D. O. Klymchuk

Morphology of Silver Nanoparticles in the Micelle-Forming Block Copolymers

Block copolymers: MOPEO-b-PААm and PААm-b-PЕО-b-PААm contained poly(ethylene oxide), its monomethyl ether and chemically complementary polyacrylamide were and used as special matrices in the borohydride reduction of Ag+ions. Ag-nanoparticles in the structure of compositions were obtained. The effect of chemical nature, molecular architecture and size stabilization of silver nanoparticles in bulk structure was shown.

Densitometry of the optically magnified dried residues representing carbon microparticles as a simple and affordable technique for determining their concentrations in aqueous suspensions

In extracorporeal blood purification, such as hemoperfusion, activated carbon (activated charcoal) beads are commonly used as an adsorbent, but their judgment in terms of extent of microparticle release is of great importance since the microparticles may represent the risk of entering the bloodstream. To quantitatively assess the release of carbon microparticles (CMPs) in the samples of the aqueous perfusion medium, in which the beads have been perfused, the calibration procedure with different concentrations of CMPs is likely to be needed. For this purpose, carbon beads were mechanically crushed to a fine powder, whose microparticles (<10 μm) were then serially diluted in the aqueous medium within the wide range of concentrations (0.2-100 μg/ml). To test these concentrations of CMPs, the micro-aliquots of each dilution of suspended CMPs were dried on a surface of hydrophobic membrane and at the optical magnification of 20× the dry residues were than analyzed by measuring the sum of densities. This simple and affordable technique was shown to be considerably more sensitive than spectrophotometry of the aqueous suspensions of CMPs.

Micelle Encapsulation of Silver Nanoparticles at Borohydride Reduction

The present work demonstrates the encapsulation of silver nanoparticles into micellar structures of the diblock copolymer (DBC) consisting chemically complementary methoxypoly (ethylene oxide) and poly(acrylic acid). The reduction of silver ions to silver nanoparticles or nanoclusters is achieved by an excess of sodium borohydride in the DBC aqueous solutions with various pH. The formation of considerably more smallest and stable Ag-nanoparticles in the DBC micellar solution at pH = 3 compare with the test of an Ag+solution without DBC micelles was revealed. The morphology of Ag-nanoparticles dispersed within DBC matrices and their average particle size were indicated by TEM images.

Processes of Encapsulation and Crystallization of Prednisolon in PAAm-b-PEO-b-PAAm Micellar Solutions

Micellar solutions of PAAm-b-PEO-b-PAAm triblock copolymer (TBC) based on chemically complementary poly(ethylene oxide) and polyacrylamide (Mn= 6 and 116 kDa) were applied to study the encapsulation of poorly soluble crystallizing drug prednisolon (PS) in a region of ϕ= 0.065 ÷ 0.39 molPS/base-molTBC. The equilibrium mechanism of the encapsulation and the effect of specific aggregation of small and large PS-loaded micelles by their “coronas” that promoted the drug crystallization were established. The fractal character of large drug-loaded micelles and unusual morphology of PS crystals allowed assuming the presence of TBC micelles inside crystalline space.