Self-healing and cell-free vascular grafts

We developed an innovative self-healing tissue engineering vessel (SH-TEV) that heals fast after repeated needle punctures, while maintaining artery like mechanical strength and toughness even under wet conditions. The SH-TEV is designed as a bilayer tube engineered by electrospinning an autonomous self-healing polyurethane, PU-DAA, around a tube of a native biomaterial, small intestinal submucosa (SIS), that can be functionalized with biomolecules to recruit host cells and promote endothelialization. The self-healing PU-DAA was designed to incorporate multi-strength H-bonds and reversible hydrazone bonds and exhibited high strength (3.95 ± 0.16 MPa), toughness (23.01 ± 2.37 MJ/m³), and fast autonomous self-healing (86.44 ± 6.65 % after 12 h) under physiological conditions. The self-healing layer supported attachment, spreading and proliferation of fibroblasts, indicating biocompatibility. When SH-TEVs were implanted as interpositional grafts into the rat aorta for 4 weeks, they remained patent without any thrombosis (100 % animal survival and 100 % graft patency), were endothelialized and developed a smooth muscle cell containing vascular wall. In addition, they showed excellent self-healing ability following needle puncture (hemostatic time <40 s) immediately after implantation and four weeks later. Collectively, these results demonstrate the potential of SH-TEVs as vascular access conduits for hemodialysis applications.