Silver-Containing Nanocomposites with Antimicrobial and Antiviral Activity

Infectious diseases caused by viruses and microorganisms continue to be one of the health problems worldwide, despite the rapid progress in the creation of drugs and the development of pharmaceutical technologies.
Therefore, today there is a need for new materials with a higher antiviral and bactericidal effect, and less toxicity for humans and the environment (ecology, medicine, and the food industry).

In this work,  silver-containing nanocomposites Na-CMC–Ag–chitosan of low, medium, and high molecular weight were synthesized by reducing silver ions in polyelectrolyte-metal complexes using ultraviolet irradiation of different wavelengths (λ = 254 nm and 365 nm) and by sputtering silver nanoparticles on the surface of polyelectrolyte complexes. 

The reduction of silver ions to metal nanoparticles was monitored by XRD.

Using the method of transmission electron microscopy, it was established that during the reduction of silver ions by ultraviolet irradiation with a wavelength of λ = 254 nm, smaller nanoparticles are formed than at 365 nm. It was found that in samples Na-CMC–Ag–chitosan  of low, medium, and high molecular weight, the size of nanoparticles increases with an increase in the molecular weight of the cationic polyelectrolyte. A layer of ~200 nm thick Ag particles is formed in nanocomposites Na-CMC–Ag–chitosan low molecular weight  obtained by sputtering silver nanoparticles.

A tendency towards an increase in antimicrobial activity in samples based on Na-CMC and chitosan was established with a decrease in the molecular weight of chitosan in relation to the test cultures of microorganisms S. aureus, E. coli, P. aeruginosa, C. albicans. It was shown that samples of Na-CMC – Ag – chitosan of low molecular weight, obtained by ultraviolet irradiation of silver ions of a shorter wavelength, exhibit higher antimicrobial activity against the microorganisms under study.

Antiviral activity of the created silver-containing nanocomposites against influenza A virus and herpes simplex virus 1 was revealed.
Cytotoxicity studies of nanocomposites on two cell lines MDCK and BHK show that the obtained samples are non-toxic.