Synthesis and characterization of multifunctional silica core-shell nanocomposites with magnetic and fluorescent functionalities.

Multifunctional core-shell nanocomposites with a magnetic core and a silica shell doped with lanthanide chelate have been prepared by a simple method. First, citric acid-modified magnetite nanoparticles were synthesized by a chemical coprecipitation method. Then the magnetite nanoparticles were coated with silica shells doped with terbium (Tb(3+)) complex by a modified Stöber method based on hydrolyzing and condensation of tetraethyl orthosilicate (TEOS) and a silane precursor.

A microemulsion preparation of nanoparticles of europium in silica with luminescence enhancement using silver.

A facile one-pot microemulsion method has been developed for the synthesis of spherical silver core-silica shell (Ag@SiO2) nanoparticles with europium chelates doped in the shell through a silane agent. The method is significantly more straightforward than other extant methods. Measurements of the luminescent emissions from the Ag@SiO2 nanoparticles, in comparison with control silica nanoparticles without silver cores, showed that the presence of the silver cores can increase the fluorescence intensity approximately 24-fold and decrease the luminescence lifetime.

Synthesis and bio-functionalization of multifunctional magnetic Fe(3)O(4)@Y(2)O(3):Eu nanocomposites.

A facile homogenous precipitation method has been developed for the synthesis of multifunctional, magnetic, luminescent nanocomposites with Fe(3)O(4) nanoparticles as the core and europium-doped yttrium oxide (Y(2)O(3):Eu) as the shell. The nanocomposites showed both super-paramagnetic behavior and unique europium fluorescence properties with high emission intensity. Their surface has been modified with a bifunctional ligand, p-aminobenzoic acid (PABA), and further biofunctionalized with biotin; the nanocomposites showed specific targeting for avidin-coupled polystyrene beads.

Magnetic/luminescent core/shell particles synthesized by spray pyrolysis and their application in immunoassays with internal standard.

Many types of fluorescent nanoparticles have been investigated as alternatives to conventional organic dyes in biochemistry; magnetic beads also have a long history of biological applications. In this work we apply flame spray pyrolysis in order to engineer a novel type of nanoparticle that has both luminescent and magnetic properties. The particles have magnetic cores of iron oxide doped with cobalt and neodymium and luminescent shells of europium-doped gadolinium oxide (Eu:Gd(2)O(3)).

Luminescent lanthanide nanoparticles as labels in DNA microarrays for quantification of methyl tertiary butyl ether degrading bacteria.

We report application of lanthanide nanoparticles for DNA quantification in a microarray platform as a substitute for conventional organic fluorophores. A non-PCR based DNA microarray assay for quantifying bacteria capable of biodegrading methyl tertiary-butyl ether (MTBE) was demonstrated. Probe DNA was immobilized on a glass surface, hybridized with biotinylated target DNA and subsequently incubated with Neutravidin-biofunctionalized nanoparticles.

Zeta-potential Analyses using Micro Electrical Field Flow Fractionation with Fluorescent Nanoparticles.

Increasingly growing application of nanoparticles in biotechnology requires fast and accessible tools for their manipulation and for characterization of their colloidal properties. In this work we determine the zeta-potentials for polystyrene nanoparticles using micro electrical field flow fractionation (mu-EFFF) which is an efficient method for sorting of particles by size. The data obtained by mu-EFFF were compared to zeta potentials determined by standard capillary electrophoresis.

Inorganic lanthanide nanophosphors in biotechnology.

Recently different types of fluorescent nanoparticles and other nanostructures have been promoted as alternatives for the fluorescent organic dyes that are traditionally used in biotechnology. Quantum dots, dye-doped polymer and silica particles have found many applications in biochemical protocols and are extensively discussed in the literature. Nanostructures based on inorganic phosphors (nanophosphors) are a new emerging class of materials with unique properties that make them very attractive for bio-application.

Rapid and quantitative DNA analysis of genetic mutations for polycystic kidney disease (PKD) using magnetic/luminescent nanoparticles.

Rapid and accurate detection of genetic mutations based on nanotechnology would provide substantial advances in detection of polycystic kidney disease (PKD), a disease whose current methods of detection are cumbersome due to the large size and duplication of the mutated gene. In this study, a nanotechnology-based DNA assay was developed for detection of SNPs (single nucleotide polymorphisms) in a feline autosomal dominant PKD (ADPKD) model which can readily be adapted to diagnosis of human ADPKD type 1. Europium and terbium phosphors were doped into gadolinium crystal hosts with a magnetic core, providing stable luminescence and the possibility of magnetic manipulations in a solution-based assay.

Quantitative DNA hybridization in solution using magnetic/luminescent core-shell nanoparticles.

Nanoscale magnetic/luminescent core-shell particles were used for DNA quantification in a hybridization-in-solution approach. We demonstrated a rapid, simple, and non-polymerase chain reaction-based DNA hybridization-in-solution assay for quantifying bacteria capable of biodegrading methyl tertiary-butyl ether. Fe3O4/Eu:Gd2O3 core-shell nanoparticles synthesized by spray pyrolysis were biofunctionalized with NeutrAvidin.

Multiplexed immunoassays for proteins using magnetic luminescent nanoparticles for internal calibration.

Suspension arrays present a promising tool for multiplexed assays in large-scale screening applications. A simple and robust platform for quantitative multiprotein immunoanalysis has been developed with the use of magnetic Co:Nd:Fe(2)O(3)/luminescent Eu:Gd(2)O(3) core/shell nanoparticles (MLNPs) as a carrier. The magnetic properties of the MLNPs allow their manipulation by an external magnetic field in the separation and washing steps in the immunoassay.

Optical characterization of eu-doped and undoped gd(2)o(3) nanoparticles synthesized by the hydrogen flame pyrolysis method.

Rare-earth-doped nanoparticles are promising materials for fluorescent labeling, as they are characterized by a high Stokes shift, narrow emission spectra, long lifetimes, minimized photobleaching, and low toxicity. We examined the structural and optical properties of europium-doped gadolinium oxide nanoparticles synthesized by the flame pyrolysis method, with specific emphasis on full spectral characterization and fluorescence kinetics. The emission-excitation characterization revealed the presence of predominantly monoclinic but also highly luminescent cubic phases with a prominent oxygen-to-europium charge-transfer band in the 230-260 nm range.

Eu3+-doped Gd2O3 nanoparticles as reporters for optical detection and visualization of antibodies patterned by microcontact printing.

Lanthanide oxide nanoparticles are promising luminescent probes in bioanalysis, because of their unique spectral properties, photostability, and low-cost synthesis. We report for the first time the application of europium-doped gadolinium oxide (Eu:Gd2O3) nanoparticles to the optical imaging of antibody micropatterns. The nanoparticles were synthesized by spray pyrolysis and coated with antibody (IgG) molecules by physical adsorption.

Application of luminescent Eu:Gd2O3 nanoparticles to the visualization of protein micropatterns.

Nanoparticle phosphors made of lanthanide oxides are a promising new class of tags in biochemistry because of their large Stokes shift, sharp emission spectra, long luminescence lifetime, and good photostability. We demonstrate the application of these nanoparticles to the visualization of protein micropatterns. Luminescent europium-doped gadolinium oxide (Eu:Gd2O3) nanoparticles are synthesized by spray pyrolysis.

Microarray immunoassay for phenoxybenzoic acid using polymer encapsulated Eu:Gd2O3 nanoparticles as fluorescent labels.

Currently, detection in microarray bioanalysis is based mainly on the use of organic dyes. To overcome photobleaching and spectral overlaps we applied a new type of fluorophore, crystalline europium-doped gadolinium oxide (Eu:Gd2O3) nanoparticles, as labels in immunoassay microarrays. The Eu:Gd2O3 nanoparticles synthesized by spray pyrolysis offer narrow red emission, large Stokes shift, photostable laser-induced fluorescence with a long lifetime (1 ms).