US 2022/0178919 A1 · METHOD AND SYSTEM FOR DETECTING ANALYTE OF INTEREST USING MAGNETIC FIELD SENSOR AND MAGNETIC PARTICLES

Abstract

A method, system, and apparatus for the rapid detection of analyte(s) of interest are disclosed which can provide high sensitivity quantification of the analyte concentration in a lateral follow assay. The method includes labeling detection molecules with magnetic particles and immobilizing the magnetic particles on a nitrocellulose membrane upon specific biochemical recognition and binding. An external magnetic field is applied to the magnetic particles to induce magnetic induction, and a magnetoresistance sensor is positioned close to the membrane and magnetic particles. A periodic signal in the sensor is produced when a mechanical oscillatory movement is provided to the membrane relative to the sensor (or vice versa). Triggered time averaging of signals in synchronization with the oscillatory motion enables noise reduction of less than 30 dB and significant improvement of assay sensitivity. An x-y motion program for scanning the test line and control line on the membrane can produce magnetic 2D mapping of the lines, further differentiating the bound particles at the lines from unbound particles in the background, rendering a more accurate assay.

Claims22

Dependent claims

A system comprising:

an apparatus comprising:
at least one permanent magnet;
and
at least one magnetic field sensor at a pole of the at least one permanent magnet and configured to be positioned sufficiently close to a surface of a membrane containing immobilized magnetic particles selectively bound to the analyte such that the magnetic particles are magnetized by the at least one permanent magnet;
a stage mechanically coupled to at least one of the apparatus and the membrane, the stage configured to move at least one of the apparatus and the membrane relative to one another with an oscillatory movement along a first direction substantially parallel to the surface of the membrane;
at least one controller configured to control the oscillatory movement of the stage and to generate first synchronization trigger signals indicative of the oscillatory movement;
and
a data acquisition unit configured to receive sensor signals from the at least one magnetic field sensor and the first synchronization trigger signals from the at least one controller.

5 more elements

A method for qualitative or quantitative measurement of analyte selectively bound to magnetic particles immobilized on a membrane, the method comprising:

providing an assembly comprising at least one permanent magnet and at least one magnetoresistance (MR) sensor attached to one pole of the at least one permanent magnet;
positioning the membrane sufficiently close to the at least one MR sensor such that the magnetic particles are magnetized by an external magnetic field generated by the at least one permanent magnet and the magnetic inductance of the magnetic particles are detected by the at least one MR sensor;
moving, in a periodic oscillation, the membrane relative to the assembly or the assembly relative to the membrane, the periodic oscillation in a first direction substantially parallel to a surface of the membrane;
generating a first trigger signal in synchronization with the periodic oscillation;
acquiring a sensor signal from the at least one MR sensor and averaging the sensor signal over time in synchronization with the periodic oscillation, the acquisition and time averaging being triggered by the trigger signal;
and
obtaining a concentration of the analyte.

4 more elements

A system for qualitative or quantitative measurement of analyte of interest,

wherein magnetic particles selectively bind to analyte and are immobilized on a membrane surface, said membrane is transported to within a close distance to a magnetoresistance sensor, whereby said magnetic particles are magnetized by an external magnetic field generated by a permanent magnet, whereby the magnetic induction of said magnetic particles are measured by said magnetoresistance sensor, and the concentration of analyte is obtained,
said magnetoresistance sensor is attached to one pole of said permanent magnet, forming an assembly,
said membrane moves in a periodic oscillation relative to said assembly of magnetoresistance sensor and permanent magnetic, or alternatively and equally effective,
said assembly of magnetoresistance sensor and permanent magnet moves in a periodic oscillation relative to said membrane,
wherein an electric trigger signal is generated in synchronization with said periodic oscillation movement,
said magnetoresistance sensor signal is acquired and averaged over time in synchronization with said periodic oscillation, said time acquisition and averaging being triggered by said electric trigger signal.

3 more elements

Dependencies are inferred from the claim text.

Method and system for detecting analyte of interest using magnetic field sensor and magnetic particles

Life of this patent

Method and system for detecting analyte of interest using magnetic field sensor and magnetic particles

Life of this patent

Abstract

Claims22