(379b) Fiber-Based Protein Hydrogel As a Vehicle for the Topical Application of Therapeutic Exosomes

Protein hydrogels are effective materials for the delivery of therapeutics due to their ability to house cargo and achieve a sustained release over a time. Recently, we developed an upper critical solution temperature hydrogel that has been shown to have possible utility in delivery applications and is based on the protein, Q, which is a variant of the coiled-coil domain of cartilage oligomeric matrix protein. Exosomes have potential as therapeutics with mesenchymal stem cell exosomes being an attractive option due to their promotion of a number of signaling pathways that are important in wound healing and bone repair. Herein, we show the efficacy of Q hydrogel loaded with exosomes (Q-Exo) as a topical treatment for the closure of wounds on animal models with compromised healing. Exosomes were successfully loaded in Q prior to gelation, with minimal impact on the solution-to-gel transition at 4˚C. Nanofibers that have previously been reported in Q hydrogel alone were also present in Q-Exo, confirming that protein self-assembly was not hindered, with Q-Exo even showing increased mechanical properties compared to Q. Accelerated wound healing of diabetic mouse models treated with Q-Exo suggests that Q is successfully able to encapsulate and deliver therapeutic exosomes.