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What Is a Bioreactor?

A bioreactor is a closed system used for upstream bioprocessing(first phase of the bioprocess from cell line development and cultivation to culture expansion of the cells through harvest). It is a technology used to culture cells in a controlled manner to produce biopharmaceuticals. Bioreactors support applications for the production of vaccines, therapeutics, gene therapies, and cell therapies.

Biopharmaceuticals are very complex and sensitive and can only be synthesized by living cells. They are used in the treatment of diseases such as arthritis, cancer, diabetes, and muscular dystrophy. They differ from traditional pharmaceuticals, such as paracetamol, which are small molecules and simply synthesized by chemicals. With biopharmaceutical production within a bioreactor, if any of the process parameters change outside the desired culture conditions, it could kill the cells or lead to a change in the product.

Bioreactors are used to grow cells in a specific environment. The bioreactor provides essential gassing, mixing, temperature control, fluid delivery, and other critical process parameters (CPPs). These CPPs support specific applications and may vary depending on the requirements of the process demands. CPPs increase the concentration of cells, the ratio of living cells (viable cell density) as well as sustain the environmental conditions required while the cells complete their cellular tasks (e.g. secrete the desired proteins).

The control of CPPs mentioned above, such as temperature, pH, and dissolved oxygen levels, uses a combination of sensors and actuators to read the process-specific condition and to drive a signaled change. This process must be done very accurately and repeatedly over time, as the types of cells used are very complex and sensitive to environmental change.

There are strict regulatory approval processes involved in biopharmaceutical production to ensure the process is controlled and validated to the product of interest. Typically, the process variables must be recorded, and any variance will mean the run does not pass regulatory controls. The cells used in biopharmaceuticals inside a bioreactor have a lifecycle. They have a lag phase, a growth phase, a stationary phase, and a death phase. In other words, they grow, secrete the desired proteins, and then die. The cells typically used are mammalian cells, such as Chinese hamster ovary cells (CHO). A typical run will last for approximately 10-14 days for fed-batch as one example.

Key features of bioreactors include Impeller, sparger, probes, aseptic seals, baffles, feed lines, drain line, air vent, and a temperature control unit.