Dielectrophoretic separation/isolation of rare particles/cell types form a heterogeneous suspension within a microfluidic system

Abstract

The isolation of fetal cells from maternal peripheral blood has long been proposed as a method for prenatal diagnosis but with only limited success. Current methods using antibody based separation strategies have proven unreliable. Here we describe a microfluidic system which can isolate specific cell types from a heterogeneous population, dependant upon their dielectric properties. A microfluidic separation chamber was fabricated using SU-8 photopolymer on glass with a glass lid bonded using UV-curable glue. Interdigitated microelectrodes were patterned onto the glass using photolithography and wet etching. When the electrodes are energized, the non-uniform AC electric fields produced result in a dielectrophoretic force acting differentially on the various cell types within the separation chamber.

Computer aided modelling was used to optimise the fluidics (STAR-CD, Computational Dynamics Ltd.) of the device. Simulation of the forces present in the device due to the electric fields was achieved with the use of the Ansoft® Maxwell 2D field simulator, this allowed the optimisation of the electrode geometries. The whole system was then modelled prior to fabrication using the MATLAB programming language.