The cytotoxic effect of graphene oxide nanoparticles on bacterial cells

The results of research on the introduction of nanotechnology in various fields of scientific activities are presented. In medical and veterinary practice, nanoparticles of various forms of carbon are considered promising, because they have a wide arsenal of biomodulatory effects on the body, exhibiting little ecotoxic and organismotoxic effects. Their antibacterial effect is of great importance for the use in medicine. Microorganisms are one of the objects of study of the cytotoxic properties of new medicinal products. The cytotoxic effect of oxidized graphene nanoparticles on the main types of bacterial cells was evaluated by light and atomic force microscopy. Light microscopy allowed to establish that the effect of subinhibitory concentrations of nanoparticles of oxidized graphene, achieved by studying the colonies of microorganisms on the border of their growth inhibition, can lead to tinctorial transversion in Gram-positive microorganisms, in particular Staphylococcus aureus, while in Gram-negative E. coli such a phenomenon is not observed. Using the method of atomic force microscopy, it was found that toxic concentrations of oxidized graphene nanoparticles lead to morphological degradation, the degree of which depends on the exposure time of nanoparticles. Morphological degradation of cells in the main types of bacteria (cocci, bacilli), accompanied by a decrease in cell contours, was observed at 30 min exposure. When the exposure was increased from 30 to 90 min, complete morphological destruction of the bacterial cells and decay of the bacterial population composition were observed. The cytotoxic concentration of oxidized graphene nanoparticles is more than 75 µg·ml-1, as determined by the results of microscopy of test culture samples (Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538).