An oxygen self-supplied CuO2@g-C3N4 heterojunction endows photodynamic antibacterial performance of scaffold

Graphite carbon nitride (g-C3N4) was regarded as a promising photodynamic antibacterial material due to its desirable bandgap and favorable visible light absorption. However, its photodynamic antibacterial effect was weakened by too rapid recombination of electron-hole and hypoxic environment of infection site. Herein, an oxygen self-supplied heterojunction was constructed via in-situ growing CuO2 on g-C3N4 (CuO2@g-C3N4). For the heterojunction, on the one hand, it could response to the weak alkaline of infected site to decompose to CuO@g-C3N4, where CuO could form a built-in electric field with g-C3N4 to promote the electron-hole separation. On the other hand, it could produce oxygen in the decomposition process, which achieved oxygen self-supply for photodynamic reaction. Subsequently, the heterojunction was introduced into poly-para-dioxane (PPDO) scaffold fabricated by laser additive manufacturing. The photoluminescence results confirmed that the electron-hole separation efficiency was significantly improved. The release kinetics results indicated that the scaffold could continuously release oxygen. As a consequence, the reactive oxygen species (ROS) generation ability of the scaffold was increased by approximately tenfold. The generated ROS effectively killed bacteria by disrupting membrane structure, triggering protein leakage and depleting glutathione. Eventually, the scaffold exhibited an antibacterial rate of 89.8% and 90.5% against S. aureus and E. coli, respectively.