Dual-luminophore-doped silica nanoparticles for multiplexed signaling.

We have synthesized dual-luminophore-doped silica nanoparticles for multiplexed signaling in bioanalysis. Two luminophores, Tris(2,2'-bipyridyl)osmium(II)bis(hexafluorophosphate) (OsBpy) and Tris(2,2'-bipyridyl)dichlororuthenium(II)hexahydrate (RuBpy), were simultaneously entrapped inside silica nanoparticles at precisely controlled ratios, with desirable sizes and required surface functionality. Single-wavelength excitation with dual emission endows the nanoparticles with optical encoding capability for rapid and high-throughput multiplexed detection. The nanoparticles can be prepared with sizes ranging from a few nanometers to a few hundred nanometers, with specific ratios of luminescence intensities at two well-resolved wavelengths and with excellent reproducibility. These nanoparticles also possess unique properties of high signal amplification, excellent photostability, and easy surface bioconjugation for highly sensitive measurements when used as signaling markers. A simplified ligand binding system using avidin-biotin and an application extension to immunoassays have been explored, demonstrating the potential use of these easily obtainable bioconjugated nanoparticles for multiplexed signaling and bioassays.