Synthesis of grafted copolymers of cod collagen and acrylamides in the presence of alkylborane – p-quinone system

The graft polymerization of acrylamide and N-isopropylacrylamide onto collagen in the presence of triethylborohexamethylenediamine complex and a number of p-quinones, including benzoquinone, naphthoquinone, 2,5-di-tretbutyl-p-benzoquinone, and duroquinone, was studied. In all cases, p-quinones act as polymerization retarders, reducing monomer conversion. An exception is the graft polymerization of acrylamide onto collagen in the presence of benzoquinone, which acts as a polymerization inhibitor. The proportion of the synthetic fragment in the obtained copolymers is determined by the structure of the monomer and p-quinone. The molecular weight distribution curves contain modes related to unreacted collagen, which differ significantly from those of the initial collagen in terms of intensity. This is related to the formation of a grafted copolymer of cross-linked structure, which cannot be analyzed by gel permeation chromatography. The degradation of copolymers under the action of enzymes was controlled by gel permeation chromatography. Enzymatic hydrolysis of copolymers proceeds slower than that of collagen, which confirms the formation of a copolymer. Following three hours after the onset of hydrolysis, the molecular weight distribution curves contain low-molecular weight modes of collagen and low-intensity modes related to polyacrylamide. The morphology of copolymers differs from that of collagen and polyacrylamides. Cytotoxicity evaluation of copolymers is an important research stage, determining their prospects as the basis of materials for regenerative medicine. An analysis of extracts obtained from the copolymers using culture medium by MTT assay showed a high rank of their toxicity, which can be reduced by dilution of collagen and N-isopropylacrylamide copolymer extracts with aqueous solutions. For the copolymers of collagen and acrylamide, the toxicity is maintained due to the high toxicity of the monomer. Their toxicity can be reduced by extraction of unreacted acrylamide with chloroform.