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Updated: May 16, 2026

LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation
Published on: January 24, 2025
Photodynamic inactivation requires innovative approach concerning numerous bacterial isolates and multicomponent
Joanna Nakonieczna1, Mariusz Grinholc
1Laboratory of Molecular Diagnostics, Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland.
Abstract:
It is known that Staphylococcus aureus is susceptible to photodynamic inactivation in general, but the significant variation among particular strains in the response to the treatment exists. However, factors that determine the observed phenomenon remain unclear. This study was aimed to explore the PDI effect of two sensitizers (protoporphyrin diarginate and toluidine blue O) against clinical as well as reference strains of S. aureus. Obtained results indicate that the same isolate could be characterized as highly resistant or highly sensitive to PDI according to a sensitizer used. Moreover, the same sensitizing agent could be successfully used for total eradication of some isolates and could be non-effective in the case of other strains. Additionally, changing the photosensitizer, we are able to reverse the PDI "resistant" phenotype into "sensitive" one. Thus, one could conclude that photoinactivation involving several sensitizing agents and several isolates of the same bacterial species should be undertaken to make antimicrobial photodynamic inactivation reliable.
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