# US 2014/0191139 A1 · Conjugates of nano-diamond and magnetic or metallic particles

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- Number: US 2014/0191139 A1
- Document ID: US20140191139A1
- Status: Published application
- Kind: A1
- Application number: 14/150,412
- Filed: 2014-01-08
- Published: 2014-07-10
- Earliest claimed: 2011-08-01
- Assignees: The Trustees of Columbia University in the City of New York
- Applicants: The Trustees of Columbia University in the City New York
- Inventors: Dirk R. ENGLUND
- Web page: https://patentgrep.com/patent/US20140191139A1

## CPC

- G01N 21/64: Fluorescence; Phosphorescence
- G01N 21/6428: {Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" (in vivo A61B5/00; immunoassay G01N33/53)}
- G01N 21/643: {non-biological material}
- G01N 21/6458: {Fluorescence microscopy (fluorescence microscopes per se G02B21/0076 and G02B21/16)}
- G01N 33/48728: {Investigating individual cells, e.g. by patch clamp, voltage clamp (investigating individual particles in general G01N15/10)}
- G01N 33/54326: {Magnetic particles}
- G01N 33/585: {with a particulate label, e.g. coloured latex}
- G01N 33/587: {Nanoparticles}
- B82Y 15/00: Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
- G01N 22/00: Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more (G01N3/00 - G01N17/00, G01N24/00 take precedence)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

Techniques for imaging a characteristic of a sample with a plurality of conjugates of diamond-metallic nanoparticles having a nitrogen vacancy center. The plurality of conjugates can be exposed to a sample and the nitrogen vacancy centers can be optically pumped. One or more microwave pulses can be applied to the nitrogen vacancy center, and a fluorescent response can be detected.

## Claims

### Claim 1

A method for imaging a characteristic of a sample, comprising:
providing a plurality of conjugates of diamond-magnetic nanoparticles, one or more of the plurality of conjugates including a diamond nanoparticle having a nitrogen vacancy center;
exposing the plurality of conjugates to the sample;
optically pumping the nitrogen vacancy center;
applying at least one microwave pulse to the nitrogen vacancy center; and
detecting a fluorescent response of the nitrogen vacancy center.

### Claim 2 (depends on 0)

The method of claim 0, wherein the providing further comprises providing at least one diamond nanoparticle bonded to a magnetic nanoparticle by a predetermined distance, the predetermined distance corresponding to a radiative enhancement.

### Claim 3 (depends on 0)

The method of claim 0, wherein optically pumping includes directing a continuous wave of pump light at approximately 532 nm to the nitrogen vacancy center.

### Claim 4 (depends on 0)

The method of claim 0, wherein optically pumping includes applying a pulse of pump light at approximately 532 nm to the nitrogen vacancy center prior to applying the at least one microwave pulse, and applying a pulse of pump light at approximately 532 nm to the nitrogen vacancy center subsequent to applying the at least one microwave pulse.

### Claim 5 (depends on 0)

The method of claim 0, wherein the providing further comprises providing a plurality of conjugates including a nitrogen vacancy center having a different orientation with respect to a corresponding magnetic nanoparticle relative to other conjugates, whereby a component of a magnetic field of the magnetic nanoparticle is exerted along an axis of the nitrogen vacancy center, and whereby a ms=+1 and a ms=+1 spin sublevel of the nitrogen vacancy center experience Zeeman splitting.

### Claim 6 (depends on 5)

The method of claim 5, wherein detecting a fluorescent response further includes detecting emitted photons over area of the sample, the area divided into a set of pixels each corresponding to a subset of the area.

### Claim 7 (depends on 6)

The method of claim 6, wherein detecting emitted photons includes, for each pixel:
applying a first microwave pulse at a first frequency, the first frequency tuned to a field splitting frequency of the nitrogen vacancy center of one of the plurality of conjugates, the field splitting frequency corresponding to the ms=+1 spin sublevel;
measuring a first intensity of a first fluorescent response based on the first frequency;
applying a second microwave pulse at a second frequency, the second frequency tuned to a zero field splitting frequency of the nitrogen vacancy center of the one of the plurality of conjugates;
measuring a second intensity of a second fluorescent response based on the second frequency;
applying at least a third microwave pulse at a second frequency, the third frequency tuned to a field splitting frequency of the nitrogen vacancy center of the one of the plurality of conjugates, the field splitting frequency corresponding to the ms=−1 spin sublevel;
measuring at least a third intensity of a third fluorescent response based on the second frequency;
determining a location of the nitrogen vacancy center based on the first, second and third intensities.

### Claim 8 (depends on 7)

The method of claim 7, wherein determining the location includes subtracting the first and second intensities from the first intensity.

### Claim 9 (depends on 7)

The method of claim 7, wherein the characteristic of the sample is magnetic field and further comprising determining a local magnetic field a the location of the nitrogen vacancy center based on the first, second, and third intensities.

### Claim 10 (depends on 0)

The method of claim 0, wherein the providing further comprises providing one or more conjugates bound to a biological molecule.

### Claim 11 (depends on 0)

The method of claim 0, wherein the characteristic of the sample is pH concentration, and further comprising determining, based on the fluorescent response, a rate of ionization or reduction of the nitrogen vacancy center.

### Claim 12 (depends on 0)

The method of claim 0, wherein the characteristic of the sample is electric field, and further comprising determining, based on the fluorescent response, a rate of switching between different charge states of the nitrogen vacancy center.

### Claim 13

A nanoparticle diamond-metal conjugate prepared by the method, comprising:
depositing a monolayer of diamond nanoparticles having approximately a predetermined radius on a substrate, one or more of the diamond nanoparticles having a nitrogen vacancy center;
etching the surface of the substrate to a depth greater than the predetermined radius;
depositing a layer of metal having a predetermined thickness over the monolayer of diamond nanoparticles, the predetermined thickness corresponding to a radiative enhancement rate of the nitrogen vacancy center based on the predetermined radius of the diamond nanoparticles; and
transferring the metal-covered diamond nanoparticles to a second substrate.

### Claim 14 (depends on 13)

The nanoparticle diamond-metal conjugate of claim 13, wherein the depositing a layer of metal comprises depositing a metal selected from the group consisting of gold, silver, or a combination thereof.

### Claim 15 (depends on 13)

The nanoparticle diamond-metal conjugate of claim 13, wherein the depositing a layer of metal comprises depositing a magnetic layer.

### Claim 16 (depends on 15)

The nanoparticle diamond-metal conjugate of claim 15, wherein the depositing a layer of metal comprises depositing a metal selected from the group consisting of nickel, cobalt, iron, or chemical compounds thereof.

### Claim 17 (depends on 13)

The nanoparticle diamond-metal conjugate of claim 13, wherein depositing a layer of metal includes depositing the layer of metal at an angle.

### Claim 18

A nanoparticle diamond-metal conjugate prepared by the method, comprising:
preparing a surface of diamond nanoparticles with an acid treatment, one or more of the diamond nanoparticles having a nitrogen vacancy center;
treating the diamond nanoparticles with one or more amino-terminated silanes to provide an amine on the surface of the diamond nanoparticles;
preparing a surface of metal nanoparticles with a molecule, the molecule having an affinity to bond with the amine; and
mixing the diamond nanoparticles and metal nanoparticles in a solution, whereby the molecule of the surface of the metal nanoparticles bonds to the amine of the surface of the diamond nanoparticles, thereby forming a diamond-metal conjugate.

### Claim 19 (depends on 18)

The nanoparticle diamond-metal conjugate of claim 18, wherein the treating further comprises selecting an amine with a length corresponding to a radiative enhancement rate of the nitrogen vacancy center.

### Claim 20 (depends on 18)

The nanoparticle diamond-metal conjugate of claim 18, wherein the preparing further comprises preparing a surface of metal nanoparticles selected from the group consisting of gold, silver, or a combination thereof.

### Claim 21 (depends on 18)

The nanoparticle diamond-metal conjugate of claim 18, wherein the preparing further comprises preparing a surface of magnetic nanoparticles.

### Claim 22 (depends on 21)

The nanoparticle diamond-metal conjugate of claim 21, wherein the preparing further comprises preparing a surface of metal nanoparticles selected from the group consisting of nickel, cobalt, iron, or chemical compounds thereof.

### Claim 23

A nanoparticle diamond-metal conjugate prepared by the method using a DNA strand, comprising:
preparing a surface of diamond nanoparticles with an acid treatment, one or more of the diamond nanoparticles having a nitrogen vacancy center;
adapting the surface of at least one of the diamond nanoparticles to link to a first end of the DNA strand;
providing metal nanoparticles, at least one of the metal nanoparticles adapted to link to a second end of the DNA strand;
mixing the diamond nanoparticles and the metal nanoparticles in solution with at least the DNA strand.

### Claim 24 (depends on 23)

The nanoparticle diamond-metal conjugate of claim 23, wherein the DNA strand comprises a DNA strand having a length corresponding to a radiative enhancement rate of the nitrogen vacancy center.

### Claim 25 (depends on 23)

The nanoparticle diamond-metal conjugate of claim 23, wherein the providing further comprises providing metal nanoparticles selected from the group consisting of gold, silver, or a combination thereof.

### Claim 26 (depends on 23)

The nanoparticle diamond-metal conjugate of claim 23, wherein the providing further comprises providing magnetic nanoparticles.

### Claim 27 (depends on 26)

The nanoparticle diamond-metal conjugate of claim 26, wherein the providing further comprises providing metal nanoparticles selected from the group consisting of nickel, cobalt, iron, or chemical compounds thereof.