Dual-Network Bioactive Implant Promotes Weight-Bearing Bone Healing via Mechano-Bioelectric Coupling

The repair of weight-bearing bone defects is critically limited by the mechanical mismatch between implants and native bone. While excessive implant stiffness causes stress shielding and inhibits bone formation, insufficient stiffness compromises structural stability and osseointegration. To address this, a dual-network, piezoelectric nanoceramic-reinforced implant is developed that replicates the mechanical properties of natural bone while actively enhancing osteogenesis for irregular defect repair. The implant combines a fast-curing polymer network and a protein-based network, strategically reinforced with high-modulus piezoelectric nanoparticles. Through optimized covalent cross-linking, physical entanglement, and nanoceramic dispersion, the system achieves synergistic mechanical and osteogenic performance—matching cortical bone in compressive strength (≈140 MPa) and elastic modulus (≈3.8 GPa). Under physiological loading, the embedded nanoceramics generate osteogenic bioelectric signals, further stimulating bone remodeling. In a tibial fracture model, the implant provides robust mechanical support and biological activity, enabling near-complete functional gait recovery. This study demonstrates a mechano-bioelectric dual-regulation strategy to advance weight-bearing bone regeneration.