To enhance cell culturing efficiency, in biotechnology increasingly membranes are used as both an attached growth matrix and semipermeable barrier to separate cells from their nutrient supply.
Efficient cell culturing through process optimization with semipermeable membranes
Whether you use a manual or automatic process to culture cells, with semipermeable membranes you will
- achieve higher cell densities,
- have a more representative production process for in vivo requirements,
- reduce medium usage, downstream purification and concentration consumables, and
- lower your labor and handling requirements.
Technical functionality of 2 compartment system
In a 2 compartment system, semipermeable membranes are used for separating substances and regulating mass transfer of a diffusion process. Semipermeable membranes allow for transport of certain substances according to mass gradients while being impenetrable for other substances. For instance, in diffusion processes, solvents can pass the membrane, while solutes cannot, because their specific molecular weight is greater than the separation limit of the membrane. This Molecular Weight Cut Off (MWCO) is specified in Daltons.
The MWCO is correlated to the pore size of the membrane. Due to molecular conformation, globular molecules diffuse better than longer chain molecules. Hydration, diffusion gradient and surface charge also determine which molecule can pass through the membrane. The effect of this is that cells are retained by the membrane while nutrients, oxygen, and metabolites can pass through the membrane when mass gradients exist. Membranes are available in a variety of materials (e.g. Cellulose, PC, PET, and Polyester) with a variety of separation, transport, and cell adhesion properties. For each application you will find the suitable material with the correct separation characteristics.
Successful use of the 2 compartment system for cell culturing
Our Cellab® Bioreactor System is available with flat-membrane- or hollow fiber bioreactors for cell culturing.
Favoring cell culturing with flat membrane bioreactors we recommend to work with our Insert Supply System. It consists of a Media Supply Plate (standard multiwell format) and up to 6 inserts. The basis of the 2 compartment system is the semipermeable membrane in each insert.
Cellab® bioreactor systems include both manual and automated systems. In the case of automated operations, a pump continuously feeds fresh medium and distills consumed ones. Diffusion processes regulate the efficient exchange of nutrients, oxygen and metabolites across the membrane. This allows for semipermeable membranes to achieve much higher cultured cell densities.
Example: production of monoclonal antibodies
For producing antibodies, the culturing of hybridoma cells using a dialysis-type membrane with a MWCO of 12-14k Daltons is recommended. Dialysis membranes consist of regenerated cellulose and have hydrophilic properties (i.e. strong interaction with water). Cells growing inside the insert are fed efficiently with nutrients from the production compartment and are separated from metabolites in the supply compartment. 10 to 50 times higher cell densities can be achieved compared with cultivation in T- or roller flasks. As a result, the produced antibodies show 10 to 50 times higher cell densities.