title: Novel probes for pH and dissolved oxygen measurements in cultivations from millilitre to benchtop scale.
abstract: pH value and the concentration of dissolved oxygen (DO) are key parameters to monitor and control cell growth in cultivation studies. Reliable, robust and accurate methods to measure these parameters in cultivation systems in real time guarantee high product yield and quality. This mini-review summarises the current state of the art of pH and DO sensors that are applied to bioprocesses from millilitre to benchtop scale by means of a short introduction on measuring principles and selected applications. Special emphasis is placed on single-use bioreactors, which have been increasingly employed in bioprocess development and production in recent years. Working principles, applications and the particular requirements of sensors in these cultivation systems are given. In such processes, optical sensors for pH and DO are often preferred to electrochemical probes, as they allow semi-invasive measurements and can be miniaturised to micrometre scale or lower. In addition, selected measuring principles of novel sensing technologies for pH and DO are discussed. These include solid-state sensors and miniaturised devices that are not yet commercially available, but show promising characteristics for possible use in bioprocesses in the near future.
authors.affiliation: School of Life Sciences and Facility Management, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, P.O. Box, 8820, Wädenswil, Switzerland. caspar.demuth@zhaw.ch.
authors.forename: Caspar
authors.identifier: http://orcid.org/0000-0002-4793-6784
authors.initials: C
authors.lastname: Demuth
authors.affiliation: School of Life Sciences and Facility Management, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, P.O. Box, 8820, Wädenswil, Switzerland.
authors.forename: Joel
authors.initials: J
authors.lastname: Varonier
authors.affiliation: School of Life Sciences and Facility Management, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, P.O. Box, 8820, Wädenswil, Switzerland.
authors.forename: Valentin
authors.initials: V
authors.lastname: Jossen
authors.affiliation: School of Life Sciences and Facility Management, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, P.O. Box, 8820, Wädenswil, Switzerland.
authors.forename: Regine
authors.initials: R
authors.lastname: Eibl
authors.affiliation: School of Life Sciences and Facility Management, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, P.O. Box, 8820, Wädenswil, Switzerland.
authors.forename: Dieter
authors.initials: D
authors.lastname: Eibl
mesh_terms: D019149:Bioreactors; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003470:Culture Media / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000032:analysis*
chemical_list: D003470:Culture Media; D010100:Oxygen
keywords: Bioprocess measurement and control; Optical sensors; Sensors for pH and dissolved oxygen; Single-use cultivation systems