Designing a Bioinert Surface by Simple Coating with Cholesterol End-Modified Poly(ethylene glycol).

Abstract

A bioinert surface has been designed by simple coating with cholesterol end-modified poly(ethylene glycol), Chol-U-Pr-mPEG, using a cholesterol anchor. A poly(propylene) (PP) surface was immersed into the Chol-U-Pr-mPEG aqueous solution, where control mPEGs without cholesterol were not suitable for the design of bioinert surfaces. The resulting surfaces coated with Chol-U-Pr-mPEG above and below its critical micelle concentration were swollen and less swollen, respectively. Chol-U-Pr-mPEG with a molecular weight of 2000, Chol-U-Pr-mPEG (2k), formed a swollen layer with a thickness of 10-15 nm and adhered to the PP surface with an estimated Kd value of 4.4×10-7 M. The resulting Chol-U-Pr-mPEG (2k)-coated surface with the swollen layer suppressed the adsorption of γ-globulin proteins and the adhesion of platelets in plasma. Although the PP surface coated with Chol-U-Pr-mPEG with a molecular weight of 5000, Chol-U-Pr-mPEG (5k), also suppressed the adsorption of γ-globulin proteins, the Chol-U-Pr-mPEG (5k)-coated PP surface did not suppress the adhesion of the platelets in plasma despite the existence of a swollen layer with a thickness of 20-25 nm. These results suggest that the Chol-U-Pr-mPEG-coated PP surface with an optimized swollen layer has been established as a bioinert surface by a facile method.