Antibacterial Activity and Mechanism of ZnO/Cu2+-Chitosan/Montmorillonite

In Vitro Antimicrobial Activity Of Layered Silicate Materials

Objective — to assess the presence of a direct antimicrobial effect of natural minerals (ammonite; montmorillonite of the Azerbaijani deposit; calcium montmorillonite, or light clay, and sodium montmorillonite, or dark clay, of the Gerpegezh deposit in Kabardino-Balkaria; serpentinite) against strains of Staphylococcus aureus, Escherichia coli and yeast-like Candida fungi. Material and Methods — The antimicrobial activity was investigated by qualitative and quantitative methods; the methods of X-ray diffraction and X-ray fluorescence analysis were used to assess the chemical composition of samples of natural minerals. The results were statistically processed. Results — We established that ammonite, montmorillonite of Azerbaijani origin and serpentinite did not have a direct antimicrobial effect against the studied cultures of bacteria and fungi (S. aureus, E. coli, Candida albicans). The growth of S. aureus was suppressed by calcium and sodium montmorillonite from the Gerpegezh deposit. Sodium montmorillonite had the strongest antibacterial effect, and its dose-dependent effect was revealed. According to the data of X-ray fluorescence analysis, in the structure of, trivalent iron and oxides of manganese and titanium predominated in the samples of dark Gerpegezh clay with a more pronounced anti-staphylococcal effect. Conclusion — Our study demonstrated the possibilities and limitations of using various samples of layered silicate minerals for antibacterial solutions. The spectrum of antimicrobial activity largely depends on the unique composition of mineral complexes. Samples with a high content of iron(III) can be considered promising in the development of natural antimicrobial preparations.