SYNTHESIS OF BIOMATERIALS BY SWIFT HEAVY-ION GRAFTING - PRELIMINARY-RESULTS OF HEMOCOMPATIBILITY

Sulfonate and sulfonamide,stoups were introduced on styrene which was radiation grafted on poly(vinylidene difluoride) (PVDF) to improve sur face thrombogenicity. Irradiation was performed with swift heavy ions (E > 1 MeV/amu) and the grafting of styrene was achieved by the peroxi de method. A characterisation of surface topography was carried out by Scanning Electron Microscopy (SEM) and Energy Dispersive X-rays (EDXA ). Compared to the SEM micrograph of PVDF, the SEM micrographs of the polystyrene grafted PVDF (PVDF-g-PS) and the functionalised polystyren e grafted PVDF (PVDF-g-PSf) show circular ''islands'' of different siz es. EDXA analysis shows that the amount of fluorine is directly depend ent on the presence of these islands. When the styrene is grafted, the amount of fluorine is lower. The swift heavy ions induce significant grafting only in small regions (the latent tracks) of the polymer. Fib rinogen and albumin adsorption from plasma on these materials was quan titatively assessed using I-125-labelled proteins prepared under a qua lity controlled procedure. The amount of adsorbed proteins is greater in the case of PVDF-g-PSf. For PVDF-g-PSf the rates of exchanged prote ins increases when the functionalisation yield increases. The distribu tion of bound proteins, determined by microautoradiography seems to be homogeneous on the three different materials studied here. (C) 1997 E lsevier Science B.V.