Biomass measurement by inductive permittivity

Siano, Steven A.

doi:10.1002/(sici)1097-0290(19970720)55:2<289::aid-bit7>3.0.co;2-e

Cited by 46 publications

(26 citation statements)

References 40 publications

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“…the Aber Biomass Monitor and the Hewlett-Packard E5050A Colloid Dielectic probe (Siano 1997). The resin has been shown to perform well after repeated steam sterilizations or CIP and is suitable for most laboratory and pilot plant applications.…”

Section: Probe Developmentsmentioning

confidence: 99%

On-line Measurements and Control of Viable Cell Density in Cell Culture Manufacturing Processes using Radio-frequency Impedance

Carvell¹,

2006

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In this work, radio-frequency (RF) impedance is reviewed as a method for monitoring and controlling cell culture manufacturing processes. It is clear from the many publications cited that RF Impedance is regarded as an accurate and reliable method for measuring the live cell bio-volume both on-line and off-line and the technology is also sutable for animal cells in suspension, attached to micro-carriers or immobilized in fixed beds. In cGMP production, RF Impedance is being used in three main areas. Firstly, it is being used as a control instrument for maintaining consistent perfusion culture allowing the bioreactor to operate under optimum conditions for maximum production of recombinant proteins. In the second application it has not replaced traditional off-line live cell counting techniques but it is being used as an additional monitoring tool to check product conformance. Finally, RF Impedance is being used to monitor the concentration of live cells immobilized on micro-carriers or packed beds in cGMP processes where traditional off-line live cell counting methods are inaccurate or impossible to perform.

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Section: Probe Developmentsmentioning

confidence: 99%

On-line Measurements and Control of Viable Cell Density in Cell Culture Manufacturing Processes using Radio-frequency Impedance

Carvell¹,

2006

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“…As will be discussed later, this technique has the advantage that it only detects cells with intact plasma membranes and so gives values that do correlate with biomass rather than necromass. The physics that forms the basis of this technique has been studied since the last century and has been reviewed in great detail by a number of authors (Grant et al, 1978;Pethig, 1979;Pethig and Kell, 1987;Takashima et al, 1988;Foster and Schwan, 1989;Rigaud et al, 1996) and how this theory relates to (dielectric) biomass measurements has also been extensively reviewed and researched (Irimajiri et al, 1975;Harris and Kell, 1983;Harris et al, 1987;Kell,1987b;Markx et al, 1991a,b,c,d;Mishima et al, 1991a;Sonnleitner et al, 1992;Davey, 1993a,b;Davey and Kell, 1994; Matanguihan et al, 1994;Siano, 1996;Asami et al, 1998;Davey and Kell, 1998a,b;Asami et al,1999;Krairak et al, 1999 ;Markx and Davey, 1999).…”

Section: Even If Biomass Was Easily Measurable There Is Still the Quementioning

confidence: 99%

“…The third method that has been used to estimate biomass is by scanning the frequencies over the β-dispersion region to generate a capacitance curve similar to that in for the non-contact electrode method from Hewlett-Packard Siano, 1996) and with the Biomass Monitor Davey and Kell, 1998b). On the BM one typically scans between 15 and 50 frequencies in random order under the control of an external computer.…”

Section: Measurement Of the ∆C Of The β-Dispersionmentioning

confidence: 99%

“…below about 100-500 kHz)(see Figure 6). As this polarisation capacitance increases as the electrodes become fouled or as the medium conductivity increases, one can see that electrode polarisation could be a limiting factor in the present applications of capacitive biomass measurements (Cerckel et al, 1993;Degouys et al, 1993;Siano, 1996;Davey and Kell, 1998a,b).…”

Section: Electrode Polarisationmentioning

confidence: 99%

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On-Line, Real-Time Measurements of Cellular Biomass using Dielectric Spectroscopy

Yardley

Kell

Barrett

et al. 2000

Biotechnology and Genetic Engineering Reviews

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“…The measured permittivity is affected as well, as it determines the rate of electrode polarization. This effect is frequency dependent and cannot reliably be subtracted out, as the ionic content of the medium changes during the fermentation process [8]. Therefore, we have explored a method that compensates for changes in the electric properties of the background electrolyte by differential measurement using a three-electrode configuration [9] in which the impedance measured between two closely spaced electrodes is made insensitive to biomass by covering it with a porous membrane that prevents cells to approach the electrodes (Fig.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of yeast cell concentration using a micromachined impedance sensor

Krommenhoek

Gardeniers

Bomer

et al. 2006

Sensors and Actuators B: Chemical

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This paper describes the design, modeling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in Saccharomyces cerevisiae cell culture show that the characteristic frequency describing the ␤-dispersion of S. cerevisiae cells is around 2.8 MHz. The permittivity change of the cell suspension was measured for the concentration range 0-9 g/l and depends linearly on the biomass concentration. In order to compensate the measurements for the electric properties of the background electrolyte, which increases the sensitivity and allows measurements in different media, the use of a three-electrode configuration in combination with a semi-permeable poly(2-hydroxyethyl methacrylate) (pHEMA) membrane was explored. Measurements show that the impedance of hydrated pHEMA varies with the background electrolyte conductivity only, and not with the concentration of cells, indicating that pHEMA is suitable for this purpose. The optimal pHEMA membrane thickness was determined using finite-element modelling and was found to be 1 m for the electrode configuration under study.

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Biomass measurement by inductive permittivity

Cited by 46 publications

References 40 publications

On-line Measurements and Control of Viable Cell Density in Cell Culture Manufacturing Processes using Radio-frequency Impedance

On-line Measurements and Control of Viable Cell Density in Cell Culture Manufacturing Processes using Radio-frequency Impedance

On-Line, Real-Time Measurements of Cellular Biomass using Dielectric Spectroscopy

Monitoring of yeast cell concentration using a micromachined impedance sensor

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