Abstract: Objective · To obtain and identify the exosomes derived human stem cells the apical papilla (hSCAPs). Methods · hSCAPs were culturedmodified tissue adherence method and the phenotypes were analyzed with stem cell surface markers CD105, CD45, CD44, CD31, CD34 and CD29. The capability of multi-differentiation in hSCAPs was identifiedosteogenic and adipogenic differentiation in vitro. Exosomes were isolated hSCAPs culture supernatants using gradient centrifugation methods. The size of vesicle was assessednanoparticle size analyzer. The morphology of exosomes was observedtransmission electronic microscope (TEM), and the of exosome molecular markers CD81, CD9, CD63 and TSG101 was analyzedWestern blotting. Results · hSCAPs were positive for the mesenchyme stem cell markers, including CD105, CD44 and CD29 and negative for the hematopoietic markers CD45, CD31 and CD34. hSCAPs could differentiate into osteoblasts and adipocytes. hSCAPs secreted microvesicles which exhibited round vesicle structure with an intact membrane observedthe TEM. The results of nanoparticle size analyzer measurement showed that the diameters of vesicles were ranged 30 to 100 nm, which were consistent with the resultsTEM. Microvesicles could express the molecular markers for exosomes, i.e. CD81, CD9, CD63 and TSG101. Conclusion · The microvesicles were successfully isolated hSCAPs and identified as exosomes.

Key words: human stem cell the apical papilla, exosome, gradient centrifugation, identification