Electrostatically tuned rate of peptide self-assembly resolved by multiple particle tracking

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Physical Chemistry

Background:

• Oligopeptide hydrogels are promising for biomedical applications.
• Kinetics and assembly forces of self-assembling peptides remain underexplored.
• Understanding gelation is vital for therapeutic development, including drug delivery.

Purpose of the Study:

• To investigate the self-assembly kinetics of the model peptide FKFEFKFE (KFE8).
• To quantitatively describe the forces controlling peptide self-assembly rates.
• To explore the influence of pH on KFE8 hydrogel formation.

Main Methods:

• Utilized multiple particle tracking to monitor self-assembly.
• Studied the model peptide KFE8, known for forming β-sheet intermediates and fibrous networks.
• Investigated gelation across a pH range from 3.5 to 4.0.

Main Results:

• Increasing pH from 3.5 to 4.0 reduced KFE8 gelation time by nearly 100-fold (hours to minutes).
• Observed self-similarity in measurements at different pH values, indicating a consistent gelation mechanism.
• Proposed a semi-quantitative model based on Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to explain gelation times.

Conclusions:

• pH significantly impacts the rate of KFE8 hydrogel formation.
• The underlying self-assembly mechanism remains consistent despite accelerated kinetics.
• DLVO theory provides a framework for understanding the forces driving peptide self-assembly for therapeutic applications.