Method for detecting small molecule analytes using magnetoresistant sensors

Abstract

Small molecule analytes (less than 1000 Daltons) in a fluid sample are detected using a competitive assay in a magnetic biosensor. The fluid sample is added to a biosensor detection chamber together with detection probes and magnetic tags which bind to the detection probes. The magnetic biosensor is functionalized with a capture probe that shares an epitope with the analytes, and the detection probe is capable of binding the epitope shared by the analytes and the capture probe, so that the presence of the analyte prevents detection probes (and magnetic tags) from binding to the biosensor. By measuring the binding of the magnetic tags to the magnetic biosensor, an amount of analytes in the solution is determined.

1 . A method for detection of analytes in a fluid sample using direct binding in a magnetic biosensor, the method comprising:
 adding the fluid sample containing the analytes and magnetic tags to the magnetic biosensor, wherein the analytes have weights less than 1000 Daltons;   wherein the magnetic biosensor is functionalized with a capture probe that changes conformation upon binding to the analytes;   wherein the conformation changes enable the capture probe to bind to the magnetic tags;   measuring binding of the magnetic tags bound to the capture probes of the magnetic biosensor;   determining an amount of analytes in the solution from the measured binding of the magnetic tags to the capture probes.