title: Rapid detection of Mycobacterium tuberculosis cells by using microtip-based immunoassay.
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 (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 O157:H7 cells have also been detected to the concentration of 30,000 cells/mL in the same way.
authors.affiliation: Department of Mechanical Engineering, University of Washington, Campus Box 352600, Seattle, WA 98195, USA.
authors.forename: Woon-Hong
authors.initials: WH
authors.lastname: Yeo
authors.forename: Shieng
authors.initials: S
authors.lastname: Liu
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Chung
authors.forename: Yaling
authors.initials: Y
authors.lastname: Liu
authors.forename: Kyong-Hoon
authors.initials: KH
authors.lastname: Lee
mesh_terms: D005455:Fluorescent Antibody Technique / Q000379:methods; D007118:Immunoassay / Q000379:methods*; D046208:Microchip Analytical Procedures / Q000379:methods*; D008839:Microelectrodes; D009169:Mycobacterium tuberculosis / Q000166:cytology*; D012680:Sensitivity and Specificity