Bonding of doxorubicin to nanosilica and human serum albumin in various media.

Interaction of doxorubicin hydrochloride (DOX) (anti-cancer drug) with hydro-compacted nanosilica A-300 (cA-300) alone or cA-300/human serum albumin (HSA) at a small content of water (h = 0.4 g per gram of dry silica) in different dispersion media (air, chloroform, and chloroform/trifluoroacetic acid) was analyzed using low-temperature 1H NMR spectroscopy, NMR cryoporometry and quantum chemistry to elucidate specific changes in the interfacial layers. Initial (bulk density ρb ≈ 0.046 g/cm3) and hydro-compacted (ρb ≈ 0.051-0.265 g/cm3 as a function of the hydration degree) nanosilicas were analyzed using nitrogen adsorption-desorption, gelatin adsorption, small angle X-ray scattering (SAXS), TEM, and infrared (FTIR) spectroscopy. Equilibrium adsorption of DOX onto cA-300 and cA-300/HSA was analyzed using ultraviolet-visible light spectroscopy. Photon correlation spectroscopy was used to analyze the particle size distribution in aqueous suspensions with various contents of components. DOX more strongly bound to HSA than silica also affects structure of interfacial water layers that depends on dispersion media because chloroform as immiscible with water changes the water organization to enlarge water structures. In aqueous media, DOX alone remains mainly in the form of nano/microparticles (50 nm-2 µm in size). However, with the presence of cA-300, cA-300/HSA, and HSA alone DOX transforms into pure nano-sized structures. These effects are explained by effective bonding of DOX to HSA having good transport properties with respect to drug molecules/ions that exceed similar properties of nanosilica alone, but cA-300/HSA can be a more effective composite as a drug carrier.

Colloidal properties and behaviors of 3 nm primary particles of detonation nanodiamonds in aqueous media.

This study was aimed to reveal the principal colloidal properties of the aqueous dispersion of extremely small primary single-crystalline diamond particles in water. Together with the non-diamond layer, the size of the colloidal species is 2.8 ± 0.6 nm as found via DLS of the initial 5.00 wt/vol% hydrosol. Anionic dyes are readily adsorbed on the colloidal species. This is in line with the positive zeta-potential. The critical coagulation concentrations of the 0.19 wt/vol% nanodiamond hydrosol were determined with a set of inorganic electrolytes and anionic surfactants. The data are in line with the Schulze-Hardy rule for "positive" sols. The fulfillment of the lyotropic (Hofmeister) series was also observed for single-charged anions. The abnormal influence of alkali gives evidence of the acidic nature of the positive charge of the nanodiamond species. Application of acid-base indicators allows estimating the value of the interfacial electrical potential of the nanodiamond particles. Upon dilution from 5.00% to 0.01%, the colloidal system under study exhibits unusual changes. The average size increases ca. ten-fold as determined by DLS. The TEM images support this observation. At the same time, the viscosity drops. This phenomenon was explained in terms of the so-called periodic colloidal structures (colloidal crystals) in concentrated solutions.

[Influence of metal nanoparticles on some microorganisms and microflora of unpasteurized beer].

The influence of nanoparticles of gold, silver, dioxide of cerium and zirconium in low concentration (0.5-7.5 mg/l) on pure cultures of Escherichia coli IEM-1, Bacillus subtilis BT-2, Candida scottii KB-2, Saccharomyces cerevisiae OB-3, Aspergillus niger R-3, Fusarium culmorum T-7 and Penicillium chrysogenum F-7 has been investigated. Silver nanoparticles, which caused a decrease of the amount of S. cerevisiae OB-3 cells by 90% after one hour of exposition, and led to almost complete death of vegetative and spore cells of B. subtilis BT-2 after 1 and 24 h of exposition, respectively, proved to be the most effective antimicrobial preparation. The decrease by one-two orders of the amount of B. subtilis BT-2 and of S cerevisiae OB-3 cells under the influence of preparations of silver nanoparicles in the presence of gold has been established. After adding silver preparations to the unpasteurized beer one could observe a decrease by 10-20% of bacterial and by about 40% of fungi which contaminated microflora on the 20th day of shelf-life. The paper is presented in Ukrainian.