Role of peroxide in AC electrical field exposure effects on Friend murine erythroleukemia cells during dielectrophoretic manipulations

Abstract

The effects of AC field exposure on the viability and proliferation of mammalian cells under conditions appropriate for their dielectrophoretic manipulation and sorting were investigated using DS19 murine erythroleukemia cells as a model system. The frequency range 100 Hz-10 MHz and medium conductivities of 10 mS/m, 30 mS/m and 56 mS/m were studied for fields generated by applying signals of up to 7V peak to peak (p-p) to a parallel electrode array having equal electrode widths and gaps of 100 μm. Between 1 kHz and 10 MHz, cell viability after up to 40 min of field exposure was found to be above 95% and cells were able to proliferate. However, cell growth lag phase was extended with decreasing field frequency and with increasing voltage, medium conductivity and exposure duration. Modified growth behavior was not passed on to the next cell passage, indicating that field exposure did not cause permanent alterations in cell proliferation characteristics. Cell membrane potentials induced by field exposure were calculated and shown to be well below values typically associated with cell damage. Furthermore, medium treated by field exposure and then added to untreated cells produced the same modifications of growth as exposing cells directly, and these modifications occurred only when the electrode polarization voltage exceeded a threshold of ~0.4 V p-p. These findings suggested that electrochemical products generated during field exposure were responsible for the changes in cell growth. Finally, it was found that hydrogen peroxide was produced when sugar-containing media were exposed to fields and that normal cell growth could be restored by addition of catalase to the medium, whether or not field exposure occurred in the presence of cells. These results show that AC fields typically used for dielectrophoretic manipulation and sorting of cells do not damage DS19 cells and that cell alterations arising from electrochemical effects can be completely mitigated.

ApoStream™, a new dielectrophoretic device for antibody independent isolation and recovery of viable cancer cells from blood

“…Buffer additives such as BSA, pluronic F-68, anti-oxidant compound, and catalase are known to provide either cell membrane stability, reduction of oxidative stress, or decreased aggregation. 48,49 BSA has been known to reduce the non-specific cell surface interactions and is widely used in flow cytometry and microfluidic applications. 49 Pluronic F-68 is a stabilizer of cell membranes; it reduces potential for membrane shearing by enhancing mechanical strength of the cell membrane with short-term exposure.…”

“…50 It has been shown that hydrogen peroxide is produced when sugar-containing buffer is exposed to AC electric fields; the addition of catalase to buffer allows hydrogen peroxide decomposition and reduces potential for cell damage. 48 These additives were used in the sample buffer to improve the device performance based on their known beneficial effects on cells and ability to increase recovery by lowering nonspecific adhesion between cell to cell and cell to contact surfaces. …”

Biophysical characterization of MDR breast cancer cell lines reveals the cytoplasm is critical in determining drug sensitivity

“…DEP is a technique whereby the frequency-dependent behaviour of cells is determined in nonuniform electric fields, and from this information regarding the electrical properties of the cell can be inferred [8; 9; 10]. DEP and related techniques have been used to characterise a wide range of cellular processes in terms of these biophysical properties in cancer research [11][12][13][14][15][16][17][18]. Our studies have also incorporated a flow cytometric technique to measure membrane potential as an additional biophysical parameter to be considered in our assessment of the cell line panel.…”

Enrichment of putative stem cells from adipose tissue using dielectrophoretic field-flow fractionation

“…Previous investigations in our lab and others have established that exposure to electric fields from DEP electrodes akin to those used in these experiments does not alter cell viability. [43][44][45] In our initial adipose-derived SVF fractionation experiments, eluted cell fractions were collected into tissue culture media, cultured for 12−24 h and assayed for plastic adherence. Cultures of viable cells possessing a fibroblast-like morphology typically associated with adipose-derived mesenchymal stem cell cultures were observed, confirming that cells remain viable following fractionation by DEP-FFF.…”