# Antimicrobial Effect of Submicron Complex Oxide Particles CsTeMoO\({}_{6}\) under Visible Light
## 5 Conclusions  
Thus, the studied complex oxide CsTeMoO\({}_{6}\) has an antimicrobial effect both in the dark and under light exposure to _E. coli_ and _S. aureus_, as well as to spores and vegetative mycelium of _P. chrysogenum_ and _A. niger_. The greatest inhibitory effect of submicron CsTeMoO\({}_{6}\) particles was noted against _E. coli_. The antimicrobial effect of the test compound CsTeMoO\({}_{6}\) against bacteria and fungi increases under visible light source power 50 W and surface radiation flux density 524 W/m\({}^{2}\), which should be explained by its photocatalytic activity. The duration of exposure had an ambiguous effect on the antimicrobial effect CsTeMoO\({}_{6}\). In some cases, the survival rate of microorganisms was decreased with an increased in the time of exposure in under light and dark conditions, but in some cases, it did not change or, on the contrary, it even increased. Comparing the antimicrobial effect of CsTeMoO\({}_{6}\) and RbTe\({}_{1.5}\)W\({}_{0.5}\)O\({}_{6}\) compounds against of the same studied microorganisms, it can be noted that the latter one has stronger antimicrobial effect. The degree of suppression of the vital activity of individual cultures by these compounds is also different, which confirms the validity of the assertion that the antimicrobial effect of nano- and submicron particles of metal oxides with photocatalytic activity depends on the nature of the metals in these compounds. It was shown that the oxidation of biomolecules by CsTeMoO\({}_{6}\) under the action of visible light can lead to the death of living organisms and can occur due to the formation of both electron-hole pairs and ROS. The variability in the extent of inhibition observed in our experiments could also be associated with the presence of anatomical, morphological, physiological, and biochemical characteristics within the studied groups of microorganisms. These factors could potentially influence the penetration processes of the compound into cells through the cell wall and cytoplasmic membrane. The obtained results expand theoretical concepts in the field of photobiology, namely, in terms of studying the antimicrobial effect and the mechanisms of its manifestation by nano- and submicron particles of complex metal oxides with photocatalytic activity. It is very important to compare the effect of submicron metal oxide particles of different chemical structure on various groups of microorganisms, as well as to reveal the dependence of antimicrobial activity on the size, shape of particles, the power of radiation sources, and the characteristics of their wave spectrum. The photocatalytic activity of complex metal oxides makes it possible to selectively regulate their antimicrobial activity against certain types of microorganisms. It facilitates the use of such compounds as antimicrobial agents in various industries, in medicine and in veterinary medicine. Moreover, these chemicals can be used for wastewater treatment. Conceptualization, L.S., V.S. ; data curation, O.S., A.S., A.K. and D.F. ; funding acquisition, E.S. ; investigation, N.A., O.S., A.K. and A.S., methodology, O.S. and D.F. ; project administration, E.S., L.S. and V.S. ; supervision, E.S. ; validation, L.S. and V.S. ; visualization, D.F. and A.S.; writing--original draft, O.S. ; writing--review and editing, A.S., N.A. and D.F. All authors have read and agreed to the published version of the manuscript. This research was funded by the Ministry of Education and Science of the Russian Federation (assignment FSWR-2023-0024) using the equipment of the Collective Usage Center \"New Materials and Resource-saving Technologies\" (Lobachevsky State University of Nizhny Novgorod). **Institutional Review Board Statement:** Ethical review and approval were waived for this study, due to There were no human or animal experiments involved. The cultures of microorganisms from the study were used only for research in the laboratory. After the experiment, all cultures of microorganisms were sterilized to prevent their release into the environment.