Polysaccharide-based hydrogels are attractive materials for biomedical applications due to their intrinsic low toxicity and biodegradability. Here we report a green, simple and economical strategy for preparing polysaccharide-based, in situ forming hydrogels. This type of hydrogel was prepared from the oxidation products of oligo(hydroxypropyl)-substituted polysaccharides. This chemoselective, sodium hypochlorite-based oxidation, recently discovered by the Edgar group, offers an approach to introduce ketone groups at the termini of oligo(hydroxypropyl) groups appended to polysaccharides, and these oxidation products are readily reacted with chitosan to form hydrogels via formation of imine bonds. As imines are dynamic covalent bonds in the presence of water, the hydrogels are self-healing, injectable, and pH responsive. In this work, we designed and prepared two different hydrogels: oxidized hydroxypropyl cellulose (HPC)-chitosan and oxidized hydroxypropyl dextran (HPD)-chitosan. Mechanical properties of the hydrogels were characterized by rheometry; the hydrogel storage moduli were tunable from 2.8 kPa to 13 kPa by controlling the degree of substitution of ketone groups. The rheological characterization also illustrated the rapid self-healing properties of these hydrogels. Moreover, the hydrogels exhibited high swelling rates, were injectable, required no toxic, small molecule crosslinkers, and degraded without external stimuli. Therefore, this work opens up a novel, promising strategy for constructing hydrogels for biomedical applications.

Self-healing, in situ forming chitosan-hydroxypropyl polysaccharide-based hydrogels with tunable modulus

2019 Spring National Meeting

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