Surface modification of polypropylene film by Radiation-induced grafting and its blood compatibility

To endow blood-compatible properties onto polypropylene (PP) film, we grafted 2,3-epoxypropyl methacrylate (EPMA) to PP film with a preirradiation grafting technique and then introduced various functional groups onto the grafted PP film. The EPMA grafting extent was dependent on the absorbed dose, reaction time, and temperature. The reactions of hydroxylation, iminodiacetation, sulfonation, phosphonation, and amination were performed under various conditions to introduce functional groups into the epoxy group of EPMA-grafted PP films, respectively. We also immobilized heparin on aminated PP film to compare blood compatibility with various functionalized samples. The grafting, functionalization, and heparinization reaction were confirmed by Fourier transform infrared spectroscopy in the attenuated total reflectance mode and electron spectroscopy for chemical analysis. The blood compatibility of various functional groups and heparin-introduced samples as well as control samples was examined by the determination of platelet adsorption and thrombus formation. For the examination of the blood compatibility of functionalized PP samples, acid citrate dextrose human whole blood and platelet-rich plasma were used. The amount of the formed thrombus and the adherent platelets on functionalized PP sample surfaces were evaluated by an in vitro method following Imai and Nose's technique and by scanning electron microscopy, respectively. The blood compatibility of various functional-group-introduced PP films after grafting was better than that of the PP control. Phosphoric-acid-group- and heparin-introduced PP films had especially good blood compatibility. (C) 2003 Wiley Periodicals, Inc.