Exam Focus: Define cell culture, organ culture, and their applications. A major question is often on the components and types of culture media, especially the advantages/disadvantages of serum-free vs. serum-containing media.
In culture, animal cells retain many of their **metabolic capabilities** that mimic the in vivo (in the body) environment. The cell must metabolize sources like glucose (energy), amino acids (protein synthesis), and lipids (membrane synthesis). The main pathways involve glycolysis, the TCA cycle, and oxidative phosphorylation, requiring essential cofactors (vitamins) and optimal O2 levels.
Cell culture is the process by which isolated cells are grown and maintained under controlled, laboratory conditions (in vitro), using a suitable culture media.
This process is used to study cellular processes, produce biopharmaceuticals, and develop vaccines.
Organ culture is the technique of culturing an **entire organ or a piece of organ tissue** in vitro, maintaining its organotypic structure and function.
Animal cell and organ cultures have wide-ranging applications:
Culture media are formulated to provide the necessary components to stimulate and sustain animal cell growth, mimicking the physiological conditions (e.g., blood plasma). The media must provide nutrients and maintain a stable pH and osmolarity.
These media use naturally occurring biological fluids and materials. They are poorly defined chemically but often effective.
These are chemically defined media prepared by mixing purified inorganic salts, organic nutrients, and vitamins in precise amounts. They provide reproducibility and consistency.
Artificial media supplemented with animal serum (e.g., Fetal Bovine Serum - FBS). The serum provides essential growth factors, hormones, attachment factors, and inhibitors.
Pro: Supports a wide range of cell types, provides robust growth factors. Con: High cost, batch-to-batch variation, and complicates product purification.
Chemically defined media where the serum is replaced by a specific, known cocktail of purified proteins (like albumin, transferrin), hormones (like insulin), and defined growth factors.
Pro: Chemically defined, excellent batch consistency, facilitates easier purification of secreted cell products (biopharmaceuticals). Con: May require specific adaptation for different cell lines, requires extensive knowledge to formulate the specific cocktail.
To ensure successful cell growth, the following properties must be maintained: