Microfluidic dielectric spectroscopy cytometer: modelling and optimization

Dielectric spectroscopy is a non-invasive method suitable for the characterization of living biological cells (e.g., analysis of normal and malignant white blood cells, or morphological inspection of erythrocytes). Nowadays, thanks to microfabrication techniques, it is possible to perform single-cell dielectric spectroscopy by means of microfluidic cytometers. In a state-of-the-art microfluidic cytometer ac signals are applied to the top microelectrodes and generate an electric field in the microchannel; when a cell passes thorough the device, an impedance variation is measured which depends on the specific cell characteristics (size, morphology and dielectric properties). In this work an innovative design for the microfluidic cytometer is proposed by exploiting the basic principle of Electrical Impedance Tomography (EIT): instead of just two pairs of opposite electrodes, two arrays of electrodes are conceived, allowing a greater versatility in the stimulation pattern. In particular, rotating spatially-harmonic distributions of electric current can be applied at the device surface, thus enabling a thorough testing of the dielectric cell response.