Improved blood compatibility of poly(ethylene terephthalate) films modified with L-arginine

In order to improve the blood compatibility of the commonly used blood-contacting biomaterial poly(ethylene terephthalate) (PET), in this study PET films were chemically modified with L-arginine (L-Arg) by a three-step-procedure using glutaraldehyde (GA) as a cross-linker. The composition and chemical structure of PET and its change with surface modification were examined by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy, while the change in hydrophilicity was judged by water contact angles measurement. The result of water contact measurement indicated that the modified films became more hydrophilic than PET with the contact angle decreasing from 78.5 degrees for PET to 43.7 degrees for PET-Arg. The protein adsorption on the film surface was evaluated by bicinchoninic acid assay (BCA) method, and the result showed that the L-Arg-modified films decreased the amount of protein adsorption by about 25%. The in vitro blood compatibility such as platelet adhesion (observed by scanning electron microscopy) and thrombus formation was also investigated, and the results demonstrated that the L-Arg-modified films significantly suppressed platelet adhesion and aggregation and reduced the thrombus formation by about 67% compared with PET.