Label-free differentiation of living versus dead single yeast cells using broadband electrical impedance spectroscopy

The use of the intrinsic electrical properties of a single cell by broadband electrical impedance spectroscopy (EIS) as a label-free and non-invasive method to monitor cellular and intracellular features is an emerging field. Here, we present a novel EIS-based sheathless microfluidic platform with an integrated coplanar waveguide to probe the interior of a single cell. This platform allows for precise single-cell trapping by dielectrophoresis, hydrodynamic focusing, and sensing the electrical properties of the trapped single cell. We measured the impedance characteristics of a single Schizosaccharomyces pombe (fission) yeast cell by a single frequency sweep (30 kHz to 6GHz) in a stagnant sucrose solution using two-port scattering (S) parameters. The measurements revealed a clear distinction between the cytoplasm impedance of live versus dead cells at 3 GHz. This platform could provide real-time monitoring of cellular electrical responses to chemical and physical antagonists for diagnostic purposes.