[Review for different sources of exosomes in bone tissue engineering research].

Exosomes are 40-100 nm vesicles that are released into the extracellular environment upon the fusion of multivesicular bodies with the plasma membrane. The biologically cargoes transported by exosomes are diverse. Exosomes are important carriers of signal transmission and interaction between cells. Exosomes are believed to play an important role in tissue repair and bone regeneration. Studies have evaluated that exosomes secreted by cells play an increasingly significant roles in bone tissue engineering and have multiple functions, including regulating immunity, promoting cell proliferation and differentiation, enhancing bone regeneration and angiogenesis. The review analyzes the characteristics and biological properties of different cell-derived exosomes in the bone environment, summarizes their research progress in bone repair, and discusses the challenges and future directions for their application in bone tissue engineering.