A form of seed train intensification, N-1 perfusion refers to the intensification of cell growth in the step prior to the production bioreactor (N). This process intensification is done by attaching a cell retention device to the N-1 bioreactor to attain high cell density and viability. This seeds the production bioreactor at a higher starting cell density and shortens 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:
N-1 perfusion can help optimize Fed-batch production in two ways:
High cell density seeding of the production bioreactor (N)
with the cell retention device attached to the N-1 bioreactor
Removal of the N-1 bioreactor
with the cell retention device attached to the N-2 bioreactor, if the N-2 bioreactor can provide enough cells for the production bioreactor (N)
Alternating Tangential Flow (ATF) Filtration
An award-winning technology, ATF allows the removal of spent media while keeping cells in culture. Applied using an XCell™ ATF device attached to a bioreactor, ATF minimizes cell shear and keeps cells in constant equilibrium with bioreactor contents. This results in faster cell growth at higher densities with higher productivity. Today, the XCell™ ATF device, in single-use or reusable format, is the leading perfusion device for mAb and rProtein production.
Integrated Tangential Flow Filtration (TFF) Systems
Turnkey, easy-to-use, cost-effective and scalable hollow fiber systems for tangential flow filtration (TFF), single-use filter modules and state-of-the-art hollow fiber membranes enable process and cost efficiencies in upstream perfusion. KrosFlo® KML 100 and KPS TFF Systems are fully integrated and ready to use out of the box, the systems include precise and reproducible control and documentation of all TFF processes.
Single-use custom flow paths
Ready-to-use connectivity between any bioreactor and the cell retention device facilitates the adoption of perfusion technologies. Defined through an engineering design process, Pro-Connex® Flow Paths are customized, configurable and complete assemblies for tangential flow filtration. The assemblies are sterile and manufactured in compliance with ISO guidelines in an ISO 7 clean room.
Potent cell culture supplements
Repligen developed and manufactures cell culture supplements that provide the benefits of serum supplementation while maintaining an animal-free process.
Filtration Primer - WIP
How Alternating Tangential Flow (ATF) works - WIP
How Tangential Flow Filtration (TFF) works - WIP
XCell ATF from Repligen - WIP
A Brief History of Perfusion Biomanufacturing: How High-Concentration Cultures Will Characterize the Factory of the Future
by John Bonham-Carter and Jerry Shevitz
BioProcess International, October 2011
Developing an Integrated Continuous Bioprocessing Platform: Interview with Konstantin Konstantinov
by Maribel Rios
BioProcess International, December 2012