Fluorescent nanoparticle-based indirect immunofluorescence microscopy for detection of Mycobacterium tuberculosis.

A method of fluorescent nanoparticle-based indirect immunofluorescence microscopy (FNP-IIFM) was developed for the rapid detection of Mycobacterium tuberculosis. An anti-Mycobacterium tuberculosis antibody was used as primary antibody to recognize Mycobacterium tuberculosis, and then an antibody binding protein (Protein A) labeled with Tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate (RuBpy)-doped silica nanoparticles was used to generate fluorescent signal for microscopic examination. Prior to the detection, Protein A was immobilized on RuBpy-doped silica nanoparticles with a coverage of approximately 5.

Using bioconjugated nanoparticles to monitor E. coli in a flow channel.

A simple and portable flow channel optical detection system combined with bioconjugated luminescent nanoparticles allows the rapid detection of single bacterial cells without sample enrichment. The optical system is designed to have single-molecule-detection capability in a microcapillary flow channel by decreasing the laser excitation probe volume to a few picoliters, which consequently results in a low background. Specific monoclonal antibodies were immobilized on nanoparticles to form nanoparticle-antibody conjugates.

Bionanotechnology based on silica nanoparticles.

We have developed uniform core/shell nanoparticles, consisting of a silica layer coating and pigments or magnetite core, using a water-in-oil microemulsion method. The nanoparticles are highly luminescent and photostable with the size ranging from 5 nm to 400 nm. Bioconjugation of these silica nanoparticles adds unique biofunctions with various molecules such as enzymes, antibodies, and DNA molecules.

Development of organic dye-doped silica nanoparticles for bioanalysis and biosensors.

The combination of two silica precursors, tetraethylorthosilicate and phenyltriethoxysilane, were utilized to synthesize organic dye-doped silica nanoparticles. The hydrophobic nature of phenyltriethoxysilane keeps the organic dye in the silica matrix, whereas the hydrophilic tetraethylorthosilicate-formed silica allows the resulting nanoparticles to be dispersed in aqueous solutions. Characterization of the nanoparticles showed that they could be synthesized in the nanometer range with high photostability and minimal dye leakage.