Centrifuge harvested cells (see Subheading 3.2 steps 1–11). in a benchtop centrifuge at 500 × g for 5 min.
Resuspend cells at a density of 1.25 × 106 cells/ml in chondrogenic differentiation medium.
Using a repeater pipette, dispense 0.2-ml aliquots of the cell suspension (2.5 × 105 cells/well) into polypropylene 96-well plates.
Spin aliquots in a benchtop centrifuge at 500 × g for 5 min.
Place the multiwell plates in the incubator at 37°C in a humidified atmosphere of 95% air and 5% CO2 for up to 3 weeks.
Twenty four hours after centrifugation, ensure that the aggregates can float freely by releasing them from the bottom of the wells by aspirating 100 μl of media and gently releasing it back into the wells using an eight-channel pipette.
Change chondrogenic medium every other day. Carefully aspirate expired medium using a sterile 200-μl pipette tip affixed to a vacuum system.
Aliquot 0.2 ml of fresh chondrogenic medium to each well.