Next-generation GTR/GBR membranes: synergistic effects of nano-hydroxyapatite and vitamin D3 on osteoinduction and scaffold performance.

To develop a multifunctional membrane for guided tissue/bone regeneration (GTR/GBR), this study investigated the effect of incorporating nano‑hydroxyapatite (nHA) and vitamin D3 (VitD3) into electrospun polylactic acid (PLA) on scaffold properties and bone regeneration performance. Electrospun PLA/nHA-VitD3 membranes were fabricated and compared with neat PLA and a commercial membrane. Fiber morphology and porosity, water contact angle, tensile properties, and VitD3 release over 28 days were evaluated. In vitro performance was assessed using MG‑63 osteoblast viability and mineralization potential, while in vivo efficacy was examined in a rabbit calvarial defect model after 8 weeks. The PLA/nHA-VitD3 membranes exhibited reduced fiber diameter ( ~ 745 vs ~1039 nm) and higher porosity ( ~ 90% vs ~81%) compared with PLA, along with improved surface wettability (contact angle from 152° to 137%). Mechanical performance was enhanced, with tensile strength increasing from 0.10 ± 0.02 to 0.21 ± 0.05 MPa, Young's modulus from 1.48 ± 0.3 to 15.1 ± 3.6 MPa, and elongation at break from 21% to 46%. VitD3 release from the composite membrane was sustained over 28 days ( ~ 85% cumulative release) without an initial burst. In vitro results showed increased MG‑63 cell viability ( ~ 1.8‑fold vs PLA at day 5) together with evidence of mineralization potential. In addition, osteogenic gene expression analysis showed upregulation of COL1A and RUNX2 in cells cultured on the PLA/nHA-VitD3 membrane, indicating enhanced early osteogenic activity. In the rabbit calvarial model, PLA/nHA-VitD3 membranes promoted ~82% new bone formation at 8 weeks, compared with ~54% for PLA and ~65% for the commercial membrane, with complete defect bridging and minimal inflammatory response. Overall, the incorporation of nHA and VitD3 improved the structural, mechanical, and biological performance of electrospun PLA membranes and contributed to enhanced bone regeneration, supporting their potential use as GBR/GTR barrier membranes.