Extracellular Vesicles in Osteogenesis: A Comprehensive Review of Mechanisms and Therapeutic Potential for Bone Regeneration.

Extracellular vesicles (EVs) are nanoscale, membrane-bound particles secreted by diverse cell types and act as pivotal mediators of intercellular communication during bone regeneration. These vesicles transport bioactive cargo including proteins, lipids, mRNAs, and microRNAs that modulate osteogenesis, angiogenesis, and immune responses within the bone microenvironment. EVs originating from mesenchymal stem cells, osteoblasts, endothelial cells, and macrophages have demonstrated substantial potential to promote bone formation, inhibit bone resorption, and enhance vascularization. This review examines the biogenesis, classification, and cellular uptake mechanisms of EVs, focusing on their roles in osteogenesis and their therapeutic applications in fracture healing, osteoporosis, and bone tissue engineering. Despite their promise, significant challenges remain, including the need for standardization, scalable production, and assessment of long-term safety to enable clinical translation of EV-based therapies. Here, we provide a comprehensive overview of EV biology, elucidate the molecular mechanisms of EVs in bone regeneration, and discuss innovative strategies to optimize their therapeutic efficacy, highlighting their potential as next-generation orthobiologics.