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Bone-derived stroma cells contain a rare subpopulation, which exhibits enhanced stemness characteristics. Therefore, this particular cell type is often attributed the mesenchymal stem cell (MSC). Due to their high proliferation potential, multipotential differentiation capacity, and immunosuppressive properties, MSCs are now widely appreciated for cell therapeutic applications in a multitude of clinical aspects. In line with this, maintenance of MSC stemness during isolation and culture expansion is considered pivot. Here, we provide step-by-step protocols which allow selection for, and in vitro propagation of high quality MSC from human bone.

Biosensor systems which enable impedance measurements on adherent cell layers under label-free conditions are considered powerful tools for monitoring specific biological characteristics. A radio frequency identification-based sensor platform was adopted to characterize cultivation and differentiation of human bone marrow-derived multipotent stem cells (bmMSC) over periods of up to several days and weeks. Electric cell-substrate impedance sensing was achieved through fabrication of sensitive elements onto glass substrates which comprised two comb-shaped interdigitated gold electrodes covering an area of 1.8 mm×2 mm. The sensing systems were placed into the wells of a 6-well tissue culture plate, stacked onto a reader unit and could thus be handled and operated under sterile conditions. Continuous measurements were carried out with a sinusoidal voltage of 35 mV at a frequency of 10 kHz. After seeding of human bmMSC, this sensor was able to trace significant impedance changes contingent upon cell spreading and adhesion. The re-usable system was further proven suitable for live examination of cell-substrate attachment or continuous cell monitoring up to several weeks. Induction of either osteogenic or adipogenic differentiation could be validated in bmMSC cultures within a few days, in contrast to state-of-the-art protocols, which require several weeks of cultivation time. In the context of medical cell production in a GMP-compliant process, the here presented interdigitated electric microsensor technology allows the documentation of MSC quality in a fast, efficient and reliable fashion., (Copyright © 2012 Elsevier B.V. All rights reserved.)