Patent ID: 8011228
Filing Date: 2011-09-06
Classification: G01N

Abstract:
1. A lateral flow quantitative assay method comprising: applying a liquid sample that is expected to contain an analyte to one end of a chromatography medium; migrating the liquid sample through the chromatography medium to react the analyte with a labeled detector adsorbed on a section located at a predetermined distance from the sample application site in a sample developed direction, thereby forming an analyte-labeled detector conjugate; migrating the analyte-labeled detector conjugate through the chromatography medium to react the analyte-labeled detector conjugate with an unlabeled captor that is identical to or different from the labeled detector and immobilized on a viewing window defined around a middle portion of the chromatography medium, thereby forming a labeled detector-analyte-unlabeled captor triple conjugate in which the analyte is captured between the labeled detector and the unlabeled captor in a sandwich-like fashion; and measuring an amount of the triple conjugate to quantify the analyte in the liquid sample, wherein the method is characterized in that: (a) the labeled detector is labeled with a fluorescent substance and reacts with the analyte in the liquid sample to form the fluorescently-labeled detector-analyte conjugate; (b) the unlabeled captor is dispensed in lines within a viewing window on the chromatography medium and reacts with the fluorescently-labeled detector-analyte conjugate that has been migrated along the chromatography medium to form the fluorescently-labeled detector-analyte-unlabeled captor triple conjugate; (c) a reference detector, which is different from the detector and the captor and labeled with a fluorescent material identical to that used in labeling the detector and reacts with a reference material in the liquid sample, is adsorbed on the section of the chromatography medium where the fluorescently-labeled detector is adsorbed, and an unlabeled reference captor that reacts with the fluorescently-labeled reference detector is dispensed and immobilized in double reference lines in front of the viewing window on the chromatography medium to provide a reference conjugate of fluorescently-labeled reference detector-reference material-unlabeled reference captor as the liquid sample passes through the chromatography medium; and (d) an amount of the analytes is determined by passing a laser presented from a shape control lens for laser beam through an exciter filter, irradiating the filtered light to the epifluorescence medium containing the triple analyte conjugate and the reference conjugate, passing light reflected from the epifluorescence medium through a collection lens to form parallel light, passing the parallel light through a fluorescent filter to remove scattered incident light and presenting only a pure fluorescence component to a condenser lens to focus the pure fluorescence component to a center of a pinhole, removing light except for the parallel light at the pinhole, presenting the parallel light to an optical detector, transmitting the incident parallel light to a CPU via an analog digital converter (ADC), and comparing a fluorescence intensity of the triple analyte conjugate with a reference fluorescence intensity of the reference conjugate to quantify the analyte.