Black phosphorus/calcium silicate-functionalized 3D hierarchical scaffolds: Coupling photothermal therapy with ion microenvironment-induced mineralization for bone repair.

The repair of large-scale bone defects remains a significant challenge in clinical orthopedics, often complicated by bacterial infection and limited self-healing capacity. Therefore, developing artificial scaffolds that can simultaneously prevent infection and orchestrate a regenerative microenvironment is critical for successful therapy. Herein, a hierarchical 3D scaffold (CaSiO3/PCL NFs + BP@PCL MSs) integrating calcium silicate (CaSiO3)-doped polycaprolactone (PCL) nanofibers and black phosphorus (BP)-encapsulated microspheres is engineered via combined electrospinning and electrospraying techniques. This design constructs a biomimetic architecture with dual photothermal-ionic regulation capabilities. Under near-infrared (NIR) irradiation, the scaffold exhibits superior photothermal conversion, which rapidly eradicates bacteria while accelerating the release of therapeutic ions to establish a pro-mineralization niche. Further in vitro and in vivo evaluations demonstrate that the scaffold exhibits excellent in situ mineralization capability while simultaneously promoting cell proliferation, migration, and osteogenic differentiation. Furthermore, the implanted scaffold effectively promotes vascularized bone regeneration at defect sites. This strategy, synergizing photothermal therapy with an optimized ionic microenvironment, provides a promising approach for bone tissue engineering applications.