detection of pathogenic mycobacteria based on functionalized quantum dots coupled with immunomagnetic separation基于功能化量子点检测致病性分枝杆菌加上immunomagnetic分离.pdfVIP

Detection of Pathogenic Mycobacteria Based on Functionalized Quantum Dots Coupled with Immunomagnetic Separation 1 2 1 3 3 Emmanouil Liandris , Maria Gazouli , Margarita Andreadou , Leonardo A. Sechi , Valentina Rosu , John Ikonomopoulos1* 1 Department of Animal Science and Aquaculture, Agricultural University of Athens, Athens, Greece, 2 Laboratory of Biology, School of Medicine, University of Athens, Athens, Greece, 3 Department of Biomedical Science, Microbiology, University of Sassari, Sassari, Italy Abstract Mycobacteria have always proven difficult to identify due to their low growth rate and fastidious nature. Therefore molecular biology and more recently nanotechnology, have been exploited from early on for the detection of these pathogens. Here we present the first stage of development of an assay incorporating cadmium selenide quantum dots (QDs) for the detection of mycobacterial surface antigens. The principle of the assay is the separation of bacterial cells using magnetic beads coupled with genus-specific polyclonal antibodies and monoclonal antibodies for heparin-binding hemagglutinin. These complexes are then tagged with anti-mouse biotinylated antibody and finally streptavidin- conjugated QDs which leads to the detection of a fluorescent signal. For the evaluation of performance, the method under study was applied on Mycobacterium bovis BCG and Mycobacterium tuberculosis (positive controls), as well as E. coli and Salmonella spp. that constituted the negative controls. The direct observation of the latter category of samples did not reveal fluorescence as opposed to the mycobacteria ment