1206-1214The interaction of gold nanoparticles
(AuNPs) with thiolated amino acid, L-cysteine, and peptide, glutathione, is
reported. Additionally, thioglycolic acid has also been employed to study the
effect of other functional groups such as amine on interparticle interaction
mechanism. The functionalized AuNPs have been characterized through UV-visible
spectroscopy, FTIR analysis and transmission electron microscopy. The
plasmon-plasmon interactions amongst the functionalized AuNPs are found to be dependent on ligand concentration, pH and salt environment. The assembly of
AuNPs mediated by L-Cys and GSH has been monitored by the evolution of the
surface plasmon resonance absorption. The optical spectra of AuNPs is shifted
to the red region, indicating dipole-dipole interactions in the AuNPs assembly.
The self-assembly is more pronounced in the case of amino acid and tripeptide,
due to the zwitterion-type electrostatic interactions between amino acid groups
of L-Cys/GSH bound to different
NPs. Furthermore, the scavenging behavior of the studied thiolated ligands and
the corresponding AuNPs has been studied by using 1,1-diphenyl 2-picryl
hydrazil radical. AuNPs significantly reduces the radical scavenging ability of
thiolated antioxidants