Accelerating Sono-Piezoelectric Charge Transport for Antibacterial Therapy and Bone Regeneration by Metal-Deficient TiO2 Spin-Polarization Effect

Sonodynamic therapy (SDT) is recognized as an effective method for treating deep tissue bacterial infections, but enhancing charge transfer to achieve efficient SDT remains a formidable challenge. Here, deficient TiO 2 (DTO) is fabricated and Barium titanate (BTO) heterojunction with oxygen vacancies (OVs) and abundant Ti 3+ species on a Ti substrate. The OVs in DTO not only narrow the band gap of TiO 2 but also expedite the transfer of surrounding electrons to Ti 3+ . Meanwhile, the spin-polarization effect induced by the unpaired spin electrons in Ti atoms can expedite the transfer of ultrasonic piezoelectric charges in BTO, enhancing surface sonocatalytic efficiency. Consequently, the DTO/BTO with US irradiation can eradicate 99.82% of Staphylococcus aureus and inhibit biofilm formation. Additionally, the microcurrent generated by ultrasound-excited DTO/BTO enhanced mitochondrial fusion and promoted osteoblastic differentiation. The successful application of this ultrasound-mediated DTO/BTO in treating bone infection defects offers an effective antibiotic-free therapeutic strategy for deep-seated infections.