Oligo(p-phenylenevinylene)-peptide conjugates: synthesis and self-assembly in solution and at the solid-liquid...

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Biophysics

Background:

• Oligo(p-phenylenevinylene) (OPV) amphiphiles are explored for self-assembly.
• Peptide sequences influence the self-assembly of hybrid materials.
• Beta-sheet and beta-turn peptide structures offer distinct conformational properties.

Purpose of the Study:

• To synthesize and characterize two novel oligo(p-phenylenevinylene)-peptide hybrid amphiphiles.
• To investigate the self-assembly behavior of these hybrid amphiphiles in different environments.
• To understand how peptide secondary structure (beta-sheet vs. beta-turn) influences supramolecular organization.

Main Methods:

• Solid-phase and liquid-phase synthesis strategies were employed.
• Scanning tunneling microscopy (STM) was used for submolecular-level imaging of 2D self-assembly.
• Spectroscopic techniques (absorption, fluorescence, circular dichroism) and microscopy (cryo-TEM, AFM) were utilized to study aggregation and self-assembly in solution and water.

Main Results:

• Two hybrid amphiphiles, OPV-GAGAG (beta-sheet) and OPV-GANPNAAG (beta-turn), were successfully synthesized.
• OPV-GAGAG formed antiparallel beta-sheet bilayers, observed via STM.
• Both amphiphiles aggregated in organic solvents; in water, they formed self-assembled nanofibers with helical OPV segments, with organization dictated by the peptide sequence.

Conclusions:

• The peptide sequence critically controls the self-assembly pathway and resulting nanostructures of OPV-peptide hybrids.
• Beta-sheet peptides promote bilayer formation, while beta-turn peptides lead to helical nanofibers in aqueous media.
• These findings highlight the potential for designing peptide-templated functional materials with tunable morphologies.