Antibacterial Action of Silver Nanoparticles

Abstract

Objective. To determine the minimum inhibitory concentration of Ag nanoparticles in relation to clinical pathogenic strains of microorganisms. Methods. The minimum inhibitory concentration of Ag nanoparticles, obtained by metal vapor synthesis was studied on six strains of pathogenic bacteria, including representatives of gram-positive and gram-negative groups. The microbiological analyzer Vitek 2 Compact was used to identify each strain and to determine the antibiogram. The metal nanoparticles used in the study were synthesized by the method of metalvapor synthesis. Ag nanoparticles were studied by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods. Determination of the minimum inhibitory concentration was performed by the method of serial dilution using sterile 96-well plates with using the tests of positive and negative control. The concentration of microorganisms was controlled by the turbidity standard. Results. All pathogenic strains of bacteria used in the study were characterized by pronounced polyantibiotic resistance, and the percentage of antibiotics against which the strain was resistant ranged from 12.5 to 93.3%. The minimum inhibitory concentration of silver nanoparticles ranged from 7.81 to 31.25 μg/ml, depending on the type of microorganism. Gram-positive microorganisms, in contrast to gram-negative ones, were characterized by lower values of the minimum inhibitory concentration. The data of transmission electron and X-ray photoelectron spectroscopy showed that the size of the studied nanoparticles is in the range of 2-15 nm. Conclusion. Silver nanoparticles (2-15 nm in size) have antimicrobial action against clinically significant, polyantibiotic-resistant strains of microorganisms. The minimum inhibitory concentration of silver nanoparticles, depending on the strain of the microorganism, varies from 7.81 to 31.25 μg/ml. Silver nanoparticles have an inhibitory impact on microorganisms and to a greater extent inhibit the growth of gram-positive versus gram-negative. The obtained materials based on silver nanoparticles represent an effective alternative to the currently used antibacterial drugs.