Preparation and characterization of a novel spongy hydrogel from aqueous Bombyx mori sericin

Abstract We attempted to obtain a novel spongy hydrogel from aqueous Bombyx mori (B. Mori) sericin by using a freeze-thaw method without any cross-linking reagent. The aqueous sericin solution utilized was extracted from silkworm cocoons by using boiling method, and showed continuous molecular weight distribution mainly from 43 kDa to 212 kDa and even higher. To optimize the conditions for hydrogel preparation, the efficiency of hydrogel transformation from sericin solution were investigated by changing sericin concentration, freezing time, freezing temperature and frozen-thawed repetition. The porous characteristics of sericin hydrogel including the porosity, density and maximal water absorbency were performed by changing freezingn conditions. The pore size and morphology of hydrogels prepared at different concentration and freezing temperatures were observed with SEM. FTIR, XRD and DSC curves indicate that the hydrogel prepared at -20 °C and -80 °C adopt mainly random coil conformation.