Biopharmaceuticals and Cell Growth Media

A field that combines natural and engineering sciences to use living organisms for products and services. It involves using bacteria, yeast, etc., to perform specific tasks or create valuable substances.

Modifying the genetic makeup of organisms (like adding genes) to create new traits or change existing ones.

Proteins artificially produced using genetic engineering techniques. They are used in research and as drugs.

Scientists insert a human gene into a common bacterium. The bacterium then produces the protein encoded by the human gene.

Recombinant human insulin, approved in 1982.

Over 130 recombinant proteins are approved for clinical use.

Recombinant proteins have revolutionized the field of biomedical biotechnology, used in research and as drugs for a range of diseases.

Essential substances synthesized by cells during their active growth phase. They are crucial for the cell's survival and development, examples include amino acids and vitamins.

The phase where cells multiply rapidly, and their genes are most active. This is also called the exponential growth phase.

Cell growth slows down as resources become scarce and waste products accumulate in the environment.

Mammalian cells require various nutrients for growth, including sugars (for energy), fatty acids, water, amino acids, electrolytes (for osmotic balance), vitamins, essential proteins, trace minerals, and hormones.

The final stage where bacterial cells die off due to lack of resources and accumulation of toxic byproducts.

Single-celled organisms lacking a nucleus and membrane-bound organelles, like bacteria. They are often used as host cells in biotechnology due to their rapid growth and ease of manipulation.

Organisms with complex cells containing a nucleus and membrane-bound organelles, like yeast and fungi. They are often used as host cells in biotechnology due to their ability to perform more complex biological processes.

E.coli is commonly used as a host cell in biotechnology due to its rapid growth rate, ability to be easily manipulated, and relatively low cost of culture.

Mammalian cells are used in biotechnology because they can correctly modify proteins, making them more biologically relevant and useful.

Mammalian cells are often difficult to cultivate, expensive to maintain, and carry a risk of contamination.

Chinese Hamster Ovary (CHO) cells are the most commonly used mammalian cell line in biotechnology. They are known for their ability to reliably produce a variety of therapeutic proteins.

The process of modifying a protein after it is synthesized. This can involve adding sugars, phosphates, or other molecules to the protein.

A type of post-translational modification where sugars are added to a protein. This modification is important for protein stability, function, and recognition.

A type of post-translational modification where a phosphate group is added to a protein. This modification can activate or deactivate the protein.

The process by which a protein takes on its correct three-dimensional structure. This structure is essential for the protein's function.

Large tanks used for cultivating cells to produce therapeutic proteins or other valuable substances.

Bioreactors are classified into three sizes:

1. Laboratory (< 50 L)
2. Experimental (50 – 50,000 L)
3. Industrial (> 50,000 L)

1. Batch processes: Cells are grown in a closed system for a short time, then the product is extracted.
2. Continuous processes: Fresh medium is constantly added, and product is continuously removed.
3. Fed-batch processes: Cells are cultured for a longer period, with fresh medium added periodically.

Cells are grown in a closed system for a few hours to days. Fresh medium is added at the beginning. The reactor is emptied after the process, and the products are purified.

Fresh medium is constantly added to the reactor, and the product is continuously removed. Cells remain in the reactor constantly.

Cells are cultured for extended periods (up to 90 days). Fresh medium is added regularly, but the reactor isn't fully emptied.

Mammalian cells are widely used to produce therapeutic proteins, such as antibodies and hormones.

They are capable of producing complex proteins with post-translational modifications.

Other types of cells used include bacteria (E.coli), yeast, insect cells, and even transgenic animals.

Mammalian cell production dominates the current biotechnology industry, with over half of new biopharmaceuticals produced in these cells.

Before the advent of genetic engineering, proteins like hormones were primarily sourced from animals (cows, pigs). This was due to the lack of efficient methods to produce them synthetically. However, this method had several drawbacks, such as potential differences in amino acid sequence compared to human proteins, difficulty in obtaining large quantities, purity issues, and the risk of immune reactions in humans.

Recombinant protein production involves several crucial steps: 1) Isolating the gene of interest and a suitable vector (often a bacterial plasmid). 2) Combining the gene and vector. 3) Integrating the recombinant vector into a host cell (e.g., bacteria). 4) Growing the host cell in a culture medium. 5) Extracting the protein from the host.

Large-scale production of biotechnology products, especially pharmaceuticals, involves optimizing several aspects: 1) Selecting suitable expression systems (e.g., bacteria, yeast, mammalian cells). 2) Developing appropriate cultivation systems (e.g., bioreactors, growth conditions). 3) Defining the ideal medium for cell growth. 4) Controlling potential contaminants. 5) Implementing robust downstream processing to purify and recover the desired product.

The choice of expression system is crucial because different organisms have different characteristics that affect protein production: 1) Bacteria (e.g., E.coli) grow quickly and are easy to manipulate, but may not always fold proteins correctly. 2) Mammalian cells often produce proteins with correct post-translational modifications, but are more complex to cultivate. 3) Yeast and insect cells offer compromises between these two extremes. Choosing the right expression system depends on the specific protein and the desired outcome.

Downstream processing is the final stage of protein production, focusing on purifying and recovering the desired protein from the culture medium. This involves a series of steps like cell separation, chromatography (to separate proteins by size or charge), filtration, and other methods to achieve the required purity for therapeutic applications.

Recombinant proteins offer numerous advantages over traditional protein sources: 1) They can be produced in large quantities, overcoming limitations of animal sources. 2) They are often highly pure, eliminating the risk of contaminants from animal products. 3) They can be designed with specific modifications for improved efficacy or stability. 4) Recombinant proteins are generally safer than animal-derived proteins, reducing the risk of allergic reactions or disease transmission.

Post-translational modifications are crucial because they can significantly affect the function, stability, and targeting of a protein. These modifications, like adding sugar molecules (glycosylation) or phosphate groups (phosphorylation), are often necessary for proper protein folding and activity. Mammalian cells are particularly adept at performing these modifications, which is why they are often preferred for producing therapeutic proteins.

Bioreactors are large vessels used to cultivate cells on a large-scale for producing proteins. They create a controlled environment with optimized conditions for cell growth and protein production. Bioreactors come in different sizes, from laboratory scales to industrial-scale production, and different types, such as batch, fed-batch, and continuous reactors.

While bacteria and other organisms are used for protein production, mammalian cells are often favored for producing therapeutic proteins. This is because mammalian cells have the ability to perform complex post-translational modifications, such as glycosylation and phosphorylation, which are essential for proper protein folding, function, and stability. These modifications often lead to proteins that are more biologically relevant and effective in treating human diseases.