Fig. 3: Revealing cryptic sites in a synthetic ECM leads to gain of biofunctionality.
From: Activating hidden signals by mimicking cryptic sites in a synthetic extracellular matrix
A Chemical structure of alginate–switch peptide hydrogel, gelled with Ca2+. An amide bond links the ε-amine of the C-terminal Lys (blue) residue with the alginate backbone, while the ε-amine of the N-terminal Lys residue (pink) remains free. B SEM images of switch peptide-functionalized alginate hydrogel. Scalebar = 2 μm (200 nm for inset). C Schematic illustration describing gain of biofunctionality in the synthetic ECM activated by addition of trypsin. Trypsin cleaves the N-terminal Lys residue of the switch peptide, leading to rearrangement into a functional YIGSR sequence. D Representative brightfield, live/dead (green/red), and merged images of HUVEC cells after 72 h on unmodified alginate hydrogel, switch peptide-modified alginate hydrogel, functional peptide-modified alginate hydrogel, and switch peptide-modified alginate hydrogel with 0.003 wt.% trypsin added. Scale bar represents 200 μm. E Schematic illustration describing gain of biofunctionality in the synthetic ECM activated by cell surface APN enzymes. APN cleaves the N-terminal Ala residue of the switch peptide, leading to rearrangement into a functional YIGSR sequence. F Representative brightfield, live/dead (green/red), and merged images of HUVEC cells after 72 h on KSYIGRK switch peptide-modified alginate hydrogel, functional peptide-modified alginate hydrogel, ASYIGRK-modified alginate hydrogel, and ASYIGRK-modified alginate hydrogel with curcumin (inhibitor, 50 μM). Scale bar represents 100 μm.
