Membrane-Based Assay Devices that Utilize Time-Resolved Fluorescence
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Abstract
A membrane-based assay device for detecting the presence or quantity of an analyte residing in a test sample is provided. The device utilizes time-resolved fluorescence to detect the signals generated by excited fluorescent labels. Because the labels can have relatively long emission lifetime, short-lived background interference can be practically eliminated through delayed fluorescence detection. In addition, the resulting fluorescent reader can have a simple and inexpensive design. For instance, in one embodiment, the reader can utilize a silicon photodiode and a pulsed light-emitting diode (LED) to accurately excite labels and detect fluorescence on a membrane-based assay device without requiring the use of expensive components, such as monochromators or narrow emission band width optical filters.
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Citations
73 Claims
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1-42. -42. (canceled)
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43. A system for detecting the presence or quantity of analyte residing in a test sample, the system comprising:
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a flow-through assay device, the flow-through assay device comprising a porous membrane in fluid communication with a conjugate pad, the conjugate pad including probes comprising particles modified with a specific binding member configured to bind with the analyte and containing a fluorescent label, said fluorescent label having a fluorescence emission lifetime of greater than about 1 microsecond, said porous membrane defining a detection zone within which is immobilized a capture reagent configured to bind with the analyte, said porous membrane defining a calibration zone positioned downstream from the detection zone within which is immobilized a capture reagent configured to bind with the probes; a pulsed excitation source configured to subject the detection zone to pulses of illumination to generate a detection signal; a time-gated detector configured to measure the intensity of the detection signal after a certain period of time has elapsed following a pulse of illumination, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal as calibrated by a calibration signal. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
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Specification