Computer simulation for electrochemical impedance of a living cell adhered on the inter-digitated electrode sensors

Abstract

The sensitivity of inter-digitated electrode (IDE) impedance sensors for adherent cell monitoring is investigated by computer simulation. Governing equation based on Maxwell’s equation is solved using finite element method by a commercially-available software to obtain impedance with/without living cells on sensor surface. For IDE, the current concentration is shown to be higher along the edges, as a result of which the electrode edges have a higher impact on impedance. The higher sensitivity is observed in case of higher cell density and larger cell size due to larger occupancy on sensor surface. It is also seen that the smaller electrode geometry displays higher sensitivity in the presence of adherent cell comparable or smaller than electrode spacing. This behavior is explained in view of the increase in number of electrode edges. It is also found out that the sensitivity of IDE outperforms to that of facing electrode (FE) for adherent cell sensing owing to the larger cell coverage and higher current concentration along the electrode edges. It is important to note that the IDE shows higher sensitivity than the FE in the presence of adherent cell, which is in contrast to the previously reported sensitivity behavior for floating cell. This makes IDE as a suitable choice of electrode for experimentalists working on adherent cell studies.

Impact of width and spacing of interdigitated electrode on impedance-based living cell monitoring studied by computer simulation

“…We observed that the sensitivity increased with the increase in the number of electrode fingers (N) validating the results from our previous report. 32) It was also found that the peak sensitivity corresponding to W/S < 1 and W/S > 1 exhibited higher sensitivity than W/S = 1. Moreover, the slope in the range of W/S < 1 showed the larger increase in sensitivity.…”

“…[25][26][27] In addition to this, there are quite a few reports that address the factors influencing the sensitivity of IDE in the absence of living cells. [28][29][30][31] Meanwhile, these issues were addressed in our previous report 32) where the sensitivity due to IDE geometry was studied in the presence of adherent cell through 3D computer simulations. However, the sensitivity study was limited to the electrode geometry where the width (W) of the electrode was equal to the spacing (S) in the presence of adherent cell.…”

An analytical formula for determining the electrical impedance between a single adherent cell and sensor substrate

“…Double-layer capacitance per unit area 46) F m 2 -0.89 Solution relative permittivity 47) 78 Solution conductivity 47) S m 1 -1.5 Cell membrane thickness 46) nm 5.0 Cell membrane relative permittivity 46) 5.0 Cell membrane conductivity 48) S m 1 -1.0 10 9…”

Simulation and Experiment for Electrode Coverage Evaluation by Electrochemical Impedance Spectroscopy Using Parallel Facing Electrodes

“…Table 1 shows the parameters used for the simulation, where almost all of the values were based on the literature of Sun et al 26 The double layer capacitance per unit area was a calculated value. 22 This study focuses on cell density and thus the cytoplasm conductivity was set to be same as that of the solution. The simulations were performed with various electrode coverage of cells existing between PFE.…”

“…27 The spherical cell diameter was 10 m and adhesive cell diameter and height were 10 m and 5 m, respectively. 22 The cell nucleus within the cell was ignored because it does not affect the R gap depending on the extracellular ion conduction. The top and bottom faces of the model domain were defined as working electrode (WE) and counter electrode (CE), respectively.…”