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A new polymer composite based on carboxymethylchitin and silver nanoparticles was obtained in order to produce biodegradable wound coating films. The number of metal nanoparticles in the composite may be easily regulated as was verified by UV-VIS-spectroscopy data. A comparative evaluation of silver nanoparticle size in the initial system and in the polymer composition was performed by means of photon correlation spectroscopy. Composite films revealed a pronounced concentration-dependent antibacterial activity towards strains Salmonella typhimurium and Staphilococcus aureus.

A method for assessing the abiotic efficiency of water-dispersed nano-sized silver particles is suggested. Nanoparticles were obtained by the method of biochemical synthesis in reversed micelles made from anionic surfactant bis-(2-ethylhexyl) sodium sulfosuccinate (AOT). A water dispersion of nanoparticles was prepared from the micellar solution in organic solvent by means of a special procedure. The abiotic efficiency assay is based on the capacity of cells to respond by the negative chemotaxis to chemical agents with harmful metabolic action. In plasmodium of myxomicete Physarum polycephalum, the biocide and repellent effects of silver nanoparticles, Ag+ ions, and AOT were tested in order to compare the abiotic efficiency of these substances in water solution and after introduction into agar substrate. The increase in the oscillation period, the reduction in the area of spreading, and the avoidance reaction in the spatial test, taken together, revealed a much higher repellent efficiency of silver nanoparticles as compared with that of Ag+ ions and AOT. The NSP concentrations lethal for Physarum were similar to those found earlier for bacteria and viruses. The chemotaxis-based tests applied in this study allow one to quantitatively assess cell reactions and monitor their time course. Besides, they have a much higher resolving capacity than the tests based on lethal effects of abiotic substances.

Changes of surface potential difference of neutral BLM in the presence of negatively charged liposomes were controlled by means of potentiodynamic method. The liposomes were prepared by sonication of PS-suspension in buffer solution. BLM was formed conventionally from lecithin--decane mixture. Measurements were carried out in buffer solution 2 mM KCL, 5 mM Tris-Cl pH 7.6) at 30 degrees C. It is shown that the liposomes are irreversibly bound to BLM, but do not fuse with it under the conditions investigated.

Potentiodynamic method was used for investigating bilayer lipid membrane (BLM)- liposomes (LS) interaction. BLM was formed from egg lecithin and its mixture with phosphatidylserine (PS); LS-from PS. It is shown that in the presence of calcium in the aqueous phase (1-10 mM) and charged phospholipids in both LS and BLM, fusion of LS with BLM is observed. The fusion event was registered by measuring the increase of negative charge density on BLM surface opposite to that facing the LS.