The
improvement of blood compatibility on a biomaterial suface aims at reducing protein
adsorption with the eventual goal of decreasing platelet adhesion [14]. Some researchers
found that in vitro coagulation time tests of the heparin-modified scaffolds were much higher
than those of the pure silk fibroin scaffolds [15]. In another work, Gu et al. improved blood
compatibility by a two-step process including NH3 gas plasma treatment and reaction with 1,
3-propane sulfone [16]. The results of studies, on effects of surface modification on
hemocompatibility provide a chance to design an artifical vascular graft. In the prior
work,Yagi et. al. prepared and characterized double-raschel knitted silk vascular grafts and
evaluated short-term function in a rat abdominal aorta [17]. In another work reported by
Aytemiz et. al., small-diameter silk vascular grafts (3 mm diameter) with a double Raschel
Knitted silk tube coated with silk fibroin spongehave been designed [18]. However,
improvement and understanding of the hemocompatibility of implanted materials designed by
natural proteins is very important for biomedical applications.