Fig. 2

Hydrogel stiffness is modified by encapsulated hMSC. Young’s modulus (E, Pa) of acellular and cell-laden a 1:0.375, b 1:0.75, and c 1:3 S-HA-PEGDA hydrogels evaluated by atomic force microscopy. Box plots (top row) showing 1st/3rd quartiles (bounds of box), high/low values (whiskers), and median (central line) E. A Mann–Whitney test (two-tailed) was used to assess statistical differences (***p < 0.001). Histograms show distributions of E on acellular and hMSC-laden hydrogels cultured under standard conditions or treated with 75 μM Exo-1 or 100 μM Vcpal for 72 h. Histograms are overlaid with fitted normal distributions, with centre ± standard error. Insets show distributions and fitted normal distributions in designated areas of the datasets. In all compositions, the presence of hMSC significantly affected the distribution of E (see Supplementary Table 2 for n values and statistical analyses of distributions of E)