A multifunctional antibacterial coating on bone implants for osteosarcoma therapy and enhanced osteointegration

• A multifunctional coating consisted of nano-shovel was fabricated on titanium. • The novel structure could improve the photothermal conversion ability of titanium. • The coating could inhibit bone tumor growth at a temperature of 48 ℃. • The coating could eliminate biofilms under 1060 nm laser irradiation. • The coating could promote angiogenesis and osteogenic differentiation. After prosthesis replacement for the treatment of bone tumors, incomplete removal of tumor cells is the main challenge. Moreover, combating implant-associated infection and simultaneously promoting osseointegration are highly demanded for orthopedic implants and therefore, a multifunctional coating that produces tumor therapeutic effects, antibacterial activity, and osteogenesis at the same time is of clinical significance. Herein, a phototherapy platform composed of rare-earth elements - doped titanium dioxide nano-shovel/quercetin/L-arginine (TiO 2 @UCN/Qr/LA) on titanium bone implant is fabricated. The stable nano-shovel structure prepared by a hydrothermal method improves the photothermal conversion ability of titanium. Incorporation of Yb and Er enhances the upconversion capability, thereby facilitating generation of reactive oxygen species (ROS) during exposure to near-infrared II (NIR-II) light. Furthermore, under the action of ROS, L-arginine is catalyzed to release nitric oxide (NO) free radicals. In vitro and in vivo experiments indicate that the combined actions of ROS, quercetin, and NO not only inhibit bone tumor growth at a temperature of 48 ℃, but also eliminate Staphylococcus aureus biofilms on the Ti implants at a mild temperature of 45 ℃ upon illumination with a 1,060 nm laser. Moreover, TiO 2 @UCN/Qr/LA promotes angiogenesis and osteogenic differentiation, reduces inflammation, and accelerates formation of new bone tissues.