Polysaccharide-based superporous hydrogels with fast swelling and superabsorbent properties

Most dried hydrogels (xerogels) require a long time to reach equilibrium swelling due to the slow absorption of water by diffusion. Superporous hydrogels (SPHs) have been developed to demonstrate fast swelling and superabsorbent properties, and thus attracted much attention for various biomedical applications. In this study, we have developed and evaluated a new polysaccharide-based SPH that can absorb a significant amount of water instantaneously by a capillary mechanism and swell to equilibrium quickly, regardless of their dimension and size. Here, starch was chemically modified to have hydrophilic sulfate groups and reactive vinyl groups and used as a water-soluble, biodegradable building block for making three-dimensional networks. Starch-based SPHs were prepared by a radical crosslinking reaction and gas-blowing foaming process to generate an interconnected pore structure. These new biodegradable, starch-based, superabsorbent SPHs with fast swelling could be useful for pharmaceutical and biomaterial applications.