This study evaluated the effi cacy of transcutaneous photodynamic therapy using blue (428 nm) LED irradiation on Staphylococcus aureus 11 in combination with a water-soluble cationic pyridyl porphyrin and optical clearing agents (OCA) in an ex vivo model. Results showed that OCA signifi cantly enhanced photodynamic inactivation with a 61% reduction in bacterial cell counts after 15 minutes of light exposure, comparable to direct irradiation.