Physicochemical approach for the modification of medical nanoporous carbon sorbents

Nanoporous carbon sorbents modified with oligomers of lactic and glycolic acids were synthesized without the use of catalysts and organic solvents. Their synthesis includes impregnation of the sorbent with a 50% aqueous solution of hydroxy acid followed by multistep thermal treatment. Physicochemical properties of the modified carbon sorbents were studied using low-temperature nitrogen adsorption, scanning electron microscopy, elemental, thermal and spectrophotometric analyses, nuclear magnetic resonance spectroscopy and viscometry. Modification of the carbon sorbent with oligomers of hydroxy acids is accompanied by the appropriate deterioration of its textural characteristics and substantial increase in the oxygen content. The deposited oligomers of glycolic and lactic acids are distributed locally on the carbon surface. It was shown that the sorbent modified with glycolic acid oligomer was more hydrophilic. It exhibited a higher adsorption capacity with respect to gelatin as compared to the sorbent modified with lactic acid oligomer. Differences were found in the biological activity of modified samples toward pathogenic bacteria Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, yeast-like fungi of the Candida genus, and bacterial-fungal Staphylococcus aureus + Candida albicans association. The higher biological activity of the modified carbon sorbents in comparison with the initial sample was attributed to the acid-base properties of deposited oligomers and their ability to biodegrade in an aqueous medium.{GRAPHIS}