Gelation behavior of short protected peptides in organic medium

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Peptide gelators are well-studied in aqueous systems for biomedical uses.
• Peptide gelation in organic solvents is less understood, despite organic solvent use in synthesis and organogel applications.

Purpose of the Study:

• To investigate the gelation behavior of a short peptide sequence (lysine-tyrosine-phenylalanine, KYF) in an organic medium (dichloromethane).
• To characterize the structure and properties of peptide-based organogels formed from protected KYF peptides.

Main Methods:

• Gelation studies of protected KYF peptides in dichloromethane.
• Structural analysis using Fourier transform infrared spectroscopy (FTIR).
• Morphological characterization via transmission electron microscopy (TEM) and dynamic light scattering (DLS).
• Rheological property assessment.

Main Results:

• Protected KYF peptides successfully formed gels in dichloromethane at concentrations comparable to deprotected peptides in water.
• FTIR confirmed antiparallel β-sheet structures in both aqueous and organogels.
• TEM and DLS revealed short, anisotropic particles in DCM organogels, contrasting with the entangled fibers of aqueous gels.
• Rheological tests showed protected KYF organogels behave like colloidal gels, exhibiting shear thinning and a strain-dependent gel-to-fluid transition.

Conclusions:

• Peptide gelation is achievable in organic solvents like DCM using protected short peptide sequences.
• The assembly and mesoscale structure of peptide gels differ significantly between aqueous and organic environments.
• Understanding peptide assembly in organic media is crucial for optimizing synthesis and applications of peptide-based organogels.