ИСТИНА

Silver nanoparticles (NPs) find wide use as effective antimicrobial agents in industrial applications and in medicine [1, 2]. The «pure» colloidal solution of silver (hydrosol) preparation method was developed. This hydrosol contains only silver NPs of the average size (20-25 nm) and stabilizing carbonate ions. Preparation method consists in the photo-chemical reduction of silver ions by oxalate-ions, which generate carbon ions. Irradiation of silver and oxalic acid salts by a low-pressure pulsed xenon lamp was carried out in water solution under aerobic conditions. The hydrosol was studied by methods of physicochemical analysis (spectrophotometry, dynamic light scattering, and transmission electron microscopy, scanning electron microscopy). The irradiation initiated Ag+ reduction with oxalate ions to give metal nanoparticles and carbonate ions. The hydrosol is aggregative stable for several weeks in water. To study the bactericidial properties NPs with an average size 22 ± 2 nm were used. The influence of silver ions was investigated for comparison. The Bacteria Escherichia coli (gram-negative, family Enterobacteriaceae) is chosen as biological object. Experiments were carried out in the presence and in the absence of air. Different concentrations of silver NPs and silver ions have been inoculated into the Adkins media (liquid nutrient media) with bacteria cells. After 5 days the cells’ number was counted and compared with control. It was observed the effect of cells division inhibition. The parameter was LD50