On-line monitoring of the progress of infection in Sf-9 insect cell cultures using relative permittivity measurements

Zeiser, A.; Bédard, Charles; Voyer, Robert; Jardin, Barbara; Tom, Roseanne; Kamen, Amine

doi:10.1002/(sici)1097-0290(19990405)63:1<122::aid-bit13>3.0.co;2-i

Cited by 72 publications

(62 citation statements)

References 21 publications

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“…The permittivity profiles are cell-line and medium-dependent but sudden changes in the signal are most often not observed. 16,31,32,46 In this experiment, the end of exponential growth phase coincided with the beginning of death phase when glutamine and glucose were simultaneously depleted ( Figure 2). The turbidity signal correlated well with the viable cell count during the growth phase but also measured dead cells and debris and kept increasing during the first part of death phase (80-100 h).…”

Section: Resultsmentioning

confidence: 73%

“…The successful application of this technology in a wide variety of cell culture processes is described in the literature. 5,6,9,[13][14][15][16] Several studies report measurements of the permittivity at one single or two frequencies (to reduce the effect of a changing media composition on the signal). Permittivity measurements are described as a tool to directly measure the viable biomass.…”

Section: Introductionmentioning

confidence: 99%

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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

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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.

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Section: Resultsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

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

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“…Non-spherical cells, cell protrusions, or cell deformation could probably be included in the mathematical description if independent information is available on these subtle geometric issues to essentially calibrate the DS measurement [Zeiser et al, 1999. However, the measurements made to provide a reference for DS measurements are often not without ambiguities either.…”

Section: Discussionmentioning

confidence: 99%

“…Examples include cell cultivation on solid surfaces, on microcarriers in suspension, on porous glass carriers in fluidized bed reactors, and on porous discs in a fixed bed reactor. Reviewed cell types include bacteria, yeast, mammalian, and insect cells [Carvell, 2008, Carvell and Dowd, 2006, Ducommun et al, 2001, Fehrenbach et al, 1992, Noll and Biselli, 1998, Sarra et al, 1996, Zeiser et al, 1999.…”

Section: Impedance Spectroscopy As a Tool For Patmentioning

confidence: 99%

“…Zeiser et al [Zeiser et al, 1999] appear to be the first to report capacitance measurements for cell cultures of uninfected and infected Spodoptera frugiperda (Sf-9) insect cells. The relative permittivity correlated well with the viable cell density for uninfected cells and a culture infected with a baculovirus encoding for β-galactosidase (MOI 10).…”

Section: Examples Of Insect Cell Culturesmentioning

confidence: 99%

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Process control in cell culture technology using dielectric spectroscopy

Justice¹,

Brix

Freimark³

et al. 2011

Biotechnology Advances

108

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Enhanced growth of sf-9 cells to a maximum density of 5.2 × 107 cells per mL and production of β-galactosidase at high cell density by fed batch culture

Elias

Zeiser

Bédard

et al. 2000

Biotechnol. Bioeng.

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Significant improvement in cell growth and protein production has been achieved in Sf‐9 insect cell cultures using pulse additions of multicomponent nutrient feed concentrates (Bédard et al., 1994; Chan et al., 1998). The present work focuses on investigating an alternative feeding strategy wherein the nutrients are fed in a semi continuous manner. Fed batch culture experiments were carried out to compare the two different feeding strategies, pulse and semi continuous and a process developed to achieve a cell density of 5.2 × 107 cells/mL of Sf‐9 cells in a 3.5 L bioreactor. Production of recombinant protein β‐galactosidase was carried out by infecting the cells with baculovirus at a MOI of 10 at cell densities of 17 × 106cells/mL. Specific productivity could be maintained at cell densities as high as 14 × 106 cells/mL. The results presented indicate that the feeding method can provide significant improvements in the performance with a reduction in the amount of total nutrients added. On‐line monitoring of the culture using the capacitance probe showed that the capacitance probe can be used successfully to monitor the biomass and infection process even at higher cell densities. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 381–388, 2000.

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On-line monitoring of the progress of infection in Sf-9 insect cell cultures using relative permittivity measurements

Cited by 72 publications

References 21 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

Process control in cell culture technology using dielectric spectroscopy

Enhanced growth of sf-9 cells to a maximum density of 5.2 × 107 cells per mL and production of β-galactosidase at high cell density by fed batch culture

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