Rubpy Dye-Doped Silica Nanoparticles as Signal Reporter in a Dot Fluorescence Immunoassay Strip

Abstract EN

This paper describes an application of Rubpy dye-doped silica nanoparticles (RSNPs) as signal reporter in a dot fluorescence immunoassay strip for rapid screening of Vibrio cholera O1 (VCO1).

These nanoparticles have a spherical shape with an average diameter of 45 nm.

They appear luminescent orange when excited with a 312 nm UV lamp.

Based on the sandwich immunoassay principle, a test strip was made of a nitrocellulose membrane dotted with monoclonal antibodies against VCO1 as analyte capture molecules.

After introducing a test sample, followed by polyclonal rabbit anti-VCO1 antibody conjugated RSNPs as detection reporters and one washing step, the presence or absence of the target bacteria could be identified under UV light by naked eyes.

A positive sample would signal a bright orange dot on the strip.

The proposed assay had a detection limit of 4.3 × 10 3 cfu/mL and was successfully applied as a rapid screening test for VCO1 in food samples with high sensitivity, specificity, and accuracy.