Publish Time: 2024-05-15 Origin: Site
Gas is one of the necessary conditions for the survival of human cell culture. The required gases mainly include oxygen (O 2) and carbon dioxide (CO 2). O 2participates in the tricarboxylic acid cycle, producing energy for cell growth and proliferation and synthesizing various components required for cell growth. During in vitro culture, cells are generally placed 2in a mixed gas environment of 95% air and 5% CO. Therefore, CO cannot be used under sealed conditions.2。
Generally, the pH of cell culture medium is between 7.0-7.4. Since the carbonate pH buffer system is a physiological pH buffer system (it is the most important pH buffer system in human blood), most culture solutions use it to maintain a stable pH. When preparing culture solution from powder, it is often necessary to add a certain amount of NaHCO 3. For most culture solutions that use carbonate as a pH buffer system, in order to maintain a stable pH, the CO in the incubator 2needs to be maintained between 2-10% to maintain 2the concentration of dissolved CO in the culture solution. At the same time, cell culture vessels need a certain degree of ventilation to facilitate gas exchange.
Q: Why does cell culture require CO?2？
CO 2is both a cell metabolite and a component required by cells. The incubator used for cell culture is generally a CO 2incubator.
First, the CO incubator can 2provide precise and stable control 2of temperature, CO concentration and humidity to facilitate the progress of research work;
Second, the CO 2incubator can effectively prevent microbial contamination in the incubator, and can eliminate contamination regularly to protect research results and prevent sample loss.
Q: Do I need a CO incubator after using other pH buffer systems 2?
The gas environment for cell culture is generally 95% air and 5% CO 2. However, the CO concentration in the air 2is very low, and the HCO in the culture medium 3will be exhausted, thus affecting the normal growth of cells. Therefore, a CO 2incubator is needed to maintain the CO concentration in the environment 2.
Other pH buffer systems, such as HEPES buffer systems, are often added to cell culture media to increase pH buffering capacity. HEPES has a strong buffering capacity between pH 7.2-7.4. When the breathable culture vessel is taken 2outside the CO incubator, due to 2the low concentration of CO in the air, the carbonate buffer system in the culture medium will lose its effect. At this time, the HEPES buffer system can continue to maintain pH stability.
Question: Why do animal cells use CO 2incubators but plant cells do not?
Generally speaking, CO 2incubators are mainly used to simulate an environment similar to the growth of cells in organisms, such as providing appropriate pH, temperature, humidity, etc. CO 2is not only an essential component for cell growth, it is also related to maintaining the pH of the culture medium and stimulating cell respiration. Plant cells can proliferate and differentiate in vitro, and their 2requirements for CO are not high. Generally, the concentration in the air is enough, as long as the air is fresh and clean. Animal somatic cells cannot do this, so animal somatic cells require a CO 2incubator, while plant somatic cells do not need a CO 2incubator.
Q: Why do most cells use 5% CO when culturing them?2？
The incubator used in cell culture is generally called a CO 2incubator. Its gas environment is 95% air and 5% CO.2。
CO 2is both a cell metabolite and a component required by cells. It is mainly directly related to maintaining the pH of the culture medium. Most animal cells require a slightly alkaline environment, with a pH of 7.2 to 7.4, preferably no more than 6.8 to 7.6. During cell culture, as 2the amount of CO released increases, the culture medium will become acidic, so NaHCO 3( 2which forms a buffer pair with H 2CO 3formed when CO is dissolved in water ) is often added to adjust the pH. NaHCO 3has 2a tendency to release CO, and adding CO 2can inhibit the progress of this reaction.
The CO concentration in the incubator 2should be balanced with the NaHCO concentration in the culture medium 3. If the CO 2concentration in the incubator is set at 5%, the amount of NaHCO added in the culture medium 3should be 1.97 g/L; if the CO 2concentration is maintained at 10%, 3the amount of NaHCO added should be 3.95 g/L.
In short, in cell culture, O 2and CO 2are necessary conditions for cell survival. Oxygen participates in the tricarboxylic acid cycle of cells, providing energy for cell survival, metabolism and synthesis; CO 2is not only a metabolic product of cells, an essential component for cell growth, but also related to maintaining the pH of the culture medium. The suitable pH range for most cells is 7.2-7.4.