A Graphdiyne-Enabled TiO2/g-C3N4 Bio-Heterojunction for Visible-Light Antibacterial Photocatalysis and Infected Wound Healing

Visible-light-driven antibacterial photocatalysis holds great promise for infected wound management; however, efficient and biologically compatible heterointerfaces remain limited. Here, we constructed a graphdiyne-enabled TiO 2 /g-C 3 N 4 based bio-heterojunction (TCN/GDY) by growing graphdiyne (GDY) onto a TiO 2 /g-C 3 N 4 scaffold, which couples enhanced visible-light harvesting with antibacterial wound therapy. Structural characterization, photoelectrochemical measurements, valence band analysis, in situ XPS, electron paramagnetic resonance, and density functional theory support interfacial electronic coupling, an enhanced photoresponse, and reactive oxygen species generation. These observations are consistent with a proposed dual S-scheme like mechanism. Under 420 nm LED irradiation, TCN/GDY achieved >99% elimination of Escherichia coli , 99.40 ± 0.34% elimination of Staphylococcus aureus , and 98.65 ± 0.74% elimination of methicillin-resistant S. aureus ( MRSA ), and reduced retained crystal-violet-stained MRSA biofilm biomass by 78.57 ± 2.38% under the tested treatment and washing conditions. Multi-omics analysis identified treatment associated changes in central metabolism and nutrient transport. In an MRSA -infected mouse wound model, visible-light-activated TCN/GDY reduced the bacterial burden by 97.98 ± 1.04% and decreased the residual wound area to 2.93 ± 1.46% by day 11. This study establishes a graphdiyne-enabled TiO 2 /g-C 3 N 4 -based bio-heterojunction as a visible-light antibacterial photocatalytic platform for infected wound healing.