A multimodal defect-rich nanoreactor triggers sono-piezoelectric tandem catalysis and iron metabolism disruption for implant infections

Tracking and eradicating drug-resistant bacteria are critical for combating implant-associated infections, yet effective antibacterial therapies remain elusive. Herein, we propose an oxygen vacancy-rich (BiFe)_0.9(BaTi)_0.1O_3-_<i>x</i> nanoreactor as a piezoelectric sonosensitizer by spatiotemporal ultrasound-driven sono- and chemodynamic tandem catalysis to amplify antibacterial efficacy. The piezoelectric charge carriers under a built-in electric field synchronize the reaction of O₂ and H₂O, efficiently generating H₂O₂. The electron-rich oxygen vacancies modulate the local electronic structure of an Fe site. It facilitates reactive oxygen species generation by piezoelectric electrons and accelerates valence state cycles of Fe(III)/Fe(II) to achieve the sustained maintenance of hydroxyl radicals via H₂O₂/Fe(II)-catalyzed chemodynamic reactions, which lead to bacterial membrane damage. Transcriptomics analysis revealed that intracellular Fe overload induced by excessive Fe(II)-mediated dysregulation of the two-component system disrupts bacterial metabolism, triggering bacterial ferroptosis-like death. Thus, the porous titanium scaffold, engineered with a piezoelectric nanoreactor, demonstrates superior antibacterial efficacy under ultrasound and facilitates osteogenesis via piezoelectric immunomodulation-activated therapy.