Immobilization of poly(ethylene glycol) or its sulfonate onto polymer surfaces by ozone oxidation

A novel surface modification method has been developed to improve biocompat ibility of polymeric biomaterials. This approach involves ozonation and the n followed by graft polymerization with acrylates containing PEG, sulfonate d PEG or by coupling of PEG derivatives. All the reactions were confirmed b y ATR FT-IR and ESCA. The degree of ozonation measured by the iodide method was dependent on the ozone permeability of the polymers used. Surface hydr ophilicity was investigated by measuring the contact angles. Ozonation itse lf yielded a slight increase in hydrophilicity and a decrease in platelet a dhesion, but PEG immobilization showed a significant effect on surface hydr ophilicity and platelet adhesion to confirm well-known PEG's passivity whic h minimize the adhesion of blood components on polymer surfaces. Both graft polymerization and coupling were effective for PU. In contrast, only graft ing gave enough yields for PMMA and silicone. Platelet adhesion results dem onstrated that all PEG modified surfaces adsorbed lower platelet adhesion t han untreated or ozonated ones. Polymers coupled with sulfonated PEG exhibi ted the lowest platelet adhesion when compared with control and PEG coupled ones by virtue of the synergistic effect of non-adhesive PEG and negativel y charged SO3 groups. This PEG or sulfonated PEG immobilization technology using ozonation is relatively simple for introducing uniform surface modifi cation and therefore very useful for practical application of blood contact ing medical devices. (C) 2001 Elsevier Science Ltd. All rights reserved.