Antibacterial polysaccharide gels for dentistry with properties similar to soft tissues based on konjac and xanthan gums

Dialdehyde polysaccharides containing from 30 to 40 oxidized links per 100 glycosidic cycles of the main chain were synthesized by periodate oxidation of xanthan gum and konjac gum. It is shown that the oxidation process is accompanied by polysaccharide hydrolysis with a decrease in the dynamic viscosity of the solution and the formation of gels with elasticity modulus G’ = 10 2 –10 4 Pa, loss modulus G” = 30–600 Pa and tgδ = 0.05–0.8, resembling the properties of gingival tissues and soft tissue fillers used in reconstructive procedures. Dialdehyde polysaccharides were used as carriers for vancomycin and amikacin to form polymers containing up to 30 weight percent of antibiotics bound covalently to the main polysaccharide chain. By pairing the antibiotics in the preparation, the risk of developing multidrug-resistant strains can be reduced when antibacterial gels are applied topically. In culture experiments on HEK 293T embryonic kidney cell cultures and HFb (d54) human fibroblasts using MTT test, it was shown that both konjac-based hydrogels and preparations containing amikacin and vancomycin are non-toxic at concentrations from 1% to 20% by volume. Xanthan hydrogels containing by weight 1% polysaccharide and 0.83% vancomycin are cytotoxic in cell culture at a concentration of 1% by volume. The bactericidal concentration of enzymatic hydrolysis products of gels against Staphylococcus aureus 209P is 31 ÷ 125 µg/mL for amikacin containing gum and 250 ÷ 500 µg/mL for vancomycin containing preparations. The concentration of antibiotics released under the action of bacterial enzymes at the site of bacterial attack exceeds the minimum bactericidal concentration by 200 times. Gels are recommended for the treatment of periodontitis.