The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

摘要: New antibacterial strategies are required in view of the increasing resistance bacteria to antibiotics. One promising technique involves photodynamic inactivation bacteria. Upon exposure light, a photosensitizer can generate singlet oxygen, which oxidizes proteins or lipids, leading death. To elucidate oxidative processes that occur during killing bacteria, Staphylococcus aureus was incubated with standard photosensitizer, and generation decay oxygen detected directly by its luminescence at 1,270 nm. At low bacterial concentrations, time-resolved showed time 6 ± 2 μs, is an intermediate for phospholipids membranes (14 μs) surrounding water (3.5 0.5 μs). Obviously, had sufficient access outside S. diffusion. Thus, seems be generated outer cell wall areas adjacent cytoplasmic aureus. In addition, detection used as sensor intracellular concentration. When measured higher increased significantly, up ≈40 because depletion these concentrations. This observation important indicator supply crucial factor efficacy will particular significance should this approach against multiresistant