Hybrid polymer-grafted graphene scaffolds for microvascular tissue engineering and regeneration

The function of organs/tissues and the success of tissue engineering fully depend on the integrity and function of blood vessels and the microvascular system. To regenerate autologous vascular grafts, both in vitro and in vivo strategies have been applied. While the in vitro approach is largely based on the use of a mixture of autologous cells (i.e., endothelial, smooth muscle cells, and fibroblasts) that can be seeded onto a decellularized scaffold, the in vivo modality is based on the recellularization process harnessing endogenous processes. The emergence of advanced nanobiomaterials (e.g., biopolymers, graphene-based and hybrid polymer-grafted graphene scaffolds) and technologies (e.g., 3D layer-by-layer bioprinting) has revolutionized engineering and regeneration of different tissues such as vessels and microvessels. Accordingly, various natural and synthetic biodegradable polymers have been utilized to serve as scaffolds for vascular tissue engineering, including polyglycolic acid (PGA), poly-l-lactic acid (PLLA), polyhydroxyalkanoate, polycaprolactone-copolylactic acid, poly(ethylene gly-col), PLLA/polylactide-coglycolide copolymer-coated PGA mesh, polyhydroxyoctanoate, and poly-caprolactoneas. Synthetic vascular grafts have also been engineered using some polymers such as expanded polytetrafluoroethylene, polyethylene terephthalate (Dacron (R)), and polyurethane. Various advanced bio-materials and nanostructures (e.g., graphene) have been used to serve as hybrid scaffolds for vascular tissue engineering. This review aims to address the applications of advanced polymer-grafted graphene-based hybrid scaffolds in microvascular tissue engineering and regeneration.