Adhesion and differentiation of adipose-derived stem cells on a substrate with immobilized fibroblast growth factor

Control of cell–matrix interactions plays a role in the regulation of stem cell function. In this study basic fibroblast growth factor (bFGF) linked to maltose-binding protein (MBP) was designed as a matrix for cell adhesion. MBP–FGF was immobilized on polystyrene (PS) surfaces by spontaneous adsorption. The amount of MBP–bFGF immobilized on the PS surface increased with increasing protein concentration, being 158 ng cm−2 at 10 μg ml−1 protein. Human adipose-derived stem cell (hASC) adhesion to MBP–bFGF immobilized on a PS surface (PS–MBP–bFGF) was inhibited by heparin. Integrin signaling and cell spreading of hASC on PS–MBP–bFGF were down-regulated compared with those on fibronectin-coated surfaces or tissue culture polystyrene (TCP). hASC differentiated into adipocytes, which stained positive for lipid vacuoles with Oil Red, more readily on PS–MBP–bFGF than on TCP. In contrast, hASC hardly differentiated into osteoblast on PS–MBP–bFGF or on TCP. These results suggest that the mechanism of hASC adhesion to MBP–bFGF immobilized on a PS substrate is mediated by a specific interaction between bFGF and heparin, and that the adhesion mechanism might provide an insight into the design of biomaterials to control the fate of stem cells.