Surface Endothelialization of Polyurethanes

One of the contemporary challenges for cardiovascular tissue engineers is to design hemocompatible biomaterials that promote neo-tissue formation. Despite many years of intensive research materials used to fabricate synthetic implants still cause clot formation in the bloodstream, which can have fatal consequences for the patient. Currently, the most promising strategy to fabricate non-thrombogenic materials is covering the implant surface with a layer of endothelial cells. Endothelial cells can be applied onto the synthetic implant before the procedure (in vitro endothelialization) or can be recruited from the bloodstream and the surrounding areas (in situ endothelialization).In the presented work, a method to modify polyurethane surface is proposed. The surface-modified materials are designed to selectively promote endothelial cell adhesion and proliferation. The modification is based on three-step process: surface activation, introduction of spacer and coupling of peptide to the spacer molecule. Colorimetric assays confirmed the successful incorporation of the proper functional groups after each modification step. As a modifying peptide we decided to use peptides containing REDV sequence, which has been proved to promote ECs adhesion and proliferation. In order to confirm the successful incorporation of peptides and visualize their surface distribution a set of materials with fluorescence stained peptides was prepared and analyzed with fluorescence microscopy. The number of HUVEC adhered to REDV-modified materials was significantly higher compared to the number of cells adhered to the non-modified polyurethane.