Bandwidth Compensation for High Resolution Impedance Spectroscopy

This paper reports on a microfluidic differential impedance cytometer, which uses a bandwidth compensation technique together with a small detection volume and multi-frequency analysis to achieve an increased sensitivity. The bandwidth compensation technique allows for measurements within small bandwidths by accounting for the increased signal amplitude dependence on the particle speed. We demonstrate detection and clear baseline discrimination of polystyrene beads with diameters of 1 μm and 2 μm and the discrimination of 5 μm beads from yeast cells of similar size. We show that using multiple frequencies in parallel significantly improves the discrimination performance of the cytometer