Trigwell Steve, De Samiran, Sharma Rajesh, Mazumder Malay K, Mehta Jawahar L
Electrostatics and Surface Physics Laboratory, YA-C2-T, Kennedy Space Center, Florida 32899, USA.
J Biomed Mater Res B Appl Biomater. 2006 Feb;76(2):241-50. doi: 10.1002/jbm.b.30359.
A method of encasing cardiovascular stents with an expandable polyurethane coating has been developed to provide a smooth homogeneous inner wall allowing for a confluent growth of endothelial cells. In this design, the metal wire stent structure is completely covered by the polyurethane film, minimizing biocorrosion of the metal (stainless steel or nitinol), and providing a homogeneous surface for surface treatment and incorporation of various eluting drugs to prevent platelet aggregation while supporting endothelialization. The polyurethane surface was treated with a helium plasma for sterilization and promotes growth of cells. The article details the performance of the coated film to expand with the metal stent up to 225% during deployment. Stress/strain behavior of polyurethane films, subsequent plasma treatment of the surface, and the adhesion of the coating to the stent structure upon expansion are presented. A film of less than 25 microm was found to be sufficient for corrosion resistance and flexibility without producing any excess stress on the stent structure. Straining the film to 225% and plasma modification did not affect the mechanical and surface properties, but allowed for improved biocompatibility as determined by the critical surface tension, surface chemistry, and roughness.
一种用可膨胀聚氨酯涂层包裹心血管支架的方法已被开发出来，以提供一个光滑均匀的内壁，使内皮细胞能够融合生长。在这种设计中，金属丝支架结构被聚氨酯膜完全覆盖，最大限度地减少了金属（不锈钢或镍钛合金）的生物腐蚀，并为表面处理和掺入各种洗脱药物提供了一个均匀的表面，以防止血小板聚集，同时支持内皮化。聚氨酯表面用氦等离子体处理以进行灭菌并促进细胞生长。文章详细介绍了涂层薄膜在展开过程中与金属支架一起膨胀至225%的性能。介绍了聚氨酯薄膜的应力/应变行为、随后的表面等离子体处理以及涂层在膨胀时与支架结构的附着力。发现小于25微米的薄膜足以实现耐腐蚀性和柔韧性，而不会在支架结构上产生任何过大的应力。将薄膜拉伸至225%并进行等离子体改性不会影响其机械性能和表面性能，但通过临界表面张力、表面化学和粗糙度测定，其生物相容性得到了改善。
