Effects of Hydrodynamics on Aggregates Formation, Growth and Metabolism of HEK 293 Cells in Suspension Culture

By using the size distribution of cell aggregates, viable cell density, cell viability, specific consumption rate of glucose qglc), specific production rate of lactate (qlac), and yield of lactate from glucose (Ylac/glc) as the evaluation indexes, the effects of hydrodynamics on aggregates formation, growth and metabolism of HEK 293 cells in suspension culture were examined in 250 mL spinner flasks by setting the agitation rates at 25, 50, 75, and 100 r/min, respectively. It was found that agitation plays an important role in HEK 293 cell aggregates formation and cell aggregates size distribution. After 7 days of cultivation in spinner flasks operated at 50 r/min and 75 r/min, the average diameter of HEK 293 cell aggregates was 201 μm and 175 μm, respectively, with the fraction of aggregates larger than or equivalent to 225 μm less than 10 %. The cell viability was kept above 90 % with the metabolic indexes, including qglc, qlac, and Ylac/glc kept constant. These results demonstrated that hydrodynamics derived from the proper agitation of the impeller play a decisive role in controlling the formation and size distribution of HEK 293 cell aggregates, and provided sufficient mass transfer to support the normal growth and metabolism of HEK 293 cells in suspended aggregates.