Collecting stem cells by shear force

The adhesion properties of human pluripotent stem cells (hPSCs) and how these properties can be exploited to separate hPSCs from other cells in a culture is described in a paper published this week in Nature Methods.

hPSCs, which are of interest for basic and applied research, are studied in many laboratories, but culture of these cells is difficult. hPSC cultures are notoriously dynamic and heterogeneous, whether due to spontaneous differentiation, to incomplete reprogramming or to the presence of added ‘feeder’ cells. Methods to isolate specific cells from heterogeneous cultures are therefore potentially valuable.

Andres Garcia and colleagues now conduct a systematic comparison of the adhesion properties of hPSCs, differentiated cells derived from them and somatic cells commonly used as donor cells for reprogramming. They report that hPSCs differ from other cell types with respect to the strength with which they cling to their culture surface.

The researchers then use fluid flow-controlled shear force, applied in a microfluidic device, to separate hPSCs from other cell types. They can even separate fully reprogrammed hPSCs from partially reprogrammed cells in this way. hPSCs isolated by shear force retain their ‘stem-like’ properties and show high viability as compared to other separation methods.

The authors conclude that adhesion-based isolation of hPSCs should prove a simple, label-free complement to isolation methods that require surface labeling of the cells.