A new method for on-line measurement of the volumetric oxygen uptake rate in membrane aerated animal cell cultures

Ducommun, P.; Ruffieux, P.-A.; Furter, Maria-Pilar; Marison, I. W.; Stockar, Urs von

doi:10.1016/s0168-1656(99)00237-0

Cited by 65 publications

(33 citation statements)

References 25 publications

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“…This value is within the range of reported SOUR values for CHO cell cultures between 0.25 and 0.29 pmol cell À1 h À1 (Ducommun et al, 2000) and 0.35 pmol cell À1 h À1 (Mostafa and Gu, 2003). This result also indicates that Equation (14) is applicable in the CHO cell culture process…”

supporting

confidence: 86%

“…P T is the pressure at the sparger (mmHg), and y O 2 and y CO 2 are the molar fraction of oxygen and carbon dioxide in the inlet gas sparge flow, respectively. The Henry coefficient H O 2 and H CO 2 (atm l mol À1 ) under ambient pressure are adapted from the empirical equations in literature (Ducommun et al, 2000;Spérandio and Paul, 1997) …”

Section: Dynamic Determination Of the Oxygen Transfer Coefficientmentioning

confidence: 99%

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Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors

Xing

Kenty

et al. 2009

Biotech & Bioengineering

183

143

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Bioprocess scale-up is a fundamental component of process development in the biotechnology industry. When scaling up a mammalian cell culture process, it is important to consider factors such as mixing time, oxygen transfer, and carbon dioxide removal. In this study, cell-free mixing studies were performed in production scale 5,000-L bioreactors to evaluate scale-up issues. Using the current bioreactor configuration, the 5,000-L bioreactor had a lower oxygen transfer coefficient, longer mixing time, and lower carbon dioxide removal rate than that was observed in bench scale 5- and 20-L bioreactors. The oxygen transfer threshold analysis indicates that the current 5,000-L configuration can only support a maximum viable cell density of 7 x 10(6) cells mL(-1). Moreover, experiments using a dual probe technique demonstrated that pH and dissolved oxygen gradients may exist in 5,000-L bioreactors using the current configuration. Empirical equations were developed to predict mixing time, oxygen transfer coefficient, and carbon dioxide removal rate under different mixing-related engineering parameters in the 5,000-L bioreactors. These equations indicate that increasing bottom air sparging rate is more efficient than increasing power input in improving oxygen transfer and carbon dioxide removal. Furthermore, as the liquid volume increases in a production bioreactor operated in fed-batch mode, bulk mixing becomes a challenge. The mixing studies suggest that the engineering parameters related to bulk mixing and carbon dioxide removal in the 5,000-L bioreactors may need optimizing to mitigate the risk of different performance upon process scale-up.

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supporting

confidence: 86%

Section: Dynamic Determination Of the Oxygen Transfer Coefficientmentioning

confidence: 99%

Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors

Xing

Kenty

et al. 2009

Biotech & Bioengineering

183

143

View full text Add to dashboard Cite

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“…The bioreactor was operated in batch or continuous (perfusion) mode at a temperature of 37°C, agitation (marine turbine) of 150 rpm with bubble-free aeration controlled by the use of 1-2 m Teflon tubing (W. L. Gore & Associates GmbH, Putzbrunn, Germany). Using a recently developed regulation system (Ruffieux et al 1998;Ducommun et al 2000), the dissolved oxygen concentration, determined using a polarographic oxygen electrode, (Ingold, Messtechnik AG, Urdorf, Switzerland) was maintained at 80% air saturation while simultaneously enabling the on-line measurement of the specific oxygen consumption rate. The pH was maintained constant at a value of 7.2 by the automatic addition of CO 2 to the inlet airflow.…”

Section: Cell Culturesmentioning

confidence: 99%

CHO immobilization in alginate/poly-l-lysine microcapsules: an understanding of potential and limitations

et al. 2007

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Microencapsulation offers a unique potential for high cell density, high productivity mammalian cell cultures. However, for successful exploitation there is the need for microcapsules of defined size, properties and mechanical stability. Four types of alginate/poly-L-Lysine microcapsules, containing recombinant CHO cells, have been investigated: (a) 800 lm liquid core microcapsules, (b) 500 lm liquid core microcapsules, (c) 880 lm liquid core microcapsules with a double PLL membrane and (d) 740 lm semiliquid core microcapsules. With encapsulated cells a reduced growth rate was observed, however this was accompanied by a 2-3 fold higher specific production rate of the recombinant protein. Interestingly, the maximal intracapsular cell concentration was only 8.7 · 10 7 cell mL -1 , corresponding to a colonization of 20% of the microcapsule volume. The low level of colonization is unlikely to be due to diffusional limitations since reduction of microcapsule size had no effect.Measurement of cell leaching and mechanical properties showed that liquid core microcapsules are not suitable for continuous long-term cultures (>1 month). By contrast semi-liquid core microcapsules were stable over long periods with a constant level of cell colonization (u = 3%). This indicates that the alginate in the core plays a predominant role in determining the level of microcapsule colonization. This was confirmed by experiments showing reduced growth rates of batch suspension cultures of CHO cells in medium containing dissolved alginate. Removal of this alginate would therefore be expected to increase microcapsule colonization.

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“…The state of the art in in vivo techniques that use wound oxygenation level as an indirect tool to assess wound healing include the use of polarographic probe or needle electrode on subcutaneous wound tissues for surface measurement of partial oxygen (PO 2 ) level, 9 and the use of luminescence lifetime imaging (LII) 10 for two dimensional visualization of PO 2 based on the quenching of phosphorescence. Even though photoacoustic imaging is a noninvasive technique to provide blood vessel mapping, it requires a long operation time.…”

Section: Introductionmentioning

confidence: 99%

Multispectral imaging of acute wound tissue oxygenation

Huong

Philimon

Ngu

2017

J. Innov. Opt. Health Sci.

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This paper investigates the appropriate range of values for the transcutaneous blood oxygen saturation (S t O 2 ) of granulating tissues and the surrounding tissue that can ensure timely wound recovery. This work has used a multispectral imaging system to collect wound images at wavelengths ranging between 520 nm and 600 nm with a resolution of 10 nm. As part of this research, a pilot study was conducted on three injured individuals with super¯cial wounds of di®erent wound ages at di®erent skin locations. The S t O 2 value predicted for the examined wounds using the Extended Modi¯ed Lambert-Beer model revealed a mean S t O 2 of 61 AE 10:3% compared to 41:6 AE 6:2% at the surrounding tissues, and 50:1 AE 1:53% for control sites. These preliminary results contribute to the existing knowledge on the possible range and variation of wound bed S t O 2 that are to be used as indicators of the functioning of the vasomotion system and wound health. This study has concluded that a high S t O 2 of approximately 60% and a large°uctuation in this value should precede a good progression in wound healing.

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A new method for on-line measurement of the volumetric oxygen uptake rate in membrane aerated animal cell cultures

Cited by 65 publications

References 25 publications

Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors

Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors

CHO immobilization in alginate/poly-l-lysine microcapsules: an understanding of potential and limitations

Multispectral imaging of acute wound tissue oxygenation

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