A stable matrix for generation of tissue-engineered nonthrombogenic vascular grafts

The potential of freeze-dried fibrin glue (FG) in combination with growth factor (GF) and gelatin (GEL) is evaluated for use as a matrix for endothelialization of artificial vascular grafts made of polytetrafluoroethylene (PTFE, Teflon) and polyethyleneterephthalate (Dacron). Improved adhesion and proliferation of human umbilical vein endothelial cells are demonstrated on different substrates coated with the FG-GF/FG-GF-GEL mixture, compared with the respective bare surfaces. The strength of adhesion of endothelial cells on the coated matrices was found to be adequate to resist shear stress when monolayers were exposed to forces of flow in an in vitro parallel plate flow chamber. The monolayers maintained physiological nonthrombogenic character as evidenced by in vitro platelet adhesion and response to agonist measurements. Nitric oxide synthesis by cells grown on the study matrices was also found to be normal. Thus, the matrix composition and the coating technique, as presented here, can be easily applied to generate tissue-engineered biomaterials with a nonthrombogenic endothelial cell monolayer for cardiovascular implants. The freeze-drying of the coated matrix ensures prolonged stability and thus the materials can be stored in a ready-to-use state for endothelial cell sodding or seeding.