Single-Stage Synthesis of Submicron Gold Particles

— Nanosized and submicron gold particles are of great interest for application in optics, biophotonics, and analytical chemistry. In spite of the great progress that has been made in the development of methods for liquid-phase chemical synthesis of such colloids, no reliable procedures have been proposed for obtaining monodisperse particles with sizes larger than 300 nm. In this work, a method has been developed for single-stage liquid-phase synthesis of submicron gold particles via the reduction of gold ions with dopamine in the presence of poly(vinylpyrrolidone) as a stabilizer. It has been found that the sizes of the targeted particles can be varied within a range of 120–500 nm by varying poly(vinylpyrrolidone) concentration in reaction mixtures. It has been shown that colloids with the narrowest size distribution of spherical particles are obtained at poly(vinylpyrrolidone) concentrations of 0.01–1 mg/mL. The synthesized submicron particles can be used as labels in surface-enhanced Raman scattering spectroscopy and for confocal laser microscopy.