Photo-Responded Antibacterial Therapy of Reinfection in Percutaneous Implants by Nanostructured Bio-Heterojunction.

Percutaneous implants may experience infection for several times during their servicing periods. They need antibacterial activity and durability to reduce recurrent infection and cytocompatibility to reconstruct biosealing. A novel photoresponse bio-heterojunction (PCT) is developed herein. It consists of TiO2 nanotubes loaded with CuS nanoparticles and wrapped with polydopamine (PDA) layer. In PCT, a built-in electric field directing from TiO2 to CuS and then to PDA is formed, and with near-infrared (NIR) irradiation, it drives photoexcited electrons to transfer in opposite direction, resulting in the separation of electron-hole pairs and formation of reactive oxygen species (ROS). Simultaneously, PCT shows photothermal effect due to nonradiative relaxation of photoexcited electrons and thermal vibration of lattices. The synergic effect of photogenerated ROS and hyperthermia increases bacterial membrane permeability and leakage of cellular components, endowing PCT with outstanding antibacterial performance. More importantly, PCT has good antibacterial durability and cytocompatibility due to the inhibited leaching of CuS by PDA layer. In reinfected models, with NIR irradiation, PCT sterilizes bacteria, reduces inflammatory response and enhances re-integration of soft tissue efficiently. This work provides an outstanding bio-heterojunction for percutaneous implants in treating reinfection by NIR irradiation and rebuilding biosealing.