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

ABSTRACT

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 log ₁₀ CFU/mL at 10 min for TBO and 4.26 log ₁₀ 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 .