Examples for Applications
More Security at Hypoxic Stem Cell Cultivation
The influence of medium change on dissolved oxygen (DO) at cultivation of human embryonic stem cells (hESC) was investigated at different oxygen tensions in the incubator atmosphere. Samples with full medium change using non-precalibrated medium showed a DO increase of 20 - 60 % air saturation. Other than expected, even half medium change with pre-incubated medium resulted in a notable DO increase of 10 - 30 % air saturation. The SensorDish® Reader can be used in hypoxia incubators, but also in small hypoxia chambers (see picture).
Barbara Ley, Prof. Oliver Brüstle, Life & Brain GmbH, Bonn, Germany
Oxygen and pH Monitoring in Tissue Engineering
Human chondrocytes with different start concentrations were cultivated in OxoDish® and HydroDish®. At medium change after 5 days, some samples with the highest cell concentration were covered with paraffin oil. Oxygen kinetics show a dynamic equilibrium between oxygen ingress and consumption. Oxygen increased after 5 days due to reduced metabolism and, for the highest cell concentration, after 2 days due to cell redifferentiation. The oil cover led to a temporary oxygen decrease due to a changed equilibrium. pH changes were detected for even lower start cell concentrations.
Dr. Andreas Thomsen, CellGenix GmbH, Freiburg, Germany
Process Monitoring in Suspension-Adapted CHO Cell Cultures
Oxygen and pH kinetics of suspension-adapted CHO cells at different start concentrations were monitored. The kinetics correlated well with the initial cell concentrations. pH values decreased only to a minimum of 6.3 due to daily media change. Samples with the lowest cell concentration did not show any pH change due to lack of cell growth. The oxygen uptake rate increased at each medium change. For the highest initial cell concentration it decreased at the end of the cultivation due to forming of aggregates. The results were confirmed by microscopic investigation.
Dr. Harry Abts, Celonic GmbH, Jülich, Germany, BioProcess Int., Jan 2008: 64-66
Real-time Monitoring of the Respiration of Marine Zooplankton
Oxygen consumption of 3 - 4 copepod nauplii per sample was monitored in air-tight glass vials for 6 h. The nauplii were offered phytoplankton at environmental concentrations. Feeding and faecal pellet production rates were estimated simultaneously. The respiration rates were linear and steady, thus revealing that the nauplii were neither influenced by the vessel walls nor by diminishing of food. The respiration rate was compared to literature values of other species.The higher oxygen consumption of the nauplii was presumably due to constant feeding.
Dr. Marion Köster, Ernst-Moritz-Arndt-Universität Greifswald, Germany, Mar Ecol Prog Ser 353: 157-164 (2008)
