Fig. 3.

Adhesive peptide type in PEG-4MAL hydrogels directs tubule formation. (A) Percentage of IMCD cells per cluster that were labeled by EdU incorporation (mean±s.e.m.) after 5 days of encapsulation in PEG-4MAL hydrogels functionalized with different adhesive peptides. At least 30 clusters were analyzed per condition. (B) Transmitted light and fluorescence microscopy images of proliferating (EdU+) IMCD cells cultured in PEG-4MAL hydrogels functionalized with different adhesive peptides. IMCD cell proliferation was assessed at 5 days after encapsulation. Scale bar: 50 μm. IMCD multicellular structure (C) projected area and (D) Feret diameter at 5 days after encapsulation in PEG-4MAL hydrogel. Graph line represents the mean of the individual data points. Each data point represents one multicellular structure. (E) Percentage of IMCD multicellular structures (mean±s.e.m.) that were classified as either ‘smooth clusters’, ‘spiked clusters’ or ‘tubules’ after 21 days of encapsulation. At least 10 multicellular structures were analyzed per condition. (F) Fluorescence microscopy images of IMCD cells at 21 days after encapsulation in PEG-4MAL hydrogel and labeled for actin (phalloidin). DAPI, counterstain. Scale bar: 50 μm. *P<0.0332, **P<0.0021, ****P<0.0001 (A,C,D); *P<0.0002 for RGD versus RDG and P<0.0021 for RGD versus YIGSR (E). (A,C,D, Kruskal–Wallis with Dunn's multiple comparisons test; E, χ² test with Bonferroni's correction). Experiments performed with six PEG-4MAL hydrogels per experimental group. Three independent experiments were performed and data are presented for one of the experiments.