Bioelectrical impedance assay to monitor changes in cell shape during apoptosis

Abstract

Apoptosis is a strictly regulated and genetically encoded cell 'suicide' that may be triggered by cytokines, depletion of growth factors or certain chemicals. It is morphologically characterized by severe alterations in cell shape like cell shrinkage and disintegration of cell-cell contacts. We applied a non-invasive electrochemical technique referred to as electric cell-substrate impedance sensing (ECIS) in order to monitor the apoptosis-induced changes in cell shape in an integral and quantitative fashion with a time resolution in the order of minutes. In ECIS the cells are grown directly on the surface of small gold-film electrodes (d = 2 mm). From readings of the electrical impedance of the cell-covered electrode, performed with non-invasive, low amplitude sensing voltages, it is possible to deduce alterations in cell-cell and cell-substrate contacts. To improve the sensitivity of this impedance assay we used endothelial cells derived from cerebral micro-vessels as cellular model systems since these are well known to express electrically tight intercellular junctions. Apoptosis was induced by cycloheximide (CHX) and verified by biochemical and cytological assays. The time course of cell shape changes was followed with unprecedented time resolution by impedance readings at 1 kHz and correlated with biochemical parameters. From impedance readings along a broad frequency range of 1-10 6 Hz we could assign the observed impedance changes to alterations on the subcellular level. We observed that disassembly of barrier-forming tight junctions precedes changes in cell-substrate contacts and correlates strongly with the time course of protease activation.

Cross-disciplinary approaches for measuring parasitic helminth viability and phenotype

“…This methodology can provide not only a measurement of viability but also of stress and does not require further manipulation such as lysing of target cells. It has been used for such diverse purposes as measuring cell shape during apoptosis (Arndt et al 2004) as well as to study the kinetics of cell growth and spreading (Wegener et al 2000). However, as cells need to be in constant contact with the gold electrodes during culturing, this technique is primarily suited for use with adherent cells.…”

Polyelectrolyte Multilayers in Microfluidic Systems for Biological Applications

“…Cell behavior such as proliferation, differentiation and death can be interpreted by impedance measurements between a cell and an underlying electrode [29][30][31]. PEMs provide a stable, biocompatible and adhesive environment for cells to grow.…”

Signal Enhancement of Electrochemical Biomemory Device Composed of Recombinant Azurin/Gold Nanoparticle

“…For example, Woolley et al monitored the electrochemical properties of anticancer compounds on cells [2]. In addition, living cells have been widely investigated under many electrochemical conditions such as electron transfer between electroactive centers in cells and electrodes [3], and electric cell substrate impedance sensing [4][5][6]. Furthermore, electrochemistry can be widely applied to biosensors using enzymes, antibodies, nucleic acids, peptide nucleic acids, and aptamers [7][8][9][10].…”