Calcium alendronate-coated composite scaffolds promote osteogenesis of ADSCs via integrin and FAK/ERK signalling pathways

Bioceramic-biopolymer composites have been used extensively as bone tissue engineering scaffolds due to their bioactive properties. However, composite scaffolds are insufficient in inducing osteogenic differentiation of stem cells. In this study, a strategy for the local delivery of bioactive factors that coating calcium alendronate (ALC) on the surface of composite scaffolds was systematically evaluated for the first time. The coated ALC not only displayed excellent cytocompatibility and cell adhesion properties but also resulted in significant upregulation of osteogenic related gene expression, osteogenic related protein levels, alkaline phosphatase (ALP) activity and calcium deposition of ADSCs. Furthermore, our results suggested that the molecular mechanism for ADSCs osteogenic differentiation induced by the constructed ALC may be related to the integrin binding and the activation FAK/ERK signalling pathways. These findings suggested that ALC-coated composite scaffolds can serve as bone tissue engineering scaffolds, providing a simple and universal method to improve the osteogenic differentiation od ADSCs for calcium phosphate-containing composite materials.