A heparin-functionalized woven stent graft for endovascular exclusion

With the increase of vascular diseases in recent years, it is of importance to develop an anti-occlusion stent graft, which can meet the requirements of transplants for a long term. In this paper, we describe a silk fibroin (SF)/heparin-functionalized bifurcated stent graft (BSG) using textile forming technology. The BSGs were prototyped based on seamless weaving technology, and the surface was modified with SF-loaded heparin under steam/air treatment to improve their patency. The physical properties such as thickness, water permeability, contact angle, mechanical properties, and in vitro drug release and coagulation time of the BSGs were examined. The results showed that heparin modification can improve its coagulation time, and the water permeability resistance of the BSGs reached 1.154 ± 0.854 mL/(cm²×min), while their thicknesses were just 0.085 ± 0.004 mm. The heparin release of the BSGs showed that the release time was prolonged upon steam treatment by means of the increase in the β-sheet structure and crystallinity of SF. The viability and attachment of human vascular smooth muscle (HVSM) cells cultured in the release of modified BSGs demonstrated that the modified BSGs could significantly inhibit the proliferation of HVSM cells. The heparin-functionalized BSG with satisfactory thickness, water permeability resistance and anti-occlusion function, which has potential applications in the treatment of vascular diseases.