Time domain dielectric spectroscopy study of biological systems

Ultrashort electric pulse induced changes in cellular dielectric properties

“…4 are consistent with the range of experimental values for eukaryotic cells obtained from the two-shell model [24]. The values we obtained for r m , r cp , r np , e ne , and r ne (data not shown for e ne and r ne ) are lower than those obtained for other malignant T-cell lines while e m is in line with these results [10,11]. These differences could be attributed to the cell lines we are considering here, different cell preparation techniques, or the number of cell passages; however, our results were consistent with each other and the standard deviations are similar to those obtained in Ref.…”

“…1. Block diagram of the TDDS system, including shapes of the incident (left) and reflected (right) voltage signals and the two-shell model of a lymphocyte, where e is the permittivity and r is conductivity [11].…”

“…TDDS enables us to nonintrusively determine the electrical properties of the cell membrane, cytoplasm, nucleus, and nucleoplasm according to the twoshell model of the eukaryotic cell, shown in Fig. 1 [10][11][12]. We note that this model has also been referred to as a ''three-shell model'' [13]; however, we follow the two-shell nomenclature Feldman et al TDDS can rapidly obtain dielectric spectra over a wide frequency range with uncertainties on the order 3-5% and 5-7% for the real and imaginary components of the permittivity [14], which are similar to frequency domain systems [15].…”

Label‐Free Impedance Biosensors: Opportunities and Challenges

“…Note that ε r is not strictly constant over frequency, as dipoles may be able to react to slow-moving excitation fields but not to higher-frequency ones. This research area, termed dielectric spectroscopy [137], has received limited attention in the biosensing community [138][139][140] but tends to be applied to measuring bulk solutions at high frequencies (≫ 1 MHz, C surf negligible) and is thus quite distinct experimentally from conventional surface-sensitive impedance biosensors (≪ 1 MHz, C surf important). Some biomolecule dielectric relaxation effects may be detectable at frequencies in the kHz range [138,141].…”

“…This research area, termed dielectric spectroscopy [137], has received limited attention in the biosensing community [138][139][140] but tends to be applied to measuring bulk solutions at high frequencies (≫ 1 MHz, C surf negligible) and is thus quite distinct experimentally from conventional surface-sensitive impedance biosensors (≪ 1 MHz, C surf important). Some biomolecule dielectric relaxation effects may be detectable at frequencies in the kHz range [138,141]. However, these effects are usually neither surface-sensitive nor specific, so dielectric spectroscopy seems better suited to studying the behavior of biomolecules (e.g., [142]) than distinguishing between similar biomolecules.…”