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

Abstract

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 recognizeMycobacterium tuberculosis, and then an antibody binding protein (Protein A) labeled withTris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate (RuBpy)-doped silica nanoparticles wasused to generate fluorescent signal for microscopic examination. Prior to the detection, Protein Awas immobilized on RuBpy-doped silica nanoparticles with a coverage of ∼5.1× 102 molecules/nanoparticle. With this method, Mycobacterium tuberculosis in bacterial mixture aswell as in spiked sputum was detected. The use of the fluorescent nanoparticles reveals amplifiedsignal intensity and higher photostability than the direct use of conventional fluorescent dye aslabel. Our preliminary studies have demonstrated the potential application of the FNP-IIFMmethod for rapid detection of Mycobacterium tuberculosis in clinical samples. Copyright © 2007 Dilan Qin et al.