Atomic-precision π-driven peptide hydrogel nanofibers with ordered water channels

Area of Science:

• Supramolecular chemistry
• Materials science
• Biomaterials engineering

Background:

• Aromatic interactions drive supramolecular assembly, while peptides form soft materials via hydrogen bonding and water-mediated assembly.
• Terminally capped peptides typically achieve strong aromatic stacking, unlike uncapped peptides which rarely form highly ordered materials.
• Integrating aromatic stacking and peptide assembly is key for advanced functional materials.

Purpose of the Study:

• To develop a new class of supramolecular hydrogels with enhanced structural order.
• To investigate the hierarchical assembly of pyrene-modified dipeptides.
• To explore the potential of combining conjugated materials and biomolecular matter.

Main Methods:

• Modification of a terminally uncapped peptide with a π-extended aromatic unit (pyrene).
• Hierarchical self-assembly of the modified dipeptide into nanofibers and hydrogels.
• Cryo-electron microscopy (Cryo-EM) for near-atomic resolution structural analysis.

Main Results:

• A pyrene-modified dipeptide self-assembles into monodisperse helical nanofibers and self-healing hydrogels.
• Cryo-EM revealed tightly packed protofilaments, ordered water channels, and a unidirectional dipole within the nanofibers.
• The study demonstrates orchestrated aromatic stacking, polar interactions, and water organization.

Conclusions:

• Reinforced aromatic stacking in terminally uncapped peptides can lead to highly ordered supramolecular hydrogels.
• Emergent electrostatics and mechanical resilience arise from the interplay of molecular interactions and water organization.
• This approach bridges conjugated materials and biomolecular matter, enabling novel functional soft materials.