Difference between revisions of "Controlling O2 and CO2 level"
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== Reasons to control O<sub>2</sub> and CO<sub>2</sub> level == | == Reasons to control O<sub>2</sub> and CO<sub>2</sub> level == | ||
| − | Cells need oxygen for their respiration and CO2 to have the correct | + | Cells need oxygen for their respiration and CO2 to have the correct pH and carbonate concentration. The pH and carbonate concentration can be controlled by "CO2-independent media" that are media with buffers, i.e. mainly carbonate salts that are balanced to keep the concentrations and pH correct. Over time, however, it is better for the media with cells to be in equilibrium with air with the correct concentration of O2 and CO2. |
| + | |||
| + | == Ways of achieving correct gas mixtures == | ||
| + | There are two basic ways of controlling the gas mixture composition: flow control or pressure-volume control | ||
| + | |||
| + | === Flow control === | ||
| + | |||
| + | Commercial gas blender measure the flow of each gas and regulate the flow of each input gas to achieve a controlled composition of the output gas. This requires a constant overall flowrate and no changes in the pressure at the outlet of the device. These gas blenders are therefore well suited to control the gases in volumes that are at atmospheric pressure | ||
| + | |||
| + | === Pressure - volume control === | ||
| + | |||
| + | == Controlling gas mixture before entry into microfluidic network == | ||
| + | After detaching cells they should be suspended in new media and transferred to either a syringe or Falcon tube to connect it with the microfluidic circuit. Once it is in a syringe the fluid will get no more regulation of O2 and CO2 since the syringe is closed. The cells use the O2 in the fluid and the respiration increases the CO2 level. If we use a syringe pump there is a limited time before the media is toxic to the cells and the cells become unhappy and die. If we use pressure controlled microfluidics with falcon tubes there is a gas-liquid interface that keep correct O2 and CO2 levels in the media. This is not straight forward, however | ||
| + | |||
| + | === Pre-equilibrating the media === | ||
| + | |||
| + | === Correct gas mixture in the control gas === | ||
Revision as of 16:05, 12 November 2021
Contents
Reasons to control O2 and CO2 level
Cells need oxygen for their respiration and CO2 to have the correct pH and carbonate concentration. The pH and carbonate concentration can be controlled by "CO2-independent media" that are media with buffers, i.e. mainly carbonate salts that are balanced to keep the concentrations and pH correct. Over time, however, it is better for the media with cells to be in equilibrium with air with the correct concentration of O2 and CO2.
Ways of achieving correct gas mixtures
There are two basic ways of controlling the gas mixture composition: flow control or pressure-volume control
Flow control
Commercial gas blender measure the flow of each gas and regulate the flow of each input gas to achieve a controlled composition of the output gas. This requires a constant overall flowrate and no changes in the pressure at the outlet of the device. These gas blenders are therefore well suited to control the gases in volumes that are at atmospheric pressure
Pressure - volume control
Controlling gas mixture before entry into microfluidic network
After detaching cells they should be suspended in new media and transferred to either a syringe or Falcon tube to connect it with the microfluidic circuit. Once it is in a syringe the fluid will get no more regulation of O2 and CO2 since the syringe is closed. The cells use the O2 in the fluid and the respiration increases the CO2 level. If we use a syringe pump there is a limited time before the media is toxic to the cells and the cells become unhappy and die. If we use pressure controlled microfluidics with falcon tubes there is a gas-liquid interface that keep correct O2 and CO2 levels in the media. This is not straight forward, however
Pre-equilibrating the media
Correct gas mixture in the control gas
Inline math
Equation
