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Online Oxygen & pH Monitoring in Shake Flasks
Sensor Flask SFS
These single-use shake flasks made of polycarbonate have an oxygen and a pH sensor integrated at the bottom. The flasks are available in sizes from 125 mL to 5,000 mL volumes, with or without baffles. The sensors inside are irradiated and pre-calibrated, so the flasks are ready-to-use. The SFS can be read out with the SFR Shake Flask Reader or the SFR vario, for simultaneous online monitoring of oxygen, pH, OUR and (in case of the SFR vario) biomass. They are used with special clamps that align the integrated sensors with the reader optics.
- Online monitoring of O2 & pH
- Contactless measurement
- Pre-calibrated sensor
- For microbes & cell culture
Process Monitoring in Suspension-Adapted CHO Cell Cultures
The online measurement of dissolved oxygen concentration and pH in shaken bioreactors paves the way for proper scale down activities from bench-top stirred-tanks to smaller scales. Adjustment of shaking speed as a function of pO2 is now possible avoiding possible oxygen limitations at high cell densities. Even a simple pH readjustment by tuning the pCO2 in the incubator is feasible to optimize the output from simple experiments with shaken bioreactors.
Dr. Robert Puskeiler, Roche Diagnostics, Penzberg, Germany
Yeast & E. coli: Ensure Enough Oxygen Supply
S. cerevisiae grows on different sugars as carbon source. While growth on glucose and fructose is mainly fermentative, growth on galactose is mainly respirative. This leads to low oxygen concentration in the shake flasks. The accurately measured oxygen indicates the need to increase rotation frequency to avoid oxygen limitation.
High oxygen demand is typical for E. coli in its exponential phase. In the cultivation shown on the left, rotation speed had to be changed twice in order to avoid oxygen limitation. In addition, changes in the metabolism can be detected by measuring DO.
Schneider et al., University of Saarland, Saarbrücken, GermanyBioprocess Biosyst Eng., 33(5), 541 - 547, 2009
|* provided Sensor Flasks are used without further handling in physiological solutions|
**HP5 and LG1 sensors require different SFR versions
*** at 100 rpm & in cell culture media
|Measurement range||0 - 100 % O2|
HP5: 5.5 - 8.0 pH**
|Resolution||± 0.01 % O2 at 0.21 % O2|
± 0.1 % O2 at 20.9 % O2
|± 0.01 pH at pH = 7***|
|Accuracy||± 0.4 % O2 at 20.9 % O2|
± 0.5 % O2 at 0.2 % O2
|± 0.1 pH at pH = 7 with one-point adjustment|
± 0.2 pH at pH = 7 with pre-calibration
|Drift||< 0.01 % O2 per day|
(sampling interval of 1 min.)
|< 0.01 pH per day|
(sampling interval of 1 min.)
|Measurement temperature range||from + 5 to + 50 °C|
|Response time (t90)***||at 25 °C: < 60 sec.|
|Compatibility||Aqueous solutions, ethanol (max. 10 % v/v), methanol (max. 10 % v/v), pH 2 - 10|
|Cross-sensitivity||Typically no cross-sensitivity||Reduced to ionic strength (salinity); a high concentration of small fluorescent molecules in the visible range can interfere|
|Disposables are delivered irradiated.|
Video: Get Started with the SFR vario
Video: SFR Shake Flask Reader
Media Release: Single-use Containers Demand Single-use Sensors
Media Release: Where does the Oxygen Go?
Media Release: Novel Single-use Sensors for Online Measurement of Glucose
Media Release: Enhancing Data Quality with a Partly Controllable System at Shake Flask Scale
Media Release: Shake Flask Feedback Controlled Feeding