Preparation of nanocellulose-silk fibroin stiff hydrogel and high absorbing-low expansion xerogel via polysaccharide-protein interactions

Inspired by the unique environmental sensitivities of polysaccharides and proteins, nanocellulose (NC) and silk fibroin (SF) nanocomposite hydrogels with tailored network structures and mechanical properties were developed by varying induction methods and assembly sequences. In the optimal process, SF was first assembled along the NC template to create a unique nanobead-like structure under thermal induction, followed by crosslinking in an acetic acid coagulation bath to form a polysaccharide-protein nanocomposite hydrogel with high mechanical strength, with elastic modulus as of 62,330 G′ in Pa at only 0.25 wt% NC and 1.5 wt% SF. The introduction of carboxyl groups to NC via TEMPO-mediated oxidation and the formation of nanobead-like structures improved structure stability and significantly enhanced water retention. The NC-SF nanocomposite hydrogels exhibited excellent mechanical properties, while the derived xerogels offered outstanding liquid absorption (up to 2300 %) and retention with minimal volume expansion upon liquid binding (dissolution ratio below 5 %). These properties make them promising candidates for biodegradable, biocompatible materials in applications such as sanitary products, diapers, and hemostatic matrices.