Injectable alendronate-functionalized GelMA hydrogels for mineralization and osteogenesis.

In a minimally invasive procedure, hydrogels can be injected into an affected area for drug loading and tissue repair. Here, gelatin methacryloyl (GelMA) was modified with alendronate (ALN), and three different alendronate-functionalized GelMA (GelMA-ALN) hydrogels were prepared. The modification greatly improved the swelling ratio, protein adsorption and mineralization. The GelMA-ALN hydrogels significantly promoted the osteogenic differentiation of hFOB cells as indicated by their higher alkaline phosphatase (ALP) activity, denser mineralization and up-regulated osteogenesis-related genes at both the mRNA and protein levels. Meanwhile, the cells maintained their activity and differentiated into osteoblasts when encapsulated in the GelMA-ALN hydrogels. Alendronate-modified hydrogels have potential for use in the minimally invasive treatment of irregular bone defects.