Defect-engineered layered double hydroxide/CuS heterojunction enabling synergistic photothermal-photodynamic antibacterial therapy

Defect-engineered a-CoMo/CuS heterojunction nanosheets enable NIR-IIb (1550 nm) synergistic PDT/PTT therapy. • The nanosheets exhibit potent ROS generation and 50.02% PCE under 1550 nm excitation. • Synergistic PDT/PTT eradicates > 98% of E. coli and S. aureus in vitro via membrane damage and metabolic disruption. • In vivo , the nanosheets reduce bacteria by > 99% on day 3 and accelerate wound healing to 97.0% by day 9. Bacterial infections pose a major global health threat. While combining photodynamic therapy (PDT) and photothermal therapy (PTT) offers a promising antibacterial strategy, its efficacy remains limited by low singlet oxygen yields, insufficient photothermal efficiency and poor tissue penetration. Herein, we report defect-engineered a-CoMo/CuS heterojunction nanosheets for synergistic PDT/PTT antibacterial therapy under 1550 nm laser irradiation. Acid etching of CoMo-LDH introduces oxygen vacancies that narrow the bandgap and promote charge separation. Meanwhile, in situ growth of CuS nanoparticles forms a heterojunction that further enhances interfacial charge transfer and enables high photothermal conversion. Consequently, these nanosheets eradicate > 98% of both Escherichia coli and Staphylococcus aureus in vitro through synergistic membrane disruption and intracellular dysfunction. In a mouse infected wound model, the nanosheets reduce bacterial burden by > 99% at day 3 and achieve 97.0% ± 1.6% healing at day 9, with suppressed inflammation, promoted M2 macrophage polarization, enhanced angiogenesis and collagen deposition. Collectively, this work provides a defect-engineered heterojunction nanoplatform that integrates efficient photodynamic and photothermal effects for synergistic antibacterial therapy and infected tissue regeneration.