Normoxia Within (down to 2% O2 inside, 21% O2 outside)
Petaka, incubated in normal atmosphere (21% Oxygen) provides a gradually decreasing Dissolved Oxygen (DO) concentration in the media where the cells are cultured, always within the physiological limits of living tissues (Graph 1).
Cell cultures begin with a DO concentration equivalent to that of arterial blood (Oxygen Partial Pressure 75 mmHg), high enough to promote exponential cell growth. As cells proliferate the concentration automatically reduces to those DO concentrations close to those levels that the cells receive in normal living mammalian tissues and in embryonic development, in which OPP is close to 15 mmHg (see references), avoiding cell damage by ROS formation and facilitating cell differentiation.
Without doubt cultured cells require oxygen, but not in excess. When cells are cultured in media, in classic cell culture devices such as flasks and Petri dishes, cells are exposed to an excess concentration of DO. The open atmosphere contains about 20% oxygen. Therefore, the oxygen of the air dissolves in the media up to the limit of its solubility in water, depending on cell culture temperature, atmospheric pressure and the degree of salinity of the media, resulting in DO concentrations that are far too high for normal cells integrating the living tissues. That is an artifact which can be the source of many misleading results and discrepancies between experimental setting and in vivo setting.
The CelartiaTM cell culture system automatically balances the partial pressure of the dissolved Oxygen in the media at 25 mmHg, reproducing the cell respiratory and growth conditions in the natural environment, that is, as if within a living being. Therefore, the PetakaTM bioreactors (patented) have been designed to provide semi-hermetic cell chambers with physiologic respiration, using a unique system of micro-tubular gas diffusion channels. With this system, the threshold of oxygen in the cellular environment is maintained at physiological levels, similar to the natural bodies of living creatures, producing a perfect environment for stem cells and all other mammalian cell types. Enabled to incubate the cells in an incubator with 21% Oxygen, the Celartia’s cell culture system reduces the Oxygen down to 5% or even as far as 2% under certain specific conditions depending on cell type and level of confluence, which avoids the use of hypoxia chambers or three gas incubators. These conditions of in vitro “Normoxia” have never been available in any other bioreactor on the market.
Average DO = 1 mg/L (0.5 to 1.1 mg/L depending on cell type), equivalent to average 22.7 mmHg (Torr) in tissues or equivalent to average 3.11 %O2 in hypoxia chambers.
Average DO = 3 mg/L (2.8 to 3.2 mg/L depending on cell type), equivalent to 66.5 mmHg in tissues or equivalent to 9.33 %O2 in hypoxia chambers.