US 2013/0171624 A1Published application

Magnetic Binding Assays Utilizing Time-Resolved Up-Converting Luminescence Detection

OwnerAimin Heinventor

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Abstract

This invention describes a general magnetic binding assay method to detect the presence and quantity of analyte in a sample. The method uses magnetic particles for separating and concentrating analytes of interest from complex samples and use time-resolved up-converting fluorescence detection technique to provide highly sensitive detection without using expensive optical components such as band-pass filters. The method uses pulsed long wavelength light for excitation and time-delayed luminescence detection, resulting in little interferences from sample matrices. Furthermore, the usage of long wavelength excitation light requires simpler sample preparation and clean-up such as removal of red blood cells, which otherwise will significantly interfere with excitation efficiency of the fluorescence probes.

Claims20

Dependent claims

A assay method for detecting the presence or quantity of an analyte in a sample, the assay method comprising:

a. contacting a sample containing the analyte with magnetic particles conjugated with a first specific binding member and a detection probe tagged with a second specific binding member, wherein the detection probe emitting luminescence at a shorter wavelength than the wavelength of an excitation light with a luminescence lifetime of more than 5 μsec, wherein the first specific binding member and the second specific binding member bind different epitopes of the analyte to form a sandwich complex;
b. separate the magnetic particles from the rest of the sample using a magnet device, wherein the magnetic particles include the sandwich complex;
c. exciting the separated magnetic particles using pulsed illumination at a first wavelength to obtain a detection signal by collecting and measuring the luminescence at a second wavelength after a certain period of time has elapsed following each pulse, wherein the second wavelength is shorter than the first wavelength.
d. comparing the detection signal with a calibration curve to obtain the amount of analyte in the sample, wherein the detection signal is proportional to the detection signal.

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Dependencies are inferred from the claim text.