- IGF-I and TGF-beta 1 incorporated in a poly(D,L-lactide) implant coating stimulates osteoblast differentiation and collagen-1 production but reduces osteoblast proliferation in cell culture. Schmidmaier, G., Wildemann, B., Lübberstedt, M., Haas, N.P., Raschke, M. Journal of biomedical materials research. Part B, Applied biomaterials. (2003)