Comparison of the Antimicrobial and Hemolytic Activities of Various Forms of Silver (Ions, Nanoparticles, Bioconjugates) Stabilized in a Zeolite Matrix.

A quantitative and qualitative comparison of the antimicrobial and hemolytic activities of silver in various states, in the form of ions, nanoparticles, and bioconjugates with the antimicrobial protein lysozyme stabilized in an inert zeolite matrix, has been carried out. A synthetic zeolite with a β structure was chosen as a zeolite matrix. Using the ion-exchange method, the method of chemical reduction, and treating the matrix with a silver hydrosol with specified characteristics, samples of zeolites with the same silver content in various forms (Ag+, Ag° - Ag°/Lyz) in the amounts of 0.8 and 5 wt % have been synthesized. The samples obtained were studied by a complex of physicochemical research methods: X-ray diffraction, UV absorption spectroscopy, low-temperature nitrogen adsorption, electron microscopy, and atomic absorption. Antimicrobial activity was assessed against antibiotic-resistant Gram-negative microbe (e.g., Escherichia coli ML-35, Pseudomonas aeruginosa 522/17 MDR, Klebsiella pneumoniae ESBL 344) and Gram-positive microbe (e.g., Staphylococcus aureus 1399/17). The hemolytic activity in relation to human erythrocytes was estimated. The results obtained showed significant antimicrobial activity with a simultaneously high hemolytic activity of ionic silver. Silver nanoparticles have a lower level of antimicrobial activity and toxicity. Bioconjugates of silver nanoparticles and lysozyme showed an optimal combination of antimicrobial properties and lack of hemolytic activity.