| Abstract Scope |
The endothelial cell layer in blood vessels plays a crucial role in anticoagulation, transmitting biochemical signals and keeping blood vessels unobstructed. Rapid endothelialization of vascular grafts can prevent thrombosis and hyperplasia and promote blood vessel regeneration. In this study, shape-morphing bilayer vascular grafts with sustained ionic dissolution products (Mg2+ and SiO43-) and heparin release were fabricated via 4D printing and electrospinning. Shape-memory PDLLA-co-TMC and nanoclay were mixed and 4D printed into composite scaffolds, which served as one layer of the grafts. A layer of electrospun PDLLA-co-TMC fibers incorporated with PDA nanoparticles which encapsulated heparin was deposited on the composite scaffold layer, forming bilayer vascular grafts. At 37℃ in culture, bilayer grafts self-folded into tubular structures. The ionic dissolution products and released heparin from bilayer grafts promoted endothelial cell attachment, expansion and proliferation, thereby achieving rapid endothelialization. The grafts were highly stretchable and had matching mechanical properties with autologous blood vessels. |