Resonance Elastic Light Scattering and Plasmonic Phenomena in Glutathione-Mediated Gold Nanoparticle Assembly

The resonance elastic light scattering (RELS) spectroscopy has been applied to study the interactions of glutathione (GSH) with citrate-capped gold nanoparticles (AuNP). A strong dependence of GSH-induced gold nanoparticle assembly on nanoparticle size has been found. The RELS intensity measurements were carried out in a short reaction time (τ = 60 s) after injection of GSH. The strong interparticle interactions between AuNP are due to zwitterionic forces and intermolecular hydrogen bonding. The AuNP assembly has been confirmed using the surface plasmon UV-Vis spectroscopy. A fast initial adsorption rate of GSH on a clean Au surface, v = 2.4 ng cm-2 s-1, has been measured using a nanogravimetric flow-cell with piezoelectric QC/Au resonator. The adsorption/desorption processes have been evaluated. The RELS spectroscopy has been found as a very sensitive tool for studying interparticle interactions and its applications can be extended to monitor reactivities and assembly of other monolayer-protected metal clusters.