Recently we reported a facile modular approach to rapidly prepare pH-responsive hydrogels by crosslinking polysaccharides with polyamines such as polyallylamine and polyethylene amine. However, these hydrogels were proven cytotoxic to mammalian cells. Biocompatibility can often be improved by utilizing biologically derived materials, and following this strategy we replaced synthetic polyamines with amino acid diamines. The dextran-amino acid diamine gels are formed by the addition of the amino acid diamines to a dextran and epicholorohydrin solution once it became homogeneous. This was demonstrated with three amino acid diamines, lysine (LysOH), lysine methyl ester (LysOMe), and Cystine dimethyl ester (CysOMe). These hydrogels were characterized by FTIR, SEM, rotational rheometry, swelling and protein adsorption studies. All the hydrogels showed the unexpected pH-responsive behavior of greater swelling at more basic pH, similar to that of an anionic hydrogel. This is uncharacteristic for amine functionalized gels as they typically exhibit cationic hydrogel behavior. Protein adsorption was examined using albumin and gels that incorporated the amino acid diamines also showed increased adsorption compared to dextran only hydrogels. Rheometry studies showed inclusion of LysOH and LysOMe to improve elasticity while CysOMe had a negative effect.

pH-responsive dextran hydrogels by crosslinking with amino acid diamines

254th National Meeting (2017)

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