Mechanically reinforced and bioactive core-shell nanofibrous membranes loaded with astragaloside IV for guided bone regeneration.

Abstract

Current barrier membranes for guided bone regeneration (GBR) are often limited by insufficient bioactivity, poor mechanical toughness, and uncontrolled degradation rates. To overcome these challenges, we developed a novel functionalized nanofibrous membrane with a core-shell structure via coaxial electrospinning. The membrane comprises a poly(lactic-co-glycolic acid)/polycaprolactone (PLGA/PCL) shell to ensure structural integrity and a gelatin (Gel) core loaded with astragaloside IV (AS) to enhance water retention capacity and bioactivity. Physically, the incorporation of the Gel core significantly enhanced the mechanical toughness of the scaffold, imparting ductile behavior to the membrane, while maintaining a controlled degradation profile and stable swelling capacity suitable for space maintenance. Biologically, the membrane effectively prevented fibroblast infiltration, fulfilling the critical barrier function. Furthermore, in vitro evaluations with rat bone marrow mesenchymal stem cells (rBMSCs) demonstrated that AS-loaded membrane significantly promoted cell proliferation and osteogenic differentiation. Notably, the 2.5% AS concentration was identified as the optimal formulation, eliciting the most robust upregulation of osteogenic genes (Runx2, Col-1, ALP, OPN, and OCN) and the angiogenic factor vascular endothelial growth factor A (VEGF), as well as maximizing extracellular matrix (ECM) mineralization. Collectively, this study presents a dual-functional GBR membrane that combines enhanced mechanical handling properties and demonstrates bioactivity associated with AS incorporation, offering a promising strategy for repairing critical-sized bone defects.