Karen Khachatryan

Formation of nanometal particles in the dialdehyde starch matrix.

Environmentally friendly method of the preparation of dialdehyde starch (DAS) based composites containing nanosilver (DAS/Ag) and nanogold (DAS/Au) as reducing and protecting agents was developed. UV-vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed formation of about 10nm ball shaped Ag and Au nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC), whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Formation of nanosilver and nanogold containing composites led to induction of the polymerization and/or crosslinking reactions of DAS molecules, resulting in a significant rise of molecular weight of polysaccharide chains constituting DAS/Ag and DAS/Au composite templates.

Formation and properties of hyaluronan/nano Ag and hyaluronan-lecithin/nano Ag films

A facile and environmentally friendly method of the preparation of silver nanoparticles embedded in hyaluronan (Hyal/Ag) and hyaluronan-lecithin (Hyal-L/Ag) matrix was developed. Thin, elastic foils were prepared from gels by an in situ synthesis of Ag in an aqueous solution of sodium hyaluronate (Hyal), using aq. d-(+)-xylose solution as a reducing agent. The gels were applied to a clean, smooth, defatted Teflon surface and left for drying in the air. The dry foils were stored in a closed container. UV-vis spectroscopy, transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectra confirmed formation of about 10nm ball-shaped Ag nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyses, whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). An increase in the molecular weight of the hyaluronate after generation of Ag nanoparticles was observed. The foils showed specific properties. The study confirmed that silver nanoparticles can be successfully prepared with environmentally friendly method, using hyaluronan as a stabilizing template. Hyaluronan and hyaluronan-lecithin matrices provide nanocrystals uniform in size and shape. The composites demonstrated a bacteriostatic activity.

Distarch Phosphate as a Matrix for the Generation of Quantum Dots

Generation of ZnS, CdS, CaS and MgS quantum dots (QDs) was attempted in the matrix of distarch phosphate, an anionic polysaccharide. Based on the analysis of FTIR spectra, thermograms and Differential Scanning Calorimetry, interactions of QDS with the matrix could be excluded. On generation of MgS QDs and also, to a certain extent, CaS QDs, hydrolysis of the salts generating these QDs took place. That process had an impact on the partial destruction of the matrix. Molecular weight and radii of gyration of the products showed that the generation of QDs was dependent on the properties of the matrix polysaccharide. The elasticity, plasticity and viscosity of the gels containing QDs were significantly lower than those of plain distarch phosphate. Generally these values changed with time similarly to gels free of QDs.

Structure and Physicochemical Properties of Water Treated w ith Low-Temperature Low-Frequency Glow Plasma

Physical and selected physicochemical properties of distilled water treated with low-temperature low-frequency glow plasma (LPGP) for 5, 15, 30, 45, 60 and 90 min are given. Particular properties of PTW non-linearly vary with the time of exposure to plasma. PTW is characterized as declusterized solution of normal water consisting of clathrates of excited, probably singlet oxygen molecules, inside the clathrates. PWT is free of hydrogen peroxide and ozone. Raman spectroscopy is the best tool for diagnostic assessment of PTW. A R T I C L E H I S T O R Y Received: May 05, 2016 Revised: June 29, 2016 Accepted: November 05, 2016 DOI: 10.2174/18779468066661611181526 13