血管支架类生物医用材料系列7--涂层材料

有关Cyanoacrylate基本事实:
1. Made of cyanoacrlate esters, most commonly methyl and ethyl cyanoacrylates; which undergo anionic polymerization in the presence of weak base such as water, and are stabilized by adding a weak acid; in contact with a surface, the water present on the surface neutralizes the acidic stabilizer in the adhesive, resulting in the rapid polymerization;
Water Based Coating Technology

Base Coat Polymers
– are crosslinkable – trap functional compounds – form tight bonding to device surface

Functional Compounds
2.
从材料上分类，涂层可为金属材料（如金、银、钛等）、各种化学物 质（氧化层、药物等）、聚合物（Polymer）、陶瓷（Ceramic）；从属 性上讲有亲水性涂层（Hydrophilic Coating）和厌水性涂层 （Hydrophobic Coating）之分；
有关涂层的基本事实:
3. 涂层加工方法有喷涂法（Spraying）、浸沾法（Dipping）、真空沉淀发 （Vacuum Deposition）、化学或等离子侵蚀发（Chemical or Plasma Etching），热处理法（Heat Treatment）；各种化学涂层可以通过热激 活(Heat curable Coating)或UV光线激活(Photocurable Coating)或等离子 激活(Plasma Actiation)； 4. 选择涂层时应考虑因素: Substrate Friendly, Environmental Friendly, biocompatibility, Functionality, Sterilization, Shelf Life, Easiness to Process and Use.

Development of Medical Devices
– Able to be applied to a wide variety of substrate, including solvent-sensitive materials – No post-coating solvent residue
Types of Lubrication

Boundary Lubrication

Lubricants, fatty acids or long-chain alcohols PTFE, MoS2, BN... Air, other gaseous materials Water or other liquids
– lubricious polymers, PVP, PEO – bioactive agents
Base Coat Polymers


Acrylic Polymers – acrylic acid - ethylene block copolymers Polyurethane Polymers – contain carboxyl groups
第五节 涂层材料
有关涂层的基本事实:
1. 在医疗器械设计中，涂层作为器械与人体组织接触的界面（Interface）而 突显其作用的至关重要；通过改变涂层的种类、成分、结构和属性等，可 以:
1) 2) 3) 4) 5) 加强(Enhance)或抑制(Inhibit)人体对器械的反应（Reactions）； 提高器材的显影性(imaging coatings); 抵抗细菌感染能力(Anti- microbial coating); Anti-thrombogenic (Heparin, protein or peptides); Anti-encrustation of calcification process by modulating surface pH and chemistry; 6) Anti-restenosis; 7) 提高材料的表面硬度； 8） 降低表面摩擦系数；
Lubricity
Static vs. Dynamic Friction
Uncoated - dynamic friction~0.01 Coated - dynamic friction Uncoated - static friction Coated - static friction 0 0.5 1 1.5 2 2.5 3
Functional Compounds



Polymers - PVP, PEO Salts - silver salts Organic Compounds - antibiotics Polysaccharides - heparin Proteins, Polypeptides - growth factors, inhibitors, enzymes, drugs

Solid-Film Lubrication

Fluid-Film Lubrication
பைடு நூலகம்
How does PVP work?


One end bonded to the polymer network & the other end fans out Absorbed water acts as lubricant Prevents materials from adhering to the surface
5. An accelerator applied to the surface prior to the application of the adhesive helps to speed up the cure of cyanoacrylate by reducing cure and fixture times;
Why a Water-Based Formulation ?

Production (Environmentally-Friendly Process)
– No special ventilation facility or X-proof equipment required – Increased worker safety – Easy waste handling

选择粘接剂应考虑的因素



Bond Strength Cure Speed Curing Technology Environment Resistance Thermal Resistance Suitability of Automation Bio- Compatibility Cosmetics Availability Economics
Coefficient of Friction
Coating Process

Plasma pretreatment for some substrates Dip or spray coat of water-based solutio
– Basecoat – Topcoat
Solution Coating Drying/Curing
2. One – part, room-temperature curing adhesive that are available in viscousities ranging from water-thin liquids to thixotrpic gels;
有关Cyanoacrylate基本事实(续)
Plasma Treatment
Oven Reactor Coating Station
Conclusions

Water based coating technology offers medical industry: – cost effective specialty coating to enhance product performance and value – easy and environmentally friendly process – flexibility to incorporate bioactive reagents Applications of water based coating technology has been demonstrated in lubricity enhancement, infection control and blood clotting prevention.
Friction
Soft Material
ADHESION
WEAR
Hard Material
Lubricious Coatings: Benefits in Medical Device Applications



Smooth insertion & removal Reduced patient/tissue trauma Low protein/cell adhesion Reduced bacterial adhesion Controlled release
有关Cyanoacrylate基本事实(续)
5. Advantages: One part system Solvent free Rapid room temperature cure Excellent adhesion to many substrates Easy to dispense in automated systems Wide range of viscosities available Excellent bond strength in shear and tensile Primers available for difficult to bond plastics
5. 亲水层涂层在与水溶液或体液接触后会大大减小摩擦阻力系数,从而减轻 病人的不适感,减小对人体组织的损害,提高器材的可操作性从而降低手术 时间；
Water Based Medical Coating Technology
Overview


Why use a water based coating on medical devices ? Applications – Lubricious – Anti-microbial – Anti-thrombogenic
Why a Water-Based Formulation ?

Formulation
– Stable, not sensitive to temperature or light – Long shelf life – Easy incorporation of compounds or drugs, particularly biomolecules
3. When pressed between two surfaces, cyanoacylates cures rapidly to form rigid thermoplastics with excellent adhesion to most substrates; 4. Available as a wide variety of specialty formulations with properties tailored to meet various applications;
Typical Medical Devices Coated





Catheters - urinary, cardiovascular, neurovascular Stents Guidewires, guiding catheters Stylets, cannulas Endoscopes Hemodialysis equipment Various disposables Diagnostic devices