Affiliation:
1. College of Materials and Chemical Engineering, Fujian Provincial University Engineering Research Center of Green
Materials and Chemical Engineering, Fujian Engineering and Research Center of New Chinese Lacquer Materials,
Minjiang University, Fuzhou, Fujian, China
2. Department of Math and Science Singapore University of Technology
and Design, 8 Somapah Road, Singapore
Abstract
Background:
Tryptophan (Trp) is an essential amino acid and plays important roles in biological
processes. The detection of Trp is very important for its biological and chemical study. Moreover,
Trp is a chiral compound; due to its importance in biological processes, researchers have been
long committed to the chiral recognition and sensing of Trp enantiomers.
Methods:
Two biosurfactants, sodium cholate and sodium deoxycholate, were used for the preparation
of functionalized gold nanoparticles (AuNPs) which were characterized by transmission electron
microscope and potentiometer. UV-Vis spectra of functionalized gold nanoparticle solutions with different
concentrations of Trp, tyrosine, phenylalanine, D-Trp, and L-Trp were analyzed. Then, the discrimination
mechanism was further investigated, and the promotion mechanism of biosurfactants was
studied by density functional theory (DFT).
Results:
Trp could induce the aggregation of unmodified AuNPs in 2 h, while phenylalanine and tyrosine
could not. Adding biosurfactants promoted the aggregation process, and D- Trp rather than LTrp
was found to be responsible for the aggregation. Therefore, there were interaction differences not
only between Trp, phenylalanine, and tyrosine but also between Trp enantiomers.
Conclusions:
UV-vis spectroscopy could be applied for the direct detection of Trp in mixtures as well
as the chiral recognition of Trp enantiomers. DFT calculations proved that the interactions of D-Trp
with biosurfactants were the strongest, which contributes to the promotion of aggregation.
Funder
National Natural Science Foundation of China
National Science Foundation of Fujian Province
Fuzhou Science and Technology Project
Publisher
Bentham Science Publishers Ltd.
Subject
Pharmaceutical Science,Molecular Medicine,Biochemistry,Biophysics