Magnetic search coil for measuring real-time brownian relaxation of magnetic nanoparticles

Patent metadata

Field	Value
Publication number	US-9778225-B2
Application number	US-201113885384-A
Country	US
Kind code	B2
Filing date	Nov 15, 2011
Priority date	Nov 15, 2010
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A device includes an excitation coil, a detector coil, and a processing circuit. The excitation coil is aligned about a volume. The excitation coil is configured to carry a first and second biasing current and generate a magnetic field in the volume. The detector coil is configured to generate an electrical signal based on a detected field within the volume. The detected field is based on the magnetic field. The processing circuit is configured to generate data based on the electrical signal.

First claim

The invention claimed is:

1. A device comprising:
an excitation coil aligned about a volume, the excitation coil configured to carry a first and second biasing current and generate a magnetic field in the volume;
a detector coil configured to generate an electrical signal based on a detected field within the volume, the detected field based on the magnetic field; and
a processor configured to generate data based on the electrical signal, wherein the data is determined by a phase delay between the detected field and the magnetic field of the excitation coil.

2. The device of claim 1 wherein the first biasing current is configured to generate a low frequency modulation of the magnetic field.

3. The device of claim 1 wherein the second biasing current is configured to generate a high frequency modulation of the magnetic field.

4. The device of claim 1 further including a fluid channel in fluid communication with the volume.

5. The device of claim 4 wherein the fluid channel includes a biological duct.

6. The device of claim 1 wherein the processor includes a wireless transceiver.

7. The device of claim 1 wherein the detector coil includes a pair of complementary windings.

8. The device of claim 1 wherein the phase delay correlates to a relaxation time of a specimen in the volume.

9. A method comprising:
generating a plurality of harmonics in a magnetic field about a volume, wherein generating includes delivering excitation to an electrical winding of a coil;
detecting a signal from within the volume, the signal based on excitation from the magnetic field; and
determining a parameter corresponding to the volume and based on the signal, and wherein determining the parameter includes processing to evaluate a delay in phase as to the magnetic field provided by the coil and the magnetic field as to the detected signal.

10. The method of claim 9 wherein generating the plurality of harmonics includes delivering excitation at a first frequency and a second frequency, the first frequency different than the second frequency.

11. The method of claim 9 wherein generating the plurality of harmonics includes delivering low frequency sinusoidal excitation configured to saturate a magnetic nanoparticle in the volume.

12. The method of claim 9 further including delivering a specimen to the volume using a fluidic channel.

13. The method of claim 12 further including labeling a target molecule of the specimen using a magnetic nanoparticle before delivering.

14. The method of claim 9 wherein determining the parameter includes processing to evaluate a plurality of equations.

15. The method of claim 9 wherein determining the parameter includes processing to evaluate magnetic relaxation.

16. The method of claim 9 wherein determining the, parameter includes processing to determine an estimate using a least squares method.

17. The method of claim 9 wherein delivering excitation to the electrical winding includes applying a swept frequency.

Assignees

• Wang Jian-Ping
• Tu Liang
• Univ Minnesota

Inventors

• Wang Jian-Ping
• Tu Liang

Classifications

• G01N27/72 Primary

  by investigating magnetic variables · CPC title

• G01R33/1269 Primary

  of molecules labeled with magnetic beads (magnetic particles for bio assay G01N33/54326) · CPC title

• G01R33/1276

  of magnetic particles, e.g. imaging of magnetic nanoparticles (G01R33/1269 takes precedence) · CPC title

• G01R33/12

  Measuring magnetic properties of articles or specimens of solids or fluids (involving magnetic resonance G01R33/20) · CPC title