Figure 2.

Initial seeding parameters play a critical role in minimizing aggregate formation. A: mESCs were seeded in triplicate onto either Solohill Collagen (solid lines) or Cultispher-S (dashed line) microcarriers at a density of 1.5 × 10⁴ cells/mL in KO-DMEM plus KO-SR and LIF. Seeding was carried out for 24 h with (i) continuous stirring of 5 rpm, (ii) 2 min stirring at 15 rpm followed by 10 min off, or (iii) 2 min stirring at 15 rpm followed by 30 min off. The average number of cells (±SD) remaining in the supernatant are shown. B–D: The diameters of more than 200 cell aggregates were measured and the percentage of aggregates in each of the ranges indicated calculated for each time and condition. B: Continuous stirring of 5 rpm; C: 2 min at 15 rpm, 10 min off, and D: 2 min at 15 rpm, 30 min off. Samples B(i), C(i), and D(i) represent data for Solohill collagen, while B(ii), C(ii), and D(ii) represent data for Cultispher-S. E: The total number of viable cells recoverable from each bioreactor at 24 h was determined (i) Solohill collagen and (ii) Cultispher-S microcarriers.