Singlet oxygen luminescence kinetics under PDI relevant conditions of pathogenic dermatophytes and molds

• Published in: Journal of photochemistry and photobiology. B, Biology Biology, 2018-01, Vol.178, p.606-613
• Main Authors: Bornhütter, Tobias, Shamali, Nedaa, Saltsman, Irena, Mahammed, Atif, Gross, Zeev, Däschlein, Georg, Röder, Beate
• Format: Article
• Language: English
• Subjects: Cations; Correlation analysis; Darkness; Deactivation; Diffusion; Drug development; Fluorescence; Fungi; Inactivation; Kinetics; Luminescence; Onychomycosis; Oxygen; Photodynamic inactivation of microorganisms; Photodynamic therapy; Scopulariopsis brevicaulis; Singlet oxygen; Studies; Trichophyton rubrum
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2017.12.015

A treatment of onychomycosis using the photodynamic effect would be a favorable alternative to currently used antimycotic drugs. This study should be considered as a first step towards development and control of an efficient photodynamic inactivation of onychomycosis causative pathogens. Here, we evaluate the usage of time-resolved 2D singlet oxygen luminescence detection in combination with 2D fluorescence scanning as a tool to understand the behavior of the photosensitizer when applied to fungi on Petri dishes. To investigate the interaction of photosensitizer with fungi in various concentrations and in different stages of live, a photodynamic inactivation was avoided by keeping the samples in darkness. Scans of singlet oxygen luminescence and photosensitizer fluorescence were performed over a period of 24days. Two different photosensitizer, a cationic porphyrin and cationic corrole and two fungi strains, the dermatophyte Trichophyton rubrum and the mold Scopulariopsis brevicaulis, were investigated in this study. The two-dimensional correlation of photosensitizer fluorescence and singlet oxygen luminescence revealed differences in the diffusion of both photosensitizer. Even though the singlet oxygen luminescence was quenched with increasing growth of fungi, it was found that the kinetics of singlet oxygen luminescence could be detected on Petri dishes for both photosensitizers and both fungi strains for up to seven days. •For PDI of onychomycosis, a time-resolved 1O2 luminescence study on agar plates with two fungi strains was performed.•2D scans of time-resolved 1O2luminescence and photosensitizer fluorescence were performed for up to 24days.•The kinetics of photosensitized generated singlet oxygen luminescence could be determined up to seven days.•Correlation of 1O2 luminescence and photosensitizer fluorescence reports about different behavior of the photosensitizers.