Multi-modal antibacterial lignin-based nanocomposites with photothermal and free radical therapy for bacterial infection treatment

Bacterial infections remain a serious global health concern, exacerbated by the rise of drug-resistant strains. In this study, we present a smart, thermo-responsive antibacterial nanocomposite that synergistically integrates photothermal therapy and free radical generation to effectively combat bacterial infections. Gold nanoparticles (AuNPs), stabilized by lignin, self-assemble into sea urchin-like LNPs-AuNPs with efficient photothermal conversion efficiency under near-infrared (NIR) irradiation. The incorporation of azo compound AIPH enables the release of oxygen-independent alkyl radicals upon heating, further enhancing its antibacterial effect. Both in vitro assays and in vivo experiments, including a rat skin infection model, demonstrated that the LNPs-Au/AIPH effectively eradicate S. aureus and E. coli, reduce inflammation, and accelerate tissue healing. This dual-mode nanoplatform offers a promising antibiotic-free strategy for combating bacterial infections, with enhanced therapeutic efficacy and minimal side effects.