Complex recombinant biomaterials that merge the self-assembling
properties of different (poly)peptides provide a powerful tool for the
achievement of specific structures, such as hydrogel networks, by tuning
the thermodynamics and kinetics of the system through a tailored molecular
design. In this work, elastin-like (EL) and silk-like (SL) polypeptides are
combined to obtain a silk-elastin-like recombinamer (SELR) with dual selfassembly. First, EL domains force the molecule to undergo a phase transition
above a precise temperature, which is driven by entropy and occurs very fast.
Then, SL motifs interact through the slow formation of β-sheets, stabilized
by H-bonds, creating an energy barrier that opposes phase separation. Both
events lead to the development of a dynamic microstructure that evolves
over time (until a pore size of 49.9 ± 12.7 µm) and to a delayed hydrogel
formation (obtained after 2.6 h). Eventually, the network is arrested due to an
increase in β-sheet secondary structures (up to 71.8 ± 0.8%) within SL motifs.
This gives a high bond strength that prevents the complete segregation of
the SELR from water, which results in a fixed metastable microarchitecture.
These porous hydrogels are preliminarily tested as biomimetic niches for the
isolation of cells in 3D cultures.
