A Photochemically Active Cu 2 O Nanoparticle Endows Scaffolds with Good Antibacterial Performance by Efficiently Generating Reactive Oxygen Species.

Cuprous oxide (Cu2 O) 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 (Cu2 O@rGO) with excellent photodynamic performance was designed via the in situ growth of Cu2 O on reduced graphene oxide (rGO). Specifically, rGO with lower Fermi levels served as an electron trap to capture photoexcited electrons from Cu2 O, thereby promoting electron-hole separation. More importantly, the surface of rGO could quickly transfer electrons from Cu2 O owing to its excellent conductivity, thus efficiently suppressing the recombination of electron-hole pairs. Subsequently, the Cu2 O@rGO nanoparticle was introduced into poly-L-lactic acid (PLLA) powder to prepare PLLA/Cu2 O@rGO porous scaffolds through selective laser sintering. Photochemical analysis showed that the photocurrent of Cu2 O@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/Cu2 O@rGO scaffold was significantly increased by about two times as compared with that of the PLLA/Cu2 O scaffold. The antibacterial results showed that PLLA/Cu2 O@rGO possessed antibacterial rates of 83.7% and 81.3% against Escherichia coli and Staphylococcus aureus , respectively. In summary, this work provides an effective strategy for combating implant-related infections.