Rapid detection of Mycobacterium tuberculosis cells by using microtip-based immunoassay

ISSN： 1618-2642

Source： Analytical and Bioanalytical Chemistry, Vol.393, Iss.6-7, 2009-03, pp. : 1593-1600

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Abstract

This paper describes a microtip-based approach of concentrating target analytes for a highly sensitive bioassay. As an example, rapid screening of bacterial whole cells is presented to detect Mycobacterium tuberculosis</i> (MTB), a pathogenic bacterium for human tuberculosis (TB). The concentration and detection is performed with three sequential steps of (1) attracting bacterial whole cells in the vicinity of a microtip by alternating current electroosmotic flow; (2) capturing the cells onto the microtip by capillary action; (3) binding fluorophore-labeled polyclonal antibodies to the cells followed by fluorescence measurement (immunofluorescence). Through this mechanism, MTB cells have been detected to the concentration of 8,000 cells/mL within 10 min. This sensitivity is comparable to that of Ziehl-Neelsen smear microscopy, a common culture-free screening method for diagnosis of TB. For comparison, Escherichia coli</i> O157:H7 cells have also been detected to the concentration of 30,000 cells/mL in the same way.