An emerging MSC-exosome delivery strategy: injectable temperature-sensitive hydrogels encapsulate exosomes for...

Mesenchymal stem cell (MSC)-derived exosomes (MSC-EXOs), nanovesicles carrying bioactive molecules, hold potential for tissue repair, but face targeting and rapid clearance challenges. Hydrogels, bioabsorbable scaffolds comprising 3D hydrophilic polymers with high biocompatibility and some mechanical strength, offer a promising solution. Injectable thermosensitive hydrogels, transitioning from liquid to gel at body temperature, enable localized, sustained EXO delivery by forming biocompatible reservoirs at injury sites. These hydrogels enhance EXO retention and therapeutic efficacy through controlled release. In this review, we discuss MSC-EXO biology, hydrogel design (gelation mechanisms and fabrication), and applications of EXO-encapsulated thermosensitive hydrogels, emphasizing injectability, controlled release, and improved site-specific dosing. Future priorities involve refining EXO purification, optimizing hydrogel porosity and mechanical tunability, and assessing long-term safety and efficacy for clinical translation.