Gelatin methacrylate hydrogel scaffold carrying resveratrol-loaded solid lipid nanoparticles for enhancement of osteogenic differentiation of BMSCs and effective bone regeneration

Critical-sized bone defects caused by traumatic fractures, tumour resection and congenital malformation are unlikely to heal spontaneously. Bone tissue engineering is a promising strategy aimed at developing in vitro replacements for bone transplantation and overcoming the limitations of natural bone grafts. In this study, we developed an innovative bone engineering scaffold based on gelatin methacrylate (GelMA) hydrogel, obtained via a two-step procedure: first, solid lipid nanoparticles (SLNs) were loaded with resveratrol (Res), a drug that can promote osteogenic differentiation and bone formation; these particles were then encapsulated at different concentrations (0.01%, 0.02%, 0.04% and 0.08%) in GelMA to obtain the final Res-SLNs/GelMA scaffolds. The effects of these scaffolds on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and bone regeneration in rat cranial defects were evaluated using various characterization assays. Our in vitro and in vivo investigations demonstrated that the different Res-SLNs/GelMA scaffolds improved the osteogenic differentiation of BMSCs, with the ideally slow and steady release of Res; the optimal scaffold was 0.02 Res-SLNs/GelMA. Therefore, the 0.02 Res-SLNs/GelMA hydrogel is an appropriate release system for Res with good biocompatibility, osteoconduction and osteoinduction, thereby showing potential for application in bone tissue engineering.