Maisch, Tim and Baier, Juergen and Franz, Barbara and Maier, Max and Landthaler, Michael and Szeimies, Rolf-Markus and Baeumler, Wolfgang (2007) The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 104 (17). pp. 7223-7228. ISSN 0027-8424,
Full text not available from this repository. (Request a copy)Abstract
New antibacterial strategies are required in view of the increasing resistance of bacteria to antibiotics. One promising technique involves the photodynamic inactivation of bacteria. Upon exposure to light, a photosensitizer in bacteria can generate singlet oxygen, which oxidizes proteins or lipids, leading to bacteria death. To elucidate the oxidative processes that occur during killing of bacteria, Staphylococcus aureus was incubated with a standard photosensitizer, and the generation and decay of singlet oxygen was detected directly by its luminescence at 1,270 nm. At low bacterial concentrations, the time-resolved luminescence of singlet oxygen showed a decay time of 6 +/- 2 mu s, which is an intermediate time for singlet oxygen decay in phospholipids of membranes (14 +/- 2 mu s)and in the surrounding water (3.5 +/- 0.5 mu s). Obviously, at low bacterial concentrations, singlet oxygen had sufficient access to water outside of S. aureus by diffusion. Thus, singlet oxygen seems to be generated in the outer cell wall areas or in adjacent cytoplasmic membranes of S. aureus. In addition, the detection of singlet oxygen luminescence can be used as a sensor of intracellular oxygen concentration. When singlet oxygen luminescence was measured at higher bacterial concentrations, the decay time increased significantly, up to approximate to 40 mu s, because of oxygen depletion at these concentrations. This observation is an important indicator that oxygen supply is a crucial factor in the efficacy of photodynamic inactivation of bacteria, and will be of particular significance should this approach be used against multiresistant bacteria.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GRAM-NEGATIVE BACTERIA; MESOSUBSTITUTED CATIONIC PORPHYRINS; CELLS IN-VITRO; STAPHYLOCOCCUS-AUREUS; PHOTOSENSITIZED PORPHYRINS; 5-AMINOLEVULINIC ACID; INDOCYANINE GREEN; ACTINIC KERATOSIS; DEUTERIUM-OXIDE; THERAPY; luminescence; oxygen depletion; Staphylococcus aureus |
| Subjects: | 500 Science > 530 Physics 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie Physics > Institute of Experimental and Applied Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2020 11:09 |
| Last Modified: | 14 Dec 2020 11:09 |
| URI: | https://pred.uni-regensburg.de/id/eprint/32876 |
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