In vitro and in vivo study of He+ ion irradiated collagen for development of small diameter stent graft material

Recently, stent graft technology for endovascular treatment of aortic dissections has made tremendous advances. It is now possible to apply this minimally invasive technique to a wider range of pathology. The aim of this study was to develop anti-thrombogenic coronary stent and graft materials using ion-beam technology. Our previous study indicted that collagen surfaces irradiated with He+ ion at a fluence of 1 × 1014 ions/cm2 have excellent blood compatibility. The ion-beam-irradiated collagen grafts demonstrated a high anti-thrombogenicity and graft patency. 150 keV-He+-irradiated collagen with a fluence of 1 × 1014 ions/cm2 has the properties of anti-thrombogenicity and cell attachment. In vitro plasma protein adsorption was evaluated to investigate the mechanisms of anti-thrombogenicity of these surfaces. From these results, anti-thrombogenicity of the He+-irradiated collagen was caused by the reduction of the plasma protein adsorption, such as fibrinogen or von Willebrand factor, by ion-beam irradiation. Japanese white rabbits weighing 3-4.5 kg were used in this animal study. Collagen-coated graft material implanted with He+ ions at a fluence of 1 × 1014 ions/cm2 exhibited excellent anti-thrombogenicity and demonstrated patency for one year.