The Multi-Conductivity Clausius-Mossotti Factor as an Electrophysiology Rosetta Stone: Dielectrophoresis, Membrane...

Dielectrophoresis (DEP) has been used for decades to estimate the passive electrical properties of cells. However, the body of work on cell electrophysiology derived from Clausius-Mossotti analysis of DEP-derived data pales to insignificance against the wider backdrop of cell electrophysiology based on the Goldman-Hodgkin-Katz equation measured by patch clamp, which focuses on membrane potential V_m-a parameter which does not appear in the Clausius-Mossotti model-and values of patch clamp-derived membrane conductance which, shorn of double-layer conductivity, are often orders of magnitude lower than those derived from DEP. Conversely, the body of work on DEP analysis is more substantial than that reporting the electrical properties of the extracellular (ζ) potential. To address this, several studies have recently been published into the interconnections between the electrical properties determined by the Clausius-Mossotti model, V_m, and ζ-potential, which analyzed the effect of varying the suspending medium conductivity over a wide range, from below 50 mSm^-1 to above 1.5 Sm^-1. The results of these studies identified relationships between the cytoplasm conductivity, V_m, membrane conductance and capacitance, surface conductance, whole-cell resistance, and ζ-potential. Significantly, many of these relationships only become apparent when analyzed as a function of the conductivity of the suspending medium. This paper assembles these interconnections, using several separate studies approaching different parameter connections, to draw together a set of equations which collectively form a "cellular electrome". This demonstrates that analysis of the Clausius-Mossotti factor across multiple conductivities allows determination of not only passive electrical properties, but also the membrane and ζ-potential, and accurately predicts DEP behavior at higher conductivity for the first time.