Impedance measurement of normal and cancerous human breast cells using a microfluidic tunnel

In this paper, a novel microelectrical impedance spectroscopy (μEIS) with three-dimensional interdigitated electrodes (3D-IDE) is developed to differentiate normal and cancerous cells. The device utilizes a microfluidic tunnel structure, which forces cells to be squeezed. Thus, the enlarged contact area between cells and electrodes allows the device to measure the intrinsic electrical signal of the cells with a higher sensitivity than a noncontact case. The cell squeezing is realized by fabricating smaller microfluidic channel than cell size. The electrical impedances are measured through 3D-IDE. The device well distinguishes normal human breast cell (MCF-10A) and early-stage human breast cancer cell (MCF-7) with a phase difference of 1.42° at 500 kHz. The proposed device also features a high repeatability because the phase change is as small as 0.27° (which is sufficiently smaller than the phase difference between normal and cancer cell) before and after the each cell assay.