Chaoyong Yang | PubMed Health

PubMed2005

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.

Animals↗

PubMed2004

Optimization of dye-doped silica nanoparticles prepared using a reverse microemulsion method.

Fluorescent labeling based on silica nanoparticles facilitates unique applications in bioanalysis and bioseparation. Dye-doped silica nanoparticles have significant advantages over single-dye labeling in signal amplification, photostability and surface modification for various biological applications. We have studied the formation of tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)) dye-doped silica nanoparticles by ammonia-catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) in water-in-oil microemulsion. The fluorescence spectra, particle size, and size distribution of Ru(bpy) dye-doped silica nanoparticles were examined as a function of reactant concentrations (TEOS and ammonium hydroxide), nature of surfactant molecules, and molar ratios of water to surfactant (R) and cosurfactant to surfactant (p). The particle size and fluorescence spectra were dependent upon the type of microemulsion system chosen. The particle size was found to decrease with an increase in concentration of ammonium hydroxide and increase in water to surfactant molar ratio (R) and cosurfactant to surfactant molar ratio (p). This optimization study of the preparation of dye-doped silica nanoparticles provides a fundamental knowledge of the synthesis and optical properties of Ru(bpy) dye-doped silica nanoparticles. With this information, these nanoparticles can be easily manipulated, with regard to particle size and size distribution, and bioconjugated as needed for bioanalysis and bioseparation applications.

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