Role of Sheet-Edge Interactions in β-sheet Self-Assembling Peptide Hydrogels

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Materials Engineering

Background:

• Hydrogels are crucial for 3D scaffolds in tissue engineering and drug delivery.
• Self-assembling peptide hydrogels are a significant area of research.
• Fiber-fiber interactions influence hydrogel properties.

Purpose of the Study:

• To investigate the impact of fiber-edge interactions on peptide self-assembly and gelation.
• To explore how lysine modifications affect amphipathic peptide hydrogel properties.

Main Methods:

• Investigated two beta-sheet-forming peptides: FEFKFEFK (F8) and KFEFKFEFKK (KF8K).
• KF8K peptides feature lysine residues on fiber edges.
• Compared self-assembly, gelation, and alignment behaviors of F8 and KF8K hydrogels.

Main Results:

• Lysine addition did not impede beta-sheet fiber formation when peptide charge was constant.
• Lysine residues reduced hydrophobic fiber-fiber edge interactions, decreasing aggregation.
• KF8K hydrogels exhibited lower moduli and faster dynamics compared to F8 hydrogels.
• KF8K fibers aligned only under high shear/concentration; F8 fibers aligned readily.
• F8 hydrogels fragmented at high concentrations due to fiber bundle stability.

Conclusions:

• Fiber-edge interactions significantly modulate self-assembly and hydrogel properties.
• Lysine modification offers a strategy to control peptide hydrogel network formation and dynamics.
• Understanding these interactions is key for designing advanced biomaterials for specific applications.