In bioprocessing, cells are cultivated using either adherent or suspension cell culture. In adherent culture, cells are grow as monolayers on artificial substrates such as microcarriers. On the other hand, in suspension culture free-floating cells are grown in a suitable culture medium.
Suspension vs adherent culture
Many cells derived from vertebrates are anchorage-dependent cells. They need a suitable cell attachment substrate, so that cells can spread and grow. Adherent cells come in two major categories:
- Fibroblast-like: have an elongated shape and migrate on the tissue culture dish or other substrate
- Epithelial-like: are stationary, feature a polygonal shape, and grow in patches
Instead of sticking to beads, suspension cells grow freely throughout a bioreactor and are kept in suspension using a rocking or stirring motion. Many of the suspension cell culture lines used in bioprocessing have been adapted from adherent cell lines.
Microcarriers cell culture FAQs
Here are some answers to frequently asked questions regarding microcarriers cell culture.
What are microcarriers?
They are matrices that support high-density growth of adherent cells in vessels such as rocking bioreactors or stirred-tank single-use bioreactors. These microscopic spheres or microcarrier beads are made from dextran or other substances that support growth of anchorage-dependent cells.
How are they used in microcarriers cell culture?
They are used in cell culture and fermentation processes. And they offer a high surface-to-volume ratio for adherent cell types to support high productivity processes in bioreactors. Key uses for microcarriers are in large-scale mammalian cell culture and vaccine production. Use them in simple suspension culture and in packed and fluidized bed systems. Yields of up to 200 million cells per milliliter are possible.
What materials are used in creating microcarriers?
The beads are derived from a wide variety of materials such as dextran, gelatin, glass, or modified polystyrene. Some have surface alterations to use in tailored systems for specific cell types.
What are the types?
There are two major categories, namely microporous and macroporous substrates. Microporous beads have very minute pores, while the latter have larger ones.
Macroporous beads offer a large surface area for cell attachment, but cells grow into the pores and may make cell harvesting difficult. Microporous beads also have a large surface area, but cells don’t grow into the small pores, which simplifies cell harvest.
Cytiva’s options for microcarriers cell culture include:
- Cytodex™ microcarriers: microporous beads with a surface that promotes efficient attachment and spreading of cells. The matrix is biologically inert and provides a strong but nonrigid substrate for stirred cultures. Beads are transparent and allow easy microscopic examination of the attached cells.
- Cytopore™ microcarriers: macroporous beads that increase cell density and yields compared with growth on tissue culture flasks. They allow suspension cell cultivation and perfusion.