Perfusion, or upstream continuous processing, has been used since the 1980s. High cell density perfusion, or XCell™ ATF perfusion, delivers high cell concentration and cell viability.
Perfusion is upstream processing which retains cells inside the bioreactor while continually removing cell waste products and media depleted of nutrients by cell metabolism. Fresh media is provided to the cells at the same rate as the spent media is removed. The most common means to achieve perfusion is the use of hollow fiber filtration.
A biomanufactured cell product like a recombinant enzyme or a monoclonal antibody can be retained within the bioreactor if perfusion is done with an ultrafiltration membrane or continually harvested in a cell free fluid stream if perfusion is done with a microfiltration membrane. The XCell™ ATF System can be used with either membrane type to achieve perfusion.
Perfusion has been practiced in cell culture since the 1980s but with limited adoption due to complex or unreliable equipment and scale-up challenges associated with cell retention. The introduction of the XCell™ ATF System has changed the paradigm, making perfusion cell culture a viable platform for continuous processing and fed-batch process intensification. Below is a partial list of commercial biologics manufactured using perfusion cell culture technology.
Source: Pollock, J. et al (2012).
"For perfusion, you don't really need exotic upstream equipment beyond robust cell retention devices."
Konstantin Konstantinov, Genzyme
Because XCell™ ATF technology minimizes cell shear and keeps cells in constant equilibrium with bioreactor contents, faster cell growth at higher densities can be achieved. This results in high cell density perfusion using the same simple mode of operation but with higher productivity. Benefits of concentrated perfusion include:
- Ultra-high cell densities of 100-200x106 cells/ml
- Cell viabilities of 90% and higher
- Requires 1-3 vessel volumes per day (vvd)
- Can be used to increase host cell density for virus production
THE XCell™ ATF SYSTEM IN PERFUSION
- Continuous, provides clarified harvest ready for capture chromatography
- Efficient, delivers 100% cell retention, increases productivity
- Convenient single-use format reduces implementation time by up to 80%
- Intensified, generates high cell concentration and viability
- Flexible, connects to any bioreactor and can be used in a variety of applications
- Gentle, reduces cell stress, increases cell viability and productivity
- Easy to use, reduces setup time and user training
- Scalable, adapts from development-scale to production-scale
- Self-cleaning, reduces biofilm build up on the hollow fiber filter
- By Day 10, the cell density in XCell™ ATF perfusion is ~ 60e6 cells/mL, compared to 12e6 cells/mL in the Fed-batch process.
- Viability drops more quickly in Fed-batch culture than in XCell™ ATF perfusion culture.
- The total cumulative protein in XCell™ ATF perfusion is ~6 times higher than in the Fed-batch culture.
Selected Third Party references