A comparative study of cell death using electrical capacitance measurements and dielectrophoresis

Patel, Pareshkumar; Bhat, Aditya; Markx, Gerard H.

doi:10.1016/j.enzmictec.2008.09.006

Cited by 50 publications

(36 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5,[64][65][66][67][68] In late stages of cultures, changes in cell diameter and viability typically occur, leading to changes in several parameters (C M , r i , and others). 20,29,38 An easily comprehensible example for the complexity of the analysis is that according to our results, an increase in f C might occur either as a result of a decrease in cell size (Eq. 2), viability (beginning of death phase), or as an indicator of a metabolic shift of the culture (phase B II in lab scale).…”

Section: Multifrequency Permittivity Measurements and Analysis Of Calmentioning

confidence: 81%

“…22,24 It also changes after viral infection and increases significantly after overexpression of cation channels, 30,49 being particularly affected by processes directly concerning cellular membrane properties, for example, exocytosis (loss of microvilli), viral release, and apoptosis. 20,29,38 One study reports that changes in C M might, in combination with a rather small drop in cell size, be responsible for changes in permittivity. These authors attributed difference in permittivity to unknown changes in membrane structure (and therefore in C M ) and found an excellent correlation between the permittivity signal and physiological state during perfusion cultures of hybridoma cells.…”

Section: Multifrequency Permittivity Measurements and Analysis Of Calmentioning

confidence: 99%

“…5,13,[17][18][19] This observation is probably caused by the fact that the ''remaining'' permittivity of a nonviable cell is dependent on the mechanism by which the cell was ''inactivated.'' 20 The classical method of counting viable cells by dye exclusion can therefore not always be expected to give data that correlate linearly with the permittivity, in particular in the late stage of cultivations during which viability is low. The relationship is rather governed by a mechanism in which dying cells loose their polarizability (and hence their permittivity) progressively.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

Ansorge

Esteban

Schmid

2009

Biotechnology Progress

View full text Add to dashboard Cite

Lab and pilot scale batch cultivations of a CHO K1/dhfr À host cell line were conducted to evaluate on-line multifrequency permittivity measurements as a process monitoring tool. The b-dispersion parameters such as the characteristic frequency (f C ) and the permittivity increment (De max ) were calculated on-line from the permittivity spectra. The dual-frequency permittivity signal correlated well with the off-line measured biovolume and the viable cell density. A significant drop in permittivity was monitored at the transition from exponential growth to a phase with reduced growth rate. Although not reflected in off-line biovolume measurements, this decrease coincided with a drop in OUR and was probably caused by the depletion of glutamine and a metabolic shift occurring at the same time. Sudden changes in cell density, cell size, viability, capacitance per membrane area (C M ), and effects caused by medium conductivity (r m ) could be excluded as reasons for the decrease in permittivity. After analysis of the process data, a drop in f C as a result of a fall in intracellular conductivity (r i ) was identified as responsible for the observed changes in the dual-frequency permittivity signal. It is hypothesized that the b-dispersion parameter f C is indicative of changes in nutrient availability that have an impact on intracellular conductivity r i . On-line permittivity measurements consequently not only reflect the biovolume but also the physiological state of mammalian cell cultures. These findings should pave the way for a better understanding of the intracellular state of cells and render permittivity measurements an important tool in process development and control.

show abstract

Section: Multifrequency Permittivity Measurements and Analysis Of Calmentioning

confidence: 81%

Section: Multifrequency Permittivity Measurements and Analysis Of Calmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

Ansorge

Esteban

Schmid

2009

Biotechnology Progress

View full text Add to dashboard Cite

show abstract

“…More recent studies found, however, that C M changes after the viral infection and overexpression of cation channels [23,64]. Therefore, it seems to be particularly affected by processes involving the cellular membrane properties, such as exocytosis (loss of microvilli), viral release, and apoptosis [42,65]. Reductions in C M of 40-60% were reported for several cell types after infection with different viruses, such as the herpes simplex virus and polyomavirus.…”

Section: Multifrequency Permittivity Spectramentioning

confidence: 99%

Monitoring lentiviral vector production kinetics using online permittivity measurements

Ansorge¹,

Lanthier²,

Transfiguracion³

et al. 2011

Biochemical Engineering Journal

View full text Add to dashboard Cite

Lentiviral vectors (LVs) are effective delivery vehicles that have been successfully used in gene and cell therapy. LVs are most commonly produced via the transient transfection of several plasmid constructs in adherent cell cultures. Recently, we described an efficient and scalable LV production in serum-free suspension cultures. To further facilitate the translation of LV-based interventions to the clinic, the robustness of the production process needs to be ensured to ultimately achieve a specified quality and quantity of LV production lots. However, routine processes are largely empirical, and strategies to monitor LV production kinetics in real-time have not yet been described.In this work, in situ real-time permittivity measurements were assessed to document the production of LVs. Characteristic process phases that were closely associated with LV production kinetics were identified. The permittivity signal evolution was interpreted by exploiting various independent online and offline monitoring measurements. Cellular membrane properties and, to a lesser extent, cell size were the main factors contributing to the permittivity variations. It is concluded that the permittivityrelated parameters can be used for the detection of viral release, allowing real-time assessment of process performance. The technology should thus greatly facilitate process development and optimization.Crown

show abstract

“…41 Capacitance probes estimate viable cell density by correlating the electrical capacitance data of the bulk cell suspension to the viable biomass as routinely done in the literature. 21,32,34 The small rate of viability drop measured by the capacitance probes relative to Cedex, as well as to our impedance based technique, is most likely because the dense background suspension of unhealthy or damaged cells (especially during the initial stages of cell death) may also offer a finite capacitance, 46 and therefore wrongly read as viable by the …”

mentioning

confidence: 99%

On-chip microelectrode impedance analysis of mammalian cell viability during biomanufacturing

Sharma

Blackburn

et al. 2014

Biomicrofluidics

View full text Add to dashboard Cite

The characterization of cell viability is a challenging task in applied biotechnology, as no clear definition of cell death exists. Cell death is accompanied with a change in the electrical properties of the membrane as well as the cell interior. Therefore, changes in the physiology of cells can be characterized by monitoring of their dielectric properties. We correlated the dielectric properties of industrially used mammalian cells, sedimented over interdigitated microelectrodes, to the AC signal response across the chip. The voltage waveforms across the electrodes were processed to obtain the circuit impedance, which was used to quantify the changes in cell viability. We observed an initial decrease in impedance, after which it remained nearly constant. The results were compared with data from the dye exclusion viability test, the cell specific oxygen uptake rate, and the online viable cell density data from capacitance probes. The microelectrode technique was found to be sensitive to physiological changes taking place inside the cells before their membrane integrity is compromised. Such accurate determination of the metabolic status during this initial period, which turned out to be less well captured in the dye exclusion tests, may be essential for several biotechnology operations. V C 2014 AIP Publishing LLC. [http://dx

show abstract

A comparative study of cell death using electrical capacitance measurements and dielectrophoresis

Cited by 50 publications

References 25 publications

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

Monitoring lentiviral vector production kinetics using online permittivity measurements

On-chip microelectrode impedance analysis of mammalian cell viability during biomanufacturing

Contact Info

Product

Resources

About