Supramolecular Gelation Based on Native Amino Acid Tyrosine and Its Charge-Transfer Complex Formation

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biochemistry

Background:

• Amino acid self-assembly is crucial in supramolecular chemistry.
• Unfunctionalized native amino acid self-assembly is less explored.
• Tyrosine (Tyr) self-assembly typically occurs in aqueous solutions.

Purpose of the Study:

• To investigate the self-assembly of tyrosine (Tyr) in organic solvents.
• To report the formation of supramolecular gels from Tyr in dimethyl sulfoxide (DMSO).
• To explore the role of noncovalent interactions in Tyr self-assembly and its response to external stimuli.

Main Methods:

• Spectroscopic techniques (UV-vis, fluorescence, FTIR, NMR) for self-assembly investigation.
• Scanning Electron Microscopy (SEM) for nanoscale morphological analysis.
• Rheological experiments to characterize gel properties.
• Computational studies to elucidate interaction mechanisms.

Main Results:

• Tyrosine self-assembles into nanofibrils in DMSO, forming a supramolecular gel.
• SEM revealed high aspect ratio nanofibril formation.
• Hydrogen bonding and π-π stacking were identified as key driving forces.
• Charge-transfer complex formation with DDQ induced gel-to-solution transition and morphology collapse.

Conclusions:

• Tyrosine can form supramolecular gels in DMSO, driven by noncovalent interactions.
• The gel system demonstrates responsiveness to electron acceptors like DDQ.
• This work expands the understanding of native amino acid self-assembly in organic media.