Endothelium regeneration on luminal surface of polyurethane vascular scaffold modified with diamine and covalently grafted with gelatin.

Using the recently developed surface modification technique, free amino groups have been introduced onto polyester-type polyurethane (PU) scaffolds. The introduction of these free amino groups increases the surface energy and provides a convenient way to further immobilize bioactive species such as gelatin, collagen or chitosan, etc. on the scaffold surface by employing glutaraldehyde as a coupling agent. These modifications are advantageous to enhance cell-material interaction. The culture of human umbilical vein endothelial cells (HUVECs) in vitro proved that the cell proliferation ratio of both the aminolyzed and the biomacromolecules-immobilized PU membranes was improved greatly comparing with the control PU. Scanning electron microscopy and confocal laser scanning microscopy observations displayed that the gelatin-immobilized PU vascular scaffold had formed a monolayer of endothelial intima on its luminal surface after HUVECs were cultured for 6 d. Therefore, the aminolysis and the following biomacromolecule immobilization is a promising way to enhance the cell-PU interaction that can accelerate the endothelium regeneration, which is crucial for blood vessel tissue engineering.