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Analytical and Numerical Modeling Methods for Electrochemical Impedance Analysis of Single Cells on Coplanar Electrodes
Author(s) -
Tsai SungLin,
Wang MinHaw,
Chen MingKun,
Jang LingSheng
Publication year - 2014
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201300544
Subject(s) - electrical impedance , capacitance , equivalent circuit , materials science , capacitive sensing , resistor , optoelectronics , analytical chemistry (journal) , voltage , electronic engineering , electrode , chemistry , electrical engineering , engineering , chromatography
Impedance measurements provide basic electrical properties and are used to analyze the characteristics of electrochemical materials for biomedical applications. The extracellular fluid (ECF) in microfluidic devices greatly affects the accuracy of impedance measurements of cells. When a single cell is placed in large amounts of ECF, the electric current mostly passes through the ECF, not the cell. Hence, this work presents a modeling method that is demonstrated in numerical and analytical solutions for eliminating the effect of ECF in coplanar impedance sensors. The proposed modeling method uses fundamental formulas of circuits that include the electrical parameters of the ECF, cytoplasm, and cell membrane. Equivalent circuit models for the coplanar impedance sensor are established to simulate the impedance as well as the measured ones for excitation frequencies in the range of 11–101 kHz. According to the calculation result using the proposed modeling method, the cytoplasm resistance, membrane capacitance, medium resistance, and medium capacitance of HeLa (human cervix adenocarcinoma) cell are 13.5 kΩ, 122.6 pF, 27.9 kΩ, and 337.7 pF, respectively. Moreover, the electric current distribution in the coplanar impedance sensor is investigated using finite element method (FEM) simulation software. The variation in the impedance during measurements with the simultaneous application of an alternating‐current (AC) voltage amplitude of 0.4 V pp in the fluid volume range of 9–144 µL is also studied.