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  1. Article: Photodynamic inactivation of Escherichia coli – Correlation of singlet oxygen kinetics and phototoxicity

    Müller, Alexander / Annegret Preuß / Beate Röder

    Journal of Photochemistry & Photobiology, B: Biology. 2017,

    2017  

    Abstract: ... luminescence kinetics and phototoxicity in E. coli cell suspension under PDI using the widely applied cationic ...

    Abstract Photodynamic inactivation (PDI) of bacteria may play a major role in facing the challenge of the ever expanding antibiotic resistances. Here we report about the direct correlation of singlet oxygen luminescence kinetics and phototoxicity in E. coli cell suspension under PDI using the widely applied cationic photosensitizer TMPyP. Through direct access to the microenvironment, the time resolved investigation of singlet oxygen luminescence plays a key role in understanding the photosensitization mechanism and inactivation pathway. Using the homemade set-up for highly sensitive time resolved singlet oxygen luminescence detection, we show that the cationic TMPyP is localized predominantly outside the bacterial cells but in their immediate vicinity prior to photodynamic inactivation. Throughout following light exposure, a clear change in singlet oxygen kinetics indicates a redistribution of photosensitizer molecules to at least one additional microenvironment. We found the signal kinetics mirrored in cell viability measurements of equally treated samples from same overnight cultures conducted in parallel: A significant drop in cell viability of the illuminated samples and stationary viability of dark controls. Thus, for the system investigated in this work – a Gram-negative model bacteria and a well-known PS for its PDI – singlet oxygen kinetics correlates with phototoxicity. This finding suggests that it is well possible to evaluate PDI efficiency directly via time resolved singlet oxygen detection.
    Keywords antibiotic resistance ; bacteria ; cell viability ; Escherichia coli ; luminescence ; models ; photosensitivity ; photosensitizing agents ; phototoxicity ; singlet oxygen
    Language English
    Size p. .
    Publishing place Elsevier B.V.
    Document type Article
    Note Pre-press version
    ZDB-ID 623022-2
    ISSN 1873-2682 ; 1011-1344
    ISSN (online) 1873-2682
    ISSN 1011-1344
    DOI 10.1016/j.jphotobiol.2017.11.017
    Database NAL-Catalogue (AGRICOLA)

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  2. Article: Photodynamic inactivation of mold fungi spores by newly developed charged corroles

    Preuß, Annegret / Irena Saltsman / Atif Mahammed / Michael Pfitzner / Israel Goldberg / Zeev Gross / Beate Röder

    Journal of Photochemistry & Photobiology, B: Biology. 2014 Apr. 05, v. 133

    2014  

    Abstract: ... of different diseases, e.g. of cancer, has recently been introduced for the inactivation of bacteria ...

    Abstract The photodynamic effect, originally used in photodynamic therapy (PDT) for the treatment of different diseases, e.g. of cancer, has recently been introduced for the inactivation of bacteria. Mold fungi, which provoke health problems like allergies and diseases of the respiratory tract, are even more resistant and their biology is also very different. This study presents the development of four new photosensitizers, which, in combination with low doses of white light, inhibit the germination of mold fungi spores. Two of them even cause lethal damage to the conidia (spores) which are responsible for the spreading of mold fungi. The photoactivity of the newly synthesized corroles was obtained by their application on three different mold fungi: Aspergillus niger, Cladosporium cladosporoides, and Penicillium purpurgenum. To distinguish between inactivation of germination and permanent damage, the fungi were first incubated under illumination for examination of photosensitizer-induced growth inhibition and then left in darkness to test the survival of the conidia. None of the compounds displayed dark toxicity, but all of them attenuated or prevented germination when exposed to light, and the positively charged complexes induced a complete damage of the conidia.
    Keywords Aspergillus niger ; Cladosporium ; Penicillium ; bacteria ; conidia ; fungi ; germination ; growth retardation ; hypersensitivity ; lighting ; neoplasms ; photosensitizing agents ; respiratory tract diseases ; therapeutics ; toxicity ; white light
    Language English
    Dates of publication 2014-0405
    Size p. 39-46.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 623022-2
    ISSN 1873-2682 ; 1011-1344
    ISSN (online) 1873-2682
    ISSN 1011-1344
    DOI 10.1016/j.jphotobiol.2014.02.013
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Photodynamic inactivation of biofilm building microorganisms by photoactive facade paints

    Preu, Annegret / Tobias BornhtterauthorDepartment of Physics, Humboldt-Universitt zu Berlin, Newtonstrae 15, 12489 Berlin, Germany / Alexander FrberauthorSto SE & Co. KGaA, Ehrenbachstrae 1, D-79780 Sthlingen, Germany / Christian SchallerauthorSto SE & Co. KGaA, Ehrenbachstrae 1, D-79780 Sthlingen, Germany / Beate RderauthorDepartment of Physics, Humboldt-Universitt zu Berlin, Newtonstrae 15, 12489 Berlin, Germany
    Language English
    Document type Article
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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