Injectable all-polysaccharide self-assembling hydrogel: a promising scaffold for localized therapeutic proteins

Biomedical/pharmaceutical applications demand hydrogels made from biobased materials without the use of potentially toxic or denaturizing crosslinking agents. In this work, a new all-polysaccharide self-assembling hydrogel system consisting of anionic TEMPO-oxidized cellulose nanofibers (TOCNs) and cationic guar gum (CGG) is proposed. The TOCNs/CGG hydrogel are formed in situ when TOCNs and CGG are mixed, due to the electrostatic interactions and abundant hydrogen bondings therein. Interactions in the hydrogel were supported by Fourier transform infrared spectroscopy (FTIR) results. The as-prepared hydrogel showed good injectability, self-healing performance and reasonable mechanical properties. Scanning electron microscope (SEM) images illustrated the network structure of the hydrogel. Furthermore, the TOCNs/CGG hydrogel system was studied for protein drug release, in which bovine serum albumin (BSA) was used as a model drug to examine the drug release performance in buffers at pH 2.0 or 7.4, simulating gastrointestinal tract conditions. The results indicate its sustained drug releasing ability. A mathematical analysis of the release results supports an anomalous transport mechanism for the TOCNs/CGG hydrogel system.