Dynamic and static impedance spectroscopy for single particle characterization in microfluidic chips

A comparison of dynamic and static impedance spectroscopy (DIS and SIS) for single particle analysis is presented in this work. Individual particles are perfused into microchannels comprising microelectrodes, which are either used to perform dynamic measurements of impedance differences, or to make static measurement after a stable immobilization of single particles at narrow orifices. Experimental results with polystyrene (PS) beads demonstrate the important characteristics of the two methods: High throughput of DIS enabling measurements of large numbers of single particles in solution, and the multi-frequency capability of SIS enabling long-term recording of immobilized single particles. These distinct features of the two microfluidic methods offer high throughput and high sensitivity in a combined application for single-cell analysis in systems biology.