An interplay between electrostatic and polar interactions in peptide hydrogels

Abstract

Inherent chemical programmability available in peptide-based hydrogels has allowed diversity in the development of these materials for use in biomedical applications. Within the 20 natural amino acids, a range of chemical moieties are present. Here we used a mixing-induced self-assembly of two oppositely charged peptide modules to form a peptide-based hydrogel. To investigate electrostatic and polar interactions on the hydrogel, we replace amino acids from the negatively charged acidic glutamic acid (E) to the uncharged polar glutamine (Q) on a negatively charged peptide module, while leaving the positively charged module unchanged. Using dynamic rheology, the mechanical properties of each hydrogel were investigated. It was found that the number, but not the location, of electrostatic interactions (E residues) dictate the elastic modulus (G′) of the hydrogel, compared to polar interactions (Q residues). Increased electrostatic interactions also promote faster peptide assembly into the hydrogel matrix, and result in the decrease of T2 relaxation times of H2O and TFA. Small-angle X-ray scattering (SAXS) showed that changing from electrostatic → polar interactions affects the ability to form fibrous networks: from the formation of elongated fibers to no fiber assembly. This study reveals the systematic effects that the incorporation of electrostatic and polar interactions have when programmed into peptide-based hydrogel systems. These effects could be used to design peptide-based biomaterials with predetermined properties.

Mixing Biomimetic Heterodimers of Nucleopeptides to Generate Biocompatible and Biostable Supramolecular Hydrogels

“…For example, it is difficult to choose the length of the alkyl chain, [9b] too many aromatic groups may inhibit cells in some cases, [4,12] too strong charge interactions results in poor reversibility. [13] Thus, it is necessary and beneficial to explore new strategies to complement the existing ones for supramolecular hydrogels.…”

Split of Chiral Degeneracy in Mechanical and Structural Properties of Oligopeptide–Polysaccharide Biomaterials

“…Larger L c corresponds to larger spatial extent of the cross-linking fibrous regions. 35 L c has been explored and successfully applied to understand the effects of ionic strength 36 and electrostatic interactions 37 on the structural characteristics of peptide-based hydrogels.…”

On the analysis of microrheological responses of self‐assembling RADA16‐I peptide hydrogel

“…The existence of salt bridges affects the formation of fibrous and porous peptide based scaffolds that are rich in β‐sheet secondary structure . Electrostatic interferences are induced by salts, ions, macromolecules, and pH changes . The effect of salt concentration on sol–gel transition in solutions containing amphiphilic peptides has been studied, and it was found that amphiphilic peptide solutions with higher salt concentrations have higher gelation rates and mechanical properties …”

“…[12][13][14] Electrostatic interferences are induced by salts, ions, macromolecules, and pH changes. [15][16][17] The effect of salt concentration on sol-gel transition in solutions containing amphiphilic peptides has been studied, and it was found that amphiphilic peptide solutions with higher salt concentrations have higher gelation rates and mechanical properties. 18,19 Rheological studies are necessary to compare different conditions of peptides.…”