Antimicrobial efficacy of mixtures of silver nanoparticles and polyhydric alcohols against health-promoting bacteria

In the present study, the effectiveness of a mixture of silver nanoparticles with polyhydric alcohols (glycerol, erythritol, mannitol and xylitol) against six species of healthpromoting bacteria have been examined. Synthesis of silver nanoparticles was carried out using trisodium citrate as the reducing and stabilizing agent. The nanoparticles were characterized by electronic absorption, scanning electron microscopy and powder X-ray diffraction measurements. Electronic absorption spectrum revealed high uniform of synthesized nanoparticles. Practically no aggregation was observed when nanoparticles were mixed with polyhydric alcohols, suggesting weak interaction between ingredients of the mixture. Spherical silver nanoparticles, as depicted by scanning electron microscopy, were found to have diameters in the range of 10 to 30 nm; mean diameter was 18 ± 4 nm. The X-ray diffraction pattern of the prepared samples indicated the face-centred cubic crystalline structure of the metallic silver nanoparticles. In biological study, quite interesting protective effect of polyalcohols on the growth inhibition of health-promoting bacteria by silver nanoparticles was observed. The most substantial protective effect of the tested silver nanoparticles-polyalcohol mixtures was estimated for B. bifidum, L. paraplantarum, and L. phamnosus species.