"DEP-Well: a new technique for electrophysiology"

Michael Pycraft Hughes, Ph.D.
University of Surrey


Abstract

Dielectrophoresis (DEP) is a phenomenon of induced motion in particles such as cells, suspended in a non-uniform electric field; the induced force is dependent on the dielectric properties of the particle and the freuqnecy of the inducing field. Since these properties are frequency dependent, a frequency spectrum typically reveals changes in cell behaviour that can be attributed to specific electrical properties of the cell, such as the capacitance of the cell membrane, or to the ionic strength of the cytoplasm. Since these properties vary from cell type to cell type, DEP offers a low-cost, non-invasive means of determining cell electrophysiology. Despite this, DEP has not been exploited widely as a tool for cell investigation. This may be attributable to many causes, such as complexity of cell tracking, limits on the number of cells to be analysed simultaneously, and the cost of the equipment. To overcome these limitations, we have developed a novel system called DEPwell. In this, electrodes are constructed around the outer wall of a “well”, about 1mm across and 2mm deep. The field is axisymmetric, eliminating the need for complex models of electric field morphology; particles are attracted to, or repelled from, the chamber walls according to their properties, and the change in light intensity of a light beam passing through the well is mathematically proportional to the force on the cells. DEPwell’s efficacy has been demonstrated in applications from stem cell differentiation to oral cancer screening, which will be described here.

Biography

Prof. Mike Hughes attended the University of Wales at Bangor for both his Master of Engineering (1992) and PhD (1995) studies, and has worked at Glasgow University (UK), University of California at Irvine (USA) and the University of Texas MD Anderson Cancer Center (USA). He has been at the University of Surrey since 1999, rising to Professor of Biomedical Engineering in 2007. He has authored or co-authored some 60 journal papers and contributed book chapters, and two books (Nanoelectromechanics in Engineering and Biology (2002) and Microengineering in Biotechnology (2010)), is named on five patents, and is a Director of DEPtech, a company created to develop products for the electrostatic analysis of cells.