Probing the Self-Aggregation of l-Tryptophan into Spherical Microstructures and Their Selective Interactions with...

Area of Science:

• Biochemistry
• Materials Science
• Analytical Chemistry

Background:

• Protein and peptide aggregation is linked to metabolic disorders.
• Understanding amino acid aggregation is crucial for biological and medical research.

Purpose of the Study:

• To investigate the self-aggregation of l-tryptophan (Trp) into novel microstructures.
• To characterize the aggregation process and its fluorescence properties.
• To develop a sensitive assay for analyte detection using Trp aggregates.

Main Methods:

• Fluorescence spectroscopy
• Field Emission Scanning Electron Microscopy (FE-SEM)
• Temperature-dependent fluorescence measurements
• Competitive interaction studies with Human Serum Albumin (HSA)

Main Results:

• l-Tryptophan spontaneously self-aggregates into spherical microstructures.
• These aggregates exhibit distinct fluorescence characteristics (λex = 345 nm, λem = 430 nm) compared to the monomer.
• The fluorescence intensity of Trp aggregates is selectively quenched by bilirubin in the picomolar range.
• The aggregation process is spontaneous and driven by noncovalent interactions.
• Bilirubin shows strong association with Trp aggregates, confirmed by competitive studies.

Conclusions:

• l-Tryptophan forms unique spherical aggregates with specific fluorescence properties.
• A highly sensitive assay for picomolar bilirubin detection was developed using Trp aggregates.
• This study provides insights into amino acid aggregation and its potential for analyte detection.