Differentiated biocompatible design of luminal and outer graft surfaces. Photocurable extracellular matrices,...

Differentiated biocompatible design of luminal and outer graft surfaces may lead to successful healing of vascular grafts. Non-cellular adhesion characteristics are required for a luminal surface, whereas enhanced cell adhesion and migration are desired for an outer surface. We molecularly designed photocurable extracellular matrices (ECMs). Photocurable chondroitin sulfate (CS) was prepared for the luminal surface and photocurable gelatin for the outer surface. Both were partially derivatized with photodimerizable groups such as cinnamate and coumarin. These ECMs were converted to produce water insoluble gels upon ultraviolet irradiation. In vitro study showed that platelet adhesion on the photogelled CS was significantly reduced, whereas endothelial cells adhered well to the photogelled gelatin. These materials were individually coated and photogelled onto respective surfaces of knitted Dacron grafts (internal diameter 5 mm, length 5 cm). The ECM coated grafts were implanted into the abdominal aortae of dogs. During acute phase implantation for up to 1 week, minimized cell adhesion was observed on the luminal surface where the photogelled CS had provided a uniform cover, and enhanced tissue ingrowth was noted at the outer surface. However, some thrombi were formed, probably because of incomplete coating of, or cracks in, the photogelled CS. Although the molecularly designed ECMs and their in vitro performance appeared to follow our concept, further improvements in coating technique and molecular design of ECMs are needed for better in vivo performance. This may result in enhanced tissue regeneration, as well as a high patency rate.