Thixotropic Hydrogels Composed of Self-Assembled Nanofibers of Double-Hydrophobic Elastin-Like Block Polypeptides

Abstract

Physically crosslinked hydrogels with thixotropic properties attract considerable attention in the biomedical research field because their self-healing nature is useful in cell encapsulation, as injectable gels, and as bioinks for three-dimensional (3D) bioprinting. Here, we report the formation of thixotropic hydrogels containing nanofibers of double-hydrophobic elastin-like polypeptides (ELPs). The hydrogels are obtained with the double-hydrophobic ELPs at 0.5 wt%, the concentration of which is an order of magnitude lower than those for previously reported ELP hydrogels. Although the kinetics of hydrogel formation is slower for the double-hydrophobic ELP with a cell-binding sequence, the storage moduli G′ of mature hydrogels are similar regardless of the presence of a cell-binding sequence. Reversible gel–sol transitions are demonstrated in step-strain rheological measurements. The degree of recovery of the storage modulus G′ after the removal of high shear stress is improved by chemical crosslinking of nanofibers when intermolecular crosslinking is successful. This work would provide deeper insight into the structure–property relationships of the self-assembling polypeptides and a better design strategy for hydrogels with desired viscoelastic properties.

Amphiphilic Polymers for Color Dispersion: Toward Stable and Low-Viscosity Inkjet Ink

“…Examples of these block copolymers include diblock, triblock, star-shaped, and hyperbranched polymers. , Polymers possessing both hydrophilic and hydrophilic segments, called amphiphilic polymers, can form a wide range of self-organized architectures, such as micelle and vesicle, via specific molecular interactions (ionic and hydrophobic attractive force). The self-organizing behaviors of amphiphilic polymers have attracted considerable attention in polymer chemistry, , supramolecular chemistry, − and biochemistry. − Moreover, the application of amphiphilic polymers in the industry has recently become an important subject. For example, amphiphilic polymers have been utilized as dispersants − of nanoparticles.…”

Self-Healing Injectable Hydrogels for Tissue Regeneration

“…Hydrogels based on hydrophobic interactions can be formed by modification of hydrophilic polymers with hydrophobic units such as alkyl chains . Alternatively, hydrogel building blocks can be modified with hydrophobic peptides, as exploited for elastin-like polypeptides with glycine-rich and proline-rich hydrophobic domains, , as well as by conjugation of poly­(γ- o -nitrobenzyl- l -glutamate) to 4-arm PEG …”

“…Hydrogels based on hydrophobic interactions can be formed by modification of hydrophilic polymers with hydrophobic units such as alkyl chains. 124 Alternatively, hydrogel building blocks can be modified with hydrophobic peptides, as exploited for elastin-like polypeptides with glycinerich and proline-rich hydrophobic domains, 125,126 as well as by conjugation of poly(γ-o-nitrobenzyl-L-glutamate) to 4-arm PEG. 93 Host−guest interactions involving hydrophobic interactions with cyclodextrin (CD) motifs as the host molecule have also been frequently exploited to construct self-healing injectable hydrogels.…”

Biological properties of self-assembled nanofibers of elastin-like block polypeptides for tissue-engineered vascular grafts: platelet inhibition, endothelial cell activation and smooth muscle cell maintenance

“…At temperatures above 37°C, GPG assembles into nanoparticles by the hydrophobic collapse of (VPGXG) 25 followed by polymerization into nanofibers through the formation of hydrogen bonds between (VGGVG) 5 domains. As the nanofibers of GPG are more than 20 μm in length and can form network-like structures to create stable hydrogels [ 45 , 46 ], GPG may have utility as components of TEVGs that mimic arterial elastin nanostructures. Furthermore, various peptide motifs, including KAAK [ 47 ], GRGDS [ 48 ] and silver-binding sequence [ 49 ], can be bound to the C-terminus of GPG to modify its physicochemical and biological characteristics without impairing its fiber-forming abilities.…”