Theory of ac electrokinetic behavior of spheroidal cell suspensions with an intrinsic dispersion

TL;DR

This paper develops an analytical theory for the ac electrokinetic behavior of spheroidal cell suspensions, accounting for intrinsic dielectric dispersion, cell shape, and interactions, to predict spectra and characteristic frequencies.

Contribution

It introduces a spectral representation method to analytically derive characteristic frequencies and dispersion strengths for spheroidal cells with intrinsic dielectric dispersion, including local-field effects.

Findings

Identified four and six characteristic frequencies for dielectric and CMF spectra.

Demonstrated the influence of cell shape, dispersion strength, and intrinsic frequency on spectra.

Showed how cell interactions affect dispersion peaks in dense suspensions.

Abstract

The dielectric dispersion, dielectrophoretic (DEP) and electrorotational (ER) spectra of spheroidal biological cell suspensions with an intrinsic dispersion in the constituent dielectric constants are investigated. By means of the spectral representation method, we express analytically the characteristic frequencies and dispersion strengths both for the effective dielectric constant and the Clausius-Mossotti factor (CMF). We identify four and six characteristic frequencies for the effective dielectric spectra and CMF respectively, all of them being dependent on the depolarization factor (or the cell shape). The analytical results allow us to examine the effects of the cell shape, the dispersion strength and the intrinsic frequency on the dielectric dispersion, DEP and ER spectra. Furthermore, we include the local-field effects due to the mutual interactions between cells in a dense suspension, and study the dependence of co-field or anti-field dispersion peaks on the volume fractions.