Expert view: Clarification of cell cultures without centrifugation

The production process of antibodies from cell cultures includes a clarification process, separating the cells from the antibody-containing cell culture fluid. Here, we describe a novel and robust clarification method for lab-scale culture volumes of up to several litres.

Lab-scale cell removal for discovery and process development applications is traditionally achieved by centrifuging the broth and then filtering the sample through a sterilising filter unit. However, this process is not very robust, as filters are prone to clogging due to particles remaining in the suspension after centrifugation.

The production process of antibodies from cell cultures includes a clarification process, separating the cells from the antibody-containing cell culture fluid. Here, we describe a novel and robust clarification method for lab-scale culture volumes of up to several litres.

Lab-scale cell removal for discovery and process development applications is traditionally achieved by centrifuging the broth and then filtering the sample through a sterilising filter unit. However, this process is not very robust, as filters are prone to clogging due to particles remaining in the suspension after centrifugation. Moreover, cell densities have increased dramatically in the last few years to boost productivity. This results in an even more challenging cell broth. High cell-density cultures require more time for centrifugation and typically multiple filters are used during sterile filtration due to clogging. The inefficiency in clarification and sterile filtration caused by high cell density cultures results in longer filtration times, frequently over 60 minutes.

To address this challenge, Sartorius has developed the Sartoclear Dynamics® Lab, which is a new one-step method for harvesting high cell density mammalian cell cultures. This new technology was inspired by the blood plasma industry and is based on the principles of body feed filtration using diatomaceous earth as a filter aid.

The addition of diatomaceous earth to mammalian cell cultures prior to sterile filtration supports the formation of a porous filter cake to prevent clogging of the filter, allowing rapid removal of cells and cell debris from the sample without affecting protein yield or product quality in a robust way. This eliminates the centrifugation step, thus avoiding issues around centrifuge capacity and availability. Direct filtration without filter clogging is possible and the process is robust for a wide range of cell densities.

Using Sartoclear Dynamics® Lab contributes to reducing the overall workload, providing a more streamlined and rapid alternative to give researchers more time to dedicate in the discovery of antibodies for drug development.