Dual elemental doping activated signaling pathway of angiogenesis and defective heterojunction engineering for effective therapy of MRSA-infected wounds

Multi-drug resistant bacterial infections pose a significant threat to human health. Thus, the development of effective bactericidal strategies is a pressing concern. In this study, a ternary heterostructure (Zn-CN/P-GO/BiS) comprised of Zn-doped graphite phase carbon nitride (g-C₃N₄), phosphorous-doped graphene oxide (GO) and bismuth sulphide (Bi₂S₃) is constructed for efficiently treating methicillin-resistant <i>Staphylococcus aureus</i> (MRSA)-infected wound. Zn doping-induced defect sites in g-C₃N₄ results in a reduced band gap (Δ<i>E</i>) and a smaller energy gap (Δ<i>E</i>_ST) between the singlet state S₁ and triplet state T₁, which favours two-photon excitation and accelerates electron transfer. Furthermore, the formation of an internal electric field at the ternary heterogeneous interface optimizes the charge transfer pathway, inhibits the recombination of electron-hole pairs, improves the photodynamic effect of g-C₃N₄, and enhances its catalytic performance. Therefore, the Zn-CN/P-GO/BiS significantly augments the production of reactive oxygen species and heat under 808 nm NIR (0.67 W cm^-2) irradiation, leading to the elimination of 99.60% ± 0.07% MRSA within 20 min. Additionally, the release of essential trace elements (Zn and P) promotes wound healing by activating hypoxia-inducible factor-1 (HIF-1) and peroxisome proliferator-activated receptors (PPAR) signaling pathways. This work provides unique insight into the rapid antibacterial applications of trace element doping and two-photon excitation.