Competitive Protein Adsorption and Platelet Adhesion on Poly(Ethylene Terephthalate) Surface Modified by Plasma Grafting

We report a study involving different molecular weight polyethylene glycol (PEG) chains grafted on polyethylene terephthalate) (PET, Dacron) films by plasma surface grafting modification. These surface-modified PETs were characterized by means of contact angle measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The contact angle of water decreased from the original 83.5° to 38.7°. The result showed that the chains of PEG were successfully grafted on the surface of PET and the water wettability of PET surface was improved. The competitive adsorption relation of plasma protein (fibrinogen and albumin) on materials surface was analyzed with respect to surface energy and interface free energy. The results reveal that PET films grafted with PEG long chain possess the characteristic of preferential adsorbing albumin and this adsorption tendency on the grafted PEG6000 sample is most distinct. The platelet adhesion test on PET films whose surfaces have been pre-exposed with fibrinogen and albumin indicates that the surface of adsorbed albumin effectively inhibits platelet adhesion and aggregation, and possesses favorable blood compatibility, but on the other hand, the adsorbed fibrinogen surface enhances platelet adhesion and aggregation.