Advances in engineered exosome-loaded hydrogels for bone and cartilage regeneration

Exosome-loaded hydrogels have emerged as a promising strategy for bone and cartilage regeneration by combining the bioactive signaling of exosomes with the structural support of hydrogels. Exosomes, nanosized extracellular vesicles, mediate intercellular communication by delivering proteins, nucleic acids, and lipids. Incorporation into hydrogels protects exosomes from rapid degradation and enables sustained, localized release at defect sites. Hydrogels provide a biocompatible, extracellular matrix-mimicking environment with tunable physical properties that support tissue repair. Recent advances include affinity-based and stimuli-responsive hydrogels, as well as 3D-printed scaffolds for osteochondral applications. Preclinical studies demonstrate superior regenerative outcomes compared to exosome- or hydrogel-only systems. However, challenges such as exosome heterogeneity, scalability, and regulatory barriers remain. Continued innovations in exosome engineering and smart biomaterials are expected to accelerate clinical translation.