BPEI-Stabilized Photocatalytic Au/Titania Nanoclusters with Enhanced Antimicrobial Activity for Wound Healing Applications.

Wound healing requires dressings with bactericidal effects, where photocatalysis utilizes solar energy to generate reactive oxygen species (ROS) for microbial inactivation. However, most photocatalysts depend on non-visible light, hindering solar-driven therapies. This study developed visible light-responsive Au/Titania/BPEI (TAB) nanoclusters embedded in PDMS, offering enhanced stability, antimicrobial efficacy, and resistance-free antibacterial action. TAB composites were synthesized as photocatalytic dressings, with Au nanoclusters enhancing visible-light activity. Characterization included XPS, BET, FTIR, XRD, SEM/TEM, and reflectance spectroscopy. Antibacterial performance was evaluated against pathogens under visible light (0-150 mW/cm²) using in vitro (3T3 cytotoxicity) and in vivo murine models, with ROS mechanisms analyzed. TA composites achieved 80% bacterial inhibition within 30 minutes of visible light exposure, attributed to ROS generation that disrupts bacterial DNA, membranes, and proteins. BPEI integration enhanced photocatalytic stability by reducing Aux aggregation and sustaining efficacy across light intensities (20-150 mW/cm²) with retained activity (>70% inhibition) even at saturation thresholds. In vivo models demonstrated reduced pro-inflammatory responses and accelerated healing, while 3T3 assays confirmed high biocompatibility (cell viability >90%). This visible light-activated system provides a resistance-free antibacterial alternative to antibiotics and alcohol-based disinfectants. While TA composites effectively address bacterial infections, limitations include residual bacteria (20% survival) and untested efficacy against fungi/viruses. Future work will optimize material performance for near-complete pathogen eradication and integrate biosensors for real-time infection monitoring. The adaptability of our platform to diverse light environments (sunlight to indoor lighting) and ROS-driven mechanism highlights its potential for clinical translation in combating multidrug-resistant infections.