Influence of the Thermodynamic and Kinetic Control of Self‐Assembly on the Microstructure Evolution of Silk‐Elastin‐Like Recombinamer Hydrogels

Abstract

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, considering the possibility of tuning the thermodynamics and kinetics of the system through a tailored molecular design. In this work, we combined elastin-like (EL) and silk-like (SL) polypeptides to obtain a silk-elastin-like recombinamer (SELR) with dual self-assembly. 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 (growing to a pore size of 49.9 ± 12.7 µm after 1 h), as observed by Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff))

Elastin-Like Recombinamer Hydrogels for Improved Skeletal Muscle Healing Through Modulation of Macrophage Polarization

“…On the other hand, the silk-elastin-like recombinamer (SELR) used for the formation of physically crosslinked hydrogels, the so-called IKRS-MMP, was based on a previously designed SELR (Ibáñez-Fonseca et al, 2020), to which a MMP-sensitive domain, similar to the one included in the HE5, was included for biodegradation.…”

“…For instance, the introduction of lysines with amine groups that can be modified for covalent crosslinking through "click chemistry" strategies, like strainpromoted alkyne-azide cycloaddition (SPAAC), may allow the formation of chemical hydrogels (González de Torre et al, 2014;Madl et al, 2016). On the other hand, physical hydrogels can be achieved by the inclusion of amino acid sequences able to form stable non-covalent interactions (e.g., H-bonds), such as the repetitive domains found in silk fibroin from Bombyx mori silkworm that, in combination with the elastin-like building blocks, form hydrogels through a concomitant self-assembly above the T t (Fernández-Colino et al, 2014;Ibáñez-Fonseca et al, 2020). Furthermore, the genetic fusion of bioactive sequences, including cell adhesion domains, like the L-Arg-Gly-L-Asp (RGD) tripeptide (Ruoslahti, 1996), or proteasesensitive sequences for improved biodegradation (Flora et al, 2019;Contessotto et al, under review), permits the obtaining of hydrogels with acquired functionalities.…”

Fibrous Scaffolds From Elastin-Based Materials

“…This approach has been explored for cartilage repair by manufacturing scaffolds including cell adhesive RGD sequences that help regenerate the hyaline cartilage in an ex vivo osteochondral model. The synergic ability of the elastin-like phase transition and the silk β-sheet self-assembling domains to capture the transient states arising during the formation of fibrillary SELR hydrogels has been recently investigated (Ibáñez-Fonseca et al, 2020). As observed, the different kinetics for the self-assembly of silk and elastin-like domains affect the structure achieved in a time-dependent manner.…”

Recent Advances in Natural Materials for Corneal Tissue Engineering

“…These silk peptides often mimic sequences from spider silk, and can be coupled with other peptide sequences [ 35 , 36 , 37 ]. Regenerated silk fibroin protein [ 38 ] can be used to form hydrogels [ 39 , 40 ], or hydrogels can be formed from recombinantly produced peptides [ 41 , 42 ]. Regenerated silk fibroin can be modified to enhance functionality via modification of native or enriched carboxylic and amide groups on the protein backbone [ 43 , 44 ], and hydrogels can be formed through amino acid coupling reactions [ 39 , 45 , 46 ].…”