My suspension-adapted HEK293 (or CHO) cells tend to clump in culture. How can I avoid this?

Efficient protein production experiments require growth of the host cell in single-cell suspension, something that is sometimes difficult to achieve since most established cell lines retain their adherent growth characteristics. Commercially available media specially formulated for propagation in suspension make this transition much easier. Lonza offers a set of optimized media for protein expression in suspension culture. Furthermore, ensure sufficient agitation (110 - 150 rpm on orbital shaker), just below generation of foam. To obtain a highly uniform single-cell suspension in passaging procedures, we recommend using 100 micron Cell Strainers (BD Falcon™) to remove cell aggregates in each passaging procedure. Be sure to have a regular and frequent cell passaging schedule and keep the cells at recommended densities.
Related URLs:
Classical Media and Reagents
Serum-free and Speciality Media
Research Areas:
Cancer Research/Cell Biology