Biodegradable Hybrid Scaffolds Integrating Synergistic Chemical and NIR-II Photothermal Antibacterial Activity

Biodegradable orthopedic materials have attracted increasing attention due to their excellent biocompatibility, controllable degradation behavior, and capacity for osteointegration, enabling effective bone regeneration while eliminating the need for secondary implant-removal surgery. However, bacterial colonization and subsequent dense biofilm formation on implanted scaffolds often lead to persistent infections, posing a major barrier to clinical translation. The development of antibacterial-functionalized biodegradable scaffolds is therefore crucial for advancing next-generation orthopedic implants. Herein, we report the fabrication of a biodegradable hybrid scaffold exhibiting synergistic chemical and second near-infrared (NIR-II) photothermal antibacterial activity. The scaffold was fabricated via a precisely controlled thermally induced phase separation (TIPS) technique, integrating a poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PELA) triblock copolymer, hydroxyapatite (HA), and mesoporous polydopamine microspheres modified with silver nanoparticles (Ag-mPDA). The biodegradable PELA matrix establishes an optimal mechanical microenvironment for bone regeneration, while HA incorporation enhances scaffold osteoconductivity. Notably, the Ag-mPDA nanoparticles exhibit a dual-mode antibacterial action, combining sustained Ag⁺ release with NIR-II laser-triggered photothermal effect. This synergistic chemo-photothermal antibacterial strategy effectively combats implant-associated bacterial infections, offering a promising and versatile platform for smart biodegradable orthopedic implants.