Fibrin microbeads (FMB) as biodegradable carriers for culturing cells and for accelerating wound healing

We have developed biodegradable fibrin-derived microbeads as potent cell ca rriers. The fibrin-derived microbeads, 50-200 mu m in diameter, were tested for their attachment to a wide range of cell types. Fibrin-derived microbe ads were shown to be greatly haptotactic to cells (such as endothelial cell s, smooth muscle cells and fibroblasts), which respond to fibrinogen in con trast to keratinocytes and different cell lines derived from leukocytic lin eage. The cells on fibrin-derived microbeads could be maintained for more t han 10 d and achieved a high density. P-31-nuclear magnetic resonance was e mployed to monitor phosphate metabolism in cells, with densities on the ord er of 100 million cells per g of fibrin-derived microbeads. The P-31-nuclea r magnetic resonance adenosine triphosphate and phosphocreatine signals, eq uivalent to the signal obtained with perfused normal skin, indicated that m etabolism of cells on fibrin-derived microbeads was responsive to oxygenati on and nutrients, Light, fluorescent, and confocal laser microscopy reveale d that the porous fibrin-derived microbeads accommodate up to 200-300 cells due to their high surface area which minimized contact inhibition. Cells c ould degrade the fibrin-derived microbeads and be transferred to seed cultu re flasks without trypsinization, In a pig skin wound healing model, fibrin -derived microbeads + fibroblasts were transplanted into full thickness pun ch wounds. This procedure was compared with other treatment modalities, suc h as the addition of human platelet-derived growth factor BB or fibrin-deri ved microbeads alone. By the third day after wounding, only the wounds in w hich fibroblasts on fibrin-derived microbeads were added showed significant formation of granulation tissue. Based on the above, we project many uses of our novel fibrin-derived microbead technology for cell culturing, wound healing and tissue engineering.