Use of an Insulation Layer on the Connection Tracks of a Biosensor with Coplanar Electrodes to Increase the Normalized Impedance Variation

Abstract

New technologies, such as biosensors and lab-on-a-chip, are reducing time consumption and costs for the detection and characterization of biological cells. One challenge is to detect and characterize cells and bacteria one by one or at a very low concentration. In this case, measurements have very low variations that can be difficult to detect. In this article, the use of an insulation layer on the connection tracks of a biosensor with coplanar electrodes is proposed to improve a biosensor previously developed. The impedance spectroscopy technique was used to analyze the influence of the insulation layer on the cutoff frequencies and on the normalized impedance variation. This solution does not induce changes in the cutoff frequencies, though it permits improving the normalized impedance variations, compared to the same biosensor without the insulation layer.

Real-Time Impedance Monitoring of Epithelial Cultures with Inkjet-Printed Interdigitated-Electrode Sensors

“…Results from the integration of the inkjet-printed sensors into cellular cultures for monitoring proliferation, detachment, and migration of a monolayer of a cell line of keratinocytes using impedance spectroscopy are presented in this section. We have measured the impedance of the electrodes embedded in the cell cultures in a frequency range of 100 Hz–1 MHz, which comprises the region of β biological dispersion [ 9 , 41 ]. At these frequencies, the extracellular resistance and membrane capacitance are the primary contributions to the impedance changes both in magnitude and phase [ 42 ].…”

Design and Modeling of a Device Combining Single-Cell Exposure to a Uniform Electrical Field and Simultaneous Characterization via Bioimpedance Spectroscopy

“…Therefore, ten cells could be simultaneously characterized during one exposure, and a device with a deficient trap could still be used. The microelectrode design was based on the human macrophage characterization of Alves de Araujo et al [ 21 ]. Because these cells have a medium diameter of about 20 µm, the sensitive part of the microelectrodes was of similar dimensions (30 µm square).…”

“…This bandwidth depends on the biological medium conductivity, the electrodes’ geometry, the environmental material, and the cell’s properties. Frequency of Beta dispersion only depends on biological medium properties (intra-extracellular medium, membrane capacitance and cell size) as described in models such as Maxwell mixture theory or Cole-Cole and already discussed in a previous work [ 21 ]. Characteristic conductivities and frequency of Beta dispersion for different human tissues can be find in the reference database based on Gabriel’s work [ 22 ].…”

Interdigitated Sensor Optimization for Blood Sample Analysis

“…Cytometric sensors use microchannels to focus on one cell at a time [ 14 ], and cells are dynamically characterized during their passage into a measurement area situated inside the channel. Matrix electrode systems use multiple electrodes to perform numerous measurements at a time [ 15 ]. Despite the fact that these three techniques have better sensitivities, they are also the most difficult to implement.…”