Thermoregulated photothermal therapy for bone defects using graphene oxide hydrogel with mesoporous silica-derived phase-change nanocapsules.

The clinical translation of photothermal therapy for bone repair is hindered by the risk of thermal damage to surrounding healthy tissues due to uncontrolled high temperatures. We addressed this by integrating phase change materials (PCMs) into a photothermal platform, developing a hydrogel scaffold with temperature regulation. Polyethylene glycol (PEG) was encapsulated in mesoporous nanosilica (MSNs) to form nanocapsules, achieving 82.5% efficiency. This encapsulation prevents PEG leakage and enhances thermal regulation and bioactivity. Graphene oxide (GO) was integrated into an alginate-chitosan matrix, yielding a GO/chitosan scaffold containing PEG@MSNs nanocapsules. The scaffold exhibits a phase transition at 41.2°C and latent heat of 95.5 J/g. Characterization confirms its physicochemical properties, biocompatibility, and cell affinity meet bone repair requirements. In vitro mineralization assays, osteogenesis studies, and in vivo bone defect models demonstrated its efficacy in temperature-controlled photothermal bone regeneration. This integration of photothermal control and biological activity represents an advance in scaffold design.