Metastructure and strain-defect engineered Cu-doped TiOx coating to enhance antibacterial sonodynamic therapy

Sonodynamic therapy (SDT) has attracted widespread attention in treatment of implant-associated infections, one of the key factors leading to implant failure. Nevertheless, constructing efficient ultrasound-triggered coatings on implant surfaces remains a challenge. Herein, an acoustic metastructure Cu-doped defective titanium oxide coating (Cu-TiO x ) with lattice strain was constructed in situ on titanium implant to realize effective sonocatalysis. The redistribution of Cu atoms broke the pristine lattice of TiO 2 during the thermal reduction treatment to regulate its energy structure, which favored separation of electron-hole pairs generated by ultrasound radiation to enhance the sonocatalytic generation of reactive oxygen species. In addition, the acoustic metastructure enhanced the absorption of ultrasound by Cu-TiO x metastructure coating, which further promoted its sonocatalytic effect. Thus, Cu-TiO x metastructure coating could efficiently eliminate Staphylococcus aureus and Escherichia coli infections under ultrasonic irradiation in 10 min. Besides, the osteogenic property of implant was significantly improved after infection clearance in vivo . This work provides a fresh perspective on the design of SDT biosurfaces based on metastructure and strain-defect engineering. • A defective titanium oxide coating of Cu-TiO x metastructure was constructed in situ on titanium surface. • Cu atomic doping led to lattice distortions, which resulted in the creation of band tailed states for enhanced sonocatalytic performance. • Cu-TiO x metastructure coating realized efficient antibacterial function under ultrasonic excitation. • The antibacterial and osteogenic properties were verified in a bacterial infection bone defect model.