3D-printed chitosan-based hydrogel scaffold doped with curcumin-loaded quantum dots enables photothermal effect and...

Bone defect remodeling remains a significant challenge due to imbalanced immune microenvironment, insufficient vascularization, and impaired bone regeneration. This study aimed to synthesize curcumin (Cur)-loaded gold-doped Ag₂Te quantum dots (Cur@Au:QDs) under ambient conditions, which were subsequently incorporated into a hydrogel matrix consisted of methacrylated gelatin (GelMA) as well as methacrylated chitosan (CHMA) to fabricate a 3D-printed scaffold (Cur@Au:QD/GC). The QDs exhibited strong fluorescence imaging capability in the near-infrared II (NIR-II) region at 1080 nm, enabling in vivo monitoring of scaffold degradation. In vitro assays demonstrated that CHMA, Ag⁺, and loaded Cur, combined with NIR-induced heating, effectively eliminated bacteria. Furthermore, Cur, together with N-acetylcysteine (NAC), stabilizer of Au:QDs, endowed the scaffold with reactive oxygen species (ROS)-scavenging functionality. Additionally, the combined effect of Cur and mild heat (42.6 °C) not only promoted macrophage phenotypic transition from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype, thereby optimizing the immune microenvironment for bone regeneration, but also enhanced angiogenic and osteogenic activities. In vivo evaluations indicated that this multifunctional scaffold, integrating immunomodulation and vascularized bone regeneration, significantly accelerated the repair process in a rat femoral defect model and enabled real-time visualization of scaffold degradation over six weeks, offering an efficient strategy for bone repair.