MEMS-based Coulter counter for cell counting and sizing using multiple electrodes

A novel MEMS-based Coulter counter is designed, fabricated and tested in this paper. The Coulter counter is used for detection and monitoring the impedance changes of cells as a function of time after they are mixed with different experimental extracellular environments. The device consists of a multilayer of the SU-8 microchannel which is divided into a passive mixing region, a focusing region using negative dielectrophoretic forces and a measuring region by multiple electroplated vertical electrode pairs. The devices were tested with both fluidic and electrical functionality using dyed fluids, microbeads with different dimensions suspended in saline water and fibroblast cells in anisosmotic phosphate buffered saline. The results are presented and discussed. The device ultimately aims at testing time-sensitive cell characteristics after exposure to different extracellular media with enhanced sensitivity.