Defect-engineered piezoelectric heterointerfaces enable ultrasound-amplified built-in electric fields for bacterial envelope destabilization and implant infection control

Built-in electric fields (BIEFs) at piezoelectric heterointerfaces are widely invoked to assist charge separation, but their contribution to antibacterial activity under ultrasound remains poorly understood. Here, we develop a defect-engineered piezoelectric heterointerface strategy to investigate BIEF-related interfacial electrical effects. Density functional theory (DFT)-guided screening identifies a dual-vacancy piezoelectric heterojunction (BTO 3-X /MoS 2-X ) with enhanced interfacial polarization. Under ultrasound, BTO 3-X /MoS 2-X efficiently kills Staphylococcus aureus , accompanied by pronounced bacterial envelope destabilization. This response is accompanied by membrane lipid perturbation, increased permeability, respiratory inhibition, and intracellular ROS accumulation. GROMACS simulations show that a model lipid bilayer destabilizes only under a sufficiently strong applied electric field. In infected implant models, ultrasound activated BTO 3-X /MoS 2-X reduces early peri-implant bacterial burden and promotes a repair-favorable inflammatory microenvironment. These findings highlight the potential contribution of BIEF-related interfacial electrical effects to ultrasound responsive antibacterial activity and offer a defect-engineering strategy for implant infection control.