A Photochemically Active CuO Nanoparticle Endows Scaffolds with Good Antibacterial Performance by Efficiently Generating Reactive Oxygen Species.

Cuprous oxide (CuO) has great potential in photodynamic therapy for implant-associated infections due to its good biocompatibility and photoelectric properties. Nevertheless, the rapid recombination of electrons and holes weakens its photodynamic antibacterial effect. In this work, a new nanosystem (CuO@rGO) with excellent photodynamic performance was designed via the in situ growth of CuO on reduced graphene oxide (rGO). Specifically, rGO with lower Fermi levels served as an electron trap to capture photoexcited electrons from CuO, thereby promoting electron-hole separation. More importantly, the surface of rGO could quickly transfer electrons from CuO owing to its excellent conductivity, thus efficiently suppressing the recombination of electron-hole pairs. Subsequently, the CuO@rGO nanoparticle was introduced into poly-L-lactic acid (PLLA) powder to prepare PLLA/CuO@rGO porous scaffolds through selective laser sintering. Photochemical analysis showed that the photocurrent of CuO@rGO increased by about two times after the incorporation of GO nanosheets, thus enhancing the efficiency of photogenerated charge carriers and promoting electron-hole separation. Moreover, the ROS production of the PLLA/CuO@rGO scaffold was significantly increased by about two times as compared with that of the PLLA/CuO scaffold. The antibacterial results showed that PLLA/CuO@rGO possessed antibacterial rates of 83.7% and 81.3% against and , respectively. In summary, this work provides an effective strategy for combating implant-related infections.