Siora I. Effect of hydrophobization and modification of nanosilica by proteins and saccharides on biocompatibility of the composites on their basis

It has been shown that limiting protein adsorption values are higher on the hydrophilic surface for silicas possessing high protein-sorptive capacity with respect to albumin. The changes in secondary structure of proteins adsorbed on partially hydrophobized silica as a result of some fragments of polypeptide chain transition from alpha-structure into unfolded beta-form were revealed by means of IR spectroscopy. It has been suggested the method of saccharides immobilization onto the silica surface preliminary modified with BSA protein due to hydrogen binding between hydroxyl groups of saccharides and aminogroups of proteins. The biocompatibility of the initial silica and silicas modified with biomolecules has been studied by the changes in shape of cells in the donor blood erythrocyte suspension. It has been ascertained that compatibility essentially depends on silica concentration (Сs). Thus, at Сs > 0.01 mass percent the hemolysis of erythrocytes occurs. Partial hydrophobization of silica surface and its adsorptive modification with biomolecules (BSA, sucrose, glucose, fructose) diminishes the hemolytic activity owing to reduction in concentration of silanols capable to contact directly with the cell surface. It has been determined and calculated the values of their hydration upon the contact with silica, interface energy, concentration of strongly and weakly bound water. The most intensive interaction of erythrocyte membranes with silica is observed at their ratio of components 1:15. One of the mechanisms of hemolytic action of silica was shown to be the destruction of erythrocyte overmembrane matrix (glycocalyx) as a result of irreversible adsorption of glycoproteins. Demonstrated promising use of the original silicas and the composites on their basis as additives to reproductive cells of farm animals in long-term storage technology of the gene pool of animals.