High throughput characterization of individual magnetic nanoparticles

Patent metadata

Field	Value
Publication number	US-2020048084-A1
Application number	US-201716343590-A
Country	US
Kind code	A1
Filing date	Oct 27, 2017
Priority date	Oct 28, 2016
Publication date	Feb 13, 2020
Grant date	—

Abstract

Technologies related to parallel characterization of individual MNPs are disclosed. A diamond chip with MNPs distributed thereon may be used with an epifluorescence microscope and camera to generate multiple different images of multiple individual MNPs. The multiple images are recorded at different microwave frequencies and under different external magnetic field strengths. The multiple images are then used to determine properties of the multiple individual MNPs.

First claim

1 . An apparatus for high throughput characterization of individual Magnetic Nanoparticles (MNPs), the apparatus comprising:
a diamond chip doped with a layer of nitrogen vacancy (NV) color centers; one thousand or more MNPs, wherein the MNPs are distributed either on the diamond chip or on a substrate layer on the diamond chip; a laser generator to direct a laser beam at the diamond chip; a controllable-frequency microwave antenna positioned proximal to the MNPs; a controllable-strength magnetic field generator positioned to generate a magnetic field at the MNPs; and a camera to record fluorescence images, of fluorescence generated by the NV color centers in response to stimulation by the laser beam, wherein the fluorescence recorded in a fluorescence image is modulated by magnetic resonance of the MNPs, and wherein the magnetic resonance is responsive to stimulation by the controllable-frequency microwave antenna under the magnetic field generated by the controllable-strength magnetic field generator.

2 . The apparatus of claim 1 , wherein the camera comprises a sCMOS camera.

3 . The apparatus of claim 1 , wherein the laser beam comprises a laser beam with a wavelength in the range of 500-600 nanometers.

4 . The apparatus of claim 1 , wherein the laser beam is directed at a side of the diamond chip at a glancing angle.

5 . The apparatus of claim 1 , wherein the controllable-strength magnetic field generator is adapted to generate a magnetic field between ±200 mT.

6 . The apparatus of claim 1 , wherein the layer of NV color centers is about 200 nanometers thick.

7 . The apparatus of claim 1 , further comprising protective layers of silver and sapphire deposited on the diamond chip.

8 . A method for high throughput characterization of individual Magnetic Nanoparticles (MNPs), comprising:
distributing one thousand or more MNPs on a diamond chip or on a substrate layer positionable on the diamond chip, wherein the diamond chip is doped with a layer of nitrogen vacancy (NV) color centers; positioning the diamond chip and MNPs, or the substrate layer and MNPs, in an epifluorescence microscope, wherein the epifluorescence microscope comprises a camera or is coupled with a camera; and recording, by the camera, fluorescence images at multiple different microwave frequencies, wherein the fluorescence images record fluorescence modulated by magnetic resonance of the MNPs, wherein each fluorescence image comprises multiple pixels, and wherein at least a first pixel in each fluorescence image records fluorescence modulated by magnetic resonance of a first individual MNP, and wherein at least a second pixel in each fluorescence image records fluorescence modulated by magnetic resonance of a second individual MNP.

9 . The method of claim 8 , further comprising setting a magnetic field strength for the fluorescence images.

10 . The method of claim 8 , further comprising calculating a resonant microwave frequency, and wherein the multiple different microwave frequencies comprise microwave frequencies above and below the resonant microwave frequency.

11 . The method of claim 8 , further comprising creating a magnetic field map from the fluorescence images.

12 . The method of claim 11 , further comprising identifying isolated magnetic features in the magnetic field map in order to identify individual MNPs.

13 . The method of claim 12 , further comprising modifying a magnetic field strength at the MNPs, recording additional fluorescence images, and using the fluorescence images and the additional fluorescence images to form magnetization curves for at least the first individual MNP and the second individual MNP.

14 . The method of claim 13 , further comprising using the magnetization curves to populate a histogram of coercivity, remanent magnetization, or saturation magnetization of the first individual MNP or the second individual MNP.

15 . The method of claim 13 , further comprising mechanically sorting the first individual MNP and the second individual MNP into different groups according to properties characterized by the magnetization curves.

16 . The method of claim 8 , wherein the fluorescence images comprise a field of view of about 200×200 micrometers.

17 . The method of claim 8 , wherein distributing the MNPs comprises:
drop casting a dilute MNP suspension in polymethylmethacrylate (PMMA); spin coating a dilute MNP suspension in a polymer matrix; or lithographically defining an array of holes in a mask, dispersing MNPs over the mask, and removing the mask.

Assignees

• Stc Unm

Inventors

• Acosta Victor
• Jarmola Andrejs

Classifications

• B82B3/009 Primary

  Characterizing nanostructures, i.e. measuring and identifying electrical or mechanical constants · CPC title

• G01R33/1269

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

• G01N15/1031

  by measuring electrical or magnetic effects · CPC title

• G01R33/1223 Primary

  Measuring permeability, i.e. permeameters (G01R33/14 takes precedence) · CPC title

• G01R33/1276

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