A hierarchical biomimetic coating mitigates bending-accelerated corrosion and enhances osteogenesis of biodegradable Zn membranes for guided bone regeneration

The repair of complex alveolar bone defects remains a major clinical challenge in guided bone regeneration (GBR), requiring barrier membranes with adequate mechanical support, structural stability, and controlled degradation behavior. In this work, a hierarchical biomimetic silk fibroin/laponite (SF/LAP) coating was engineered on Zn membranes to achieve adequate mechanical performance, improve bending-adaptive degradation, and promote osteogenic activity. This coating integrates a laminated “brick-and-mortar” architecture that enhances resistance to bending-induced cracking and establishes tortuous ion-diffusion pathways, thereby imparting bending-resistant corrosion resistance. The coating also modulates the osteogenic microenvironment by mitigating burst Zn²⁺ release while enabling the sustained release of osteogenic Li⁺ and Si⁴⁺ ions from LAP. The optimized SF/LAP coating containing 10 wt% LAP (SL10) reduced the in vivo degradation rate under bending to 15.03 μm·yr⁻¹, significantly lower than those of bare Zn and SF-coated membranes in vitro and in vivo. In a rat cranial defect model, SL10-coated membranes markedly enhanced bone regeneration and accelerated defect closure without inducing systemic toxicity or histopathological abnormalities. This work presents a hierarchical biomimetic coating strategy that simultaneously confers stress-adaptive degradation control and pro-osteogenic functionality on Zn membranes, offering a translatable approach for improving the performance of biodegradable Zn-based membranes in GBR and other mechanically demanding orthopedic applications.