Ultrasound-Activated BiOI/Ti(3)C(2) Heterojunctions in 3D-Printed Piezocatalytic Antibacterial Scaffolds for Infected Bone Defects.

Piezocatalytic therapy (PCT) is a promising strategy for combating implant-associated infections due to its high tissue penetration depth and non-invasive nature. However, its catalytic efficiency remains limited by inefficient electron-hole separation. In this work, an ultrasound-responsive heterojunction (BiOI/Ti(3)C(2)) was fabricated through in situ growth of bismuth iodide oxide on titanium carbide nanosheets. Subsequently, we integrated BiOI/Ti(3)C(2) into poly(e-caprolactone) (PCL) scaffolds using selective laser sintering. The synergistic effect between BiOI and Ti(3)C(2) significantly facilitated the redistribution of piezo-induced charges under ultrasound irradiation, effectively suppressing electron-hole recombination. Furthermore, abundant oxygen vacancies in BiOI/Ti(3)C(2) provide more active sites for piezocatalytic reactions. Therefore, it enables ultrahigh reactive oxygen species (ROS) yields under ultrasound irradiation, achieving eradication rates of 98.87% for Escherichia coli (E. coli) and 98.51% for Staphylococcus aureus (S. aureus) within 10 minutes while maintaining cytocompatibility for potential tissue integration. This study provides a novel strategy for the utilization of ultrasound-responsive heterojunctions in efficient PCT therapy and bone regeneration.