细菌硒纳米球组装过程

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纳米硒制作过程

纳米硒制作过程
纳米硒制作过程可以分为以下步骤：
1. 基础材料的准备：需要准备纯度高的硒粉和合适的溶剂。

常用
的溶剂有水、丙酮、乙醇等。

2. 溶解硒粉：将硒粉放入溶剂中，通过搅拌和加热等方法，将硒
粉完全溶解，得到硒离子溶液。

3. 加入还原剂：将还原剂加入硒离子溶液中，例如聚乙烯吡咯烷
酮 (PVP)、次氯酸钠等，还原剂可以将硒离子还原成纳米硒颗粒。

4. 搅拌混合：加入还原剂后，需要进行搅拌混合，促进还原反应
的进行。

5. 沉淀分离：还原完成后，将纳米硒颗粒沉淀下来，分离出溶液。

6. 洗涤干燥：将分离出来的纳米硒颗粒进行洗涤干燥处理，得到
最终的纳米硒产品。

需要注意的是，在制备过程中要控制反应条件，例如溶剂的选择
和温度、pH值等，以获得纯度高、粒径均一的纳米硒产品。

同时，生
产过程中要注意安全和环保，避免对环境和人员造成危害。

硒纳米胶囊的制备工艺

硒纳米胶囊的制备工艺
硒纳米胶囊的制备工艺主要包括以下几个步骤：
1. 材料准备：准备硒纳米粒子的原材料，如硒化合物、表面活性剂等。

2. 溶剂选择：选择合适的溶剂，通常是有机溶剂，如石油醚、苯等。

3. 溶液制备：将硒化合物加入溶剂中，通过搅拌等方式使其充分溶解。

4. 催化反应：将溶液加热，引入催化剂，使硒化合物发生还原反应生成硒纳米粒子。

5. 表面修饰：根据需要，可以在硒纳米粒子表面引入功能化基团，以改变其性质。

6. 胶囊化处理：将硒纳米粒子与适当的胶体材料混合，通过一定的工艺使硒纳米粒子包裹在胶体中，形成硒纳米胶囊。

7. 分离与纯化：将制备好的硒纳米胶囊进行分离与纯化，去除杂质，得到纯净的硒纳米胶囊。

8. 测定与评价：对制备好的硒纳米胶囊进行测定与评价，包括颗粒大小、稳定
性、释放性能等。

需要注意的是，具体的制备工艺会根据实际情况和需要进行调整和优化。

一种球形硒纳米颗粒及其制备方法[发明专利]

专利名称：一种球形硒纳米颗粒及其制备方法专利类型：发明专利
发明人：王震宇,王传洗,乐乐,曹雪松
申请号：CN202011043553.7
申请日：20200928
公开号：CN112010271B
公开日：
20220325
专利内容由知识产权出版社提供
摘要：本发明公开了一种球形硒纳米颗粒及其制备方法，属于纳米材料制备技术领域。

本发明采用了低热固相法，利用不同Se源和不同还原剂，先快速合成Se纳米颗粒，后期在超声和表面修饰剂作用下，合成不同表面修饰剂修饰的Se纳米颗粒，并采用离心分离法分离产物，最终得到不同尺寸的球形Se纳米颗粒。

超声的作用是为了使实验产物成核速度加快，成核数目增加，颗粒粒径减小。

本发明在后期加入表面修饰剂，一是为了让前期的产物形成过程更加充分彻底，二是为了在形成的产物表面进行修饰，使其带不同电荷，带有不同电荷的颗粒在进入生物体的难易程度不同，中性和负电荷更容易进入生物体产生作用。

申请人：江南大学
地址：214000 江苏省无锡市滨湖区蠡湖大道1800号
国籍：CN
代理机构：哈尔滨市阳光惠远知识产权代理有限公司
代理人：林娟
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自组装空心纳米球的制备

Synthetic Metals156(2006)357–369The azanes:A class of material incorporating nano/micro self-assembled hollow spheres obtained by aqueous oxidative polymerization of aniline Everaldo C.Venancio a,Pen-Cheng Wang a,A.G.MacDiarmid a,b,∗a Department of Chemistry,University of Pennsylvania,Philadelphia,PA19143,USAb Alan G.MacDiarmid Laboratory for Technical Innovation,Department of Chemistry,The University of Texas at Dallas,Richardson,TX75083,USAReceived18April2005;received in revised form23August2005;accepted29August2005Available online20February2006AbstractThe nature of the product of the“conventional”aqueous oxidative polymerization of aniline by ammonium peroxydisulfate and HCl is extremely sensitive to the pH of the polymerization system.This is observed when the concentrations of reagents are sufﬁciently dilute(at a pH of3–4)to isolate theﬁrst-formed product of the reaction which we believe is a member of the class of azanes,polymeric or oligomeric species containing a N N backbone in which each N atom is forming three covalent single bonds.The brown solid isolated has been characterized by its elemental analysis, UV–vis,FTIR,and1H NMR spectra.We believe,in the simplest case,it may be an organic-substituted hexa-azane.It is completely different in every way from any known form of“polyaniline”,in any oxidation state,of any degree of protonation.It is isolated as hollow microspheres(diameter,∼1.5–6␮m),which have an essentially identical SEM appearance to hollow microspheres previously ascribed to conventional polyaniline.As the pH of the reactant system falls during the polymerization,polyaniline in its conventional forms begins to be formed;however,especially if the pH is held constant by a buffer solution,the pure azane can be isolated.We believe the azanes open up a newﬁeld of self-assembled nano/micro particles of very considerable potential applicability to the emergingﬁeld of nanoscience.©2006Elsevier B.V.All rights reserved.Keywords:Aniline;Azanes;Self-assembly;Nano/micro hollow spheres1.IntroductionIn view of the increasing activity in nano/micro science/ technology during the past few years,it is of interest to re-examine and build upon earlier observations of organic poly-mers,which were of much of interest in the past primarily because of their unusual electronic properties[1,2].The sen-sitivity of the type of nano/micro morphology on the synthetic method employed including variation in pH[3]opens up a vast unexplored potentialﬁeld,which has not as yet been tapped. For example,chemical and/or electrochemical synthesis of an electroactive polymer,such as polyaniline,alone yields a wide variety of materials depending on the pH of the system[4] and morphologies ranging from theﬁrst reported synthesis of nanoﬁbers of polyaniline[5]to the dependency of the nucleation step and resulting morphology on the nature of the counter ion ∗Corresponding author.Tel.:+12158988307;fax:+12158988378.E-mail address:macdiarm@(A.G.MacDiarmid).[6],to the chemical synthesis of polypyrrole which can yielda matte-likeﬁlm[7,8]or nanospheres(diameter25–125nm) [7,8].Indeed it is not unlikely that the nucleation step may well dictate the subsequent nanoscience,and may be dependent on the presence of dust and related nucleation-inducing suspended particulate matter[9],as for example,in“seeding”to produce nanoﬁbers of polyaniline,polypyrrole[10].The present study reported here involves only one small step involving particles of self-assembled nano/micro spheres derived from the oxidative polymerization of aniline.We believe the spheres are composed of members of the class of polyazanes,little studied material containing N N single bonds in the polymer backbone[11].During the past20years much excellent research has been carried out world-wide on“polyaniline”—its chemical and elec-trochemical synthesis,characterization and electronic,mag-netic,optical,and related properties[12].Polyaniline and its derivatives have attained considerable world-wide importance principally because of their unique set of electronic proper-ties.From the present study it seems highly likely that in the future new products of the oxidative polymerization of aniline0379-6779/$–see front matter©2006Elsevier B.V.All rights reserved. doi:10.1016/j.synthmet.2005.08.035358 E.C.Venancio et al./Synthetic Metals 156(2006)357–369may claim considerable importance not because of their elec-tronic properties but because of their contribution to the ﬁeld of nano/micro science and potential future technology.To understand the importance of aniline in the ﬁeld of azanes it is highly desirable to appreciate some of the key aspects of the “polyanilines”—the most highly studied material obtained by the oxidative polymerization of aniline.The base forms of the polyanilines contain only N C and C C (covalent)aromatic bonds as shown below.The base form of polyaniline,which has the generalized com-position[12]consists of alternating reduced and oxidized repeatedunitsThe terms “leucoemeraldine”,“emeraldine”and “pernigrani-line”refer to the different oxidation states of the polymer where y =1,0.5,and 0,respectively,either in the base form,for exam-ple,emeraldine base,or in the protonated “salt”form,for exam-ple,emeraldine hydrochloride.In principle,the imine nitrogen atoms can be protonated in whole or in part to give the corre-sponding salts,the degree of protonation of the polymeric base depending on its oxidation state and on the pH of the aqueous plete protonation of the imine nitrogen atoms in the emeraldine base by aqueous HCl,for example,results in the for-mation of the hydrochloride “salt”accompanied by an increase in conductivity of about 1010[13,14].Polyaniline of the above emeraldine type of structure is eas-ily synthesized by the chemical (or electrochemical)oxidative polymerization of aniline in aqueous solution,the most com-mon method,based with many modiﬁcations on our original method [5,15],employs ammonium peroxydisulfate as the oxi-dizing agent.Sulfuric acid is produced during the reaction as shown by Scheme 1below and hence the polymerizationsystembecomes more acidic during the course of the polymerization [12,16].For simplicity the process in Scheme 1is divided into two hypothetical parts—Part A:polymerization;Part B:protona-tion by the H 2SO 4produced or by any other acid that has been added to the polymerization system.It should be noted that the quantity of acid formed during the polymerization step signif-icantly exceeds the amount of acid required in the protonation step—hence,a net increase in acid concentration duringpoly-Scheme 1.Release of acid during polymerization of aniline by (NH 4)2S 2O 8(A −is an anion of appropriate charge).E.C.Venancio et al./Synthetic Metals156(2006)357–369359merization should be expected.In view of the variety of synthetic conditions which have been described[3,10,17–22]using differ-ent reagents,different absolute concentrations of reagents and different molar ratios of reagents,homogeneous and heteroge-neous(interfacial)polymerization and different dopant acids, and different derivatives of aniline,etc.,it is not necessarily sur-prising that,as we stated in an earlier paper[23]“—there are as many different types of polyaniline as there are people who make it!”.Previous studies strongly suggests that in order for oxidative coupling to occur to form C N bonds as found in“polyaniline”it is necessary to have a sufﬁciently low pH in the reaction system to give meaningful protonation of the aniline[16].Complex aro-matic rearrangements may also occur under acidic conditions. It is well known that relatively high pH values promote simple oxidative polymerization of N H bonds on adjacent molecules to give,for example,the large well-known class of hydrazines containing a N N single bond[11,24–28].Essentially every variation of synthetic method of polyani-lines will result in a different initial pH of the reaction system. To the best of our knowledge there have been few studies of the effect of pH on the oxidative polymerization of aniline [4,29].Electrochemical studies show the nature of the prod-ucts is dependent on the pH of the system[4].The results of a calorimetric/pH study[29]show that two different polymeriza-tion reactions involving aniline occur depending on the pH of the reaction system.Even cursory examination of the literature shows the impor-tance of pH on the nature of the product obtained by the aqueous oxidative polymerization of aniline.It should be stressed that using a weak protonic acid in place of a strong acid such as HCl at the same concentration,is expected to result in a H+concen-tration several orders of magnitude lower,resulting in a higher pH of the reaction system.Recent observations[3]show that as the concentration of HCl is decreased,i.e.higher pH,the relative concentration of granular products of polyaniline increases and ﬁnally prevails over nanoﬁber formation.A series of papers[18]and a very recent study involving addition of sodium hydroxide(NaOH)describes the forma-tion of a product containing“—...polyaniline(PANI)hollow microspheres...the emeraldine base form of PANI...”and “—multi-morphology of polyaniline,such as nanotubes,micro-grains and solid micrograins,were obtained by just changing the An/NaOH”[20].In view of the complex nature of the oxidative polymerization of aniline,we do not wish to dispute the reported chemical nature of the spheres but under our experimental con-ditions we believe the essentially pure spheres we obtained were not mixed with conventional polyaniline and that they are not polyaniline in any of its known“PANI”forms but instead consist of an azane material containing N N single bonds.Indeed an examination of the UV–vis spectrum of the material reported in the above very recent[20]paper suggests to us that the material obtained probably consisted of a mixture(in varying propor-tions)of hollow microspheres,nanotubes,and micrograins.We expect that a collaborative interaction between the authors of the above paper and ourselves will solve this important and complex problem.We propose that the nature of the product obtained by the oxidative polymerization of aniline depends critically on the pH of the reaction system.From our preliminary studies at higher pH values than commonly used in the aqueous synthesis of“polyaniline”using aniline,hydrochloric acid,and ammo-nium peroxydisulfate,weﬁnd that the solid product isolated is completely different in chemical composition,spectroscopic properties,and morphology from the“polyaniline”obtained using the same reagents at the usual lower pH value of∼0[12]. Instead we obtain a yellowish brown solid which appears to belong to the azane class of material containing a backbone of N N single bonds in which each N atom is forming three single covalent bonds.The material is obtained in the form of microspheres.2.Experimental2.1.“Falling pH Method”2.1.1.Synthesis of microspheres using the“Falling pH Method”An aqueous polymerization bath of0.010M aniline in the presence of0.010M ammonium peroxydisulfate(APS)and 0.010M hydrochloric acid was prepared by adding10mL of 0.02M aniline aqueous solution in0.010M hydrochloric acid to a30mL glass beaker under mild magnetic stirring(no vortex), followed by the addition of10mL of the0.020M ammonium peroxydisulfate aqueous solution in0.010M hydrochloric acid. This(total volume of reactant solution,20mL)was assumed as being the beginning of the polymerization reaction,i.e.time t=0.Stirring was stopped after5min and then aliquots of 3mL of the polymerization bath were transferred via a plas-tic syringe toﬁve12-mL glass vials that had been rinsed with high purity water(MarCor Filtering System,MarCor Co.).The vials were sealed with polyethylene caps and labeled as vial number1,vial number2,vial number3,vial number4,and vial number5,respectively.The pH(pH paper)of the con-tents of each vial was determined and was plotted as a function of time in Fig.1.After22h(pH3.0),7mL of1.0M ammo-nium hydroxide aqueous solution was added to vial number1 in order to quench the reaction resulting in a yellowish brown colored aqueous dispersion of product.The contents of vial1 were transferred to a2.5cm×10cm segment of dialysis tubing (Spectra/Por tubing,12–14,000mol wt.cutoff)and were then placed in a bottle containing1L of deionized water and a mag-netic stir bar.The dialysis bath was kept under mild magnetic stirring and it was changed six to seven times over the course of24h.The pH of the water(pH paper)remained essentially constant after24h.The dispersion in the dialysis tubing was then transferred to a12mL glass vial that had been rinsed previously with high purity water,and was then sealed with a polyethylene cap.The materials formed in vials2–5,were treated in similar manner after∼49,∼72,∼102,and∼171h, respectively.It should be noted that by using the experimental condi-tions described above and in Fig.1,the color change pattern observed during the polymerization reaction was different from360 E.C.Venancio et al./Synthetic Metals156(2006)357–369Fig.1.“Falling pH Method”:Change in pH as a function of time of an aqueous polymerization solution containing0.010M aniline,0.010M ammonium per-oxydisulfate and0.010M hydrochloric acid at room temperature(∼25◦C,no stirring).Note:Absolute concentrations:aniline=HCl=APS=0.010M;molar ratios,aniline:HCl:APS=1.0:1.0:1.0.that reported for polymerization of aniline using conventional synthesis[15].In other words,using the experimental con-ditions described above,the“Falling pH Method”(Fig.1),a color change pattern from light yellow to yellow to yellowish brown and then to a yellowish brown precipitate were observed, from t=0to22h.After t=49h,the amount of precipitate had increased and became dark green in color.2.1.2.UV–vis studiesApproximately2mL of the dispersion in vial1(22h)and vial5(171h)were removed by a Pasteur pipette and were trans-ferred to two different test tubes and centrifuged for7min. The supernatants were removed by a Pasteur pipette and then 5mL of N-methyl-2-pyrrolidone(NMP)(Aldrich)was added to the wet precipitate.The tubes were then shaken for40s.A yellowish brown solution was obtained.This was then diluted with an additional∼6mL of NMP.The UV–vis spectrum was obtained with a Perkin-Elmer Lambda9spectrometer using quartz curvettes(1cm path length).NMP was used in the ref-erence beam.The UV–vis spectrum from vial1as shown in Fig.2has a strong␲–␲*peak at272nm,a medium␲–␲*peak at377nm,and a very weak n–␲*absorption at∼552nm.The spectrum was compared with other possible compounds such as of1,2-diphenylhydrazine[30],azobenzene[30],benzidine[30], and also with28substituted quinone compounds[30].The spec-trum is very different from that of1,2-diphenylhydrazine[30], azobenzene[30],and benzidine[30].The spectrum in Fig.2is consistent with the proposed substituted quinones(strong␲–␲* peak centered at250–314nm,a medium␲–␲*peak centered at 308–398nm,and in some cases,a weak n–␲*band centered at 424–525nm).The spectrum in vial5is given in Fig.3,and as can be seen from Fig.2it is consistent with a mixture of emeral-dine base(Fig.3)and the new compound(microspheres;Fig.1, pH3.0)parison of UV–vis spectrum of the NH4OH-treated material(pH 3.0)prepared using the“Falling pH Method”(Fig.1)(vial1,22h)with theλmax of28substituted benzoquinones[29].Note:The numbers inside each“()”refer to the number of reports from the28substituted quinones(absorption intensity: s,strong;m,medium;w,weak).2.1.3.Morphological characterization—SEM studiesThree drops of the dispersion from vial1(22h)and vial5 (171h)prepared as described in Section2.1.1were deposited drop-wise on separate small segments of a glass microscope slide that had been rinsed with acetone and nitrogen gas-dried. The solvent evaporated in air.The samples were then attached to aluminum sample stubs using double-sided carbon tape.Elec-trical contact was maintained between the sample surface and the aluminum stub with a short strip of copper tape.All sam-ples were vacuum sputtered coated with a gold–palladium alloy prior to imaging on a JEOL6300FVﬁeld emission scanning electron microscope,operating at an accelerating voltage of 5kV.Average dimension of the nano-and micro-structures were measured on randomly chosen structures at several regionson Fig.3.UV–vis spectrum(solid line)of the NH4OH-treated material(pH3.0) prepared using the“Falling pH Method”(Fig.1)(vial2,171h);solvent:N-methyl-2-pyrrolidone(NMP).UV–vis spectrum(dotted line,this study)of commercial polyaniline emeraldine base(Aldrich Co.).E.C.Venancio et al./Synthetic Metals156(2006)357–369361Fig.4.SEM image of the NH4OH-treated material(pH3.0,Fig.1)prepared using the“Falling pH Method”(vial1,22h).Average diameter:1.5–6␮m (arrows show possible the holes or joining of the microspheres).each sample.All measurements were made on images obtained at1000–30,000×magniﬁcation(using standard imaging soft-ware).The SEM image obtained from vial1(22h)is given in Fig.4,which shows only microspheres.Other3000×magniﬁca-tion SEMs show traces of granular/ﬁbrilar materials.The SEM image obtained from vial5(171h)is given in Fig.5,which shows mainly granular/ﬁbrillar structures,the major product, mixed with a few microspheres.It should be noted that these low magniﬁcation SEM studies in which a large sample is viewed show that granular/ﬁbrillar material is the main product of the reaction after171h.In addition,the results shown in Figs.1–3,5 suggest that the microspheres might possibly be coated with con-ventional polyaniline,the microspheres acting as a substrate!rge quantity sample preparation2.1.4.1.Ammonium hydroxide-treated sample—“Dedoped”sample.A large quantity sample was prepared in a manner identical to that described in Section2.1.1except that the total volume of reaction solution was increased to600mL.To ensure good mixing the reactant solution was poured backwards and forwards several times between two beakers.Immediately after mixing(i.e.t∼0)3mL of the reactant solution was removed from the600mL for observation purpose and was then trans-ferred to a vial,and covered with a polyethylene cap.After 18h the3mL of the polymerization mixture was quenched with aqueous NH4OH as described previously in Section2.1.1.At the same time,the remaining∼597mL of reactant solution was quenched by the addition of100mL of1.0M aqueous NH4OH,was well mixed and thenﬁltered.The precipitate was collected on a Buchner funnel by using aﬁlter paper(4.25cm in diamater,particle retention>2.5␮m,Whatman number5, Whatman–Fisher Sci.Catalog No.09-830G).Theﬁlter paper containing the precipitate was then transferred to a600mL glass beaker containing150mL of0.10M aqueous ammonium ing plastic forceps,theﬁlter paper was carefully shaken inside the0.10M ammonium hydroxide aqueous solu-tion until all precipitate fell off theﬁlter paper.Theﬁlter paper was then carefully removed from the beaker.The beaker was then shaken by hand for30s,resulting in a suspension of prod-uct in the0.10M ammonium hydroxide solution.This process was repeated two more times.The precipitate was thenﬁltered and theﬁlter paper containing the precipitate was transferred to a glass Petri dish(5.5cm in diameter)covered with weighing paper(Fisherbrand,Cat.No.09-898-12B)containing several punched holes.It was then placed inside a dessicator and dried under dynamic vacuum(mechanical pump)at room temperature for24h.After24h,the Petri dish containing theﬁlter paper and the precipitate was removed from the dessicator.The precipi-tate was then transferred to a12mL glass vial and sealed with a polyethylene cap.The vial and content were stored inside a desiccator containing desiccant.2.1.4.2.Elemental analysis(C,N,H,Cl).A carbon,hydro-gen,nitrogen and chlorine elemental analysis was performed on part of the sample described in Section2.1.4.1,with the fol-lowing results(wt.%):C=67.63;H=4.52;N=11.08;Cl=0.0; O=16.77(by difference).2.1.4.3.FTIR studies.Material for a FTIR spectrum was taken from the material obtained in Section2.1.4.1.FTIR(KBr pel-let)studies were carried out by using a Bomem(M102)FTIR spectrometer.The spectrum(Fig.6)exhibits absorptions at 3237cm−1(N H stretching bonded to carbonyl)[31].Thepeak Fig.5.SEM image of the NH4OH-treated material(pH1.9,Fig.1)prepared using the“Falling pH Method”(vial5,171h).362 E.C.Venancio et al./Synthetic Metals 156(2006)357–369Fig.6.Fourier transform infrared (FTIR)spectrum (pH 3.0,Fig.1)of the NH 4OH-treated material prepared using the “Falling pH Method”(600mL sample,18h).Assignments [30]:(a)N H;(b)C H (aromatic);(c)aromatic ring;(d)C N stretching;(e)C O,(f)N N stretching (absorption intensity:s,strong;m,medium;w,weak).at 3055cm −1is assigned to C H stretching (aromatic ring).The peak at 1640cm −1is assigned to a carbonyl group (C O).The peaks at 1508and 1445cm −1are assigned to C C stretching vibrations.The peak at 1571cm −1is consistent with a carbonyl group (C O)or C C stretching vibrations [31].The peaks at 1354,1287,1232,1185,1077,and 1041cm −1are consistent with N H bending,C N and C C stretching [31].The peaks at 895,858,759,742,726,694,and 592cm −1are consistent with C C and C H bending (aromatic ring)[31].In addition,a careful examination of the FTIR spectrum presented in Fig.6shows that the peaks at 1450cm −1and around 1040–1070cm −1are also consistent with the presence of N N single bonds [4,31].2.1.4.4.1H NMR studies.The proton (1H)nuclear magnetic resonance (1H NMR)spectrum was measured by a NMR spec-trometer (Bruker,model AMX 500,500MHz).The sample,prepared as described in Section 2.1.4.1,was dissolved in deuter-ated dimethyl sulfoxide (DMSO-d 6)(Aldrich)and TMS was used as a reference.The 1H NMR spectrum is given in Fig.7.The signals centered at δ5.74ppm (H d ,H e ,H f ,H d ,H e ,H f)and at δ6.23ppm (H g ,H h )are consistent with the presence of substituted 1,4-parabenzoquinones [31].The signals centered atδ6.96,7.18,and 7.42ppm (H a ,H a ,H b ,H b ,H c ,H c;multiplets)are benzenoid aromatic protons [31].The signal at δ8.56ppm (H N ;singlet)is consistent with amine proton due to the presence of a R 2N H group [32].The signals at δ9.04,9.13,9.23and 9.29ppm (H O )are characteristic of protons hydrogen-bonded to a carbonyl group (C O ···H R ),where R could be a R 2N-group [31].2.1.4.5.Hydrochloric acid-treated sample—“Doped”sample.The experiment described in Section 2.1.4.1was repeated except that it was not treated by the addition of the 100mL of 1.0M NH 4OH.After 18h the 597mL of the reactant solution was ﬁltered.The precipitate was collected on a Buchner funnel by using a ﬁlter paper (4.25cm in diameter,particle retention >2.5␮m,Whatman number 5,Whatman–Fisher Sci.Catalog No.09-830G).The ﬁlter paper and the precipitate were then transferred to a 600mL glass beaker containing 150mL of 0.010M hydrochloric acid aqueous ing plastic for-ceps,the ﬁlter paper was carefully shaken inside the 0.010M HCl aqueous solution until all precipitate fell off the ﬁlter paper.The ﬁlter paper was then carefully removed from the beaker.The beaker was then shaken for 30s,resulting in a suspension of polymerized aniline in the 0.010M HCl.This process was repeated two more times.The ﬁlter paper con-taining the precipitate was then transferred to a glass Petri dish (5.5cm in diameter).It was then dried under dynamic vacuum (mechanical pump)and stored as described in Sec-tion 2.1.4.1.The chlorine content only was determined to be 0.36wt.%(Schwarzkopf Microanalytical Lab.,Woodside,NY ,USA).2.1.5.Summary of the results from the “Falling pH Method”Experimental results from the elemental analysis (C,N,H,and Cl)and spectroscopic studies (UV–vis,FTIR,and 1H NMR)are all approximately consistent with,but do not necessarily prove,the suggested azane or polyazane chemical composition of the microspheres of the polymerized anilineE.C.Venancio et al./Synthetic Metals156(2006)357–369363Fig.7.1H NMR spectrum of the NH4OH-treated material(pH3.0,Fig.1)prepared using the“Falling pH Method”;solvent:deuterated dimethylsulfoxide(DMSO-d6). (a–e)Possible chemical groups present in the azane material structure.which contain these different chemical groups.These groups are:(A)N-substituted-1-aminobenzene,(B)2-amino-1,4-parabenzoquinone,and(C)1,4-parabenzoquinone(Fig.8). Two hydrogen atoms are kept as the constant end groups while the number of middle groups,A–C,are varied.These chemical groups can be combined in such way to satisfy the criteria given in Table1.It should be stressed that in these preliminary studies the oxygen content was obtained by difference.As can be seen from Table1,our present analytical data agree best with a structure where A=B=3and C=1(Table1),i.e.the structure given in Fig.8(b).In the simplest case(n=1),there are six nitrogen atoms all joined to each other by N N single bonds,i.e.a hexa-azane.The calculated elemental composition Table1Possible speciﬁc composition of the azane material(Fig.8)prepared using the “Falling pH Method”(Fig.1;pH3.0)A B C C:N ratio C:O ratio From experimental elementalanalysis7.1 5.4Calculated a for chemical structure given in Fig.8Structure1(C42N6O8H27)33142:6=7.042:8=5.3 Structure2(C48N7O10H30)34148:7=6.948:10=4.8 Structure3(C54N8O10H35)44154:8=6.854:10=5.4 Structure4(C60N9O12H39)45160:9=6.860:12=5.0 a Two hydrogen atoms are kept as the constant end groups while the number of middle groups,A–C,are varied(Fig.8(a)).Fig.8.(a)General chemical structure of azane material synthesized using the “Falling pH Method”(see Fig.1).The suggested values for A–C,are presented in Table1.(b)a possible proposed structure of the material obtained at pH3.0 both by the“Falling pH Method”and by use of a buffer at pH3.0.364 E.C.Venancio et al./Synthetic Metals156(2006)357–369 Table2Experimental and calculated weight percentage composition of the azane mate-rial prepared by using the“Falling pH Method”(see Fig.1)C (wt.%)H(wt.%)N(wt.%)Cl(wt.%)O(wt.%)(bydifference)Experimental a67.63 4.5211.080.016.77 Calculated67.83 3.6611.300.017.21 Structure1(see Table1):A=3;B=3;C=1(also see Fig.10).a Schwartzkopf Microanalytical Lab,Woodside,New York.is the same for all values of n.In view of the good agreement of all the different types of experimental data(Tables2and3) with the proposed structure(Fig.8(b))it is highly likely that it is not composed of a physical mixture of species of the type shown in Fig.8(a).The hollow sphere morphology(Fig.4) may be caused by pre-existing optimum bond angles and steric requirements suited to such a structure.2.2.Synthesis using buffer systems2.2.1.Citrate/phosphate buffer aqueous solution at pH3.0The citrate/phosphate buffer aqueous solution[33]at pH 3.0was prepared by mixing80mL of0.1M aqueous solution of citric acid and20mL of0.2M dibasic sodium phosphate (Na2HPO4)aqueous solution.The0.10M aqueous solution of citric acid aqueous solution was prepared by placing3.84g of citric acid anhydrous in a200mL glass volumetricﬂask.Then high purity water was added to the volumetricﬂask up to a total volume of200mL.It was then shaken by hand for1min. The0.20M Na2HPO4aqueous solution was prepared by plac-ing2.84g of Na2HPO4anhydrous in a100mL glass volumetric ﬂask.Then high purity water was added to the volumetricﬂask up to a total volume of100mL.It was then sonicated for1.5min. The pH of the resulting buffer solution was conﬁrmed by usinga pH paper.2.2.2.Synthesis of polymerized aniline usingcitrate/phosphate buffer at pH3.0The synthesis of the azane using buffer at pH3.0was carried out as described in the“Falling pH Method”(Section2.1.1,abso-lute concentrations:aniline=0.010M,APS=0.010M;molar ratio,aniline:APS=1.0:1.0),where the total volume of reactant solution was20mL,except that:(i)the citrate/phosphate buffer solution at pH3.0was used instead of the0.010M hydrochloric acid aqueous solution,and(ii)samples were taken at two dif-ferent polymerization reaction times,i.e.at∼24h(vial1)and Table3Experimental and calculated atomic composition of the azane material prepared by using the“Falling pH Method”(Fig.1)C H N Cl O(by difference) Experimental 5.63 4.480.790.0 1.05 Calculated 5.25 3.380.750.0 1.00Structure1(see Table1):A=3;B=3;C=1(also see Fig.10).Fig.9.UV–vis spectrum(solid line)of the NH4OH-treated azane material pre-pared using citrate/phosphate buffer system at pH3.0(vial1,24h);solvent: N-methyl-2-pyrrolidone(NMP).UV–vis spectrum(dotted line,this study)of commercial polyaniline emeraldine base(Aldrich Co.).∼51h(vial2),respectively.The pH of the buffered reaction solution was measured at the beginning(t=0)and after24h (vial1)and after51h(vial2).The pH values were constant and equal to3.0(pH paper).After it had been treated with7mL of 1.0M NH4OH aqueous solution and dialyzed,the contents of each vial were transferred to separate vials and which were then sealed with a polyethylene cap as described for the“Falling pH Method”(Section2.1.1).2.2.2.1.UV–vis studies.UV–vis studies on the sample described in Section2.2.2(vial1,24h)were carried out exactly as described in Section2.1.2.The UV–vis spectrum is shown in Fig.9.It was identical to that described in Fig.2(vial1,22h) obtained by the“Falling pH Method”.It is clearly very different from the spectrum of the emeraldine base form of polyaniline obtained by the(NH4)2SO4/HCl/C6H5NH2polymerization of aniline(see Fig.9).2.2.2.2.Morphological characterization—SEM studies.SEM studies were carried out on the sample described in Section 2.2.2(vial1,24h,vial2,51h)exactly as described in Sec-tion2.1.3.The SEM images obtained from vial1(24h)con-sisted mainly of microspheres and possible agglomerates of microspheres as shown in Fig.10(a).Fig.10(b)is at a higher magniﬁcation than Fig.10(a)and it is taken from a location different from that of Fig.10(a).The SEM obtained from vial2(51h)is shown in Fig.11.The very low magniﬁcation (550×)clearly shows that the material consists essentially only of spheres.Noﬁbrillar or granular species are apparent.The insert to Fig.11(a)shows a free-standingﬁlm of the product that had come displaced from the walls of the reaction vessel. These SEM results show that the microspheres are identical in appearance to those obtained using the“Falling pH Method”(Fig.4).。

细胞合成硒纳米

细胞合成硒纳米粒子的方法主要利用微生物细胞，如细菌、真菌或藻类等。

这些微生物细胞在含有硒酸盐的培养基中培养，通过细胞表面的硒酸还原酶催化还原硒酸盐，生成纳米尺度的硒颗粒。

以下是细胞合成硒纳米粒子的具体步骤：
1.选择合适的微生物细胞，例如大肠杆菌或硅藻等，并进行预培养。

特定的过氧化物酶阳
性菌株可以加速纳米硒的产生。

2.制备含有硒酸盐的培养基，通常硒酸盐的浓度为0.1-5mm。

3.将微生物细胞接种在含硒基质的培养基上，按照常规方法进行培养。

细菌富硒代谢及生物活性的研究进展

细菌富硒代谢及生物活性的研究进展作者：刘昊张宇靖李婧祎拓晓宏来源：《北京联合大学学报》2020年第04期[摘要] 硒是人和動物代谢所必需的微量元素，具有抑癌抗癌、抗自由基、解除重金属中毒、提高机体免疫力、延缓衰老、维持正常细胞功能等作用。

富硒微生物能通过生物转化将无机硒转变为纳米硒，这种纳米硒生产过程具有成本较低、硒浓度高、生物利用率高、环境污染小等优势。

细菌硒纳米颗粒具有独特的硒原子排列，不同于化学合成纳米硒的结构、理化和光电特性，已经在新一代光电、生物化学传感器上进行了开发利用;同时纳米硒颗粒作为药物载体和富硒菌及纳米硒颗粒具有的抗菌、抗氧化、抗金属毒性、抗肿瘤和调节免疫作用的生物活性受到广泛的关注。

[关键词] 富硒菌;富硒代谢途径;纳米硒;生物活性[中图分类号] O 613.52 [文献标志码] A [文章编号] 1005-0310（2020）04-0071-08Abstract： Selenium （Se），an essential trace element across the tree of life， plays a significant role in the metabolism of human and animal life. Selenium is known to be capable of a range of functions， including anti-cancer， anti-free radical， improving immunity， anti-aging，relieving heavy metal poisoning， maintaining normal cell function and so on. Selenium-enriched microorganisms convert inorganic selenium into SeNp through biotransformation with the advantagesof lower cost， higher bioavailability， higher selenium content， and less environmental pollution. The selenium nanoparticles synthesized by selenium-rich bacteria have complex and unique selenium atom arrangement， which gives it unique structural， physical， chemical and photoelectric properties different from chemical synthesis， and have been developed and utilized in a new generation of photoelectric and biochemical sensors. Selenium nanoparticles have been increasingly attracting the attention of researchers over the recent years， one of the reasons is Selenium nanoparticles as a drug carrier and meanwhile selenium-enriched bacteria and Selenium nanoparticles have been widely concerned with the biological activities of antibacterial， anti-oxidation， anti-metal toxicity， anti-tumor and immune regulation.Keywords： Selenium-enriched bacteria; Selenium-enriched metabolism; Nano-selenium particles; Bioactivity0 引言富硒微生物通过生物转化把无机硒转变成纳米硒，具有成本较低、生物利用率较高、硒含量较高、对环境污染小等优势，富硒菌生物转化得到的纳米硒相比于无机硒的毒性更小，安全性更高，也易被机体吸收，同时纳米硒颗粒作为药物载体和富硒菌及纳米硒颗粒具有的抗菌、抗氧化、抗金属毒性、抗肿瘤和调节免疫作用的生物活性受到广泛的关注。