How can the visible spectra describe interaction of nanoparticles with microbes

Spectroscopic studies are widely used in biological and biomedical studies to evaluate sample composition, concentration, biological activity of drugs, etc. Mainly the ultraviolet spectra are studied. However, visible spectra with preliminary dyeing may also be used. In the work we show that the visible spectra of microbes with nanoparticles show the nanoparticles adsorption on the microbes and allow one to evaluate the microbes death due to the action of the nanoparticles. Experiments were conducted with Au nanoparticles and Bacillus subtilis B-5007, Lactobacillus delbrueckii subsp. bulgaricus and Saccharomyces cerevisiae. The results of the study may be used for a quick analysis of the nanoparticles action on microbes. Furthermore, the results indicate a similar mechanism of interaction of nanoparticles with different microbes.