Quantum dots nanoparticle-based lateral flow assay for rapid detection of Mycobacterium species using anti-FprA antibodies

A lateral flow (LF) device combined with quantum dots (QDs) technology was developed for rapid detection of a specific mycobacterial flavoprotein reductase (fprA). In order to develop the LF assay based on a double-antibody sandwich format, two monoclonal antibodies recognizing different epitopes located in separated fprA domains were identified. The first monoclonal antibody was immobilized onto the detection zone of a porous nitrocellulose membrane, whereas another monoclonal antibody was conjugated to QDs nanoparticles as a detection system. Using these monoclonal antibodies we recorded a good fluorescence signal, the intensity of which was directly proportional to the concentration of fprA protein. The use of antibodies conjugated with fluorescent semiconductor QDs via biotin-streptavidin bridge, allowed the detection of fprA protein at concentrations as low as 12.5 pg/μL in less than 10 min. The reported technology could be useful in the diagnostic investigation of Mycobacterium tuberculosis and other human pathogens in clinical specimens.