Immunoassay method and device with magnetically susceptible bead capture
First Claim
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1. A magnetic immunosensing device for detecting an analyte in a sample, comprising:
- a sample entry port for receiving the sample,a sample entry chamber in fluid communication with the sample entry port;
a dry reagent comprising magnetically susceptible beads coated with an antibody to the analyte in the sample, wherein the dry reagent is present in the device as a coating in the sample entry port or the sample entry chamber, and is dissolved into the sample upon receiving the sample in the sample entry port or the sample entry chamber;
a first conduit comprising a first portion in fluid communication with the sample entry chamber;
a substantially planar chip positioned in a second portion of the conduit in fluid communication with the first portion of the first conduit, the chip comprising;
a sensing electrode positioned in the second portion of the first conduit to detect activity of an electroactive species caused by binding of the analyte to the antibody and generate a sensor response; and
a conductivity sensor positioned in the second portion of the first conduit and adjacent to the sensing electrode to monitor a position of the sample within the second portion of the first conduit relative to the sensing electrode;
a sample diaphragm in communication with the sample entry chamber via a second conduit, wherein the sample diaphragm is capable of forcing air through the second conduit causing the sample and the beads to move from the sample entry chamber into the second portion of the first conduit and over the chip;
an analyzer comprising a motor driven plunger to move the sample through the conduit, wherein the analyzer is in contact with the sample diaphragm; and
a magnet that is either a permanent magnet or an electromagnet having a magnetic field of greater than 0.1 Tesla, wherein the magnet is positioned proximate to the chip for attracting the beads in the second portion of the first conduit substantially proximate to the sensing electrode and substantially retaining the beads at the sensing electrode surface during removal of unbound sample and washing of the sensing electrode with a wash fluid.
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Abstract
The present invention provides apparatus and methods for the rapid determination of analytes in liquid samples by immunoassays incorporating magnetic capture of beads on a sensor capable of being used in the point-of-care diagnostic field.
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Citations
34 Claims
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1. A magnetic immunosensing device for detecting an analyte in a sample, comprising:
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a sample entry port for receiving the sample, a sample entry chamber in fluid communication with the sample entry port; a dry reagent comprising magnetically susceptible beads coated with an antibody to the analyte in the sample, wherein the dry reagent is present in the device as a coating in the sample entry port or the sample entry chamber, and is dissolved into the sample upon receiving the sample in the sample entry port or the sample entry chamber; a first conduit comprising a first portion in fluid communication with the sample entry chamber; a substantially planar chip positioned in a second portion of the conduit in fluid communication with the first portion of the first conduit, the chip comprising; a sensing electrode positioned in the second portion of the first conduit to detect activity of an electroactive species caused by binding of the analyte to the antibody and generate a sensor response; and a conductivity sensor positioned in the second portion of the first conduit and adjacent to the sensing electrode to monitor a position of the sample within the second portion of the first conduit relative to the sensing electrode; a sample diaphragm in communication with the sample entry chamber via a second conduit, wherein the sample diaphragm is capable of forcing air through the second conduit causing the sample and the beads to move from the sample entry chamber into the second portion of the first conduit and over the chip; an analyzer comprising a motor driven plunger to move the sample through the conduit, wherein the analyzer is in contact with the sample diaphragm; and a magnet that is either a permanent magnet or an electromagnet having a magnetic field of greater than 0.1 Tesla, wherein the magnet is positioned proximate to the chip for attracting the beads in the second portion of the first conduit substantially proximate to the sensing electrode and substantially retaining the beads at the sensing electrode surface during removal of unbound sample and washing of the sensing electrode with a wash fluid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A kit for performing an analyte immunoassay in a whole blood sample, comprising:
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a magnetic immunosensing device comprising; a sample entry port for receiving the sample, a sample entry chamber in fluid communication with the sample entry port; a dry reagent comprising magnetically susceptible beads coated with an antibody to the analyte in the sample, wherein the dry reagent is present in the device as a coating in the sample entry port or the sample entry chamber, and is dissolved into the sample upon receiving the sample in the sample entry port or the sample entry chamber; a first conduit comprising a first portion in fluid communication with the sample entry chamber; a substantially planar chip positioned in a second portion of the conduit in fluid communication with the first portion of the first conduct, the chip comprising; a sensing electrode positioned in the second portion of the conduit to detect activity of an electroactive species caused by binding of the analyte to the antibody and generate a sensor response; a conductivity sensor positioned in the second portion of the first conduit and adjacent to the sensing electrode to monitor a position of the sample within the second portion of the first conduit relative to the sensing electrode; a sample diaphragm in communication with the sample entry chamber via a second conduit, wherein the sample diaphragm is capable of forcing air through the second conduit causing the sample and the beads to move from the sample entry chamber into the second portion of the first conduit and over the chip; an analyzer comprising a motor driven plunger to move the sample through the conduit, wherein the analyzer is in contact with the sample diaphragm; a magnet that is either a permanent magnet or an electromagnet having a magnetic field of greater than 0.1 Tesla, wherein the magnet is positioned proximate to the chip for attracting the beads substantially proximate to the sensing electrode and substantially retaining the beads at the sensing electrode surface; and a reader for receiving the immunosensor cartridge and comprising; a motor driven plunger to apply pressure to the sample diaphragm and force the air through the second conduit causing the sample and the beads to move from the sample entry chamber into the second portion of the first conduit and over the chip; and an electrical contact to receive the sensor response from the sensing electrode, wherein the reader is capable of determining a concentration of the analyte from the sensor response. - View Dependent Claims (29, 30, 31, 32, 33, 34)
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Specification