Impedance spectroscopy applied to the fast wounding dynamics of an electrical wound-healing assay in mammalian cells

Abstract

Electrical wound-healing assays are often used as a means to study in vitro cell migration and proliferation. In such analysis, a cell monolayer that sits on a small electrode is electrically wounded and its spectral impedance is then continuously measured in order to monitor the healing process. The relatively slow dynamics of the cell healing have been extensively studied, while those of the much faster wounding phase have not yet been investigated. An analysis of the electrical properties of a particular cell type during this phase could give extra information about the changes in the cell membrane due to the application of the wounding current, and could also be useful to optimize the wounding regime for different cell types. The main issue when trying to register information about these dynamics is that the traditional measurement scheme employed in typical wound-healing assays doesn’t allow the simultaneous application of the wounding signal and measurement of the system’s impedance. In this paper, we overcome this limitation by implementing a measurement strategy consisting of cycles of fast alternating low- and high-voltage signals applied on electrodes covered with mammalian cells. This approach is capable of registering the fast impedance changes during the transient regime corresponding to the cell wounding process. Furthermore, these quasi-simultaneous high- and low-voltage measurements can be compared in order to obtain an empirical correlation between both quantities.

Assay based on electrical impedance spectroscopy to discriminate between normal and cancerous mammalian cells

“…(3) During the confluent phase, cells can be deliberately damaged to carry out a wound-healing assay. This kind of assay, when performed properly, can give information about the dynamics of the transient regime that corresponds to the cell death process [20] in what we call the "wounding phase. "…”

“…tion after a defined portion of the layer has been mechanically or electrically damaged [22][23][24][25]. A different approach has been used in a previous work to study the dynamics of the wounding phase [20], i.e., during the time at which the wound develops. We performed an analogous assay to analyze impedance changes during the wounding phase, with some modifications.…”

“…These four parameters were included in the set of discrimination features. Previous results showed that the measured impedance changes as the applied voltage increases over some threshold [20] and the relationship between high-and low-voltage measurements was modeled as follows:…”

Design and testing of a microelectrode array with spatial resolution for detection of cancerous cells in mixed cultures

“…(iii) Wounding phase: during this phase, the confluent cell monolayer is deliberately damaged to carry out a wounding assay. A specific technique aimed to obtain information about the wounding dynamics has been recently developed [20] and used to discriminate between normal and cancerous cells [13]. We used a similar A c c e p t e d M a n u s c r i p t technique in this work, with some variations.…”

Real-Time Monitoring of Wound Healing on Nano-Patterned Substrates: Non-Invasive Impedance Spectroscopy Technique

“…On the other hand, electrical wound healing assay [4], [5] is label free and non-invasive. Electrical pulses are applied to create the specific wound and the healing process is monitored online by recording the impedance variation with time using electric cell substrate impedance sensing (ECIS) platform [6]- [8].…”