Comparison of Three Kinds of Electrode–Skin Interfaces for Electrical Impedance Scanning

Abstract

Low, uniform, and stable electrode-skin impedance is required to achieve good performance of the electrode-skin interface for electrical impedance scanning (EIS) examination. This can be used to measure the real impedance distribution of breast tissue beneath the skin. In this study, the gel interface, the cotton fine grid thin layer (CFGTL) interface, and the hydrogel interface were compared. Experiments were conducted to assess the influence of each interface on the multi-frequency EIS data and their capacity to retain moisture. Results showed that the CFGTL and hydrogel interfaces decreased contact impedance and made the impedance between the electrodes and the breast skin more even and stable. The Cole-Cole model was also used to fit the multi-frequency EIS data. The results demonstrated that the CFGTL and hydrogel interfaces were advantageous for measuring the impedance of the breast tissue under the gel interface. In general, the CFGTL and hydrogel interfaces had good contact with the skin, and both interfaces were proper choices for EIS examination at present. The hydrogel interface was a better choice for our new EIS system.

Performance Evaluation of Five Types of Ag/AgCl Bio-Electrodes for Cerebral Electrical Impedance Tomography

“…18,19,22,24,28,29,35,36,40,43 Hydrogel electrode was investigated to be superior to Ag/AgCl electrode to some extent, 36 but the size of it is too huge to be suitable for long-term cerebral monitoring in clinical application. In general, Ag/AgCl electrode is preferable in biosignal recording applications like EIT measurements because it features low and stable offset potentials, low and matched interface impedance, and low polarization, 20 but up to now, there have been many types of Ag/AgCl electrodes by the different techniques, such as powder pressing, filming, hot dip coating and electrolyzing, etc., and the influences on the data measurements of cerebral EIT with different types of Ag/AgCl electrodes have not been explored.…”

Electrogelation and rapid prototyping of Bombyx mori silk fibroin

“…Native Bombyx mori silk is composed of SF protein coated with silk sericin proteins. Due to favorable biocompatibility and minimal inflammatory reaction [4], SF has been fabricated into a variety of silk-based materials, such as gels, fibers and films and so on [5][6][7][8][9][10], and these silk-based materials have been widely used for tissue engineering scaffolds, drug delivery, photonic crystal materials and electronic device [11][12][13][14].…”

Statistical Estimation of EIT Electrode Contact Impedance Using a Magic Toeplitz Matrix

“…As follows from those graphs: 1) both models give similar results; 2) contact impedances vary across electrodes; and 3) contact impedances drop with frequency. A decrease of electrode–skin contact resistivity with frequency increase was also reported in [13]. For each frequency, we compute the average voltage drop as Z times median value of J/U ; the voltage drop due to contact impedance is estimated to be approximately 11% of the applied voltage.…”

“…Several techniques to reduce the unwanted surface impedance have been studied over the years, including application of skin hydrogel [11], or covering electrodes with a cotton fine grid [12]. A recent paper [13] compares several electrode–skin interface aids and their dependence on the current frequency. Despite some improvements the electrode contact impedance remains a challenging problem in clinical setting especially when it varies from electrode to electrode.…”