ENHANCED BIOADSORPTION CHARACTERISTICS OF A UNIQUELY NANOSTRUCTURED THIN-FILM

At the two previous AVS symposia we reported on both the growth mechan ism and the structural characteristics of a uniquely nanostructured or ganic thin film consisting of an extremely dense (similar to 50/mu m(2 )), random array of crystalline whiskers (similar to 50 nmx2 mu m), un iformly oriented with their long axes normal to the substrate. We have found that by simply metal coating the whiskers, the unique physical morphology of the surface provides significantly enhanced protein adso rption characteristics. Using radio-labeling techniques, the adsorptio n kinetics of Protein A, human IgG and BSA were measured for two buffe r solutions and four types of meal whisker coatings. The best metal co ating, Pt, adsorbs up to 70 times as much protein as the control subst rates. The absolute protein binding levels are similar to 10 mu g/cm(2 ), with 85%-95% being tightly bound and viable. The speed of binding i s also very rapid, reaching similar to 50% coverage in 15 min and full coverage in 2 h, without vortexing. The nanostructured films are easi ly produced in large area formats and the exposed whisker surfaces can be readily functionalized. (C) 1996 American Vacuum Society.