Abstract
Background. Bacterial resistance to antibiotics is a constantly growing challenge.
Photodynamic therapy (PDT) offers a new approach to the treatment of bacterial and viral diseases. The aim of this study was to compare the efficacy of photosensitizers used in PDT applied to cell lines and bacterial strains.
Methods. We tested the cytotoxicity and phototoxicity of 3 photosensitizers: TPPS 4, ZnTPPS 4 and TMPyP applied to the NIH3T3 cell line using two established methods for measuring ROS production and, MTT viability assay.
Bacterial viability was determined spectrophotometrically over 24 h following PDT. Results.
The most efficient photosensitiser was TMPyP as it reduced the viability of the NIH3T3 cell line by more than 85%. In general, the photosensitisers were more phototoxic to the two Gram-positive bacterial strains, Enterococcus faecalis and Staphylococcus aureus.
The viability of E. faecalis was reduced to 78 % by a dose radiation 0.5 J/cm2 and concentration of TMPyP 1.562 mol/L. The viability of bacterium S. aureus was reduced to 23 % when exposed to a radiation dose 0.5 J/cm2 and 100 mol/L concentration of ZnTPPS 4.
The highest viability decrease (15 %) for Pseudomonas aeruginosa was caused by 0.5 J/cm2 radiation dose and 50 mol/L TMPyP concentration. Escherichia coli proved to be PDT resistant as the bacterial viability was higher than 90%.
Conclusions. The goal of the present study was to test the efficiency of photosensitizers on the NIH 3T3 cell line and bacterial cells.
Subsequently we would like to study effectiveness of photosensitizers bound to carriers (for example cyclodextrins) on other cell line and bacterial strain.