Surface treatment of biomaterials by gamma and swift heavy ions grafting

To date, the successful substitution of small diameter arteries by vascular grafts has not been achieved in humans. In order to reduce their thromboge nicity which remains the major obstacle, polymeric materials endowed with a specific affinity for Antithrombin III (ATIII) and thus able to catalyse t he inhibition of thrombin by ATIII, as heparin does, were devised. Sulfonat e and sulfonamide groups were introduced on phenyl rings belonging to styre ne residues which were radiation grafted (swift heavy ions and gamma radiat ion) onto poly(vinylene difluoride) (PVDF) and poly(hexafluoropropylene vin ylidene fluoride) (P(VDF-HFP)). Contrary to gamma radiation grafting, with swift heavy ions grafting, only small regions are modified; thus, the prope rties of the initial substrate are preserved. A characterization of surface topography was carried out by Scanning Electron Microscopy and Atomic Forc e Microscopy. The efficacy of the surface modification was monitored with r espect to the total amount of bound "heparin-like" molecules measured by a toluidine blue assay, and the anticoagulant potential estimated by the thro mbin time test. (C) 1999 Elsevier Science B.V. All rights reserved.