Magnesium-reinforced sandwich structured composite membranes promote osteogenesis

• The magnesium-reinforced sandwich structured composite membranes are designed and fabricated by inner-layer magnesium scaffolds and a bottom and top layer PLGA/collagen hybrid. • The composite membranes exhibited good shaping properties and support effects, biocompatibility properties, and osteogenic effects in vivo and in vitro. • The composite membranes significantly enhanced bone defect repair via the MAPK/ERK 1/2 pathway by the Mg 2+ released from the composite membranes. Guided bone regeneration (GBR) membranes are extensively utilized in dental implantation. However, the existing GBR membranes showed insufficient space-maintaining capability and poor bone promoting ability, affecting the effectiveness of clinical bone augmentation, which in turn resulted in poor implant outcomes and even failure. In this study, we designed a novel magnesium reinforced sandwich structured composite membrane, consisting of an inner magnesium scaffold and a PLGA/collagen hybrid (mixture of poly(lactic-co-glycolic acid) and collagen) top and bottom layer. The magnesium scaffold provided mechanical support and released Mg 2+ to enhance osteogenesis. The PLGA/collagen hybrid regulated membrane degradation and improved biocompatibility, promoting cell adhesion and proliferation ( P < 0.05). The PLGA/collagen hybrid regulated the release of magnesium ions, such that the MgP10C (mass ratios of PLGA and collagen =100:10) group showed the best in vitro osteogenic effect. Further mechanism exploration confirmed that MgP10C membranes significantly enhanced bone defect repair via the MAPK/ERK 1/2 pathway by the Mg 2+ released from the composite membranes. In rat calvarial defect and rabbit alveolar defect model ( P < 0.05), the in vivo osteogenic effect of the MgP10C group was superior to that of other groups. Finite element analysis models validated the support effect of composite membranes, demonstrating lower stress and a significant reduction in strain on the bone graft in the MgP10C group. In conclusion, the magnesium-reinforced sandwich structure composite membrane, with its space-maintaining properties and osteoinductive activity, represents a new strategy for GBR and enhancing osteogenic potential that meets directly clinical needs. Magnesium-reinforced sandwich structured composite membranes promote osteogenesis through mechanical support property and MAPK/ERK 1/2 pathway