Dielectrophoresis (DEP) is a technique in microfluidics that has demonstrated trapping, concentration, manipulating, and sorting of biological cells. However, there has been less emphasis on the development of analytical
DEP devices. Analytical DEP devices have been rarely pursued due to the inherent non-uniform nature of the dielectrophoretic force, which is proportional to the gradient of the field-squared, thereby generating a highly non-uniform force field within a microfluidic device. Our device overcomes this limitation by applying a unique isomotive dielectrophoresis (isoDEP) field. Decades ago Herbert Pohl first used the phrase âisomotive dielectrophoresisâ and suggested an electrode geometry for particle sorting applications. We have modified and adapted his solution for a microfluidic isoDEP device where the gradient of the field-squared is constant thereby enabling a constant DEP force to be applied to all particles in the field of view. In combination with particle tracking velocimetry the Clausius-Mossotti factor for each particle can be extracted. With this approach detailed dielectric measurements of each individual cell is possible with a greater throughput than the current practice using electrorotation.
This presentation will describe design considerations and scaling laws associated with two fundamentally different isoDEP platforms. The unique isoDEP analytical solution will be presented. AC electrokinetic products inherent to such systems such as Joule heating, AC electro-osmosis, and electrothermal flow will be discussed. The current status of isoDEP platform automation and proof-of-concept results using biological particles will be presented.