Cationic, anionic and neutral dyes: effects of photosensitizing properties and experimental conditions on the photodynamic inactivation of pathogenic bacteria
Author(s) -
Sonia Sabbahi,
Layla Ben Ayed,
A. Boudabbous
Publication year - 2013
Publication title -
journal of water and health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.482
H-Index - 59
eISSN - 1996-7829
pISSN - 1477-8920
DOI - 10.2166/wh.2013.219
Subject(s) - staphylococcus aureus , methylene blue , chemistry , pseudomonas aeruginosa , rose bengal , antimicrobial , photodynamic therapy , microbiology and biotechnology , photosensitizer , porphyrin , bacteria , potency , pathogenic bacteria , nuclear chemistry , in vitro , photochemistry , biochemistry , photocatalysis , organic chemistry , biology , genetics , catalysis
The aim of this study was to evaluate the photobactericidal effect of four photosensitizers (PSs) with different structural and physico-photochemical properties, namely mesotetracationic porphyrin (T4MPyP), dianionic rose Bengal (RB), monocationic methylene blue (MB) and neutral red (NR). Their photokilling activity was tested in vitro on pathogenic bacteria such as Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) suspended in nutrient broth (NB) and in phosphate buffered saline (PBS) through following their influence on the PSs antimicrobial efficacy. Photodynamic inactivation (PDI) experiments were performed using visible light (L) and different PSs concentrations (20–70 μM). The ability of these PSs to mediate bacterial photodynamic inactivation was investigated as a function of type of PS and its concentrations, spectral and physico-chemical properties, bacterial strain, irradiation time and suspending medium. Indeed, they showed antibacterial effects against S. aureus and P. aeruginosa with significant difference in potency. Staphylococcus aureus suspended in NB showed 0.92 log units reduction in viable count in the presence of T4MPyP at 20 μM. Changing the suspending medium from NB to PBS, S. aureus was successfully photoinactivated by T4MPyP (20 μM) when suspended in PBS at least time exposure (10 and 30 min), followed by MB and RB.
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