Thiol-Functionalized IGEPAL® Surfactants as Novel Fluorescent Ligands for the Silica Coating of Gold Nanoparticles.

A synthesized thiol-functionalized non-ionic surfactant based on the IGEPAL® (polyoxyethylene(5) nonyl phenyl ether) structure, has been used to replace citrate ions from the surface of gold nanoparticles with 13.5 nm diameters. Upon IGEPAL®-type stabilization in water, the nanoparticles were transferred to ethanol, where a layer of silica was efficiently grown on the nanocrystal surface through the conventional Stöber approach. This method allows fine control over the silica thickness, showing uniform and homogeneous core-shell nanoparticles. Additionally, the luminescent properties of the IGEPAL® surfactant allow the versatile preparation of robust fluorescent nanoparticles with multiplexing potential as simultaneous plasmonic and fluorescence probes. [ABSTRACT FROM AUTHOR]