Delivery of Basic Fibroblast Growth Factor from Gelatin Microsphere Scaffold for the Growth of Human Umbilical Vein Endothelial Cells

One of the major obstacles for engineering large tissue or organs such as the liver in vitro is the insufficient supply of nutrients and oxygen to the cells growing inside the scaffold, which reduces cell viability significantly. Therefore, vascularization of the scaffolding system is necessary for successful engineering of such tissues. In this study, we investigated the use of gelatin microsphere as scaffold to culture human umbilical vein endothelial cells, which is considered to be the basis and premise for the formation of blood vessels. The gelatin microspheres were crosslinked with different concentrations of glutaraldehyde to study the effects of crosslinking extent on the growth of endothelial cells. The swelling ratios of the gelatin microspheres decreased from 5.9 +/- 0.8 to 3.9 +/- 0.6 with the increase of the crosslinking extent. Basic fibroblast growth factors (bFGFs), which can improve endothelial cell proliferation as well as stimulate the formation of capillary vessels, were incorporated into the gelatin microspheres through ionic complexation. Sustained delivery of the growth factors was achieved for at least 2 weeks. The proliferation of the cells cultured on the bFGF-encapsulated microspheres was improved by about two times as compared to control and about 1.3 times as compared to blank microspheres, which indicated that the bioactivity of bFGF was well maintained, and the delivery of the growth factors directly to the cells significantly improved the success of this tissue engineering system.