Zusammenfassung
Singlet oxygen (O-1(2)) is an important reactive intermediate in photodynamic reactions, particularly in antimicrobial PDT (aPDT). The detection of O-1(2) luminescence is frequently used to elucidate the role of O-1(2) in various environments, particularly in microorganisms and human cells. When incubating the fungus, Candida albicans, with porphyrins XF73 ...
Zusammenfassung
Singlet oxygen (O-1(2)) is an important reactive intermediate in photodynamic reactions, particularly in antimicrobial PDT (aPDT). The detection of O-1(2) luminescence is frequently used to elucidate the role of O-1(2) in various environments, particularly in microorganisms and human cells. When incubating the fungus, Candida albicans, with porphyrins XF73 (5,15-bis-[4-(3-Trimethylammonio-propyloxy)-phenyl]-porphyrin) or TMPyP (5,10,15,20-Tetrakis(1-methyl-4-pyridinio)-porphyrin tetra(p-toluenesulfonate)), the O-1(2) luminescence signals were excellent for TMPyP. In case of XF73, the signals showed strange rise and decay times. Thus, O-1(2) generation of XF73 was investigated and compared with TMPyP. Absorption spectroscopy of XF73 showed a change in absorption cross section when there was a change in the concentration from 1 x 10(-6) M to 1 x 10(-3) M indicating an aggregation process. The addition of phosphate buffered saline (PBS) substantially changed O-1(2) luminescence in XF73 solution. Detailed experiments provided evidence that the PBS constituents NaCl and KCl caused the change of O-1(2) luminescence. The results also indicate that Cl- ions may cause aggregation of XF73 molecules, which in turn enhances self-quenching of O-1(2) via photosensitizer molecules. These results show that some ions, e. g., those present in cells in vitro or added by PBS, can considerably affect the detection and the interpretation of time-resolved luminescence signals of O-1(2), particularly in in vitro and in vivo. These effects should be considered for any other photosensitizer used in photodynamic processes. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
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