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