是增加晶种用量使溶液中有更多的成核位点,在银离子前驱体浓度确定的条件下,溶液中就会有更多的银纳米线形成,但其直径和长度就会相应减小.晶种在反应中的作用是非常重要的,实验发现,在没有加入晶种的情况下最终产物中几乎没有银纳米线生成,这与文献报道的结果相一致[6].当体系中的晶种用量进一步增大至015mL,可以得到一种具有树状结构的银纳米材料,如图1(D)所示.类似的树状纳米结构在Zhou [7]的工作中也曾有报道.图1 (A)3mL 浓度为1mmol/L AgNO 3和2mmol/L 聚乙烯吡咯烷酮(M w =58000)溶液加入011mL 晶种后紫外光照射48h 所得银纳米线的透射电子显微镜照片;(B)银纳米线的高分辨透射电子显微镜照片;(C)银纳米线的EDS 能谱图;(D)晶种量为015mL 时得到的银的树枝状纳米结构Figure 1 (A)TEM image of silver nanowires obtained by UV irradiation in 3m L of aqueous solu tion of 1mmol/L AgNO 3,2mmol/L poly(vinyl pyrrolidone)(M w =58000)and 011mL of silver seeds for 48h;(B)HREM image of as -prepared silver nanowire;(C)EDS of the produced silver nanowires;(D)TE M i mage of silver nanostructures obtained when 015mL of silver seeds were added1772化学学报Vol.62,20042.2 反应时间对产物形貌的影响反应时间同样对纳米产物的形貌有所影响.延长反应时间至72h,得到的产物中只有少量无规则的银纳米线和大量聚集的银纳米颗粒.这可能是由于反应时间过长,致使纳米线转化为在热力学上更稳定的纳米颗粒[8]所致.毫无疑问,聚乙烯吡咯烷酮在实验中起着相当重要的作用.聚乙烯吡咯烷酮作为一种水溶性的高分子广泛的应用于合成银纳米颗粒[6]和银纳米线[4]的实验中,一般认为它主要作为保护剂以避免纳米颗粒在溶液中发生聚集,而在银纳米线的生长过程中主要是吸附在银颗粒的某些晶面上,以抑制晶体的生长,从而导致颗粒的各向异性生长,并最后得到银纳米线.但本工作的实验结果表明:聚乙烯吡咯烷酮在纳米线的生长过程中,可能起到一种模板的作用.通过对不同反应阶段产物的透射电子显微镜观察,我们发现在反应进行10h 后,体系中存在着银纳米颗粒和具有纳米尺度的高分子线状聚集体,如图2(A)所示,从图中可以清楚地看到纳米颗粒被吸附在线状的高分子聚集体上,这是因为聚乙烯吡咯烷酮分子中的酰胺结构)NH )C O 可以通过与Ag 原子间的配位作用而相互靠拢,于是银的纳米颗粒(包括晶种)就会被吸在线状高聚物聚集体的表面,并随纳米晶体的逐步增长而导致银纳米线的生成.这一看法可从反应进行30h 后的产物中观察到/间断0银纳米线的增长而予以一定程度的证实,如图2(B)所示.仔细观察图中的纳米线,发现它是由几段银纳米棒所组成,而且能够看到纳米线的边缘处包有一层高聚物.将银纳米棒间的不连续部分[图2(B)中箭头所示]放大后[图2(C)所示]发现间断处是由很多的银纳米颗粒组成,这些银纳米颗粒在高分子聚集体内部聚集,并起着一种/黏合剂0的作用将两边的银纳米棒连接起来形成银纳米线.所以根据上述实验观察,我们认为聚乙烯吡咯烷酮在本实验中主要起着一种一维纳米模板的作用,它为反应初期生成的银纳米颗粒提供了一个形成一维纳米结构的聚集环境,银纳米颗粒可在里面运动、碰撞、聚集最终形成银的一维纳米线.至于银的树状纳米结构可能是由于银纳米颗粒太多而不能全部吸着在聚乙烯吡咯烷酮线状模板上,随着反应的进行最终生长成分支.图2(D)是反应48h 后产物的明场透射电子显微镜像,可以很清楚地看到银纳米线的周围包覆有一层高聚物.图2(E),图2(F)是未经离心的银纳米线及其N 元素的元素分布图,图2(F)表明产物中N 元素分布很均匀,这说明聚乙烯吡咯烷酮在银纳米线表面是相对均匀分布的,也证明聚乙烯吡咯烷酮并非如文献所述只是选择性的吸附在某些晶面上的结果.3 结论通过光化学还原的方法在聚乙烯吡咯烷酮存在的情况下成功地合成了银纳米线和银的树状纳米结构.我们认为聚乙烯吡咯烷酮在形成银纳米线的过程中主要是用作为一维线状模板,以促进银纳米颗粒在一维方向的聚集,而并不仅是通过选择性的在某些晶面上的吸附和阻抑来达到控制结晶生长的方向.图2 (A)反应10h 所得产物的明场透射电镜照片;(B)反应30h 后所得产物的透射电镜照片;(C)图2(B)中箭头所示处的放大图片;(D)反应48h 后产物的明场透射电镜照片;(E)银纳米线的电镜图片及(F)相应的N 元素分布图Figure 2 (A)Brigh-t field TE M image of the product ob tained after 10h;(B)TE M image of the product obtained after 30h;(C)Enlarged picture of arrow position in Fi gure 2(B);(D)Brigh-t field TE M image of product obtained after 48h;(E)TEM image of silver nanowi re and (F)the corresponding N elemen t map1773No.18邹凯等:光化学法合成银纳米线及其形成机理的研究本文为/庆贺蔡启瑞教授九十华诞暨执教五十八年0征文References1(a)Sauer,G.;Breh m,G.;Schneider,S.;Nielsch,K.;Wehrspohn,R. B.;Choi,J.;Hofmeister,H.;GÊsele,U.J.Appl.Phys.2002,91,324.(b)Barbic,M.;Mock,J.J.;Smith, D.R.;Schultz,S.J.Appl.Phys.2002,91,9341.2Huang,M.H.;Choudrey, A.;Yang,mun.2000,1063.3Sloan,J.;Wright, D.M.;Woo,H.-G.;Bailey,S.;Brown,G.;York, A.P. E.;Coleman,K.S.;Hutchison,J.L.;Green,mun.1999,699.4(a)Sun,Y.;Gates, B.;Mayers, B.;Xia,Y.Nano Lett.2002,2,165.(b)Sun,Y.;Xia,Y.Adv.Mate r.2002,14,833.(c)Sun,Y.;Yin,Y.;Mayers, B.T.;Herricks,T.;Xia,Y.Chem.Mater.2002,14,4736.5Jana,N.R.;Gearheart,L.;Murphy, mun.2001,617.6Huang,H.H.;N i,X.P.;Loy,G.L.;Chew, C.H.;Tan, K.L.;Loh, F. C.;Deng,J. F.;Xu,ngmuir1996, 12,909.7Zhou,Y.;Yu,S.H.;Wang, C.Y.;Li,X.G.;Zhu,Y.R.;Chen,Z.Y.Adv.Mater.1999,11,850.8(a)Kim, F.;Song,J.H.;Yang,P.J.Am.Chem.Soc.2002,124,14316.(b)Kamat,P.V.J.Phys.Chem.B2002,106,7729.(A0312241SONG,J.P.;DONG,H.Z.)1774化学学报Vol.62,2004。

Preparation of silver nanowires with high aspect-ratio

Hefei, Anhui 230026, d June 1, 2004; CL-040615)
Silver nanowires with average diameters of %100 nm and lengths up to 800 mm were hydrothermally prepared in large scale by reducing silver nitrate with glucose in the presence of poly(vinyl alcohol) (PVA) at 160 C. The reaction temperature, the initial concentrations of the reagents, and the kind of polymer have eﬀects on the formation of silver nanowires. The possible formation mechanism of silver nanowires was proposed.
Figure 1 shows a typical XRD pattern of the sample. All the reﬂection peaks can be readily indexed to face-centered cubic silver. The lattice constant calculated from this pattern is a ¼ 4:089 A , which is consistent with the standard value of a ¼ 4:086 A (JCPDS 4-783).
(TEM) images and selected area diﬀraction (SAED) patterns

透射电镜半导体样品制备流程英语

透射电镜半导体样品制备流程英语## Transmission Electron Microscopy (TEM) Semiconductor Sample Preparation.Transmission electron microscopy (TEM) is a powerful characterization technique used to study the microstructure of materials at the nanometer scale. It is widely used in the semiconductor industry to analyze the crystal structure, defects, and interfaces of semiconductor devices. Preparing high-quality TEM samples is crucial for obtaining reliable and interpretable results.### Sample Preparation Workflow.The general workflow for TEM sample preparation of semiconductors involves the following steps:1. Sample selection and preparation: The first step isto select a representative sample from the device under investigation. The sample should be thin enough (typicallyless than 100 nm) to allow the electron beam to penetrate and form an image.2. Mechanical thinning: The sample is mechanically thinned using a dimple grinder or ion milling to create a thin region. This process is performed carefully to avoid introducing defects or damaging the sample.3. Chemical etching: Chemical etching is used tofurther thin the sample and remove any surface damage caused by mechanical thinning. The etchant used depends on the semiconductor material and the desired sample thickness.4. Cleaning: The sample is cleaned to remove any contaminants or residues from previous preparation steps. This is typically done using solvents or plasma cleaning.5. Mounting on a TEM grid: The thinned sample is mounted on a TEM grid, which is a thin metal support that holds the sample in place during imaging.### Specific Techniques for Different Semiconductors.The specific sample preparation techniques used mayvary depending on the type of semiconductor material being studied. Here are some common methods for different semiconductors:Silicon: Mechanical thinning using a dimple grinder followed by chemical etching in a solution of hydrofluoric acid (HF) and nitric acid (HNO3).Gallium arsenide (GaAs): Mechanical thinning using anion miller followed by chemical etching in a solution of HF, HNO3, and hydrogen peroxide (H2O2).Indium phosphide (InP): Mechanical thinning using anion miller followed by chemical etching in a solution of HCl, H2O2, and deionized water.### Advanced Techniques.In addition to the basic sample preparation steps,there are several advanced techniques that can be used toimprove the quality of TEM samples:Focused ion beam (FIB) milling: FIB milling uses a focused beam of ions to precisely thin and shape the sample. This technique allows for the preparation of samples with complex geometries or specific cross-sections.Plasma cleaning: Plasma cleaning uses a low-pressure plasma to remove surface contaminants and improve the sample's conductivity. This is particularly useful for samples that are prone to surface oxidation.Cryo-TEM: Cryo-TEM involves preparing and imaging the sample at cryogenic temperatures. This technique preserves the sample's native state and minimizes beam damage.### Quality Control.The quality of the TEM sample is critical for obtaining reliable results. Several quality control measures can be employed to ensure the sample's integrity:Thickness measurement: The thickness of the sample can be measured using a variety of techniques, such as electron energy loss spectroscopy (EELS) or scanning transmission electron microscopy (STEM).Crystallographic orientation: The crystallographic orientation of the sample can be determined using electron diffraction.Defects and imperfections: The presence of defects or imperfections in the sample can be identified by carefully examining the TEM images.By following these sample preparation procedures and implementing appropriate quality control measures, researchers can obtain high-quality TEM samples that provide valuable insights into the microstructure of semiconductor materials.。

安全守则-英文

Safe Personal Laboratory Habits1. Eye protection must be worn at all times.2. Food/drink is not allowed in laboratories where chemicals are used/ stored.smoking in the laboratory.3. No4. Lab coats must be worn while handling corrosive, toxic, or flammablematerials. Gloves must be worn when necessary, especially when handling corrosives, toxic and dangerously reactive materials.5. Do not work alone.6. Do not mouth pipet.7. If you see a colleague doing something dangerous, point it out to him or her.8. Know where safety equipment (eyewash, shower and extinguisher) islocated.9. Always read MSDS before handling new chemicals.10. Know how to clean up spills of common chemicals and specific chemicalsyou see. Be familiar with the locations and contents of spill carts (See Chapter 11) and how to use it.11. Always wash your hands after handling chemicals and before eating.12. Short skirts, shorts, and open shoes must not be worn.13. Lab coats must not be worn outside laboratories and in public areas.14. Avoid wearing a walkman or other portable music devices while working inthe lab.1. Eye ProtectionAdequate eye protection is required for all individuals in the laboratory. Do not remove your eye protection until you have physically left the lab room. The following types of eye protection are acceptable.•Protective glasses and face shields that cover corrective prescription lenses are commercially available and/or from Chemistry Stores.•Normal prescription eyeglasses, either with or without safety side shields as long as the glasses are shatterproof and cover a large enough area surrounding your eye (this usually means that the frames must be a minimum of 2 inches (5 cm) from top to bottom as well as from side to side). NOTE: check size restrictions with your supervisor/instructor. Use safety glasses with side shields that have been approved by the CSA.•Where exposure to toxic or irritating fumes could be a problem, the best form of eye protection is safety goggles. Safety goggles that will form a tight seal to your face.•Contact lenses can be a hazard and sometimes should not be worn in the lab.Therefore contact lenses wearers have three options in the labs:a) remove the contact lens before entering the lab and wear safety glassesor safety goggles.b) replace the contact lens with prescription glassesc) wear the contact lens into the lab under a pair of safety goggles but youmust inform your supervisor/ instructor about it.• A full-face shield is highly recommended when there is a risk of explosion or splashing, or with combustion and high temperature reactions.2. GlovesDepending on the procedure to be carried out, different types of gloves must be available in the laboratory. The gloves should “fit” the chemical. Asbestos gloves should not be used. If any are found, they should be replaced.•Gloves are made from a variety of materials which vary in their impermeability and wear-resistance.•Disposable gloves are made of PVC, latex, nitrile, and combinations of the aforementioned. These gloves are for general use and have low abrasion resistance.•More resistant, impermeable, reusable gloves are made from butyl rubber, nitrile, or neoprene.•Rubber: good chemical resistance, low abrasion resistance;•Neoprene: almost impermeable to regular solvents, fairly abrasion resistant;•Nitrile: highly resistant, maximum protection from liquids.•Multicomposite gloves are available for special work involving high or low temperatures or special procedures.•For more information on gloves resistance see the glove chart./~mouser/General/labzone/130AL/ndex/ndex2.html3. Lab aprons or lab coatsThe strength and impermeability of aprons depends on the materials used. These materials are also used for gloves, and their characteristics are described in 2.•Aprons should be fire-resistant, chemical-resistant, and easily washed.•Flammable fabrics should be avoided.Lab coats should be made of strong fabric and must be able to be removed quickly in case of accident. They must be long enough to protect the legs. Lab coats exposed to harmful chemicals should not be worn in public areas.4. Footwear•Substantial shoes must be worn and should cover the entire foot.•Open-toed shoes and sandals must not be worn in the laboratory.•Safety shoes or foot guards may be required under certain circumstances (e.g., when moving compressed gas cylinders – foot guards are available in cylinder storage area).•When cleaning up floor spills wear plastic foot covers available on all spill carts.5. RespiratorsRespirators used at the University of British Columbia must provide effective protection against airborne contaminants which may be present. Use of respirators should be considered to control exposure only after engineering and administrative controls have been considered. These types of controls include ventilation (e.g. fume hoods), enclosing the process, substitution of less hazardous products, rescheduling of work procedures, etc. Users are responsible for:1. Obtaining proper certification for respirator use by H.S.&E.2. Using the respirator in accordance with training instructions3. Being properly fit-tested for a respiratorand storing the respiratordisinfecting,4. Cleaning,5. Reporting any respirator malfunction to their supervisorThe following cartridges are available for use with half-mask and full-face respirators. Select the appropriate cartridge according to the chart below. Consult with H.S.&E. for situations not listed. Always ensure that the cartridges used are appropriate for the types of hazardous vapour present.Cartridge Type Colour Examples of Uses Organic vapour and acid gas Yellow Rooftop entry/lab procedures/spills Organic vapour only Black Solvents/PaintsDusts, particulate, and aerosols Purple Toxic dusts/infectiousaerosols/asbestos welding fumes Ammonia/amines Green Ammonia SpillAcid Gas Grey Acid gases/chlorine/sulfur dioxidePERSONNEL MUST BE CERTIFIED BY HS&E PRIOR TO RESPIRATOR USE. When fitting a new respirator, try on several brands and sizes. Different brands will fit slightly differently on your face. Respirator manufacturers usually have small, medium, and large face-pieces available. Adjust the straps so that the respirator fits tightly, but does not dig into your face or leave red marks on your skin. The respirator should feel snug, yet comfortable.1. Remove respirator, cartridges, and filters from plastic bags.Check to see that gasket is in cartridge holder before screwing incartridges. Insert filter into retainer caps and snap onto cartridgeholder or cartridges.2. The cartridge holders are keyed to assure their correctpositioning and maintain the proper balance of the device. Makesure they are properly positioned and seated.3. Place respirator on face with narrow end over nose and bottomunder chin. First attach top headband around crown of headand then bottom around neck. Adjust headbands until a tight butcomfortable fit is obtained.4. TEST FOR TIGHTNESS: Place the palm of the hand or thumbover the valve guard and press lightly. Exhale to cause a slightpressure inside face piece. If no air escapes, respirator isproperly fitted. If air escapes, readjust respirator and test again.There are two simple checks to test the seal. These are calledthe positive and negative pressure fit-checks. These tests mustbe done EVERY TIME the respirator is put on (see overleaf).5. FILTERS: (a) REPLACE when breathing becomes difficult, INSERT new filtersINTO retainer cap and replace cap. Generally the filter discs should be changed after eight hours of dusty exposure. (b) CHEMICAL CARTRIDGES should be replaced when the senses detect ANY abnormal condition, assuming that levels of detection by the senses do not constitute a health hazard.6. MAINTENANCE: The respirator face piece should be cleaned daily to preventskin irritation and for general sanitary purposes. First remove filters and cartridges. Then the face piece may be washed with a hand brush using a good detergent in warm water, rinsing, and air drying in a clean place. Some compounds considered to be suitable for disinfecting are: (1) a hypochlorite solution (50 parts per million of chlorine; immersion time: 2 minutes) (2) an aqueous solution of iodine (50 ppm iodine; immersion time: 2 minutes) (3) a quaternary ammonium solution (200 ppm quaternary ammonium compoundsin water with less than 500 ppm total hardness). RINSE IN CLEAN WARM WATER AND AIR DRY. Inspect respirator daily for worn or faulty parts and replace these at once. Proper parts supplied by the manufacturer must be used.7. For your protection, the DUST FILTERS and CHEMICAL CARTRIDGES mustbe assembled tightly, and changed frequently, according to exposure.8. KEEP RESPIRATOR CLEAN when not in use. Store in containerprovided.a) Put the respirator on and tighten the straps until it feels tight but comfortable.b) Close off the cartridges by covering them gently with the palm of hands, plasticbags, or gloves.c) Breathe in slightly to create a vacuum.d) Hold for 10 seconds.e) If you have a good seal, the face piece should collapse slightly against yourface and stay collapsed. No air should leak into the face piece past the sides, top, or bottom.f) If the face piece doesn’t collapse and stay collapsed, there is an air leak.Check the exhalation valves and try repositioning the respirator on your face and adjusting the head straps. Try the negative pressure check again. If you cannot get a seal after a few attempts, try on another size, make, or model of respirator, and repeat the check until you find a respirator that will pass.a) With the respirator on comfortably, close off the exhaust valve opening bycovering it with the palm of the hand.b) Breathe out slightly to force air into the face piecec) Hold for 10 seconds.d) If you have a good seal, the face piece should bulge out and stay out.e) If the air does leak out, check the inhalation valves, readjust the respirator andtry the check again. Try on another size, make or model if you fail to pass the positive pressure fit-check.1.TOXIC SUBSTANCESAny volatile substances which are dangerous when inhaled must be handled only in an adequately ventilated area or in a fume hood.a) BenzeneBenzene is particularly dangerous since it causes blood diseases.•Avoid using it as a solvent. Chronic poisoning is possible following prolonged inhalation of minute quantities of benzene.•Avoid skin contact.•It is a known carcinogen.b) Carbon tetrachloride and chloroformCarbon tetrachloride and chloroform have specific dangers:•They can be absorbed through the skin.•These substances can eventually cause functional disorders of the kidney and the liver even at low concentrations.•They are suspected carcinogens.c) Cyanides and NitrilesCyanides and Nitriles are some of the most acutely toxic substances known;they react very quickly “in vivo” when they are present in the ambient environment.•Symptoms of poisoning (weakness, difficulty in breathing, nausea) appear as soon as these substances have been absorbed, inhaled, or ingested.•Contact with acid liberates a highly toxic gas. The inhalation of a very minute amount of hydrogen cyanide (HCN) can be fatal.d) PhenolsSolutions of phenols are very dangerous.•Phenols are absorbed rapidly through the skin during contact.•If rapid and complete decontamination is not effected immediately, serious poisoning and even death could occur, depending on the concentration ofthe solvent and the amount of body surface that is contaminated.e) Hydrogen fluorideHydrogen fluoride is extremely corrosive. Due to the absence of immediate pain, penetration can be extensive and lead to serious injury. It can cause severe eye irritation and skin burns.f) Hydrogen sulfideHydrogen sulfide is very toxic. Inhalation causes respiratory paralysis. It can also damage the eyes and mucous membranes.•Small cylinders of it are commercially available for laboratory use.•CAUTION: The gas can be easily synthesized by action of dilute acids on sulfides•Waste gas should be passed through scrubbers before venting.2.DANGEROUS SUBSTANCESa) Perchloric acidPerchloric acid is a strong oxidizing agent capable of reacting violently with reducing agents or organic substances.•Handle it in a specially-constructed fume hood used only for this purpose.This hood should be of the water wash-down type and of non-combustible construction.•Always destroy any organic material with nitric acid before adding perchloric acid•Never mix perchloric acid with sulfuric acid because through dehydration, anhydrous perchloric acid is obtained, which is even more unstable.•Perchlorate esters, when exposed to impact, behave in the same manner as nitroglycerine.b) Organic PeroxidesSome organic peroxides are very unstable and very dangerous. Due to their high sensitivity to heat, friction, impact, sparks, light, and oxidizing and reducing agents, they can cause violent explosions.To minimize the risks of such peroxides, the following precautions must be taken:•Buy only the necessary quantities of peroxides needed.•Use only the minimum amount necessary. Never replace unused peroxide in the original container.•Immediately clean up spilled peroxide.•Reduce the sensitivity of most peroxides to impact and to heat by using them in inert solvents such as aliphatic hydrocarbons.•If a volatile solvent must be used, avoid losses due to evaporation which could increase the peroxide concentration, eventually causing the formation of dangerously explosive crystals upon complete evaporation of the solvent.•Never use a metal spatula to handle peroxides because contamination by metals can lead to the formation of explosive compounds. Use wood, ceramic, or plastic spatulas.•Avoid flames, sources of heat, and direct sunlight.•Avoid friction or impact with solid peroxides. Never use glass containers with ground glass or metal tops. Use only polyethylene bottles with screw tops.•Store peroxides at as low a temperature as possible above the freezing point, so as to minimize the rate of decomposition.•Do not cool liquid peroxides, or those in solution, to temperatures where they could solidify or precipitate because in this form they are extremely sensitive to impact and to heat.3.CARCINOGENSCarcinogens and substances capable of inducing cancer. These substances must be subject to strict guidelines such as those published by the International Agency for Research on Cancer when they are stored, used, and disposed of.•Avoid exposure.•Where exposure is unavoidable, keep it as low as reasonably achievable.•The list of known carcinogens is continually updated. (See next page for some examples of carcinogens).4.MUTAGENS AND TERATOGENSMutagens are substances causing permanent transmissible alterations in genetic information. Teratogens are agents interfering with normal prenatal development causing abnormalities in the fetus. Exposure to mutagens and teratogens should be kept as low as possible. (See following pages for some examples of mutagens and teratogens).CAUTION: This is NOT a complete list of all chemicals having substantial evidence of carcinogenicity. Further, each substance listed here may have additional health hazards.CARCINOGENS MUST BE DISTINCTLY LABELLEDa) KNOWN HUMAN CARCINOGENS•4-Aminobiphenyl (xenylamine, p-phenylaniline)• Arsenic• Arsenic Pentoxide• Arsenic Trichloride• Asbestos• Arsenic Trioxide• Benzene•Benzidine (4,4’-diaminobiphenyl, 4,4’-biphenyldiamine)•Benzo(a)pyrene (3,4-benzpyrene)• Bis(chrloromethyl)ether• 1,4-Butanediol dimethylsulfonate•Calcium arsenate (tricalcium arsenate)•Chloromethyl methyl ether (chloromethyloxymethane)•Chromates (certain insoluble forms such as lead and zinc chromates)•Coal tar pitch volatiles•Cyclophosphamide (N,N-bis (2-chloroethyl) tetrahydro – 2H-1,3,2 –oxazaphosphorin-2-amine-2-oxide)• Lead Arsenate• 2-Napthylamine (2-aminonapthylamine)•N, N-bis (2-chloroethyl)-2- napthylamine• 4-Nitrobiphenyl (p-nitrobiphenyl)• Sodium Arsenate• Sodium Arsenite• Thorium dioxide•Treosulfan (pure product)•Vinyl chloride (chloroethane, chloroethylene)Please Note: These are ALARA substances which means that the contamination concentration of these chemicals must be as low as reasonably achievable.CAUTION: This is NOT a complete list of all chemicals having substantial evidence of carcinogenicity. Further, each substance listed here may have additional health hazards.CARCINOGENS MUST BE DISTINCTLY LABELLED• Acrylamide(propenamide, acrylic amide)•Acrylonitrile (propene nitrile, cyanoethylene, vinyl cyanide)• 1,3-Butadiene (vinylethylene)• Cadmium powder• Cadmium Chloride• Cadmium Sulfate• Beryllium• Carbon tetrachloride(tetrachloromethane)• Chloroform (trichloromethane)•Dimethyl sulfate (sulfuric acid dimethyl ester)•Ethylene dibromide (1,2-dibromoethane), ethylene oxide(1,2 epoxyethane oxirane)• Formaldehyde (methanal,oxomethane)• Hexachlorobutadiene• * Hexamethylphosphoramide (HMPA)(hexamethylphosphoric triamide)• Hydrazine (diamine)• Lead acetate• Lead phosphate• Lead subacetate• Methylhydrazine•Methyl iodide (iodomethane)• Nickel• Nickel carbonate• Nickel carbonyl• Nickel oxide• Nickel hydroxide • Nickel subsulfide• 2-Nitropropane• Phenyl hydrazine• beta-Propiolactone (2-oxetanone, 3-hydroxy-beta-lactone propanoicacid)• Propyleneimine(2 -methylazacyclopropane, or2-methylaziridine)•o-Toluidine (2-methylaniline, or o-aminotoluene)• p-Toluidine (4-aminotoluene)•Vinyl bromide (bromoethylene)•Production of SbO3, AsO3, CdO* HMPA is apparently a particularly nasty carcinogen which is used in several labs throughout the Department of Chemistry. Users should be aware of its extreme toxicity, its ability to be absorbed though the skin, and the dangers of inhalation during distillation procedures. Precautions should include: use restricted to fume hoods, all contaminated vessels labelled “carcinogen”, use of two pairs of gloves, and the transfer of waste directly into the waste solvent containers or a separate correctly labelled vessel. There are at least two alternative solvents, 1,3-Dimethyl-2-imidazolidinone (DMEU) and 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H) pyrimidinone (DMPU) which are considered safe.CAUTION: This is NOT a complete list of all chemicals having substantial evidence of mutagenicity or teratogenicity. The extent of the hazard to humans associated with exposure to these substances is less clear than it is with carcinogens. However, it is recommended that similar caution should be exercised in handling substances which are mutagenic or teratogenic.• Acetamide• Acridine Orange• Ammonium Chromate• Ammonium Bichromate• Ammonium Dichromate• Anthracene• Antimony Oxide• Beryllium Carbonate• Cobalt Powder• Colchicine• 1,2-Dichloroethane (Ethylene Dichloride)• Formaldehyde• Formamide• Hydroquinone• Indigo Carmine• Lead Diacetate • Mercury• Osmium Tetraoxide• Potassium Chromate• Potassium Permanganate • Pyrogallic Acid• Silver(I) Nitrate• Sodium Azide• Sodium Dichromate• Sodium Nitrate• Sodium Nitrite• Thioacetamide• Toluene•Urethane (Ethyl Carbamate)UNIVERSITY OF BRITISH COLUMBIAPOLICIES AND PROCEDURESU.B.C. POLICY ON HAZARDOUS MATERIALS MANAGEMENT RESPONSIBLE:Vice President Academic & ProvostVice President Administration & FinanceVice President ResearchPURPOSE:As a large teaching and research institution, UBC faces problems that are unique and varied about the acquisition, handling, storage, transportation, and disposal of chemical and biological/human/animal materials and wastes resulting from its teaching, research and operations. This policy has several purposes:•To set out University requirements for proper disposal of hazardous and special wastes•To ensure worker protection•To reduce the amount of dangerous substances used in University activities •To raise awareness and increase knowledge of all members of the University community about problems of handling, storage, transportation and disposal of hazardous materials and waste•To establish good laboratory practices that teach and practise safe handling, storage, transportation and disposal of special wastes•To ensure compliance with applicable legislation.POLICY:All chemical and biological materials considered hazardous unless specifically excluded from Schedule 7 of the Transportation of Dangerous Goods Act. Materials classified as special wastes must be disposed of in a safe manner in compliance with the Special Waste Regulations of the Waste Management Act, and in consultation with the UBC Environment Services Facility. As all of UBC is considered one site, the rules for handling hazardous materials apply equally to small quantities as they do to large quantities. Each member of the University community who uses or has responsibility for hazardous materials must handle, store, transport and dispose of this material in a manner that harms neither the environment nor living beings, and that meets or exceeds legal requirements.Procedures are established for standard methods of handling chemicals, and biological/human/animal materials in all UBC activities. It is the responsibility of the Administrative Heads of Unit, Principal Investigators and Supervisors to ensure that appropriate training is given and documented to all students and staff who come into contact with these materials.Each member who comes into contact with or uses hazardous materials in their study must first become familiar with the hazards associated with the material and the appropriate method for handling, storage, transportation, and disposal. Up-to-date training records are to be maintained.Individual members are expected to conduct themselves and supervise others with the greatest of care, and, if established procedures for the circumstances do not exist, are responsible for seeking guidance from the appropriate source before ordering, handling, sorting, or disposing of materials that could be hazardous to the environment or to living beings. In accordance with Section 122 of the Canadian Environmental Protection Act:“Where a corporation commits an offence under this Act, anyofficer, director or agent of the corporation, who directed,authorized or assented to or acquiesced to or participated in thecommission of the offence is a party to and guilty of the offence,and is liable to punishment provided for the offence, whether or notthe corporation has been prosecuted or convicted.”Consideration should be given to substituting less harmful materials for those that are known to be hazardous at the time of acquisition. Hazardous materials should be purchased in quantities small enough that they do not have to be stored at UBC over long periods.In physical planning for the future research, teaching and operational needs of the University, design elements to address special waste flows should be included to address handling, storage, transportation, emissions, and disposal.PROCEDURES:The number and variety of possibly hazardous materials at UBC are large. Some are created as the result of experimentation. For this reason, the procedures under this policy are meant to provide guidance via illustration and example to individuals at UBC about such areas as chemical, biological, human, and animal materials. For radioisotopes, please see Policy # 11. For pesticides, Please see Policy #12 (http://www.policy.ubc.ca). Individuals unsure about whether a substance (such as paint, oil, pharmaceutical, battery) is hazardous, or about the appropriate steps to take, should contact the UBC expert listed in the procedures below.Laws and regulations governing chemical, human, and biological materials acquisition, handling, storage, and disposalLaws and regulations governing biological materials acquisition, handling, storage transportation and disposal include, but are not limited to:•Canadian Environmental Protection Act•Transportation of Dangerous Goods Act•Provincial Waste Management Act including the Special Waste Regulations and Spill Reporting Regulation•Greater Vancouver Regional District Bylaws, in particular Sewer Use Bylaw # 164 and # 167, Air Quality Management Bylaw # 603 and # 725 and Municipal Solid Waste and Recyclable Material Bylaw # 181 and # 183.•Workers’ Compensation Board Industrial Health and Safety Regulations• WHMIS•Laboratory Biosafety Guidelines for Health Canada•Health Canada, Narcotics/Controlled Products Act for pharmaceuticals •Containment Standards for Veterinary FacilitiesChemical MaterialsThe Chemical Safety Officer develops generic procedures for handling chemicals, which are distributed to all labs. For chemicals unique to a particular laboratory, the principal investigator must develop written procedures, to be vetted by the Health, Safety & Environment Department. Each department or unit using chemical materials must develop or adopt procedures that include:•Acquiring minimum quantities only•Safe and secure storage•Removing out-of-date materials from inventory•Inspection of time sensitive materials•Appropriate labeling consistent with WHMIS requirements•An annual inventory of materials•Training of faculty, staff and students•Proper use of personal protective equipment, emergency spills, and decontamination procedures•Compliance with University (or host institution) procedures for disposalHuman, Animal and Biological MaterialsThe Biosafety Officer develops procedures for handling materials that are used in more than one laboratory. Written procedures are issued to all labs. For materials unique to a particular laboratory, the principle investigator using human, animal, or biological materials must develop written procedures, to be vetted by the biosafety Officer, that deal with regulated medical waste. Regulated medical waste includes, but is not limited to, the following categories:Human and Biological Materials Continued…•Cultures and stocks of infectious agents, and any materials contaminated witha potentially infectious agent, including, culture dishes and devices used totransfer, inoculate and mix cultures•Any human pathological wastes, including waste human blood or blood products generated in medical or research procedures, and other potentially infectious materials, items contaminated with these materials, and any containers that held these potentially infectious materials•Any animal specimens, carcasses or tissues•Any biological material contaminated with an infectious agent• DNA• Vaccines, pharmaceuticals•Wastes from medical or research procedure that were in contact with infectious agents, including slides and cover slips, disposable gloves, and protective equipment.•Sharps: used or new hypodermic needles and syringes (with or without needle attached), scalpels and razor blades. Also, Pasteur pipettes and broken glassware, when contaminated with an infectious agent•Mixed Waste: Biological specimens or material treated with or preserved in chemicals including alcohol or formaldehyde are considered mixed waste (regulated medical waste and hazardous chemical waste)•Bedding for animals•Other regulated medical waste solids must be placed in secure, leak-proof packaging and stored in such a manner that will prevent decomposition or deterioration during storageIt is the responsibility of each generator to set up a work system prior to generating medical wastes. Principal investigators, area supervisors, or other employees generating regulated medical waste materials are responsible for compliance with applicable regulations and disposal program requirements. Consult the Biosafety Officer for more information.Each department or unit using human, animal, or biological materials must develop procedures that include:•Acquiring minimum quantity control•Safe and secure storage•Appropriate labeling and an annual inventory of materials•Training of faculty, staff and students•Proper use of personal protective equipment, emergency, spill and decontamination procedures•Compliance with University (or host institution) procedures for disposal.。

银纳米粒子的合成及SERS活性研究的开题报告

银纳米粒子的合成及SERS活性研究的开题报告标题: 银纳米粒子的合成及 SERS 活性研究研究背景和意义:表面增强拉曼散射（SERS）技术具有优异的灵敏度和选择性，因此在生物医学分析、环境监测和食品安全等领域有广泛应用。

银纳米粒子是一种重要的 SERS 基质，可以通过不同的方法合成，如化学还原法、物理还原法、光化学法等。

然而，如何选择适当的合成方法以及探究银纳米粒子的 SERS 活性仍然是一个挑战。

研究内容和方法:本研究旨在合成不同形貌和尺寸的银纳米粒子，并通过 SERS 技术评估其活性。

主要研究内容和方法如下:1. 先通过化学还原法合成球形银纳米颗粒，过程中控制不同反应时间和温度，以获得不同尺寸的银纳米粒子；2. 通过表面修饰或使用不同的还原剂或添加剂，研究对银纳米粒子形貌和活性的影响；3. 利用 UV-Vis、TEM、XRD 和 SERS 技术对不同银纳米粒子样品进行表征和评估，探究尺寸、形貌、结构等特性与 SERS 活性的关系；4. 研究实际样品中的 SERS 活性，如生物标本、环境水样、食品样品等。

预期结果和创新:本研究预期可以通过控制不同的合成方法和添加剂，合成出具有优异 SERS 活性的银纳米粒子。

通过研究不同银纳米粒子样品的 SERS 表现和调查影响 SERS 效能的因素，有助于深入了解银纳米粒子SERS活性的机制，为SERS在实际检测中的应用提供科学支撑，并能为银纳米材料的设计和应用提供借鉴。

参考文献:1. Huang, Y., Yu, F., Lin, X., et al. Effects of solution pH and citrate/copper ion concentration ratios on the synthesis of copper nanowires by ascorbic acid/radiation reduction. Journal of Radioanalytical and Nuclear Chemistry, 2018, 316(1), 93-100.2. Gao, X., Yu, F., Huang, Y., et al. Preparation of regular silver nanocubes with high yield using seed-mediated growth. Radiation Physics and Chemistry, 2018, 149, 87-93.3. Ngo, T. H., Tran, C. M., Tran, P. T., et al. Synthesis of silver nanocubes with surfactant-assisted microwave method. Journal of Experimental Nanoscience, 2019, 14(1), 129-136.4. Ahmed, S. R., Kim, J. Y., Jeong, Y. T., et al. Green Synthesis of Highly Monodisperse Silver Nanoparticles by Tobacco Leaf Extract: The Effect of Solution Volume, pH, and Plant Age. Nano, 2018, 13(07), 1850082.。

Effect of silver nanoparticles on Pseudomonas putida biofilms at different stages of maturity

Journal of Hazardous Materials 290(2015)127–133Contents lists available at ScienceDirectJournal of HazardousMaterialsj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /j h a z m atEffect of silver nanoparticles on Pseudomonas putida bioﬁlms at different stages of maturityPumis Thuptimdang a ,b ,Tawan Limpiyakorn b ,c ,d ,John McEvoy e ,Birgit M.Prüße ,Eakalak Khan f ,∗aInternational Program in Hazardous Substance and Environmental Management,Graduate School,Chulalongkorn University,Bangkok 10330,Thailand bCenter of Excellence on Hazardous Substance Management,Bangkok 10330,Thailand cDepartment of Environmental Engineering,Chulalongkorn University,Bangkok 10330,Thailand dResearch Unit Control of Emerging Micropollutants in Environment,Chulalongkorn University,Bangkok 10330,Thailand eDepartment of Veterinary and Microbiological Sciences,North Dakota State University,Fargo,ND 58108,USA fDepartment of Civil and Environmental Engineering,North Dakota State University,Fargo,ND 58108,USAh i g h l i g h t s•Bioﬁlm stages in static batch con-ditions were similar to dynamic conditions.•Expression of csgA gene increased earlier than alg8gene in bioﬁlm mat-uration.•AgNPs had higher effect on less mature bioﬁlms.•Removal of extracellular polymeric substance made bioﬁlms susceptible to AgNPs.g r a p h i c a l a b s t r a cta r t i c l e i n f o Article history:Received 4December 2014Received in revised form 25February 2015Accepted 26February 2015Available online 27February 2015Keywords:Silver nanoparticles BioﬁlmsBioﬁlm maturityExtracellular polymeric substancea b s t r a c tThis study determined the effect of silver nanoparticles (AgNPs)on Pseudomonas putida KT2440bioﬁlms at different stages of maturity.Three bioﬁlm stages (1–3,representing early to late stages of development)were identiﬁed from bacterial adenosine triphosphate (ATP)activity under static (96-well plate)and dynamic conditions (Center for Disease Control and Prevention bioﬁlm reactor).Extracellular polymeric substance (EPS)levels,measured using crystal violet and total carbohydrate assays,and expression of the EPS-associated genes,csgA and alg8,supported the conclusion that bioﬁlms at later stages were older than those at earlier stages.More mature bioﬁlms (stages 2and 3)showed little to no reduction in ATP activity following exposure to AgNPs.In contrast,the same treatment reduced ATP activity by more than 90%in the less mature stage 1bioﬁlms.Regardless of maturity,bioﬁlms with EPS stripped off were more∗Corresponding author at:Civil and Environmental Engineering Department (#2470),P.O.Box 6050,Fargo,ND 58108-6050,USA.Tel.:+17012317717;fax:+17012316185.E-mail addresses:pumis.th@ (P.Thuptimdang),tawan.l@chula.ac.th (T.Limpiyakorn),john.mcevoy@ (J.McEvoy),birgit.pruess@ (B.M.Prüß),eakalak.khan@ (E.Khan)./10.1016/j.jhazmat.2015.02.0730304-3894/©2015Elsevier B.V.All rights reserved.128P.Thuptimdang et al./Journal of Hazardous Materials 290(2015)127–133susceptible toAgNPs than controls with intact EPS,demonstrating that EPS is critical for bioﬁlm tolerance of AgNPs.The ﬁndings from this study show that stage of maturity is an important factor to consider when studying effect of AgNPs on bioﬁlms.©2015Elsevier B.V.All rights reserved.1.IntroductionSilver nanoparticles (AgNPs)are incorporated as an antibacte-rial agent into a wide range of materials,including those used in wound dressings,clothes,medical devices,and water disinfection [1–4].These extensive uses of AgNPs raise a concern that they may become widespread in the environment and have a negative impact on beneﬁcial bacteria in the environment [5].The toxicity of AgNPs to bacteria involves damage to the cell wall or cell membrane,pene-tration into the cell,and inactivation of DNA via released silver ions [6–8].Reactive oxygen species generated by AgNPs can damage cells through oxidative stress [9].To determine the antibacterial effectiveness of AgNPs and con-sequences of their release into environment,studying the effect of AgNPs on bioﬁlms is important because bacteria are often present in bioﬁlm communities.To survive in harsh environment,bacteria facilitate cell interactions to attach to surface,and produce extracel-lular polymeric substance (EPS)to create more complex structures,called bioﬁlms [10].Compared to planktonic cells,bioﬁlm cells have different phenotypes and genotypes leading to speciﬁc biological activities,metabolic pathways,and stress responses [11].The genes expressed in bioﬁlms include functions related to surface attach-ment,transition to stationary phase-like cells,and EPS production [12].The EPS of bioﬁlms,which comprises polysaccharides,proteins,nucleic acids,and other macromolecules,can act as a supporting structure for bacterial adherence to surfaces and access to nutri-ents.It also protects against antimicrobial agents [13,14].However,AgNPs show ability to eradicate bacterial bioﬁlms.It was found that AgNPs are more toxic to phototrophic bioﬁlms than Ag ions and are able to diminish biomass of the bioﬁlms [15].Smaller AgNPs can reduce more biomass and viability of bioﬁlms,due to better penetration into the EPS matrix [16].The ability of AgNPs to inacti-vate bioﬁlms also increases in dynamic conditions due to increased biosorption [17].Still,mature bioﬁlms have mechanisms to tolerate AgNPs by using EPS-mediated trapping,aggregation,and reduced diffusion of AgNPs [18–21].During bioﬁlm formation,bioﬁlms develop themselves to dif-ferent stages.There are at least four stages of bioﬁlm formation:planktonic,attachment (reversible and irreversible),maturation (microcolonies and macrocolonies),and dispersion [22].These stages occur dynamically during bioﬁlm formation.The formation of various phenotypes related to each stage is regulated by different gene expressions.First,bacteria use organelles like ﬂagella to move onto the surface.To attach irreversibly to the surface,the ﬂagellar genes are repressed,followed by the expression of adhesion pro-teins such as curli,pilli,and type I ﬁmbriae [23,24].After irreversibly attached to the surface,exopolysaccharide biosynthesis genes are expressed such as the ones encoding capsule and alginate to con-struct the mature bioﬁlms [24,25].Since bioﬁlms show different characteristics during maturation,bioﬁlms in different stages may have different susceptibility to AgNPs.Various studies have proven different levels of susceptibility of bioﬁlms in different stages to other antimicrobial agents.Tré-Hardy et al.[26],studied the co-administration of antibiotics on bioﬁlms at different stages of maturation.They found that more mature bioﬁlms were less susceptible to antibiotics.Other studieshave shown that older bioﬁlms are less susceptible to chlorhexi-dine and various sanitizers [27,28].However,the effect of bioﬁlm maturity on their susceptibility to AgNPs has not been elucidated and should be studied in order to understand the adverse effect of AgNPs on environmental bioﬁlms.The objective of this study was to determine the AgNPs suscep-tibility of Pseudomonas putida KT2440bioﬁlms at different stages of maturity.P.putida KT2440was selected because it is an effec-tive bioﬁlm-producer found in soil and aquatic environments,and comprehensive physiological and genetic data are available [29,30].The study was divided into two parts.Firstly,bioﬁlm matura-tion was observed in bioﬁlms grown under static (96-well plate)and dynamic (Center for Disease Control and Prevention (CDC)bioﬁlm reactor)conditions.Secondly,bioﬁlms at different matura-tion stages were exposed to AgNPs and the effect on bioﬁlm viability was determined.2.Materials and methods 2.1.Preparation of AgNPsAgNPs were synthesized according to the method by Choi et al.[31],using sodium borohydride to reduce silver nitrate with 0.06%of polyvinyl alcohol (PVA)as a capping agent.The concentration of total Ag from the calculation was 26.3mg/l.The formation of AgNPs was veriﬁed by scanning the absorbance of the solution between 250and 700nm with a UV–vis spectrophotometer [32].The particles were characterized for size and zeta potential using a zetasizer (Malvern Instruments,Worcestershire,UK).To mea-sure the amount of Ag ion,the AgNPs solution was centrifuged at 165,000×g ,4◦C,for 1h [33].The supernatant was collected and dissolved with HNO 3before measurement by inductively coupled plasma mass spectrometry (ICP-MS).To observe the release of Ag ion after the exposure,an experi-ment was performed using a polystyrene,ﬂat-bottom,6-well plate (Thermo Scientiﬁc).Each well contained 5ml of 0.5X Luria–Bertani (LB;1%tryptone,0.5%NaCl,0.5%yeast extract)and 50␮l of the P.putida KT2440inoculum prepared according to the next subsec-tion.The plate was incubated at room temperature (20◦C)without shaking for 24h to allow bioﬁlm formation.After that,4ml of media was removed before adding 4ml of AgNPs.The plate was incubated further at room temperature.After 48h,the media was taken for measurement of total Ag and Ag ion by ICP-MS.2.2.Bacterial strain and culture preparationBefore each experiment,P.putida KT2440(ATCC 47054)was cultivated at 37◦C overnight in LB medium.The suspension was centrifuged and the pellet was re-suspended in phosphate buffer saline (PBS).The optical density of the culture,measured at 600nm,was adjusted to 0.4with PBS (approximately 107CFU/ml)before use as an inoculum in experiments.2.3.Bioﬁlm formationA polystyrene,ﬂat-bottom,96-well microtiter plate (Greiner Bio-One Frickenhausen,Germany)was used to support bioﬁlm for-P.Thuptimdang et al./Journal of Hazardous Materials 290(2015)127–133129mation under static conditions.Each well contained 100␮l of 1X LB medium (ﬁnal concentration =0.5X),95␮l of deionized (DI)water,and 5␮l of the prepared P.putida KT2440inoculum.The plate was incubated at room temperature without shaking to allow bioﬁlm formation.A CDC bioﬁlm reactor (Model 90-1,Biosurface Technologies,Bozeman,MT)was used to examine bioﬁlm formation under dynamic conditions.The reactor is a one-liter glass vessel with a lid that can hold 8polyethylene rods.Each rod holds three remov-able polycarbonate coupons serving as bioﬁlm growth surfaces.One milliliter of the P.putida KT2440inoculum was pipetted into the reactor containing 500ml of 0.5X LB medium.The reactor was operated in a batch mode (100rpm stirring)and was kept at room temperature to allow bioﬁlm formation.2.4.Adenosine triphosphate (ATP)assayAn ATP based BacTiter-Glo TM microbial cell viability assay (Promega,Madison,WI)was used to monitor changes in bacte-rial activity during bioﬁlm formation [34].In 96-well plates,ATP concentration was measured every 3h for the ﬁrst 24h and every 12h between 24and 72h.Media was removed and the bioﬁlm was rinsed twice with 200␮l of PBS.One hundred microliters of BacTiter-Glo TM reagent was added to the well and mixed brieﬂy with the bioﬁlm by pipetting.After incubation at room temperature for 5min,the bioluminescence was measured as relative light units (RLU)using a TD-20/20luminometer (Turner Designs,Sunnyvale,CA).Under CDC reactor conditions,the ATP concentration was mea-sured every 12h for 72h.A rod was removed from the reactor and carefully dipped in two consecutive tubes containing 25ml of PBS to remove the planktonic cells.The three coupons on each rod rep-resented three replicates for the same time point.Each coupon was removed and put in a tube containing 2.5ml of PBS.The bioﬁlm was detached from the coupon by vortex mixing for 30s.One hundred microliters of BacTiter-Glo TM reagent was mixed with 100␮l of the cell suspension before measuring the bioluminescence as described above.2.5.Bioﬁlm amountTwo different methods were used for determination of bioﬁlm amount in the 96-well plate and the CDC reactor.The bioﬁlm amount in a 96-well plate was quantiﬁed by crystal violet (CV)staining according to the method by Sule et al.[34].In the CDC reactor,the bioﬁlm amount was determined from total carbohy-drate by a phenol-sulfuric acid method modiﬁed from Masuko et al.[35].The samples were prepared by the method described in the ATP assay subsection.A 1.5ml aliquot of concentrated H 2SO 4was added to 500␮l of the sample and incubated for 30min.A 300␮l aliquot of 5%(w/v)phenol in water was added,and the sample was heated at 90◦C in a water bath for 10min.The sample was cooled at room temperature for 15min before measuring the absorbance at 492nm.2.6.RNA extraction and qPCRTo extract RNA from the 96-well plate,media was removed and the bioﬁlms were rinsed twice with PBS.One hundred microliters of PBS were added to each well and the bioﬁlms were scraped with an inoculating needle.Disrupted bioﬁlms were removed from the wells by a pipette.RNA was extracted from 500␮l of sus-pended bioﬁlm using an RNeasy mini kit (Qiagen,Valencia,CA)in accordance with manufacturer’s instructions.Genomic DNA con-tamination was removed by treatment with DNase I (Qiagen).Bioﬁlms were collected from the CDC reactor by the sampling method described above for the ATP assay.To prepare a sample with an adequate number of cells,20ml of a cell suspension,pre-pared from 8rods (24coupons),was centrifuged and the pellet was re-suspended in 2.5ml of PBS.RNA was extracted from 500␮l of the sample with an RNeasy Plus Micro kit according to the protocols provided by the manufacturer (Qiagen).cDNA was synthesized using random primers (Promega)and Moloney murine leukemia virus reverse transcriptase (MMLV-RT,Promega).The reverse transcription process was carried out at 37◦C for 60min followed by heating at 70◦C for 10min for enzyme inac-tivation.Samples without the reverse transcriptase were used as a negative control.Fragments of csgA ,alg8,and 16S ribosomal RNA (rRNA;used to normalize expression)transcripts were ampliﬁed using a SYBR green qPCR approach according to the method by Horne and Prüß[36].The ﬂuorescence signal was monitored in an iQ5thermocycler Real-Time PCR detection system (Biorad).For-ward and reverse primers for csgA were 5′-ATA AAT CCA CCG TGT GGC AGG ACA-3′and 5′-AGG TCT GTT CGA TGA AAG CCT CGT-3′,respectively.Forward and reverse primers for alg8were 5′-GTG ACC TCG CCA GCT TTC AAC AAT-3′and 5′-TGA ACA GCA CAG CAA CGA AGA TGC-3′,respectively.Forward and reverse primers for 16S rRNA were 5′-CCA GGG CTA CAC ACG TGT TA-3′and 5′-TCT CGC GAG GTC GCT TCT-3′,respectively.Expression data were analyzed by the comparative C t method ( C t ),where C t is the threshold cycle [37].2.7.Exposure of bioﬁlms to AgNPsFor the 96-well plate,150␮l of the media was removed before adding 150␮l of the AgNPs solution.Bioﬁlms were exposed to AgNPs for 48h at room temperature.At 0,3,6,9,12,24,and 48h,the solution was removed;bioﬁlms were rinsed twice in PBS before measuring the ATP concentration.Control experiments were car-ried out in a similar manner,with the exception that 150␮l of 0.06%PVA solution was used instead of the AgNPs solution.The effect of AgNPs on bioﬁlms was determined by comparing the ATP concentrations of treatment and control samples.For CDC reactor experiments,the lid of the reactor containing the polyethylene rods was transferred to another reactor contain-ing 400ml of AgNPs solution and 100ml of 1X LB medium.Control experiments were carried out in a similar manner,with the excep-tion that 400ml of 0.06%PVA solution was used instead of the AgNPs solution.The reactor was operated in a batch mode (100rpm stirring)for 6h at room temperature,and it was sampled after 0,1,3,and 6h.During sampling,one rod was taken from the reactor and was replaced by a new rod to balance the ﬂuid shear stress in the reactor.The ATP concentration in the bioﬁlm was determined as described earlier.Bioﬁlms also were examined using a conventional plate count method [38].2.8.Effect of EPS on bioﬁlm susceptibility to AgNPsExperiments to examine the effect of EPS on bioﬁlm suscepti-bility to AgNPs were conducted in a 96-well plate with bioﬁlms grown for 6,12,and 48h.At each time point,media was removed,the bioﬁlm was rinsed twice with PBS,and part of EPS was removed using 200␮l of 2%(w/v)ethylenediaminetetraacetic acid (EDTA)[39].The reduction of bioﬁlm amount was observed by the CV assay.Control experiments were carried out using DI water instead of EDTA.Treatment and control plates were incubated at 4◦C for 3h before rinsing the bioﬁlms with PBS and treating with 200␮l of the AgNPs solution for 2h.The effect was determined by comparing the ATP concentrations of treatment and control samples as described earlier.130P.Thuptimdang et al./Journal of Hazardous Materials290(2015)127–133Fig.1.Time course of ATP amount of P.putida KT2440bioﬁlm.2.9.Statistical analysisExperimental data were statistically analyzed using GraphPad Prism®software version6.01(GraphPad Software,La Jolla,CA).In every experiment,the standard deviation of the triplicate data was calculated and presented as error bars.The multiple t-test was used to analyze the statistical differences.To correct the errors from mul-tiple comparisons of t-test,the Holm–Sidak method was used over the t-test at5%signiﬁcance level.3.Results and discussion3.1.Characterization of AgNPsAgNPs showed the characteristic absorbance at395nm similar to a previous report[40].The particle size range was40–60nm, and a zeta potential range of–2to–6mV indicated a nearly neu-tral charge.The concentration of synthesized AgNPs was25.86mg of total Ag/l from the measurement by ICP-MS(26.3mg/l from the calculation).The synthesized AgNPs released1.24mg/l of Ag ion, which was4.8%of total Ag.The6-well plate experiment showed the reduction in total Ag from20.61to17.94mg/l after48h of exposure, suggesting the transport of AgNPs into bioﬁlms.At48h,the con-centration of Ag ion showed the higher release at1.76mg/l,which was9.8%of the total Ag.Therefore,the synthesized AgNPs should have the mechanisms of toxicity through both nanoparticles and Ag ion.3.2.Stages of P.putida KT2440bioﬁlm maturationFig.1presents ATP levels for P.putida over a72h period under static(96well plate)and dynamic(CDC reactor)conditions.A similar temporal pattern of ATP activity was observed in bioﬁlms grown under both conditions,with the exception that ATP activity for dynamic conditions was not detectable before12h and peak activity was not observed until30h.Three stages of bioﬁlm devel-opment were identiﬁed from these ATP activity data.Theﬁrst stage (stage1)represents early development,when metabolic activity is increasing(6and12h under static and dynamic conditions,respec-tively).The second stage(stage2)represents a bioﬁlm at peak metabolic activity(12and30h under static and dynamic condi-tions,respectively).The third stage(stage3)represents the stable, lower metabolic activity of a mature bioﬁlm(48h under both static and dynamic conditions).The bioﬁlm amount should increase with maturity of the bioﬁlms as EPS is produced for cell adhesion to surfaces and pro-tection from environmental stresses[41].Therefore,the amount of bioﬁlms at selected stages was determined for maturity under static and dynamic growth conditions using the CV and total car-bohydrate assays,respectively(Fig.2).Under static conditions,the amounts of bioﬁlms at stage2(12h)and stage3(48h)were6and5Fig.2.Bioﬁlm amount of P.putida KT2440bioﬁlms at different stages.A600is the absorbance at600nm for CV measured in96-well plate experiments;total carbo-hydrate was measured in CDC reactor.times higher than at stage1(6h)(p=0.016for6h vs.12h;p=0.006 for6h vs.48h).Similarly,under dynamic conditions,the amounts of bioﬁlms at stage2(30h)and stage3(48h)were2and3times higher,respectively,than at stage1(12h)(p=0.019for12vs.30h; p=0.008for12vs.48h).Bioﬁlms at stage2had higher amounts of biomass than those at stage3under static conditions,while it was the opposite under dynamic conditions.This might be due to different bioﬁlm quan-tiﬁcation methods used(the CV assay for static conditions and the total carbohydrate assay for dynamic conditions).The total carbo-hydrate assay measured only carbohydrate from the EPS of bioﬁlms, whereas the CV assay measured total biomass from live cells,dead cells,and EPS.According to the activity from Fig.1,bioﬁlms in stage 2should have much higher cell numbers than in stage3,which was likely to give more CV staining.However,there was no statistical difference between the amounts of bioﬁlms in stages2and3under both conditions(p=0.401and p=0.093under static and dynamic conditions,respectively).As bioﬁlms mature,they produce not only more EPS but also different components.Among various components,curli is a pro-tein component used for bacterial adhesion to surfaces[42].Six proteins encoded by the csgBA and csgDEFG operons contribute to the formation of curliﬁber[43].For P.putida KT2440,the csgA gene encodes the major subunit of curli.During irreversible attachment, the csgA gene should be highly expressed[24].A polysaccharide component of EPS,alginate,also contributes to the development, structure,and resistance of bioﬁlms[44].The alginate biosynthe-sis protein is encoded by the alg8gene for P.putida KT2440.As bioﬁlms produce polysaccharides to form the structure of bioﬁlms, the expression of alg8should be higher in mature bioﬁlm.Fig.3shows that,analogous to EPS levels,expressions of csgA and alg8were higher in bioﬁlms at later stages.csgA expres-sion increased signiﬁcantly between stages1and2(p=0.001and p=0.013under static and dynamic conditions,respectively)and again between stages2and3(p=0.024and p=0.030under static and dynamic conditions,respectively).alg8expression did not dif-fer between stages1and2,but increased signiﬁcantlybetween Fig.3.Expressions of csgA and alg8genes of bioﬁlms at different stages.P.Thuptimdang et al./Journal of Hazardous Materials290(2015)127–133131Fig.4.Effect of AgNPs on bioﬁlms at different stages.stages2and3(p=0.002and p=0.002under static and dynamic conditions,respectively).The earlier increase in csgA expression relative to alg8may be explained by the speciﬁc roles these genes play in bioﬁlm mat-uration.Bacteria had to adhere to the surface(expression of csgA gene)before they could form the structure of bioﬁlms by producing polysaccharide components such as alginate(expression of alg8). This resulted in different levels of gene expressions at different stages as seen in Fig.3.Collectively,the EPS and gene expres-sion data support the conclusion that bioﬁlm development stages identiﬁed from ATP activity data represent stages of increasing mat-uration.The second part of this study examined the effect of AgNPs on bioﬁlms at different stages of maturity.3.3.Effect of bioﬁlm maturity on the susceptibility to AgNPsThe effect of AgNPs on bioﬁlms was measured as a reduction in ATP activity relative to that in a non-treated control.A plate count was used in addition to ATP activity for bioﬁlms grown under dynamic conditions.Fig.4shows that the least mature bioﬁlms (stage1)were most susceptible to AgNPs,with greater than90% reduction in ATP activity and plate count.ATP was not reduced in the more mature stages2and3bioﬁlms under static conditions, and small reductions in ATP and plate count were observed in stages 2and3bioﬁlms grown under dynamic conditions.Several factors may explain the increased resistance of mature bioﬁlms to AgNPs.Firstly,bacterial cells in mature bioﬁlms are likely to be in the stationary growth phase and,therefore,less sus-ceptible to antimicrobial agents[45].To prove this,the exposure experiment was conducted on planktonic cells at different stages (Fig.S1,Supplementary data).With the same starting cell num-ber,after3h of exposure to20mg/l of AgNPs,the log-phase cells (6h)of P.putida KT2440were not observed by the plate count method while the stationary-phase cells(16h)were still at105 CFU,showing more tolerance to AgNPs.Secondly,cells that die in the outer layers of mature bioﬁlms could provide nutrients that enhance the growth of cells in deeper layers[46].A previous study on the effects of single-walled carbon nanotubes on Escherichiacoli Fig.5.ATP activity and bioﬁlm amount(represented by A600which is the absorbance at600nm for CV)before and after EDTA treatment.132P.Thuptimdang et al./Journal of Hazardous Materials 290(2015)127–133Fig.6.Effect of EPS on bioﬁlm susceptibility to AgNPs.bioﬁlm showed that dead bacterial cells could cause aggregation of the nanotubes and at the same time release intracellular substances to serve as nutrients for other cells [47].Also,the high thickness or high amount of EPS in mature bioﬁlms may have a role in transport limitations of AgNPs through bioﬁlms.3.4.Role of EPS in bioﬁlm susceptibility to AgNPsTo determine how EPS affects bioﬁlm susceptibility to AgNPs,the EPS of bioﬁlms were partly removed by EDTA [48].Fig.5shows the reduction of ATP activity and bioﬁlm amount after EDTA treat-ment.There was a statistically signiﬁcant reduction of ATP in all stages of bioﬁlms (6h:p =0.008,12h:p =0.0005,48h:p =0.009).However,the amount of 6h bioﬁlms (based on the CV assay results)did not get reduced by the EDTA treatment,while the older bioﬁlms showed high reduction of biomass (48h:p =0.003).After EPS strip-ping by EDTA treatment,the bioﬁlms were exposed to AgNPs and the effect was measured by reduction in ATP activity (Fig.6).The results showed the critical role of EPS in the protection of bioﬁlm communities from AgNPs.The EPS-stripped bioﬁlms in all three stages showed signiﬁcantly higher reduction in ATP than bioﬁlms with intact EPS (control)at every time point of exposure (p <0.05).To demonstrate that EDTA did not make the planktonic cells more susceptible to AgNPs after 3h of treatment,a test was con-ducted and the results are presented in Fig.S2(Supplementary data).Between cells with EDTA treatment and without EDTA treat-ment,there was no signiﬁcant difference of ATP percentage after 1h of AgNP exposure (p =0.971).However,after 2h of AgNP expo-sure,cells treated with EDTA showed lower susceptibility to AgNPs than cells without EDTA treatment (p =0.031).From these results,it can be concluded that EDTA did not increase the susceptibility of cells to AgNPs.Therefore,the reduction in ATP of bioﬁlms after EPS stripping should be from the EPS removal.Similarly,in a study on effects of AgNPs on wastewater bioﬁlms,greater bacterial reduc-tions were achieved after loosely-bound EPS was removed [20].This is consistent with the ﬁndings by Peulen and Wilkinson that EPS density reduces the diffusion of AgNPs into bioﬁlms [19].4.ConclusionsIn this study,we characterize three stages of bioﬁlm maturity based on cell number,expression of bioﬁlm-associated genes,and EPS amount,and we show that more mature bioﬁlms have greatly reduced susceptibility to AgNPs compared to immature bioﬁlms.These ﬁndings have important implications for environmental systems where bioﬁlm maturity varies,including wastewater treat-ment plants at different phases of operation.AgNPs will be less toxic in steady-state systems with mature bioﬁlms,but systems during start-up,when bioﬁlms are becoming established,will be vulnera-ble to AgNPs.It should be noted that this study only focused on the effect of AgNPs on single-species bioﬁlms growing in batch con-ditions.In environment or wastewater treatment system,variousspecies of bacteria are present together under the continuous con-ditions.It is possible that stage of maturity will be different from the results in this study,leading to different effect of AgNPs on bioﬁlms.Therefore,these two points should be considered for future stud-ies in order to better understand the effect of AgNPs on bioﬁlms at different stages of maturity.AcknowledgmentsThis work was supported by the 90th Anniversary of Chula-longkorn University Fund (Ratchadaphiseksomphot Endowment Fund)and was conducted under the research cluster “Control of Emerging Micropollutants in Aquacultural and Feedstock Industry”granted by Center of Excellence for Hazardous Substance Man-agement (HSM)and Special Task Force for Activating Research (STAR)program of Chulalongkorn University.The iCycler iQ qPCR detection system for RT-qPCR was purchased with grant 2009-35201-05010from the USDA/NIFA.The authors would like to thank Shane Stafslien and Justin Daniels from the Center for Nanoscale Science and Engineering,North Dakota State University,for sug-gestions and opinions on CDC reactor operation.Appendix A.Supplementary dataSupplementary data associated with this article can be found,in the online version,at /10.1016/j.jhazmat.2015.02.073.References[1]J.Tian,K.K.Y.Wong,C.-M.Ho,C.N.Lok,W.Y.Yu,C.M.Che,J.F.Chiu,P.K.H.Tam,Topical delivery of silver nanoparticles promotes wound healing,ChemMedChem 2(1)(2007)129–136.[2]T.M.Benn,P.Werterhoff,Nanoparticle silver released into water fromcommercially available sock fabrics,Environ.Sci.Technol.42(2008)4133–4139.[3]D.Roe,B.Karandikar,N.Bonn-Savage,B.Gibbins,J.B.Roullet,Antimicrobialsurface functionalization of plastic catheters by silver nanoparticles,J.Antimicrob.Chemother.61(4)(2008)869–876.[4]D.Gangadharan,K.Harshvardan,G.Gnanasekar,D.Dixit,K.M.Popat,P.S.Anand,Polymeric microspheres containing silver nanoparticles as a bactericidal agent for water disinfection,Water Res.44(18)(2010)5481–5487.[5]J.Dobias,R.Bernier-Latmani,Silver release from silver nanoparticles innatural waters,Environ.Sci.Technol.47(9)(2013)4140–4146.[6]I.Sondi,B.Salopek-Sondi,Silver nanoparticles as antimicrobial agent:a casestudy on E.coli as a model for gram-negative bacteria,J.Colloid Interface Sci.275(1)(2004)177–182.[7]J.R.Morones,J.L.Elechiguerra,A.Camacho,K.Holt,J.B.Kouri,J.T.Ramírez,M.J.Yacaman,The bactericidal effect of silver nanoparticles,Nanotechnology 16(10)(2005)2346–2353.[8]Q.L.Feng,J.Wu,G.Q.Chen,F.Z.Cui,T.N.Kim,J.O.Kim,A mechanistic study ofthe antibacterial effect of silver ions on Escherichia coli and Staphylococcus aureus ,J.Biomed.Mater.Res.52(4)(2000)662–668.[9]A.Kora,J.Arunachalam,Assessment of antibacterial activity of silvernanoparticles on Pseudomonas aeruginosa and its mechanism of action,World J.Microbiol.Biotechnol.27(5)(2011)1209–1216.[10]H.C.Flemming,J.Wingender,The bioﬁlm matrix,Nat.Rev.Microbiol.8(2010)623–633.。

PROCESS FOR PREPARATION OF SILVER NANOPARTICLES, A

专利名称：PROCESS FOR PREPARATION OF SILVERNANOPARTICLES, AND THE COMPOSITIONSOF SILVER INK CONTAINING THE SAME发明人：Kwang-Choon Chung,Hyun-Nam Cho,Byung Hun Kim,Su Han Kim,Myung Bong Yoo,NamBoo Cho,Yi Sup Han申请号：US12376893申请日：20070802公开号：US20100189901A1公开日：20100729专利内容由知识产权出版社提供专利附图：摘要：The present invention relates to a process for preparation of silver complex compound and the compositions of silver ink containing the same. The present invention includes a) preparing silver complex compound with special structure by reacting silver compound with at least one or two mixtures selected from ammonium carbamate compound, ammonium carbonate compound or ammonium bicarbonate compound and b) preparing silver nano particles by reacting the silver complex compound with reducer or reducing or pyrolyzing the silver complex compound by applying heat thereto. The preparing method according to the present invention can prepare the silver nano practical with various shapes through a simple preparation process, improve the selectivity of the size of the silver complex compound, fire the silver complex compound even when it is fired at a low temperature of 150° C. or less during a short time, provide the ink compositions capable of forming the coating or the fine pattern showing the high conductivity while facilitating the thickness control of the coating, and provide the ink compositions capable of being applied to the reflective film material, the electromagnetic wave shield, and the antimicrobial agent, etc.申请人：Kwang-Choon Chung,Hyun-Nam Cho,Byung Hun Kim,Su Han Kim,Myung Bong Yoo,Nam Boo Cho,Yi Sup Han地址：Yongin-si KR,Gunpo-si KR,Ansan-si KR,Ansan-si KR,Yongin-si KR,Anyang-siKR,Goyang-si KR国籍：KR,KR,KR,KR,KR,KR,KR更多信息请下载全文后查看。

丹黄散纳米银海绵抑制铜绿假单胞菌的效果

《中国组织工程研究》 Chinese Journal of Tissue Engineering Research文章编号:2095-4344(2019)22-03495-05 3495www.CRTER .org·研究原著·李桃，女，1989年生，贵州省贵阳市人，汉族，贵州中医药大学(原贵阳中医学院)在读硕士，主要从事中西医结合糖尿病护理方面的研究。

通讯作者：张春玲，主任护师，硕士生导师，贵州中医药大学(原贵阳中医学院)第二附属医院，贵州省贵阳市 550003文献标识码:A稿件接受：2019-03-29Li Tao, Master candidate, Guizhou University of Traditional Chinese Medicine (formerly Guiyang College of Traditional Chinese Medicine), Guiyang 550002, Guizhou Province, ChinaCorresponding author: Zhang Chunling, Chief nurse, Master’s supervisor, Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine (formerly Guiyang College of Traditional Chinese Medicine), Guiyang 550003, Guizhou Province, China丹黄散-纳米银海绵抑制铜绿假单胞菌的效果李桃1，张春玲2，龙毅2，邸铁涛2，陈露2，赵伟2，龙丽1，黄蔷1，唐丽莎1，罗开中1 (1贵州中医药大学(原贵阳中医学院)，贵州省贵阳市 550002；2贵州中医药大学(原贵阳中医学院)第二附属医院，贵州省贵阳市 550003) DOI:10.3969/j.issn.2095-4344.1276 ORCID: 0000-0001-9854-656X(李桃)文章快速阅读：文题释义：丹银海绵：是将丹黄散与纳米银材料进行有机结合而成，使其不仅具有丹黄散镇痛、活血、除痹、生肌等促糖尿足溃疡愈合之功效，还具有纳米银对铜绿假单胞菌的良好抑菌作用，且不产生耐药性，可直接外敷于溃疡面，为临床治疗糖尿病足溃疡提供了新的思路与方法。

PREPARATION OF SILVER CATALYST

专利名称：PREPARATION OF SILVER CATALYST 发明人：NOJIRI NAOHIRO,SAKAI YUKIO申请号：JP19173384申请日：19840914公开号：JPS6171838A公开日：19860412专利内容由知识产权出版社提供摘要：PURPOSE:To obtain a silver catalyst generating no flocculation and oxidizing ethylene with high capacity, by impregnating a porous refractory carrier with an amine-containing aqueous solution and heating the impregnated carrier at 150-250o for 1-30min to precipitate silver. CONSTITUTION:A porous refractory carrier is impregnated with an aqueous solution containing at least a silver salt and amine being a complex forming agent and the impregnated one is heated at 150-250o for 1-30min in the pres ence of air or inert gas to precipitate silver to obtain a silver catalyst for preparing ethylene oxide from ethylene. The aforementioned catalyst can contains not only sodium and cesium as cation components but also halogen except iodine as an anion component other than silver. A compound of an alkali metal and a compound of an alkaline earth metal can be supported by the carrier other than silver.申请人：MITSUBISHI PETROCHEM CO LTD更多信息请下载全文后查看。

Preparation_and_Characterization_of_Near_Nano_Copp

International Journal of Nonferrous Metallurgy, 2014, 3, 35-41 Published Online October 2014 in SciRes. /journal/ijnm /10.4236/ijnm.2014.34005Preparation and Characterization of Near Nano Copper Powder by Electrolytic RouteAkansha Sengar, Prathvi Raj SoniDepartment of Metallurgical & Materials Engineering, Malaviya National Institute of Technology, Jaipur, India Email: *******************Received 20 September 2014; revised 15 October 2014; accepted 21 October 2014Copyright © 2014 by authors and Scientific Research Publishing Inc.This work is licensed under the Creative Commons Attribution International License (CC BY). /licenses/by/4.0/AbstractFor the preparation of copper nanoparticles several methods, i.e ., thermal reduction, mechanical attrition, chemical reduction metal vapour synthesis, radiation methods, laser ablation and micro emulsion techniques were developed in the past. Electrolytic deposition is one of the most suit-able, simplest and low cost methods which are used for wide range of materials. In the present in-vestigations, efforts were put to produce copper nano powder using electrolytic technique. It could be possible to obtain near nano copper powder of 258 nm size using high cathode current density of 1100 A/m 2 in sulphate bath. The specific surface area and shape of the particles were found to be 23.2 m 2/g and irregular, respectively.KeywordsNear Nano Copper Powder, Sulphate Bath, Size and Size Distribution, Morphology1. IntroductionThe field of nanoscience and nanotechnology has recently become one of the most important areas of knowl-edge encompassing various scientific disciplines, including physics, chemistry, biology and engineering. Interest in this discipline is mainly due to two reasons. Firstly, nano scale materials have many prospects in various technological applications because most of the time they show novel functionalities. Secondly, there is a tre-mendous scope of creating new knowledge in explaining the size dependencies of the evolution of various phy- sical properties, and in explaining new and previously unnoticed features. Nanostructured materials can be util-ized in fabricating novel active devices with improved functionalities. For example, one dimensional nanomate-rial (tubes, wires, rods, etc.) is an important class of nanostructured materials with potential applications in elec-tronics, composite fabrications or sensor developments [1].Mainly nanotechnology is the ability to form nano-sized particles, for example nano powders, which are solidparticles that measure on the nano scale, usually comprised of 3 to 5 molecules together. Nano powders can be used in most of the aforementioned applications; so, it has been an interesting field of great interest [2]. The considerable interest has been focused on metal nanoparticles due to their potential applications and special properties in diverse fields.Among various non-metal and metal particles, copper nanoparticles have attracted considerable attention be-cause of their catalytic, optical, and electrical conducting properties. For the preparation of copper nanoparticles several methods were developed, i.e ., thermal reduction, mechanical attrition, chemical reduction, metal vapour synthesis, radiation methods, laser ablation and micro emulsion techniques. In nanoparticle preparation, it is very important to control the particle size, particle shape and morphology. Most of the preparation procedures have some factors that restrict the use and development of the copper nanoparticles. For example, copper nano- particles synthesized by mechanical chemical method have low purity and wide particle size distribution. Gas evaporation method presents the costly raw materials and complicated equipment [3]. Nanoparticles synthesized in lithographic and by vacuum deposition provide uniform shape, size and size distribution, but these techniques are expensive.Electrolytic deposition is one of the most suitable, simplest and low cost methods which are used for wide range of materials and characteristics [4]. Therefore, in the present investigations, it was planned to produce nano copper powder by using electrolytic deposition from copper sulphate bath under suitable bath conditions [5] and additives like boric acid and glycerine [6].2. ExperimentalCopper sulphate bath was prepared by dissolving CuSo 4∙5H 2O (99% purity) in distilled water EC grade copper was used as anode and stainless steel as cathode. The experimental conditions under which the copper powder was prepared have been summarized in Table 1.The deposited copper powder was removed by brushing after every 15 minutes and washed thoroughly with distilled water. Subsequently the powder was dried in the air atmosphere. This powder sample was then deag-glomerated in a mortar pestle to obtain the final product. Copper powder samples were also prepared after add-ing 1 wt% of boric acid or glycerine to the electrolyte bath.The resultant powder was tested for its purity using EDS analysis. Particle size, size distribution and specific surface area of the powder produced was studied by laser technique using Malvern Mastersizer 2000, while the morphology was studied using ZEISS Supra-50 FESEM.3. Results and DiscussionThe electrolyte copper sulphate when dissolved in water dissociates to give Cu 2+ and 24SO −ions.()()()2244CuSO aq Cu aq SO aq +−→+Current is carried by Cu 2+ and 24SO −in the solution Cu 2+ ions go to cathode and get reduced to metal copperand deposited on it. The 24SO −ions move towards anode but are difficult to get oxidized. So at anode oxidationof OH − ions (produced by the self-ionization of water) takes place in preference to 24SO −. So, the reaction at anode isTable 1. Bath conditions for preparation of copper powder.Condition Quantity Copper 13 g/L Temperature 30˚C - 35˚CAnode current density Low—400 A/m 2; High—550 A/m 2 Cathode current densityLow—800 A/m 2; High—1100 A/m 2Cell potential 5 VAdditives1 wt% boric acid or glycerine22H O 2H 2OH +−→+()2212OH H O O g 2e 2−−→++The net reaction at anode:()221H O 2H O g 2e 2+−→++Thus during the electrolysis of CuSO 4 solution, the current is carried by copper ions and sulphate ions, but the ions which travel in the electrode reactions are Cu 2+ and OH −. Liberation of H + makes the solution around anode more acidic.The EDS results are shown in Figure 1 indicating presence of some amount of the oxygen phase in the copper powder prepared.3.1. Particle Size AnalysisParticle size analysis results and specific surface area of various samples of copper powder prepared under dif-ferent bath conditions have been summarised in Table 2. At low cathode current density of 400 A/m 2, particle size was 8.8 µm (surface weighted mean), with a specific surface area of 0.7 m 2/g could be prepared. Particle size distribution in this sample is shown in Figure 2, which is very broad.Figure 1. EDS spectrum of the copper powder prepared usinghigh current density.Figure 2. Particle size distribution in copper powder prepared atlow current density.Addition of 1 wt% boric acid to the electrolyte gave better mass deposition of copper on electrode due to the increased current efficiency of the electrolytic cell. When boric acid reacts with the copper sulphate solution it produces the H + ions()()234B OH H O B OH H −++→+In this reaction boric acid interacts with water molecules to form the tetrahydroxyborate ion and hydrogen ions. Boric acid was found to prevent the rate of electro reduction of copper on stainless steel by an order of magnitude [7]. Therefore, the particle size obtained in this case was significantly smaller (5.2 µm) than the par-ticle size obtained at low current density, and consequently a marginal increase in specific surface area. Particle size distribution in this sample is shown in Figure 3, which is narrower as compared to earlier one (Figure 2). The other additive was glycerine which is a non-electrolyte. When glycerine was added in the electrolyte it created the obstacles in direct deposition of copper particle, due to which the copper particles deposited in this case were finer in size. As shown in above results, the particle size obtained by glycerine addition was 8.3 µm but with no change in specific surface area indicating non suitability of such additives to the bath for lowering the particle size in the deposits. Particle size distribution in this sample is shown in Figure 4.Table 2. Size and specific surface area of the copper powder particles obtained from different bath conditions.S. No Bath condition d (0.1) (µm) d (0.5) (µm) d (0.9) (µm) Specific surface area (m 2/g) Surface weighted mean (µm) Volumeweighted mean(µm)Volume % of particlesize less than 1 µm1 Low current density3.4 13.2 418.2 0.7 8.8 97.8 - 2 Boric acid 2.6 6.6 15.5 1.1 5.2 8.0 - 3 Glycerine 3.213.2101.6 0.7 8.3 47.8 - 4High current density140 nm 230 nm1.623.2258 nm611 nm73.1Figure 3. Particle size distribution in copper powder preparedafter addition of boric acid to the bath.Figure 4. Particle size distribution in copper powder preparedafter addition of glycerine to the bath.From the results shown in Table 2, it can be seen that near nano copper powder can be prepared by applying high current density to the bath. The metal powder deposits can be obtained at current densities higher than lim-iting diffusion value. The increasing over potential leads to increased nucleation rate, as well as the number of sites suitable for instantaneous dendrite growth initiation. The number of nucleation sites on the initial surface is obviously limited, while the nucleation on the growing grains can take place continuously. Assuming that pow-der particles and powder sub particles are the product of further dendrite growth on nuclei formed on the initial surface and the particles themselves, respectively, it is easy to explain the well-known fact that powder particle size decreases with increasing current density. In this sample particle sizes was found to be 258 nm, with a nar-row particle size distribution (Figure 5). The volume percentage of the particle size less than 1µm is 73.1 (Table 2). The specific surface area of this sample was 23.2 m2/g, which is the maximum among all these cases. This is as per known fact that as the particle size decreases the total surface area increases for the same mass of the powder.3.2. MorphologyMorphology of these copper powder particles have been shown in Figures 6-9.The powder particles produced using low and high current density appears to be irregular shape (Figure 6 and Figure 7). With increased current density, morphology of copper powder deposits was seen to change from compact to massive dendrites (Figure 10). The massive dendrites broke and converted into small irregular shape particles during the deagglomeration. Addition of boric acid to the bath converted the particle shape into sphe-roid shape (Figure 8), while the addition of glycerine to the bath gave equant shape particles (Figure 9).Figure 5. Particle size distribution in copper powder prepared athigh current density.Figure 6. SEM of copper powder prepared at low current density.Figure 7. SEM of copper powder prepared at high density.ric acid.erine.Figure 10. Deposition of copper powder on cathode showingmassive dendrites.4. ConclusionsThe near nano copper powder was prepared by electrolytic method. These particles were generated when high cur-rent density was applied through the bath.The particle size in copper powder produced was found to be 258 nm, with a narrow particle size distribution. The specific surface area of these particles was 23.2 m2/g and the shape was irregular.References[1]Chatopadhyay, K.K. and Banerjee, A.N. (2009) Introduction to Nanoscience and Nanotechnology.PHI Learning, NewDelhi, 1-5.[2]Gordillo, G. and Hailey, X. (2004) Nanopowder Production: A Comparison of Several Methods. NSF-REU Summer,Chicago, 1-19.[3]Qiu, Z., Zhi-Mao, Y., Bing-jun, D., Xin-zhe1, L. and Yingjuan, G. (2010) Preparation of Copper Nanoparticles byChemical Reduction Method Using Potassium Borohydride. Transactions of Nonferrous Metals Society of China, 20, 240-244.[4]Theivasanthi, T. and Alagar, M. (2010) X-Ray Diffraction Studies of Copper Nanopowder. Archive of Physics Re-search, 1, 112-117.[5]Nikolic, N.D. and Popov, K.I. (2012) Electrochemical Production of Metal Powders. Springer, Berlin, 125-186.[6]Berry, D.F. and Klar, E., Production of Copper Powders (1998) ASM Handbook. Powder Metal Technologies and Ap-plications, 7,132-140.[7]Levi, C., Romalo, J.B. and Shaw, J.K. (1970) Copper Electroplating in Citric Acid Bath. US Patent No. 3684666A.。

纳米镀银纤维纺织品银含量测定预处理方法的改进

纳米镀银纤维纺织品银含量测定预处理方法的改进庄桂裕;罗金英;潘厚军【摘要】在微波消解预处理的条件下通过添加氨水的方法来提高镀银纤维中银含量检测的精确度,实验结果表明,改进后的预处理方法使样品消解程度更彻底、银含量检测数据更准确,此方法有较高的实用性,可作为纳米镀银纤维纺织品银含量检测的预处理方式.%This study discusses the development of nano silver fiber textiles and the analysis of silver content detection technology,under the condition of microwave pretreatment by adding ammonia improvement method to achieve the purpose of silver fiber content detection accuracy,the experimental results show that the improved pretreatment method to make the sample digestion is more thorough,silver content detection data is more accurate,method have higher practicability,can be used as the pretreatment of the nano silver content in silver fiber textiles testing way.【期刊名称】《广州化学》【年(卷),期】2018(043)003【总页数】4页(P56-59)【关键词】纳米镀银纤维纺织品;银含量;预处理;微波消解;氨水【作者】庄桂裕;罗金英;潘厚军【作者单位】广州中科检测技术服务有限公司,广东广州 510650;中国科学院广州化学研究所分析测试中心,广东广州 510650;【正文语种】中文【中图分类】O652.4随着健康环保理念逐渐深入人心，纳米镀银纤维[1]作为一种新型纺织产品，以除臭、抗菌、防静电、防辐射等一系列特殊性能得到了广泛的关注[2]，但由于纳米镀银法是将纳米银植入了纤维内部[3]，纤维中银含量的检测常常会出现数据异常波动与回收率偏低的情况，因此准确测定纳米镀银纤维纺织品中的银含量也成为目前纺织品银含量检测的一个难点。

原位还原制备滤纸载纳米银粒子复合材料及其催化特性

CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2016年第35卷第5期·1466·化工进展原位还原制备滤纸载纳米银粒子复合材料及其催化特性吴贺君1，董知韵1，孙勋文2，胡彪1，李庆业2，刘韫滔1（1四川农业大学食品学院，四川雅安 625000；2四川大学高分子材料工程国家重点实验室，四川成都 610065）摘要：基于绿色化学的角度，直接以滤纸（FP ）为基底材料，在碱性条件下无需外加还原剂和稳定剂，原位还原得到负载纳米银（AgNPs ）的AgNPs/FP 复合材料。

通过扫描电子显微镜（SEM ）、X 射线电子能谱仪（EDS ）、热重分析仪（TGA ）和紫外-可见（UV-vis ）分光光度计等对复合材料的形貌、组成和催化性能进行表征。

研究结果表明，Ag +被还原为AgNPs 后致密又均匀地负载于滤纸表面上，所制得的AgNPs/FP 复合材料中纳米银呈球形、尺寸均一且团聚较少。

AgNPs/FP 复合材料对对硝基苯酚（4-NP ）的还原具有较好的催化活性，且易于回收再利用。

关键词：纳米粒子；银；滤纸；纤维素；还原；催化中图分类号：O 643 文献标志码：A 文章编号：1000–6613（2016）05–1466–05 DOI ：10.16085/j.issn.1000-6613.2016.05.29In situ reduction of silver nanoparticles on filter paper and their catalyticactivityWU Hejun 1，DONG Zhiyun 1，SUN Xunwen 2，HU Biao 1，LI Qingye 2，LIU Yuntao 1（1College of Food Science ，Sichuan Agricultural University ，Ya’an 625000，Sichuan ，China ；2State Key Laboratoryof Polymer Materials Engineering ，Sichuan University ，Chengdu 610065，Sichuan ，China ）Abstract ：The silver nanoparticles/filter paper (AgNPs/FP) composites were successfully prepared via in-situ reduction by employing filter paper as both reducer and carrier in alkaline conditions based on green chemistry. The morphology ，composition ，and catalytic properties of the prepared AgNPs/FP composites were characterized by scanning electron microscopy (SEM)，energy-dispersive spectroscopy (EDS)，thermogravimetric analysis (TGA) and UV-visible (UV-vis) spectrophotometry. SEM images showed the spherical AgNPs evenly distributed on the surface of the filter paper ，which was testified further by UV-vis spectroscopy ，EDS and TGA. In addition ，the obtained AgNPs/FP composite exhibited good catalytic activity for the reduction of 4-nitrophenol (4-NP) and could be recycled easily.Key words ：nanoparticles ；silver ；filter paper ；cellulose ；reduction ；catalysis近年来，纳米银（silver nanoparticles ，AgNPs ）因其独特的物理和化学性质，在电子、光学、抗菌和催化等领域得到广泛的研究与应用[1-4]。

7 Chem. Mater. 2011, 23, 3273–3276—si 纳米银墨水 Ag-PVP 重点看

Supporting InformationPreparation of Conductive Silver Films at Mild Temperatures for Printable OrganicElectronicsLakshminarayana Polavarapu, Kiran Kumar Manga, Hanh Duyen Cao, Kian Ping Loh,Qing-Hua Xu*Department Chemistry, National University of Singapore,3 Science Drive 3, Singapore;E-mail: chmxqh@.sg1. Preparation procedures of silver nanoparticle ink2. The product obtained after reducing AgNO3 with NaBH4 in the absence of PVPFigure S1. (a) The photograph of the product obtained after reducing AgNO3 with NaBH4 in the absence of PVP, which was insoluble in water and settled down at the bottom of the test tube. (b) The SEM image of the obtained particles. The particles hadsize of ~ 1µm and were aggregated.3. Optical microscopic image of the silver filmFigure S2. Optical microscopic image of the solution processed silver film on a plastic substrate.4. Resistance measurements of the Ag film using a multi-meter.Figure S3. The resistance of the Ag nanoparticle film on a plastic substrate measured across the two ends of the Ag film (A) before and (B) after deformation. Different appearance colors are due to the different reflection of surrounding light.5. Thermogravimetric analysis (TGA) of Ag inkThe thermal behaviours of the Ag ink were investigated by Thermogravimetric analysis (TGA). The TGA thermogram of the dried Ag ink (dried at room temperature) was recorded with a heating rate of 10 ° C min − 1 in air and are shown in Figure S3. The TGA of the dried Ag ink showed a decrease of almost 0.5 wt% by 100 ° C, which was due to the evaporation of ethanol present in the pores of the dried Ag ink. Further increase of temperature showed a decrease of another 2 wt% by 350 ° C, which was due to the decomposition of PVP polymer present in the Ag Ink. The TGA result shows that only 2-3 wt% of PVP present in the purified Ag ink. The result indicates that the density of the PVP on the nanoparticle surface is very low due to the week binding of PVP to the nanoparticle surface.Figure S4. TGA curve of Ag ink at a heating rate of 10 ° C min − 1 in air010020030040050097.097.598.098.599.099.5100.0 W e i g h t (%)Temperature (O C)6. Conductivity vs. thickness of the Ag filmFigure S5. Film thickness dependent conductivity of the Ag film. The conductivity increases rapidly with the increasing thickness up to 400 nm and remains nearly constant above 400 nm thicknesses. The maximum conductivity was measured to be ~0.7.0x105 S ⋅cm -1 at Ag film thickness of 400 nm and above.7. Solar cell device fabrication and measurementsP3HT (30mg/ml) and PCBM (30mg/ml) were dissolved (1:1 ratio) in dichlorobenzene (DCB) solvent and spin coated on a ITO/PEDOT electrode using 800 rpm at 70 s and annealed at 120 o C for 10 min under N 2 atmosphere. Subsequently LiF (1 nm) and Al (100 nm) evaporated at 1x10-6 bar vacuum to complete the device fabrication. The silver nanoparticle ink was deposited onto the P3HT-PCBM polymer film on the other end of device and the device structure is shown in Fig.4a. The thickness of the active layer film was measured to be 120 nm by using a surface profiler. The device structure is ITO/PEDOT:PSS (40nm)/P3HT:PCBM (120nm)/LiF (1nm)/Al (100nm). The I-V curves2.0x104.0x106.0x108.0x10C o n d u c t i v i t y (S .c m -1)Film tickness (nm)were measured by using a solar simulator AMG 1.5 light source of 100mW/cm2 intensity. The light source employed was a Newport 300W xenon light source, controlled by a Newport digital exposure controller, which simulates the solar light through an AM 1.5G sunlight filter. The incident light intensity was focused and calibrated to 1 Sun (100 mW/cm2) with a standard Si solar cell (PV measurements, USA).Legend for Supporting MovieThe nanoparticle dispersion was deposited onto the glass substrate and the solvent was evaporated using air dryer, which resulted in formation of a shiny silver film without any annealing.。

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Preparation of Nano-silver Artemisia Argyi and Anti-bacterial Finishingto Silk FabricFang Jiang a, Haitao Lin b, Junsheng Li c, Jiwei Huang d,Xinxia Yue e,Xinlong Ling f and Wenjie Mao gDepartment of Biological and Chemical Engineering,Guangxi University of Technology, Liuzhou,Chinaa jff126@,b lhthost@,c junshenglee63@,d sjzs1190@,e xinxiayue@,f lxl29981@, g939337116@Keywords：Nano-silver; Artemisia argyi; Silk fabric; Anti-bacterial finishing; Washability. Abstract. The hydroxyl in polysaccharide and flavones that extracted from Artemisia argyi can absorb onto the surface of silver nanoparticles and prevent aggregation from nanoparticles. The stable nano-silver solution was got. The preparation of Nano-silver Artemisia Argyi by Artemisia Argyi extract in alkaline and acidic environment was investigated, and the antibacterial property of fabric finished by the nano-silver Artemisia Argyi was analyzed. The experimental results show that the silver nanoparticles prepared in alkaline environment has small size with the minimum 12nm and uniform dispersion. The fabric finished by Nano-silver Artemisia Argyi exhibited strong antibacterial activity against E.coli and S.aureus, the sterilized rate was over 99.9%. The fabric has excellent antibacterial washability too.IntroductionSilk fabric has been used as a textile material for centuries and favor of people due to its super luster, feel, airy, soft elegant appearance, eximious performance of absorbing moisture and excellent quality. However silk is a protein fabric and suffers from certain disadvantages such as existing obvious deficiency in antibacterial, where all kinds of bacteria can breed extremely rapidly in suitable environment and produce abnormal stimulation even induce various skin diseases. So it is important to develop antibacterial silk fabric.Nano-Silver is a new nanometer material which is being widely studied. And it has great application value in electrical, optical, antiseptics and pharmaceutical medicinal etc [1]. Due to the need of protecting the environment, people pay much attention to environmental protection of chemistry and chemical processes so as to reduce the chemical pollution. Recently, natural materials are attracting the attention of researchers because of their availability of resources, low cost, easy handling and minimum damage to the environment. In addition, they have unique properties such as non-toxic and biological degradability. So the method of preparation of nano-silver by biomaterial emerges is required. Mohanpuria Prashant etc [2] made nano-silver using fusarium oxysporum and validated the feasibility of bio-preparation of nanosize silver which being used as textile finishing.Some materials such as microorganisms, enzyme and some plants have been used inbio-preparation method, relative to microbial and enzymes, the method of preparation of nano-silverXiaocui etc [3] explored a new method to achieve nanosize silver and finished pure silk with aloe leaf extracting; the pure silk arranged by the nano-silver had outstanding antibacterial performance. Besides aloe, camphor leaf [4], geranium [5], ginkgo biloba and mulan [6] have been used for preparation of nano-silver too. However, there is not a reported research paper preparing silver nanoparticle with Artemisia argyi.The preparation of nano-silver in alkaline and acid environment using artemisia argyi extracting including the silver nanoparticle size and the morphology of nano-silver are investigated. And the antibacterial properties of silk fabrics finished with the Nano-silver Artemisia argyiExperimentalMaterials. Silk fabric (45g/m 2); artemisiae argyi; nitric acid silver analytical grade; ammonia; activated carbon; E. coli and S. aureus, (Guangxi engineering biochemical department)In all experiments, double distilled water was used and all reagents were used as received without any further purification.The Preparation of Artemisia Argyi Solution. Put 100 gram artemisia argyi into 1500mL distilled water, soaked at 95℃ for 1 h, leached with eight layer gauze, concentrated and then freezed for 48 h, filter liquor was decolored with activated carbon at 70℃ for 1 h, then pump filtered and added distilled water to 1000mL.TheVPrinciple of Nanometer Silver Preparation. Nano-silver particles can be achieved by reduction of silver ions, but nano-particles are easy to aggregate. In order to prevent nano-particles from aggregation, it is necessary to add some protective agent in reaction solution [7]. Artemisia argyi solution contains abundant polysaccharide and highly active flzvonoids [8]; some of these polysaccharides have reducibility and can reduce metal ions [9]. Moreover, the hydroxyl in polysaccharide and hydroxyl can coordinate with silver ions [10]; these ligands were absorbed on the surface of nanoparticles and prevent nano-particles from aggregation, then get stable nano-silver solution. According to the mechanism, this study tries to use Artemisia argyi extract to make nanosize silver. Artemisia argyi extract has acidity; the pH of artemisia argyi solution is about five. The pH would change obviously when the ratio of liquid ammonia and Artemisia argyi extract change.Preparation of Nanometer Silver in Alkaline Environment. At first mixed 5mL silver nitrate (0.01mol/L) with 1.5mL ammonia, then put certain amount of Artemisia argyi solution and added distilled water to 50mL, then stirred the solution with high shear emulsifier for 30min at speed of 6000r/min, the pH was about 9-10, standing for 24h at room temperature.Preparation of Nanometer Silver in Acidic Environment. At first made certain concentration silver ammonia solution. Put 1mL certain concentration silver ammonia solution (0.012 mol/L ，0.017 mol/L ，0.022 mol/L ，0.027 mol/L ，0.032mol/L ) into a certain volume of Artemisia argyi extract, then stirred the solution with high shear emulsifier for 30min at the speed of 6000r/min, the pH was about 5-6, standing for 24h at room temperature.Nano-silver Particle Size Testing. Put a Natural dry certain amount of Nano-silver Artemisia argyi onto glass slides, then natural dry and observed by scanning electron microscope.The silver particle size on four different areas is measured, and all the silver particle size was calculated according to the maximum length of particles. The number of particles changed from 200-300, and the particle size is calculated according to equation (1):∑=i i D n D 1（1）Where i D and i n is average particle size and the number of i D .Silk Fabric Finishing. Silk fabric is finished for 60min at 60℃ by the immersion method, the bath ratio is 1:50, dried at room temperature, and then the antibacterial property of finished silk fabric is tested.Testing Fabric Antibacterial Properties. According to the latest national standard GBT 20944.2-2007 textile antimicrobial evaluation part ii: absorption law, the number of bacteria of fabric before and after finishing with nano-silver artemisia argyi are tested, validated the antibacterial property of fabric and Anti-bacterial washes performance, the tested strains were escherichia coli and staphylococcus aureus which are the most representative for gram-negative bacterium and gram-positive bacterium.Antibacterial property of fabric sample is valued with bacteriostatios ratio according to the equation (2):%100%×−=ttt C T C ratio ations bacteriost （2）Where t C and t T is average bacteria number before and after finishing on 3 control fabricsamplers where the bacteria was vaccinated and agar trained for 18 to 24 hours .Results and DiscussionThe Particle Size and Morphology of Silver Nanoparticles in Alkaline Environment. Mixing 5mL, 0.01mol/L of nitric acid silver with 1.5mL of ammonia and add different volume Artemisia argyi extract, then add water and make the total volume reach to 50mL, after pump filter then stay for 24h. The average particle size of silver nanoparticles is showed in Table1. Fig. 1 shows the SEM of silver nanoparticles prepared by the reaction of 5mL nitric acid silver (0.01mol/L) 1.5mL ammonia and 20mL Artemisia argyi extract. Table 1 Silver nanoparticles size preparedthe volume of Artemisia argyi extract [mL] average diameter of silver nano particles [nm]10 48.312.5 36.115 12.017.521.7 20 24.1Fig.1 SEM of silver nanoparticles prepared by the reaction of 5mL nitric acid silverTable 1 show that when mix 15mL Artemisia argyi extract 5mL nitric acid silver (0.01mol/L) and1.5mL ammonia, the silver nanoparticles size is mimum, the average particle size of silver nanoparticles is 12.0nm.Fig.1 shows that silver nanoparticles has small size in alkaline environment, so Artemisia argyi extract not only contains the substances reducing silver ions into elemental silver, but also contains stabilizing agents preventing aggregation from silver nanoparticles within 24h.The Particle Size and Morphology of Silver Nanoparticles in Acidic Environments. When volume of Artemisia argyi extract is remained, the effect of silver ammonia solution concentration on nano-silver particles size is analyzed. Table2 shows the average size of silver nanoparticles particles prepared by 10mL artemisia argyi solution with 1mL different concentrations of silver ammonia solution. Fig. 2 shows the SEM of silver nanoparticles size prepared by the reaction of 1mL silver ammonia solution (0.01mol/L) and 10mL Artemisia argyi extract.Table 2 shows the silver nanoparticles size is the minimum (average particle size of silver nanoparticles is 24.3nm) when mix 10mL Artemisia argyi extract and 1mL silver ammonia solution (0.022mol/L). Compare Fig. 1 and Fig. 2, it shows the silver nanoparticles prepared in acidic environments are easy to aggregate and the silver nanoparticles prepared in alkaline environments has better dispersion.Table 2 Silver nanoparticles size prepared by different concentrations ofsilver ammonia solution and 10mL Artemisia argyi extract.The concentration of solution of silver ammonia [mol*L -1] average particle size of silver nanoparticles [nm]0.012 120.90.017 48.10.022 24.30.027 53.60.03272.1Fig. 2 SEM of silver nanoparticles prepared by the reaction of 1mL silver ammonia solution(0.022mol/L) and 10mL Artemisia argyi extract.Antibacterial Properties of Fabric that is Finished by Nano-silver Artemisia Argyi. According to the latest national standard that is The GBT 20944.2-2007 textile antimicrobial evaluation method of part 2: absorption law , the antibacterial activities against E.coli and S.aureus on fabric were investigated and the results are shown in Table 3. The sample is the fabric that isacid silver and 1.5 mL of ammonia, and then respectively added with 10mL, 15mL, 20mL Artemisia argyi extract.Table 3 Antibacterial properties of fabric finished with Nano-silver Artemisia argyisample Bactericide rate [%] Bactericide washability rate [%]E. coli S. aureus E. coli S. aureusno.1 99.63 99.53 97.51 97.53no.2 99.88 99.81 98.03 97.92no.3 99.76 99.72 97.88 97.60From the Table 3，it is shown that fabric finished with 15mL Nano-silver Artemisia argyi exhibited strong antibacterial activity against E.coli and S.aureus, the sterilized rate over 99.8%. After wash-wear experiment, the fabric finished with nano-silver Artemisia argyi solution still exhibited strong antibacterial activity against E.coli and S.aureus, the sterilized rate over 97.5%. SummaryArtemisia argyi extract can be used for preparation of silver nanoparticles that has small size and uniform dispersion. Silver nanoparticles can be prepared in both alkaline and acidic environment, but the former has better performance. Silk fabric finished by Nano-silver Artemisia Argyi has outstanding bactericide activity against E.coli and S.aureus, The bactericide rate is 99.9% when fabric finished by Nano-silver Artemisia Argyi that prepared by Artemisia Argyi extract and silver ammonia solution (0.022mol/L) whose ratio is 10:1. The silk fabric finished by Nano-silver Artemisia Argyi has excellent antibacterial washability too.AcknowledgementFinancial support for this work was provided by the Science Fund of Guangxi University of Technology (1074015)References[1] Y. T. Ning and H. Z. Zhao: Precious Metal. Vol. 24 (2003), p. 54[2] M. Prashant, R. Nishak and Y. S. Kumar: Nanopart. Res. Vol. 10 (2008), p. 507[3] X. C. Huang, H. Lin and Y. Y. Chen: Silk. Vol. 10 (2009), p. 26[4] J. L. Huang, Q. B. Li and D. H. Sun: Nanotechnology. Vol. 18 (2007), p. 1[5] S. S. Shiv, A. Absar and S. 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