The effect of gamma irradiation on physical-mechanical properties and cytotoxicity of polyurethane-polydimethylsiloxane microfibrillar vascular grafts.

Poly(ether) urethane (PEtU)-polydimethylsiloxane (PDMS) based materials have been processed by a spray, phase-inversion technique to produce microfibrillar small-diameter vascular grafts; however the effect of sterilization upon these grafts is still unknown. This study investigated the effect of gamma irradiation on grafts made of PEtU-PDMS materials containing different PDMS concentrations. Sterilisation-induced changes in surface chemical structure and morphology were assessed by infrared spectroscopy, light and scanning electron microscopy. Tensile tests were used to examine changes in mechanical properties and the cytotoxicity evaluation was performed on L929 fibroblasts. The study demonstrated that physical-chemical and mechanical properties of PEtU-PDMS grafts, at each PDMS concentration, were not significantly affected by the exposure to gamma irradiation, moreover no sign of cytotoxicity was observed after sterilisation. Although in vitro experiments have been promising, further in vivo studies are necessary to evaluate the biodegradation behaviour of PEtU-PDMS graft after gamma irradiation, before any clinical application.