Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7704238 | Bioelectrochemistry | 2018 | 16 Pages |
Abstract
Nutrient depletion in fed-batch cultures and at the end of batch cultures is among the main causes of stress on cells and a trigger of apoptosis. In this study, we investigated changes in the cytoplasm conductivity of Chinese hamster ovary (CHO) cells under controlled starvation. Employing a single-cell dielectrophoresis (DEP) cytometer, we measured the DEP response of CHO cells incubated in a medium without glucose and glutamine over a 48-h period. Using the measured data in conjunction with numerical simulations, we determined the cytoplasm conductivity of viable and apoptotic cell subpopulations. The results show that a small subpopulation of apoptotic cells emerges after 24 to 36â¯h of starvation and increases rapidly over a short period of time, <12â¯h. The apoptotic cells have a dramatically lower cytoplasm conductivity, â¼0.05â¯S/m, than viable cells, â¼0.45â¯S/m. Viability of starvation cultures was measured by fluorescent cytometry, DEP cytometry, and trypan blue exclusion assays. DEP, Annexin V, caspase-8, and 7-AAD assays show a similar decline in viability after 36â¯h of starvation and indicate a very low viability after 48â¯h. Trypan blue exclusion assay fails to detect early-stage viability decline and estimates a much higher viability after 48â¯h.
Related Topics
Physical Sciences and Engineering
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Authors
Elham Salimi, Katrin Braasch, Azita Fazelkhah, Samaneh Afshar, Bahareh Saboktakin Rizi, Kaveh Mohammad, Michael Butler, Greg E. Bridges, Douglas J. Thomson,