Towards an Injectable Hydrogel for the Delivery of Thermostable Chondroitinase ABC

Chondroitinase-ABC (ChABC) is a bacterial enzyme that has immense potential as a therapy for central nervous system injuries due to its ability to degrade the chondroitin sulfate proteoglycans of the glial scar; however, its clinical translation has been thwarted by its thermal instability and lack of an optimal delivery strategy. In this thesis, we compared two delivery vehicles for the affinity-release of thermostabilized ChABC expressed with a Src homology 3 domain (ChABC-37-SH3): a tetrazine-norbornene-crosslinked carboxymethylcellulose hydrogel (CMC), and a biodegradable, oxime-crosslinked dextrin-gelatin-based hydrogel (Dexime). Cytocompatibility of both gels was demonstrated using neural progenitor cells and microglia in vitro . Rigorous mechanical characterization revealed their tuneability with crosslink density. Notably, sustained release of bioactive ChABC-37-SH3 was achieved from CMC over 7 days. In contrast, limited release was observed from Dexime due to the potential adsorption of ChABC-37-SH3 to gelatin. Based on these studies, CMC was the preferred hydrogel for affinity-release of ChABC-37-SH3.