Cyanobacterial\nAmpholyte Hydrogels Developed by the\nCationization of Sulfated Polysaccharides and Their Cell-Compatibility

Sacran is a cyanobacterial supergiant polysaccharide\nwith carboxylate\nand sulfate groups that exhibits antiallergic and antiinflammatory\nproperties. However, its high anionic functions restrict cell compatibility.\nQuaternary ammonium groups were substituted to form sacran ampholytes,\nand the cell compatibility of the cationized sacran hydrogels was\nevaluated. The cationization process involved the reaction of <i>N</i>-(3-chloro-2-hydroxypropyl)trimethylammonium chloride with\nthe primary amine or hydroxyl groups of sacran. The degree of cationization\nranged from 32 to 87% for sugar residues. Hydrogels of sacran ampholytes\nwere prepared by annealing their dried sheets by thermal cross-linking;\nthese hydrogels exhibited anisotropic expansion properties. The water\ncontact angle on the hydrogels decreased from 26.5 to 15.3° with\nan increase in the degree of cationization, thereby enhancing hydrophilicity.\nThe IC<sub>50</sub> values of sacran ampholytes decreased with an\nincreased degree of cationization, resulting in a reduction in cytotoxicity\ntoward the L-929 mouse fibroblast cell line. This reduction was associated\nwith an increase in the cell proliferation density after 3 days of\nincubation. Scanning electron microscopy images showed fibroblast\nintercellular connections. Therefore, the sacran ampholyte hydrogel\nexhibited increased hydrophilicity and cell compatibility, which is\nbeneficial for various biomedical applications.