A biomimetic composite scaffold with near-infared light controlled shape-memory properties for bone defect healing

In this study, an shape-memory 3D scaffold with photothermal capability to heal bone defect was developed by a multifunctional porous composite network. The fabrication contains in-situ polymerization with gas foaming process, by incorporating surface-modified iron oxide nanoparticles (functionalized by polydopamine) into a biodegradable polyurethane matrix derived from poly(propylene glycol) and poly(ε-caprolactone) precursors. Enhanced osteoinductive signaling through these bioactive surface, enabling controlled mineralization and cell-matrix interactions. Robust osteogenic differentiation of mesenchymal stem cells across interconnected networks. Reversible shape memory transition (melting transition at 37°C) enabling minimally invasive deployment through 4mm diameter cannulas. Synergistic therapeutic effects combining localized heat shock protein induction with sustained bioactive ion release. This programmable biomatrix platform addresses critical unmet needs in complex craniofacial and orthopedic reconstruction by integrating shape-morphing delivery, spatially controlled thermotherapy, and sequential bone regeneration cues within a single implantable system. • The smart scaffold material was composed of PDA-modified iron oxide nanoparticles within a polyurethane (PPG/PCL) matrix, the scaffold achieves photothermal efficiency , while providing stable light-to-heat conversion. • The shape of obtained scaffold could be temporarily deformed at low temperatures (e.g., 0°C) then recover its original shape under NIR light, and this non-contact shape memory effect could be used for minimally invasive delivery, reducing surgical trauma and scarring in bone defect repair. • Beside well performed mechanical shape-changing capability, the scaffolds demonstrated superior MSC proliferation, ALP activity, and collagen deposition in vitro, and rat cranial defect models demonstrate significant bone regeneration (higher BV/TV and trabecular density vs. controls) .