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Behavior of Bone Marrow Mesenchymal Stem Cells on Collagen Scaffolds in a Dynamic Culture System

Aim: BMSCs cultivation in vitro under three-dimensional (3D) dynamic conditions. Methods: a novel bioreactor system without shear stress acting on cells was developed by the combined use of collagen gel, hollow fiber membranes (HFMs) and air-lift loop bioreactor (ALB). During the expansion period, the cell growth curves were measured and after 7 days, the cell viability and morphology were assayed by fluorescence staining microscopically. Moreover, the BMSC characters of expanded cells were identified by specific expressions of CD29, CD34, CD44 and CD45 and by multilineage differentiation into osteoblasts, chondrocytes and adipocytes. Results: the cultured BMSCs expanded about 17-fold under dynamic condition, 13-fold under static condition with the initial density of 5×105 cells·mL-1; after 7 days, the cells maintained high viability of about 92% and spread with a spindle appearance and long cell protrusions in gel; the expanded cells were CD29 and CD44 positive, CD34 and CD45 negative, and they could differentiate into osteoblasts, chondrocytes and adipocytes; the cells expanded under dynamic condition spread more and showed stronger multi-differentiation potentials.