Basic conditions for culturing cells in cell factories - gas environment and pH value

 The cell factory is a multi-layer structure of cell culture consumables, mainly used for large-scale in vitro cell culture. When culturing cells, a specific environment is required, and the gas environment and pH value are one of the most important conditions.

The gas environment that the cell factory refers to when cultivating cells is mainly carbon dioxide and oxygen. Oxygen participates in the cell's tricarboxylic acid cycle to generate energy for cell growth, proliferation and synthesis of various required components. Some cells can obtain energy through glycolysis under hypoxic conditions, but most cells cannot survive under hypoxia. Oxygen tension is usually maintained at slightly below atmospheric conditions, and if the partial pressure of oxygen exceeds the amount of oxygen in the atmosphere, some cells may be detrimental. When using open culture (dish or culture bottle loose-cap culture or culture plate culture), the cells are generally placed in a mixed gas environment of 95% air and 5% carbon dioxide.

Carbon dioxide is not only a metabolite of cells, but also an essential component for cell growth, and is related to maintaining the pH of the culture medium. In the case of low carbon dioxide concentration in a closed environment, cells are easy to grow; generally it cannot be lower than 1%, otherwise the cells will be damaged. If the open culture is placed in a gas environment containing 5% carbon dioxide, it is advisable.

Most cells are suitable for growth at pH 7.2~7.4, lower than pH 6.8 or higher than pH 7.6 are harmful to cells, and even degenerate or die. Different cells have different requirements for pH value. Generally, primary culture cells are less tolerant to alkaline pH value than acid tolerance, and an acidic environment is more beneficial to cell growth than an alkaline environment. In order to maintain a constant pH value of the culture environment, a method of adding a buffer such as phosphate to the medium is often used.

With the rapid development of the field of life science, cell factories are being applied to more fields. But no matter which field it is used in, the gas environment and pH value during cell culture are still one of the important conditions for cell growth.