Household LED Light-Mediated Photodynamic Therapy for Effective Inhibition of Multidrug-Resistant Staphylococcus aureus.

This study evaluates toluidine blue-O and curcumin (CUR) as photosensitizers (PSs) for photodynamic therapy against Staphylococcus aureus, each activated using a household light-emitting diode bulb selected to approximate the absorption profiles of the respective PS. The colony-forming unit (CFU) assay revealed time-dependent bacterial reductions, achieving 4.85 log10 CFU/mL at 10 min for TBO and 4.26 log10 CFU/mL at 15 min for CUR under their respective LED illumination conditions. Extracellular polymeric substance production decreased by 96.22% with TBO and 48.98% with CUR, accompanied by enhanced reactive oxygen species generation. Confocal laser scanning microscopy provided semi-quantitative evidence of an increased dead-to-live cell ratio following PDT. In vivo results, supported by histopathological examination and cytokine expression profiling, demonstrated modest but significant bacterial load reduction and improved tissue architecture following TBO- and CUR-mediated PDT. These findings suggest that readily available household LED bulbs may serve as accessible illumination sources for aPDT against S. aureus.