Molecular characteristics of the photosensitizer TONS504: Comparison of its singlet oxygen quantum yields and photodynamic antimicrobial effect with those of methylene blue

TONS504 (C51H58O5I2) is a chlorin derivative that exhibits photodynamic antimicrobial effect (PAE) on various infectious keratitis pathogens. However, the molecular characteristics of are not well understood. This study aimed to investigate by comparing its singlet oxygen (1O2) quantum yields and PAE with those methylene blue (MB). To measure 1O2 yields, MB were dissolved in phosphate-buffered saline containing 1% Triton X-100. The solutions then activated Nd:YAG laser an average output power 8 mW. Near-infrared luminescence was detected as indicator yields. evaluate PAE, light-emitting diode total light energy 30 J/cm2. We compared minimum molar concentration each photosensitizer show apparent PAEs Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans. exhibited higher than PBS/Triton X-100 but PBS. S. aureus C. albicans reduced at lower concentrations MB, this case for P. aeruginosa. Our results provide insight suggest has excellent PAE. Compared PBS stronger efficacy toward some pathogens others.