Fig. 1
Evaluation of critical parameters required to achieve efficient chondrogenic differentiation of heMSC-Cytodex 1 microcarrier constructs. a Brightfield images (scale bar = 100 μm) and kinetics of heMSC growth on Cytodex 1 microcarriers in agitated spinner culture. Numbers indicate the cell confluency (dotted line represents 100% cell confluency of 4.7 × 104 cells/cm2 as calculated from monolayer cultures). *Cell-laden microcarriers taken from spinner culture at the indicated time point were used to seed heMSC-Cytodex 1 constructs. b Schematic of experimental design. Stage 1: heMSC attached to Cytodex 1 microcarriers were seeded as chondrogenic heMSC-microcarrier constructs at either day 3 (early-log phase with 43% cell confluency), day 5 (mid-log phase with 68% cell confluency), or day 7 (late-log phase with 95% cell confluency), using different cell numbers per construct. Stage 2: heMSC-microcarrier constructs generated under critically defined conditions as identified at Stage 1 were evaluated for the effect of cell density (addition of empty microcarriers at seeding) or the effect of compaction (centrifugation at seeding or agitation throughout differentiation)