Cole–Cole, linear and multivariate modeling of capacitance data for on-line monitoring of biomass

Dabros, Michal; Dennewald, Danielle; Currie, David J.; Lee, Mark H.; Todd, Robert W.; Marison, I. W.; Stockar, Urs von

doi:10.1007/s00449-008-0234-4

Cited by 57 publications

(53 citation statements)

References 43 publications

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“…Even more recently, yeast cultures were analyzed using Cole-Cole, linear, and multivariate statistical regression analysis, with the authors finding the multivariate statistical method to provide the most satisfactory results. 38 Also in yeast, Maskow et al 33 observed a departure from a linear response between permittivity and biomass that arose during changes in intracellular lipid formation. They further analyzed the changes in the f c and a values that occurred during this time, and found they correlated well with the physiological changes during the culture.…”

Section: Eðf þ ¼mentioning

confidence: 98%

Quantitative modeling of viable cell density, cell size, intracellular conductivity, and membrane capacitance in batch and fed‐batch CHO processes using dielectric spectroscopy

Opel

Amanullah

2010

Biotechnology Progress

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Dielectric spectroscopy was used to analyze typical batch and fed-batch CHO cell culture processes. Three methods of analysis (linear modeling, Cole-Cole modeling, and partial least squares regression), were used to correlate the spectroscopic data with routine biomass measurements [viable packed cell volume, viable cell concentration (VCC), cell size, and oxygen uptake rate (OUR)]. All three models predicted offline biomass measurements accurately during the growth phase of the cultures. However, during the stationary and decline phases of the cultures, the models decreased in accuracy to varying degrees. Offline cell radius measurements were unsuccessfully used to correct for the deviations from the linear model, indicating that physiological changes affecting permittivity were occurring. The beta-dispersion was analyzed using the Cole-Cole distribution parameters Deltaepsilon (magnitude of the permittivity drop), f(c) (critical frequency), and alpha (Cole-Cole parameter). Furthermore, the dielectric parameters static internal conductivity (sigma(i)) and membrane capacitance per area (C(m)) were calculated for the cultures. Finally, the relationship between permittivity, OUR, and VCC was examined, demonstrating how the definition of viability is critical when analyzing biomass online. The results indicate that the common assumptions of constant size and dielectric properties used in dielectric analysis are not always valid during later phases of cell culture processes. The findings also demonstrate that dielectric spectroscopy, while not a substitute for VCC, is a complementary measurement of viable biomass, providing useful auxiliary information about the physiological state of a culture.

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Section: Eðf þ ¼mentioning

confidence: 98%

Quantitative modeling of viable cell density, cell size, intracellular conductivity, and membrane capacitance in batch and fed‐batch CHO processes using dielectric spectroscopy

Opel

Amanullah

2010

Biotechnology Progress

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“…For example, in vitro impedance measurements have been shown to detect cell proliferation and cell-drug interaction 12 , quantify biomass in suspensions 11,13 and create two-dimensional images of cell migration 14 . Much of this work utilizes the electrical 'signature' of the cell membrane: a well-functioning cell membrane is relatively impermeable and thus behaves like a capacitor in the presence of electric current [9][10][11]13,15 . Cell damage or death results in a loss of membrane structure and integrity, allowing ions and current to pass through the membrane.…”

mentioning

confidence: 99%

Impedance sensing device enables early detection of pressure ulcers in vivo

et al. 2015

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When pressure is applied to a localized area of the body for an extended time, the resulting loss of blood flow and subsequent reperfusion to the tissue causes cell death and a pressure ulcer develops. Preventing pressure ulcers is challenging because the combination of pressure and time that results in tissue damage varies widely between patients, and the underlying damage is often severe by the time a surface wound becomes visible. Currently, no method exists to detect early tissue damage and enable intervention. Here we demonstrate a flexible, electronic device that non-invasively maps pressure-induced tissue damage, even when such damage cannot be visually observed. Using impedance spectroscopy across flexible electrode arrays in vivo on a rat model, we find that impedance is robustly correlated with tissue health across multiple animals and wound types. Our results demonstrate the feasibility of an automated, non-invasive 'smart bandage' for early detection of pressure ulcers.

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“…The fitting algorithm was described in details by Dabros et al [26]. The parameters (DC and f C ) of the fitted model were calculated by the software.…”

Section: Dielectric Spectroscopy and Cole-cole Model Fittingmentioning

confidence: 99%

Impact of apoptosis on the on-line measured dielectric properties of CHO cells

Zalai

Tobak

Putics

2015

Bioprocess Biosyst Eng

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Apoptosis is a common type of cell death in biopharmaceutical cell culture processes which causes decrease in viable cell density and product yield. The progression of apoptosis has been reported to influence the dielectric properties of mammalian cells; however, the on-line detection of these effects has been rarely described. This study provides a comprehensive analysis of the on-line detectability of dielectric changes upon apoptosis induction in an industrial fed-batch process of CHO cells expressing a recombinant monoclonal antibody. Using capacitance signals, measured at 25 frequencies, the impact of apoptosis on the dielectric spectra was investigated in eight bioreactor cultivations in which various process conditions were combined with two different apoptosis induction strategies (camptothecin treatment and glucose starvation). To differentiate the apoptosis-related information from the cell concentration-associated variance in the multivariate capacitance datasets, principal component analysis (PCA) was used. A second principal component, explaining an explicit proportion (>20%) of the variance, was identified to be related to dielectric changes induced by apoptosis. Furthermore, the analysis of caspase-3 and -7 activation and DNA fragmentation showed that the detected dielectric change occurred in the early phase of apoptosis. The presented results verify that apoptosis has a considerable impact on the dielectric features of CHO cells and it can be monitored on-line with the introduced tool-set combining capacitance measurement with multivariate data analysis.

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Cole–Cole, linear and multivariate modeling of capacitance data for on-line monitoring of biomass

Cited by 57 publications

References 43 publications

Quantitative modeling of viable cell density, cell size, intracellular conductivity, and membrane capacitance in batch and fed‐batch CHO processes using dielectric spectroscopy

Quantitative modeling of viable cell density, cell size, intracellular conductivity, and membrane capacitance in batch and fed‐batch CHO processes using dielectric spectroscopy

Impedance sensing device enables early detection of pressure ulcers in vivo

Impact of apoptosis on the on-line measured dielectric properties of CHO cells

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