Bioimpedance Spectroscopy

Abstract

In the context of biology, electrical phenomena are usually identified with ionic currents through protein channels, for example as they are postulated during nerve signalling (Andersen et al. Prog Neurobiol 88(2):104-113, 2009; Sakmann and Neher Annu Rev Physiol 46:455-472, 1984). However, there are more electrical phenomena that play a significant role in biological systems, namely those arising from polarization effects (Grimnes Bioimpedance and Bioelectricity, 2008; Polk Handbook of Biological Effects of Electromagnetic Fields 1996). Local inhomogeneities in charge distributions give rise to the formation of permanent molecular dipoles as in uncharged molecules such as (hydration) water, or due to the polar groups in proteins and lipid molecules. Non-permanent electrical dipoles can originate from the presence of ions in solution. Structured distributions of counter-ions at all polar interfaces, for example along the surface of proteins and especially along the polar membrane interfaces of cells, cause the formation of Stern and Helmholtz layers. All non-uniform distributions of charges and dipoles initiate and modify internal local electrical fields. Moreover, the application of external fields causes relaxation processes with characteristic contributions to the frequency-dependent complex dielectric constant. These dipolar relaxations were initially described by Debye (

The Cole relaxation frequency as a parameter to identify cancer in breast tissue

“…In comparison to previous work cited earlier, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] we note that the work reported here differs primarily in the concentration on a single parameter classification scheme (the Cole relaxation frequency) and the subsequent need to separate Cole frequencies from samples of mixed tissue types, or nonperfect tissues. Jossinett and Schmitt, 8 Wang et al, 11 and Chauveau et al 9 all describe various types of tissue components found in the breast.…”

“…Each of the dispersion regions is attributed to different frequency dependent phenomena in the tissue. 6 Schwan identified 12 biomaterial elements that can be probed by bioimpedance measurements in the various dispersion regions (see Fig. 1).…”

Effects of heat and freeze on isolated erythrocyte submembrane skeletons

“…6). According to Kell (1987) and Klösgen et al (2011) each semicircle arc in Fig. 6 revealed a dielectric relaxation of Debye type, i.e.…”

“…Based on the theory of dielectroscopy (Kell 1987;Klösgen et al 2011) the frequency dependences of corrected amplitudes ΔZ re and ΔZ im were studied plotting the -ΔZ im vs. ΔZ re for each denaturation temperature, T A and T C . Complex plane (Nyquist) plot of -ΔZ im vs. ΔZ re , determined at the spectrin denaturation temperature, T A , had the form of a semicircle arc, situated below the argument axis (Fig.…”

“…Hence, the respective changes in Z* and C* at 49.5°C were considered as contribution of spectrin skeleton to the dielectric properties of native EGMs. Based on the strong frequency dependences of the changes in Z* and C* at 49.5°C, the methods of dielectric spectroscopy (Klösgen et al 2011) revealed two dielectric relaxations on the membrane skeleton of EGMs. The first relaxation depended on the availability of linkages between the integral proteins and spectrin and was detected at such frequencies whereat the lipid bilayer did not allow penetration of the field into cytosole.…”