A novel 3D-assembled NIR-responsive scaffold create a bone-mimicking niche for infectious bone regeneration

Natural bone grafts, including autologous and allogeneic bone, have been extensively utilized in bone defect owing to their superior microarchitecture and bioactivity, but their clinical application is constrained by donor-site morbidity and immune rejection. In recent years, bioactive scaffolds have emerged as promising alternatives. However, achieving an optimal combination of sufficient mechanical strength, high porosity, robust osteogenic and angiogenic properties remains a significant challenge in the treatment of critical-sized bone defects. Moreover, infectious defects further demand effective infection control. Inspired by the native bone niche, we developed a 3D-assembled, NIR-responsive biomimetic scaffold. A 3D printed porous polylactic acid framework mimics trabecular bone for mechanical support, with an interconnected porous network loaded with collagen-encapsulated graphene oxide (GO) and black phosphorus (BP) to enhance toughness. The collagen (Col) matrix not only improves GO-BP dispersion but also mimics the extracellular matrix (ECM), boosting biocompatibility. Subsequently, BP releases phosphate ions to recruits calcium, while GO enhances ionic attraction for in situ mineralization. In vitro and in vivo evaluations demonstrate that this bone niche scaffold exhibits excellent biocompatibility, resists inflammation and infection under NIR modulation, recruits host-derived cells, and reconstructs an osteogenic milieu conducive to cell proliferation, angiogenesis, and osteogenesis, thereby significantly promoting vascularized bone regeneration. Collectively, this study provides a promising strategy for fabricating biomimetic scaffolds matching the bone microenvironment to support bone regeneration.