Construction of Nanocellulose-Silk Fibroin Stiff Hydrogel and High Absorbing-Low Expansion Aerogel Via Polysaccharide-Protein Nanostructure Design

Abstract

Inspired by the different environmental sensitivities of polysaccharide and proteins, composite hydrogels consisting of nanocellulose (NC) and silk fibroin (SF) with different network structures and mechanical properties were designed and prepared by applying different induction methods and sequences. In the desirable case, SF was firstly assembled along the NC template to form a unique nanobead structure under temperature induction, and then crosslinked under acetic acid coagulation bath to form polysaccharide-protein composite hydrogels with excellent mechanical properties (the elastic modulus as high as 62,330 G' in Pa at a relatively low concentration of 0.25 wt% NC and 1.5 wt% SF). The abundant carboxyl groups of NC (introduced by TEMPO-mediated oxidation) and the existence of the nanobead structure enhanced the structure stability and greatly improved the water retention capacity of hydrogels. The results showed that NC-SF interpenetrating network (IPN) hydrogel had ideal mechanical properties, the corresponding aerogel had excellent liquid absorbing and retention ability (water absorption up to 2300%), noteworthy, the volume of aerogel had almost no expansion after binding aqueous solutions (dissolution ratio less than 5%), which could be used as biodegradable and biocompatible daily necessity material such as sanitary napkins and diapers, as well as hemostatic matrix.

Keywords: Silk fibroin, Nanocellulose, Hydrogels, aerogels, High absorbing, Low expansion