When an embryonic stem cell is in the first stage of its development it has the potential to grow into any type of cell in the body, a state scientists call undifferentiated.

A team of researchers from Scotland has now demonstrated a way to easily distinguish undifferentiated embryonic stem cells from later-stage stem cells whose fate is sealed. The results are published in the American Institute of Physics' (AIP) journal Biomicrofluidics.

The researchers used an electric field to pull stem cells through a fluid in a process called dielectrophoresis.

They varied the frequency of the voltage used to generate the electric field and studied how the cells moved, a response that was affected by the cell's electrical properties.

The researchers found that differentiated stem cells could store a significantly greater charge on their outer membranes, a characteristic that might be used to effectively identify and separate them from undifferentiated cells.

The researchers write that the wrinkling, folding, and thinning of a cell's membrane as it differentiates may explain why the later-stage cells can store more charge. The sorting method may prove useful in separating cells for biomedical research or ultimately for treatments of diseases such as Parkinson's.

Article: "Dielectrophoresis based discrimination of human embryonic stem cells from differentiating derivatives" is published in the journal Biomicrofluidics; Authors: Srinivas Velugotla (1), Steve Pells (2), Heidi K. Mjoseng (2), Cairnan R. E. Duffy (2), Stewart Smith (1), Paul De Sousa (2) and Ronald Pethig (1). (1) Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Scotland (2) Centre for Regenerative Medicine, College of Medicine and Veterinary Medicine, The University of Edinburgh, Scotland.