N-1 Perfusion


N-1 perfusion is done by attaching a cell retention device, such as the XCell ATF® Device, to the N-1 bioreactor to attain high cell density and viability. This seeds the N production bioreactor at a higher starting cell density and shortens the production bioreactor run time. The process dramatically increases facility output without direct change to the core Fed-Batch production process. A robust cell retention device is required to attain a high cell density inoculum for the production bioreactor.​

The combination of implementation ease and productivity increase makes N-1 perfusion the most frequent starting point for upstream intensification. Once in place, further intensify the seed train by adding High Productivity Harvest (HPH) to the N bioreactor or transition to continuous.

Repligen solutions help overcome key challenges in N-1 perfusion, with hands-on process and implementation consultation from global Field Applications Specialists.


N-1 Perfusion Cell Culture Workflow

Click on the workflow link below to find productivity and throughput solutions you can implement today. 


N-1 perfusion intensifies the Fed-Batch process, increasing facility throughput. Seeded at a higher initial density, cells in the N bioreactor grow faster, reach a higher max VCD and produce more product than traditional Fed-Batch. Harvest sooner and increase the number of batches per year as compared to a standard Fed-Batch process.  Alternatively, maintain the N bioreactor run time to increase overall yield.

Maintain a Fed-Batch process 

N-1 perfusion intensification increases N bioreactor productivity and throughput while maintaining a Fed-Batch process. No perfusion or media exchange of the N bioreactor is required, allowing the N bioreactor to maintain a single and discreet Fed-Batch harvest point.  

Minimize validation impact 


N Bioreactor reached 350 x 106 VCD

N-1 perfused Fed-Batch reached 350 million cells/mL VCD in just 6 days. In comparison, standard Fed-Batch achieved 30 million cells/mL viable cell density (VCD) over a course of 14 days. Productivity of the N bioreactor with N-1 perfusion increased 20X while maintaining viability above 90%. 

Higher cell density and viability

  • 10X VCD over Fed-Batch
  • VCD as high as 350 x 106 cells/mL
  • 生産時間を50%削減
  • 20X increase in productivity
  • COGを削減

N-1 Perfusion increased VCD 10X, reduced production time by 50%

The perfused N-1 bioreactor cell density rapidly increased from 8 to 80 million cells/mL (10x VCD) in 4-5 days. Inoculation of the N bioreactor with the N-1 perfused culture established a 10X higher initial viable cell density over Fed-Batch (A). After 3 days, the N-1 inoculated bioreactor achieved 35 million VCD. In comparison, the control required 6 days to achieve 25 million VCD (B). 

Leverage higher VCD to either increase throughput or increase yield. Harvest of the N-1 Fed-Batch bioreactor at day 8 was equivalent to harvesting the Fed-Batch control at day 14, saving 6 days of N bioreactor suite time (C). Alternatively, harvest the N-1 Fed-Batch process at day 14 for a 25% overall yield increase. 

  • N-1 bioreactor reached 10X VCD in 4-5 days
  • N-1 perfused Fed-Batch bioreactor reached maximum VCD of 35 million compared to 25 million with traditional Fed-Batch
  • Maximum VCD was achieved 3 days earlier
  • 同じ収量を6日早く達成
  • 14日目までに25%の収量向上を達成

N-1 Bioreactor VCD

Production Bioreactor VCD




  • Field Application Support
  • カスタマーサービス
  • フィールドサービスエンジニア