Boundary Reflection Derivation Method for Intracellular Structure Change Based on GHz Electrical Impedance Spectroscopy

Abstract

Boundary reflection derivation method has been proposed in order to clarify intracellular structure change among the cell wall, membrane, and cytoplasm in the frequency range from 1 MHz to 3 GHz. This method is composed of three steps, which are 1) dielectric properties extraction of dispersed medium $\varepsilon _{\mathrm {dis}}^{\ast }$ and yeast cells $\varepsilon _{\mathrm {cell}}^{\ast }$ ; 2) dielectric properties fitting of cell wall $\varepsilon _{\mathrm {wall}}^{\ast }$ , membrane $\varepsilon _{\mathrm {mem}}^{\ast }$ , cytoplasm $\varepsilon _{\mathrm {cyto}}^{\ast }$ , and intracellular components $\varepsilon _{\mathrm {IC}}^{\ast }$ by a multishelled sphere model; and 3) reflection coefficients calculation at boundaries between cell wall and membrane $\Gamma _{\text {wm}}^{\ast }$ , and between membrane and cytoplasm $\Gamma _{\text {mc}}^{\ast }$ . With this method, $\Gamma _{\text {wm}}^{\ast }$ and $\Gamma _{\text {mc}}^{\ast }$ in living (LC) and dead (DC) yeast cell solutions with various volume concentrations are calculated from experimental impedances. $\Gamma _{\text {wm}}^{\ast \text {DC}}$ shows a difference as compared with $\Gamma _{\text {wm}}^{\ast \text {LC}}$ in GHz range. $\Gamma _{\text {wm}}^{\ast \text {LC}}$ and $\Gamma _{\text {mc}}^{\ast \text {LC}}$ illustrate electromagnetic waves penetrate yeast cell membrane and cytoplasm in GHz range nevertheless they are reflected in MHz range.