Oxygen-vacancy-rich LDH sonosensitizers potentiate narrow-spectrum antibiotics via membrane-disruption strategy for mixed bacterial wound infections.

Mixed bacterial infections, including Gram-positive and Gram-negative pathogens, remain a major global health concern. Achieving efficient treatment of synergistic polymicrobial infections stills a tremendous clinical challenge due to antibiotic permeability barriers and resistance. Here, we construct a defect-engineered layered double hydroxide (LDH)-based sonosensitizer platform loaded with clindamycin (a-CoW/CLD) for mixed bacterial infection therapy, which not only demonstrates high efficacy against Gram-positive bacteria, but also exploits reactive oxygen species (ROS)-mediated membrane disruption of Gram-negative bacteria to facilitate CLD penetration, thereby achieving broad-spectrum and highly efficient killing of mixed bacteria. The amorphous a-CoW nanosheets, enriched with oxygen vacancies via acid etching, exhibit a substantially narrowed bandgap (1.22 eV) and markedly enhanced charge separation, producing 22.1-fold higher singlet oxygen under ultrasound (US) irradiation compared with pristine CoW. This ROS burst synergized with CLD achieves potent killing of Staphylococcus aureus (>99.9% at 20 μg mL-1). More critically, ROS disrupt the outer membrane of Gram-negative Escherichia coli, promoting CLD internalization and consequently boosting its lethality by 18.4-fold (from ∼5% to >92.1%). Mechanistic transcriptomics reveals ROS and CLD synergy: ROS disrupt the bacterial membrane via lipid peroxidation, enabling CLD penetration to block protein synthesis and metabolism, while ROS also induce oxidative stress, collectively leading to bacterial death. In a murine wound model co-infected with both pathogens, a-CoW/CLD plus US eradicates >99.9% of mixed bacteria, suppresses systemic inflammation, and significantly accelerates angiogenesis and re-epithelialization. This paradigm establishes a low-dose, broad-spectrum sonodynamic-antibiotic strategy that overcomes antibiotic permeability bottleneck, offering a promising therapeutic avenue against mixed bacterial infections.