Effects of cell detachment methods on the dielectric properties of adherent and suspension cells

Abstract

Cell analyses such as flow cytometry, dielectrophoresis, and some patch-clamp techniques require that cells be in monodisperse suspension in order for analysis to occur. Where cells have a normally adherent phenotype in vivo, this requires that cells be removed from the surface of the culture flask or vessel. This can be achieved in many ways, but most commonly either by the use of a dissociation medium of some form, or by scraping the cells from the surface. Both methods have potential drawbacks; chemical methods may alter the properties of the cells to such a degree that the measurement might be regarded as meaningless, whilst scraping could cause physical damage to the structure of the cells. In this paper, we use dielectrophoresis to analyse the electrical properties of two adherent cell lines detached by multiple methods, and compare these against a control cell line of suspension cells, examined in both the native state and when subject to the same chemical treatments. The results indicate that most chemical agents do not alter the electrophysiology of cells directly, though they may trigger some potential cell deterioration processes such as apoptosis in the cells. This can be observed in the production of apoptotic body-like particles and the alteration of cytoplasmic conductivity (which has been associated with apoptotic water efflux). However, cells detached by scraping exhibited statistically significant differences in their electrophysiological properties when compared to those detached by the chemical methods, indicating that this method is unsuitable for detachment of adherent cells prior to analysis of isolates suspension cells.

Impact of Detachment Methods on M2 Macrophage Phenotype and Function

“…Moreover, some cell surface molecules are sensitive to environmental protease activities which are often used for cell dissociation ( emoldonnell and Le andro s i 1 emoldonnell 1 0 art ne - Pomares et al 1998). Specifically, studies across different cell types have revealed that detachment/separation processes affect cell viability, cell membrane properties, and influence cell function (Malorny, Neumann, and Sorg 1981;Batista U 2010;Mahabadi, Labeed, and Hughes 2015;Wachs et al 2003). In this study, we evaluated the impact of different cell detachment methods on the efficiency of cell recovery, viability, phenotype and function.…”

Ten–Second Electrophysiology: Evaluation of the 3DEP Platform for high-speed, high-accuracy cell analysis

“…Motion of particles tracked across the wells, using an image analysis algorithm on the host PC. Light absorbance is monitored across ten concentric rings inside each well, and the rate of change in light intensity within these rings is determined and scaled to relative area 29,32 . This parameter is proportional to the Clausius-Mossotti factor, a mathematical relationship for the relative polarisability of the suspended particles which is based, in this instance, on the dielectric properties of cytoplasm, membrane and suspending medium and on the applied frequency 14,27 .

Figure 3Schematic of the 3DEP reader platform.

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Accurate quantification of apoptosis progression and toxicity using a dielectrophoretic approach

“…The remaining cells were detached following incubation with Accutase® which has been shown to not significantly alter the DEP properties of the cells. 22 These cells were then centrifuged at room temperature at 259g for 6 minutes. The supernatant was removed and the pellets were resuspended in the previously-described experimental medium.…”