Method and apparatus for making measurements of accumulations of magnetically susceptible particles combined with analytes

• US 6,927,570 B2
• Filed: 07/22/2003
• Issued: 08/09/2005
• Est. Priority Date: 11/21/1997
• Status: Expired due to Term

• Current Assignee: Quantum Design International, Inc.
• Original Assignee: Quantum Design, Inc.
• Inventors: Diederichs, Jost Hermann, Jensen, Kurt Gordon, Black, Randall Christopher, Simmonds, Michael Bancroft
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US10/625,720
• Publication Number:
  US 20040150396A1
• Time in Patent Office: 749 Days
• Field of Search: 324/201, 324/204, 324/225, 324/226, 324/237, 324/71.4, 324232-234, 324/236, 324/243, 324/239, 422/68.1, 436/526
• US Class Current: 324/239
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01N 27/745 for detecting magnetic beads used in biochemical assays concerning the assays G01N33/54326; sensors therefor G01R33/1269; automatic analysers therefor G01N35/0098
• CPC Class Codes: G01N 35/0098 involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C
• CPC Class Codes: G01R 33/12 Measuring magnetic properties of articles or specimens of solids or fluids involving magnetic resonance G01R33/20
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/838 Magnetic property of nanomaterial
• CPC Class Codes: Y10S 977/96 Of magnetic property

Abstract

An apparatus is provided for quantitatively measuring samples whose amount or other characteristic quality is to be determined. The samples are arranged in a predefined pattern and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one substantially flat sensor such as sensing coils fabricated in a gradiometer configuration.

Claims

1. An apparatus for quantitative magnetic measurement of samples, each sample arranged in a predefined pattern and disposed in a sample holder, comprising:

a magnetic field source to apply a magnetic field to the sample, the magnetic field source defining a gap in which a sample holder is movably disposed;

a substantially flat magnetic field sensor to sense an induced magnetic moment from the sample and configured and arranged in a gradiometer configuration to substantially eliminate the contribution of the magnetic field source to the sensing, the magnetic field sensor having a sensing area substantially the same as the extent of each sample, the magnetic field sensor having an output to communicate output signals to provide quantity of the samples in the pattern, the magnetic field sensor disposed substantially within the gap of the magnetic field source.