N-1 perfusion refers to the use of an XCell™ ATF device to achieve high cell density in the seed train step before the production bioreactor (N), achieving a more rapid and robust process while maintaining an existing Fed-batch based production scheme.
N-1 perfusion refers to the intensification of cell growth in the step prior to the production bioreactor (N). This process intensification is done using perfusion in the N-1 bioreactor to attain high cell density and viability. This allows seeding the production bioreactor at a higher starting cell density and shortening the production bioreactor run time. This can dramatically increase the facility output without direct change to the core production process. A robust cell retention device is required to attain a high cell density inoculum for the production bioreactor.
Benefits of N-1 perfusion include:
- Increased Fed-batch process efficiency
- Time and cost savings
- Reduced operational risk
- Smaller bioreactor footprint
High cell density perfusion can impact Fed-batch production to shorten process time in two ways.
1. High cell density seeding of the production bioreactor (N) - the XCell™ ATF System is attached to the N-1 bioreactor
2. Removal of the N-1 bioreactor, if the N-2 bioreactor can provide enough cells for the production bioreactor (N) - the XCell™ ATF System is attached to the N-2 bioreactor
THE XCell™ ATF SYSTEM IN N-1 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
Higher seeding densities achieved through use of the XCell™ ATF System helped reduce production reactor time from 14 days to 8 days.
Viable Cell Density (VCD) and Viability
Production Fed-Batch: Cells were inoculated directly from n-1 perfusion bioreactor at 0.5E6 and 10E6 cells/mL seeding densities.
Comparable titer was observed at high seeding density production Fed-batch bioreactor, in shorter time.
The cell specific productivities are very similar (~6.3 pg/cell/day) for both 0.5E6 and 10E6 cells/mL seeding densities in production Fed-batch.