Cell technology animal cell large-scale culture method
round dining table set,stone dining table,tables set,Home Furniture Kumusi (Dongguan) Furniture Co., Ltd. , https://www.coombesfurniture.com
Animal cell culture can be classified into three main methods: adherent culture, suspension culture, and immobilization culture, depending on the type of cells being cultured. These techniques are widely used in large-scale production for biopharmaceuticals and research purposes.
First, it's important to understand the growth characteristics of animal cells. They grow slowly, making them more susceptible to contamination, which often requires the use of antibiotics during culture. Additionally, these cells lack a cell wall, resulting in low mechanical strength and poor adaptability to environmental changes. They are also less aerobic and cannot tolerate strong agitation or ventilation. Another key feature is their anchorage dependence—most animal cells must attach to a surface to grow. The products of the culture process are often found both inside and outside the cells, leading to higher costs. Moreover, primary cultured cells typically have a limited lifespan, usually surviving up to 50 generations before degenerating and dying.
In vitro, animal cells can be divided into two categories based on their attachment requirements: adherent-dependent and non-adherent-dependent cells. Adherent-dependent cells require a solid or semi-solid surface with a moderate charge to grow, such as most non-lymphoid tissue cells and many aneuploid cells. Non-adherent-dependent cells, on the other hand, can grow without attaching to a surface, including blood cells, lymphoid tissue cells, and certain tumor cells.
The optimal temperature for cell culture is generally close to the normal body temperature of the organism from which the cells were derived. For human and mammalian cells, this range is typically 35–37°C. Deviating from this range can impair cellular metabolism and even lead to cell death. While cells can tolerate lower temperatures better than higher ones, prolonged exposure to temperatures above 43°C can cause significant damage. At lower temperatures, like 20–30°C, metabolic activity slows down, and cells may detach from the substrate. However, when the temperature returns to normal, cells can often recover their original function.
Adherent culture involves growing cells attached to a solid surface. This method is ideal for adherent-dependent cells, which spread rapidly once they adhere to the vessel walls, eventually forming a dense monolayer. Advantages include easy medium exchange, suitability for perfusion culture, and enhanced product expression. However, challenges include difficulty in scaling up, large space requirements, and limited monitoring capabilities. Common systems include rotating bottles, hollow fibers, and microcarriers.
Suspension culture, on the other hand, is suitable for non-adherent-dependent cells that grow freely in the culture medium. This method is often modeled after microbial fermentation and is useful for producing monoclonal antibodies and other biologics. Serum-free suspension cultures are becoming increasingly popular due to their benefits in downstream processing and product quality.
Immobilization culture involves attaching cells to a solid carrier, which offers advantages such as high cell density, resistance to shear stress, and ease of product separation. Various methods, including adsorption, covalent binding, cross-linking, encapsulation, and microencapsulation, are used to achieve this. Each method has its own pros and cons, such as varying levels of cell retention, diffusion limitations, and ease of implementation.
Finally, apoptosis is a major challenge in large-scale cell culture, with up to 80% of cell deaths attributed to this programmed cell death. Strategies to combat apoptosis include supplementing nutrients, modifying gene expression (such as using Bcl-2), and employing chemical inhibitors to prevent the biochemical changes associated with apoptosis. These approaches help maintain cell viability, extend culture duration, and improve the yield of recombinant proteins.