Injectable biodegradable gelatin-methacrylate/β‐tricalcium phosphate composite for the repair of bone defects

Maintaining appropriate mechanical strength and tissue volume is important to provide for sufficient alveolar bone growth. Recently, synthetic bone graft materials (BGM) including hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) have been widely studied for alveolar bone regeneration. Here, we applied gelatin-methacrylate (GelMA) hydrogel into the β-TCP to produce a GelMA/β-TCP composite (GelMA-B). This reinforced the mechanical strength and regulated the absorption period of β-TCP. To characterize the physical properties of the formed composite, GelMA-B was tested using a mechanical tester and a rheometer. It was then analyzed for biocompatibility and osteogenic differentiation using human adipose-derived stem cells. Further, the bone regeneration effects of GelMA-B were confirmed by an animal study. The cell viability analysis and qPCR results revealed that GelMA-B showed high cell viability and relatively high bone differentiation ability. In a rheological analysis, GelMA-B showed higher mechanical strength than β-TCP and GelMA alone. These features were confirmed in the animal study as GelMA-B maintained its volume and shape during regrowth, which can be favorable for alveolar bone regeneration. In addition to the regenerative effect, GelMA-B composite has an advantage for clinical use as the material enables structural molding for customized application.