3D cell culture experiments and assays are often still carried out in the standard incubator at 5% CO2, which means around 19% oxygen. However, physiological values are different. In your opinion, how important is it to consider the physiological oxygen concentration when performing 3D cell culture assays?
We are currently working on a research project that focuses on these issues, including high-throughput and automation. I would appreciate a discussion and also participation in a short survey on this topic:
https://www.survio.com/survey/d/Y9S2O2W7P5P1E7O4G
The use of "non-physiological oxygen" in in vitro experiments masks the true mechanisms of action of small molecules, increases oxidative stress, affects the expression of DNA repair genes, causes oxidative DNA damage, disables mechanisms dependent on hypoxia-inducible factors (HIFs), changes cell metabolism, etc. This is an adverse effect in both 2D and 3D cultures.
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2. Augustyniak J, Kozlowska H, Buzanska L., Genes Involved in DNA Repair and Mitophagy Protect Embryoid Bodies from the Toxic Effect of Methylmercury Chloride under Physioxia Conditions., Cells. 2023 Jan 21;12(3):390. doi: 10.3390/cells12030390.
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It is important to also consider that the availability of oxygen to the outer layer of cells is different to what the inner cells in the 3D culture are receiving.