Ultrasound-responsive ZnS:Ag QDs loaded TiO₂ biointerfaces: In situ sonodynamic antimicrobial therapy for biomedical implants

Sonodynamic therapy (SDT) is extensively utilized for its profound tissue penetration capabilities in treating deep-seated infections, yet achieving precise ultrasonic treatment at the implant surface remains challenging. Herein, details the development of a novel infection microenvironment-sensitive nano-interface (TN-HHTZ), aimed at enhancing SDT efficacy for treating implant-related infections. The ZnS:Ag quantum dots (ZnS:Ag QDs) are functionalized using tyramine-modified hyaluronic acid (HA-Tyr) and horseradish peroxidase (HRP), resulting in the formation of a hydrogen peroxide (H₂O₂)-sensitive composite sonosensitizer (HHTZ). HHTZ is loaded onto a titanium dioxide nanotube (TN) array to form TN-HHTZ. Upon infection, ultrasonic triggering causes the rapid release of HHTZ, which interacts with H₂O₂ in the infected area to form a gel, thereby enabling prolonged enrichment of ZnS:Ag QDs at the site of implant infection. The doping of Ag in ZnS:Ag QDs enhances energy conversion, enabling TN-HHTZ to generate a significant amount of reactive oxygen species (ROS) during the SDT process, thereby boosting its antimicrobial efficacy and ensuring sustained antimicrobial activity throughout the infection period. The TN-HHTZ hydrogel on the implant surface promotes bone cell proliferation and recovery, providing an innovative and holistic strategy for treating and recovering from implant-associated microbial infections.