Comparison of the sorting efficiency and influence on cell function between the sterile flow cytometry and immunomagnetic bead purification methods. 
Currently, flow cytometry and immunomagnetic bead purification are the most commonly used cell sorting methods.  We performed this study because there are few reports that directly compare the sorting efficiency and influence on cell functions of these two methods.  The in vitro cultured third-generation bone marrow mesenchymal cells from newborn Sprague-Dawley rats were sorted and purified using sterile flow cytometry and immunomagnetic beads to obtain CXCR4-positive bone marrow mesenchymal stem cells (CXCR4(+)-MSCs).  The yield and purity (detected by flow cytometry), in vitro viability (detected by the MTT method), and in vitro chemotactic capacity (detected by stromal cell-derived factor-1α [SDF-1α] induction) of sorted target cells using these two methods were compared.  The purity of CXCR4(+)-MSCs obtained using sterile flow cytometry was higher than that using immunomagnetic bead purification.  The MTT method and growth curves showed that the viability of cells was lower and that the amplification rate of cells decreased using sterile flow cytometry, whereas the cell viability was higher after cells were sorted using immunomagnetic beads (p < 0.01).  The number of CXCR4(+)-MSCs cells that underwent chemotactic migration induced by SDF-1α after sorting using sterile flow cytometry was smaller than that using immunomagnetic bead purification (15.60 ± 1.14 vs. 26.40 ± 1.67, p < 0.01).  Although the purity of CXCR4(+)-MSCs sorted by the immunomagnetic bead purification method was lower than that by sterile flow cytometry, the influence on cell activity of the former was smaller, including improved cell viability and improved SDF-1α -induced chemotactic migration in vitro.