Phe-Phe Di-Peptide Nanostructure Self-Assembling Modulated by Luminescent Additives.

Area of Science:

• Supramolecular chemistry
• Materials science
• Biophysics

Background:

• Self-assembly of peptide-based nanostructures is crucial for developing novel functional materials.
• Controlling the morphology of self-assembled structures is key to tailoring their properties.
• Luminescent additives can influence self-assembly processes and introduce photophysical functionalities.

Purpose of the Study:

• To investigate the self-assembly of l-l-diphenylalanine (Phe-Phe) nanostructures.
• To explore the influence of solvent polarity and luminescent additives on Phe-Phe nanostructure morphology.
• To understand the role of additive-nanostructure interactions in self-assembly and charge-transfer.

Main Methods:

• Self-assembly of Phe-Phe in solvents of varying polarity (e.g., THF, water).
• Inclusion of luminescent additives with varying conjugation lengths and electronic properties (e.g., electron-donating polymers, electron-accepting molecules).
• Morphological characterization using scanning electron microscopy (SEM).
• Photophysical characterization using steady-state and time-resolved fluorescence spectroscopy.

Main Results:

• Phe-Phe formed vesicle-like structures in THF with an electron-donating polymer additive.
• Phe-Phe formed nanotubes in water with a structurally similar electron-donating polymer additive.
• Nanotube formation was also observed in THF when using electron-accepting additives like 9-vinyl-carbazole or poly(vinyl carbazole).
• Distinct interactions between additives and Phe-Phe structures were identified, influencing self-assembly and charge-transfer.

Conclusions:

• Solvent polarity and the electronic nature of luminescent additives significantly dictate the morphology of self-assembled Phe-Phe nanostructures.
• The formation of complexes between additives and Phe-Phe structures plays a critical role in directing self-assembly.
• Understanding these structure-property relationships enables the rational design of peptide-based nanomaterials with tunable characteristics for various applications.