Microwave-assisted functionalization of polyurethane surface for improving blood compatibility

In order to improve the hemocompatibility of polyurethane (PU), we report a rapid and efficient two-step approach to graft poly(ethylene glycol) (PEG) onto PU surface by a microwave-assisted method, involving diphenylmethane diisocyanate (MDI) – functionalization and subsequent PEG coupling. Compared with conventional heating, the effects of solvent, time and MDI concentrations on the microwave-assisted MDI-functionalization, and the effect of time on the microwave-assisted PEG coupling were studied. PEGs with different molecular weights were successfully grafted onto PU surface under the optimum microwave-assisted conditions within only 20 min, and characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and chemical titration. The hydrophilicity and in vitro blood compatibility of the surfaces were evaluated by water contact angle measurements, blood coagulation time (whole blood clotting time and prothrombin time) and platelet adhesion tests, respectively. All the PU-PEG surfaces had improved surface wettability and hemocompatibility. The results suggested that microwave-assisted functionalization may be a promising method for rapidly and effectively decorating polyurethane surfaces.