Investigation of the influence of the photodynamic effect on micro-organisms using the laser photothermal cytometry method

An investigation of the influence of the photodynamic effect on S. aureus and E. coli bacteria in the presence of blood cells was made by the laser photothermal cytometry method. Elements of the theory of the photothermal method are considered for the case of pulsed lasers used in microscopy. Chlorin in doses of 0.02 mg litre(-1) was used as a photosensitiser. The results of the investigation made it possible to propose the possibility of an immunomodulation effect caused by introducing photoactivated chlorin into the cell-microbe system. It was found that the photothermal parameters of the cells interacting with microbes in the presence of photoactivated chlorin differed from the parameters of intact cells much less than in the absence of chlorin. However, a more pronounced bactericidal effect was observed in the samples treated with chlorin.