In vivo subcutaneous implantation in rats revealed the connective tissue formation with no foreign body response after 8 weeks.232 Based on the assumption that insulin growth factor (IGF) plays an important role in maintaining bone strength, IGF adsorbed as a last layer on Gel/CHI LbL demonstrated significantly higher osteogenic differentiation of MSCs and new bone formation in rat with osteoporosis.233. This evidence concerns the gene IGF1 and osteoporosis.