Tuning the pH Responsiveness of β-Hairpin Peptide Folding, Self-Assembly, and Hydrogel Material Formation

Citations Over TimeTop 10% of 2009 papers

Abstract

A design strategy to control the thermally triggered folding, self-assembly, and subsequent hydrogelation of amphiphilic beta-hairpin peptides in a pH-dependent manner is presented. Point substitutions of the lysine residues of the self-assembling peptide MAX1 were made to alter the net charge of the peptide. In turn, the electrostatic nature of the peptide directly influences the solution pH at which thermally triggered hydrogelation is permitted. CD spectroscopy and oscillatory rheology show that peptides of lower net positive charge are capable of folding and assembling into hydrogel material at lower values of pH at a given temperature. The pH sensitive folding and assembling behavior is not only dependent on the net peptide charge, but also on the exact position of substitution within the peptide sequence. TEM shows that these peptides self-assemble into hydrogels that are composed of well-defined fibrils with nonlaminated morphologies. TEM also indicates that fibril morphology is not influenced by making these sequence changes on the hydrophilic face of the hairpins. Rheology shows that the ultimate mechanical rigidity of these peptide hydrogels is dependent on the rate of folding and self-assembly. Peptides that fold and assemble faster afford more rigid gels. Ultimately, this design strategy yielded a peptide MAX1(K15E) that is capable of undergoing thermally triggered hydrogelation at physiological buffer conditions (pH 7.4, 150 NaCl, 37 degrees C).

Related Papers

• → Cooperative organizations of small molecular surfactants and amphiphilic block copolymers: Roles of surfactants in the formation of binary co‐assemblies(2021)34 cited
• → Synthesis and controllable self-assembly of 3D amphiphilic organoplatinum(ii) metallacages in water(2019)24 cited
• → Self-assembly of amphiphilic molecules: A review on the recent computer simulation results(2010)7 cited
• Recent Development of Self-Assembly of Amphiphilic Block Copolymers in Solutions(2003)
• → Hierarchical self-assembly of amphiphilic building blocks into various supramolecular architectures(2018)