A comparative study of the effects of concentrated growth factors in two different forms on osteogenesis in vitro

Extending the release cycle of growth factors to match the cycle of bone remodeling is difficult. When using concentrated growth factors (CGFs), the release of growth factors is excessively rapid. In the present study, CGF samples were prepared by centrifugation. CGF samples were then lyophilized and grinded into a powder, which was termed freeze-dried CGF. The freeze-dried CGF samples were mixed with chitosan-alginate composite hydrogels, and the mixture was lyophilized. The result was a chitosan-alginate composite CGF membrane, which was called sustained-release CGF. This study investigated whether freeze-dried CGF in a chitosan-alginate composite gel can release CGF steadily to achieve effective osteogenesis. The proliferation and osteogenic expression of MC3T3-E1 cells induced by the supernatants from incubation with freeze-dried CGF and sustained-release CGF were evaluated. The concentrations of the growth factors, transforming growth factor β1 (TGF-β1), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-AB (PDGF-AB) and vascular endothelial growth factor (VEGF), in these two experimental groups at different times were determined by ELISA kits. The freeze-dried CGF showed better osteogenic performance than the sustained-release CGF in the early stages. At later stages, the sustained-release CGF had significant advantages over freeze-dried CGF in terms of promoting osteogenic mineralization. By characterizing the biologic properties of the CGF in the two different forms in vitro, we obtained a better understanding of their clinical effects.