Method for the detection of lateral flow assay and strip and laser-induced epifluorescence and compact scanner therefor
Inventors
Nahm, Kie-Bong • Choi, Eui-Yeol • Kim, Jae-hoon
Assignees
BIO-MED PHOTONICS Co Ltd • Boditech Med Inc • Bio Med Photonics Co Ltd
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Publication Number
US-8011228-B2
Publication Date
2011-09-06
Expiration Date
Abstract
Disclosed is a lateral flow quantitative assay method capable of quantitatively determining the concentration and analyzing the spatial distribution of a disease marker by employing the principle of the laser-induced fluorescence detection technique, which is based on detecting emitted fluorescence when laser light is focused to the disease marker deposited onto a lateral flow quantitative assay chip. The present invention discloses a strip, a laser-induced epifluorescence detection device and a small scanner for the assay method. The present assay method is advantageous in terms of allowing quantitative point-of-care diagnostics in hospitals, being capable of specifically detecting a disease marker by optimizing a lateral flow assay biochip for diagnosis of a specific disease, allowing more accurate quantitative analysis of analytes, and being capable of simultaneously analyzing several cancer markers, reducing the hook effect and expanding the detection range and accurately measuring concentration of analytes.
Core Innovation
A lateral flow quantitative assay method applies a liquid sample expected to contain an analyte to one end of a chromatography medium. The liquid sample migrates through the chromatography medium to react the analyte with a labeled detector adsorbed at a predetermined distance from the sample application site in a sample developed direction, thereby forming an analyte-labeled detector conjugate. The analyte-labeled detector conjugate further migrates to react with an unlabeled captor immobilized on a viewing window, thereby forming a labeled detector-analyte-unlabeled captor triple conjugate in a sandwich-like fashion. An amount of the analyte is quantified by measuring the amount of the triple conjugate.
The method is characterized in that the labeled detector is labeled with a fluorescent substance and forms a fluorescently-labeled detector-analyte conjugate. The unlabeled captor is dispensed in lines within the viewing window on the chromatography medium and reacts with the fluorescently-labeled detector-analyte conjugate to form the fluorescently-labeled detector-analyte-unlabeled captor triple conjugate. A reference detector different from the detector and the captor is labeled with a fluorescent material identical to that used for labeling the detector, reacts with a reference material in the liquid sample, and is adsorbed where the fluorescently-labeled detector is adsorbed. An unlabeled reference captor is dispensed and immobilized in double reference lines in front of the viewing window to provide a reference conjugate of fluorescently-labeled reference detector-reference material-unlabeled reference captor as the liquid sample passes through the chromatography medium.
Quantification is performed by passing a laser presented from a shape control lens through an exciter filter and irradiating filtered light to an epifluorescence medium containing the triple analyte conjugate and the reference conjugate. Light reflected from the epifluorescence medium is passed through a collection lens to form parallel light, and the parallel light is passed through a fluorescent filter to remove scattered incident light. The pure fluorescence component is focused to a center of a pinhole using a condenser lens, leaving parallel light at the pinhole for measurement by an optical detector. The incident parallel light is transmitted to a CPU via an analog digital converter (ADC), and the fluorescence intensity of the triple analyte conjugate is compared with the reference fluorescence intensity of the reference conjugate to quantify the analyte.
Claims Coverage
The partial content provides three independent claims (clm-00001, clm-00005, clm-00009). Across these independent claims, the inventive features center on a fluorescent lateral flow quantitative assay with a triple-conjugate sandwich and double reference lines, fluorescence comparison against a reference conjugate, and a laser-induced epifluorescence measurement arrangement in a strip and scanner format.
Fluorescent triple-conjugate sandwich on a viewing window with double reference lines
A lateral flow quantitative assay method in which a liquid sample migrates through a chromatography medium to form a labeled detector-analyte-unlabeled captor triple conjugate on a viewing window, while a reference detector and an unlabeled reference captor are provided using double reference lines in front of the viewing window to form a reference conjugate as the sample passes through the chromatography medium.
Fluorescence intensity comparison between triple analyte conjugate and reference conjugate
The method determines an analyte amount by comparing a fluorescence intensity of the triple analyte conjugate with a reference fluorescence intensity of the reference conjugate, where the labeled detector is labeled with a fluorescent substance and the reference detector is labeled with fluorescent material identical to that used in labeling the detector.
Laser-induced epifluorescence optical train with pinhole selection and CPU/ADC comparison
Quantification uses laser irradiation of an epifluorescence medium containing the triple analyte conjugate and reference conjugate, followed by collection optics to form parallel light, a fluorescent filter to remove scattered incident light, focusing of a pure fluorescence component to a center of a pinhole, optical detection of the parallel light at the pinhole, transmission of incident parallel light to a CPU via an ADC, and fluorescence intensity comparison to quantify the analyte.
Lateral flow quantitative assay strip with fluorescent detector and reference conjugate formation
A lateral flow quantitative assay strip including a backing, a sample pad, a conjugate releasing pad with a fluorescently labeled detector releasably attached, a chromatography medium with a captor immobilized and sandwich conjugate formation, and an absorption pad; the strip further includes captor lines within a viewing window and double reference lines with an unlabeled reference captor to form both the fluorescently-labeled detector-analyte-unlabeled captor conjugate and a reference conjugate as the liquid sample passes.
Small integrated scanner for laser-induced epifluorescence quantitative analysis in a single body
A small scanner integrated with a laser-induced epifluorescence detection device in a single body, including a strip in a cartridge and a structured optical system arranged to irradiate an epifluorescence medium containing triple analyte conjugate and reference conjugate, focus fluorescence to a pinhole, remove light except for parallel light at the pinhole, detect optical signal, transmit to the CPU via ADC, and determine analyte amount by comparing fluorescence intensity of triple conjugate with reference conjugate.
Across the independent claims, the core claim coverage is directed to fluorescent lateral flow quantitative assays that form a triple conjugate on a viewing window while producing a separate reference conjugate via double reference lines, and to determining analyte amount by comparing fluorescence intensities. The claims also require a laser-induced epifluorescence measurement scheme using filtered irradiation, optical focusing to a pinhole, optical detection, and CPU/ADC processing. Independent clm-00005 additionally specifies the strip architecture for the fluorescent detector and reference conjugate formation.
Stated Advantages
Documented Applications
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