Chondrogenic differentiation of sub-populations after > 8 pds. Chondrogenic differentiation was performed in hydrogels and induced with TGFβ3, control cells were cultured in hydrogels in the same medium without TGFβ3. Four weeks after induction gene expression of the chondrogenic markers, the transcription factor SRY (sex determining region Y)-box 9 (SOX9), collagen type II (COL2) was analyzed and compared to the expression of the cells before being embedded into the hydrogels (ML > 8pds). Expression relative to GAPDH is shown for each individual culture (top). Quantification cycles (Cq) for GAPDH expression are shown in the box plot. GAG synthesis (GAG content of the hydrogel + content in the cumulated culture supernatants) is presented as normalized to the DNA content (lower right). Boxes represent 25% / 75% percentiles, whisker 5% / 95% percentiles, mean (dotted line) and median (solid line) values. *: significant difference (p < 0.05) between all ML > 8 pds cultures compared to all gel control cultures and compared to gel cultures under induction conditions. (For mean expression values see Additional file 1: Tables S7 and S8).