Large-Scale Cell Concentration and Buffer Exchange Prepares CHO Cells for Electroporation
Recombinant protein production is an essential step in the development of many novel, life-saving therapies and diagnostics. Stable cell line development enables consistent protein yields and product quality, but the process is lengthy, costly and time-consuming. Transient protein expression could be a viable alternative to stable cell line development producing material for pre-clinical development and early clinical trials.
To realize the potential of transiently expressed protein, very large quantities of transfected cells are required. MaxCyte’s ExPERT VLxTM enables the transfection of up to 200 billion cells in under 30 minutes. Cell concentration and buffer exchange prepare cells for electroporation; one solution is tangential flow filtration (TFF), which offers gentle processing that is scalable, fast and easy to use. In collaboration with Repligen, we developed an optimized process using the KTF-600 KrosFlo® system and hollow fiber TFF devices to deliver CHO cells in MaxCyte electroporation buffer, at the required concentration of 2x108 cells/mL.
Figure 1. Cell concentration and buffer exchange yields healthy, electroporation-ready cells which can be efficiently transfected. CHO cells from the seed train at 8x106 cells/mL in growth media were concentrated to 2x108 cells/mL in MaxCyte electroporation buffer. Vi-CELLTM analysis confirmed that high cell viability was maintained throughout. Cells were transfected with 300μg/mL of pGFP DNA using the MaxCyte VLx. Transfection efficiency was assessed 24 hours post electroporation; 99% of transfected cells expressed GFP.