BIOACTIVE SCAFFOLDS WITH TOPOGRAPHICAL AND BIOCHEMICAL CUES FOR VASCULAR TISSUE ENGINEERING

Abstract

Small-diameter vascular grafts face implantation problems such as thrombosis, increased rate of infection, chronic inflammatory responses and compliance mismatch between the native tissue and the prosthetic material. It has been hypothesized that a fully-endothelialized lumen would enhance biocompatibility and improve graft patency. This could be done by introducing either topographical or biochemical cues to the graft. In this study, two types of polymers were used; the polysaccharides pullulan and dextran, and a synthetic polymer, poly(vinyl alcohol) (PVA). Both material types were previously characterized as potential graft materials by Chaouat et al., in which they demonstrated short-term graft patency, although both materials were relatively inert and did not facilitate vascular tissue regeneration. The incorporation of poly-electrolyte complexation (PEC) fibers, which are known to be able to perform sustained release of various biologics, with the polysaccharide and PVA materials respectively have improved the scaffolds¿ abilities to perform a sustained release of proteins. PVA-PEC fiber composites further showed that mechanical strength was enhanced compared to PVA-only scaffolds. Finally, a novel method of solvent casting with PVA was developed, allowing micro- and nanometer-sized gratings to be fabricated on the surface of PVA films. Further in-vitro endothelial cell adhesion studies performed demonstrated that the grating patterns enhance adhesion of endothelial cells to the PVA surface.