Figure 1.

Schematic of the modular design strategy used to create two families of protein-engineered biomaterials. Top: A chemically-crosslinked hydrogel fabricated from multiple repeats of elastin-like modules, cell adhesion modules, and protease degradation modules [6, 37]. The engineered proteins form a chemical hydrogel network through covalent bonding between a crosslinker and multiple lysine amino acid residues on neighboring protein chains. Bottom: A mixing-induced two-component hydrogel fabricated from two repeating peptide sequences that hetero-assemble [14]. The engineered proteins form a physical hydrogel network through transient hydrogen bonding between WW domains and PPxY domains on neighboring protein chains.