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Researchers Submit Patent Application, "Conjugates of Nano-Diamond and Magnetic Or Metallic Particles", for Approval

July 31, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventor ENGLUND, Dirk R. (New York, NY), filed on January 8, 2014, was made available online on July 17, 2014.

The patent's assignee is The Trustees of Columbia University in the City of New York.

News editors obtained the following quote from the background information supplied by the inventors: "The disclosed subject matter relates generally to techniques for fabricating conjugates of nano-diamond and magnetic or metallic particles for use in imaging and sensing applications.

"Fluorescent biomarkers are used in a wide range of applications in biology, chemistry, and other fields. Certain biomarkers can have brightness approximately around an order of magnitude of less than 10 5 counts/sec, can bleach, blink, or degrade during excitation, and/or are toxic to cells. Optical probes that are non-toxic and efficient and stable light emitters are desirable to sensing in biology and medicine.

"Additionally, resolution for imaging with conventional fluorescent biomarkers can be limited by the optical diffraction limit of

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"Accordingly, techniques providing resolution below the diffraction limit are also desirable."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "In one aspect of the disclosed subject matter, a method for imaging a characteristic of sample includes providing a plurality of conjugates of diamond-magnetic nanoparticles, one or more of which including a nitrogen vacancy center. The conjugates can be exposed to the sample. The nitrogen vacancy centers can be pumped with a pump light and one or more microwave pulses can be applied. The fluorescent response of the nitrogen vacancy center can then be detected.

"In one embodiment, the diamond-magnetic conjugates can include a diamond nanoparticle coupled to a magnetic nanoparticle at a predetermined distance corresponding to a radiative enhancement. Additionally or alternatively, the individual diamond-magnetic conjugates can have a variety of alignments between the magnetic field of the magnetic nanoparticle and the axis of a nitrogen vacancy center in the diamond nanoparticle.

"In one embodiment, optically pumping can include directing a continuous wave of pump light. Alternatively, optically pumping can include applying a pulse of pump light prior to applying the at least one microwave pulse and applying an additional pulse of pump light subsequent to applying the at least one microwave pulse.

"In one embodiment, detecting a fluorescent response can include detecting emitted photons over an area of the sample. The area of the sample can be divided into a set of pixels. For each pixel, a first, second, and third microwave pulse can be applied and the intensity of a corresponding fluorescent response can be measured. The first frequency can be tuned to a field splitting frequency of the nitrogen vacancy center of one of the conjugates and can correspond to the m.sub.s=+1 spin sublevel. The second frequency can be tuned to the zero filed splitting frequency of the nitrogen vacancy center of the nitrogen vacancy center. The third frequency can be tuned to a field splitting frequency of the nitrogen vacancy center of the nitrogen vacancy center. The location of the nitrogen vacancy center can be determined based on the first, second, and third intensities.

"In one embodiment, the characteristic of the sample can be magnetic field. For example, a local magnetic field at the location of the nitrogen vacancy center can be determined based on a first, second, and third intensity measurement corresponding to a first, second, and third microwave pulse. Additionally or alternatively, the characteristic of the sample can be pH concentration. For example, the pH concentration can be inferred from, based on the fluorescence response, a determined rate of ionization or reduction of the nitrogen vacancy center. Additionally or alternatively, the characteristic of the sample can be electric field. For example, the electric field can be inferred from, based on the fluorescent response, a determined rate of switching between different charge states of the nitrogen vacancy center. In certain embodiments, the diamond-magnetic conjugates can be bound to a biological molecule.

"In another aspect of the disclosed subject matter, a method for fabricating diamond-metal conjugates can include depositing a monolayer of diamond nanoparticles having a predetermined radius on a substrate. The surface of the substrate can be etched to a depth greater than the predetermined radius of the diamond nanoparticles. A layer of metal having a predetermined thickness can be deposited over the monolayer of diamond nanoparticles. The predetermined thickness can correspond to a radiative enhancement rate of a nitrogen vacancy center in a diamond nanoparticle. The metal-covered diamond nanoparticles can be transferred to a second substrate.

"In certain embodiments, the metal layer can include gold, silver, or a combination thereof. Additionally or alternatively, the metal layer can include a metallic metal, for example nickel, cobalt, iron, and/or chemical compounds thereof. In one embodiment, the layer of metal can be deposited at an angle.

"In another aspect of the disclosed subject matter, a method for fabricating diamond-metal conjugates can include preparing a surface of diamond nanoparticles with an acid treatment. The diamond nanoparticles can undergo silanization with amino-terminated silanes to provide an amine on the surface of the diamond nanoparticles. A surface of the metal nanoparticles can be prepared with a molecule, the molecule having an affinity to bond with the amine. The diamond nanoparticles and metal nanoparticles can be mixed in a solution, whereby the molecule of the surface of the metal nanoparticles can bond to the amine of the surface of the diamond nanoparticles, thereby forming a diamond-metal conjugate.

"In one embodiment, the amine is an amine with a length corresponding to a radiative enhancement rate of a nitrogen vacancy center in a diamond nanoparticle. In certain embodiments, the metal nanoparticles can include gold, silver, or a combination thereof. Additionally or alternatively, the metal nanoparticles can include a metallic metal, for example nickel, cobalt, iron, and/or chemical compounds thereof.

"In another aspect of the disclosed subject matter, a method for fabricating diamond-metal conjugates can include preparing a surface of diamond nanoparticles with an acid treatment. The surface of at least one of the diamond nanoparticles can be adapted to link to a first end of a DNA strand. Metal nanoparticles adapted to link to a second end of the DNA strand can be provided. The diamond nanoparticles and the metal nanoparticles can be mixed in solution with the DNA strand.

"In one embodiment, the DNA strand can have a length corresponding to a radiative enhancement rate of the nitrogen vacancy center of a diamond nanoparticle. In certain embodiments, the metal nanoparticles can include gold, silver, or a combination thereof. Additionally or alternatively, the metal nanoparticles can include a metallic metal, for example nickel, cobalt, iron, and/or chemical compounds thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 is a diagram showing a nitrogen-vacancy (NV) center in diamond.

"FIG. 2 is a block diagram of a conjugate of a diamond nanoparticle and a metallic nanoparticle in accordance with an embodiment of the disclosed subject matter;

"FIG. 3 is a flow diagram illustrating a process of fabricating a diamond-metal conjugate in accordance with one embodiment of the disclosed subject matter.

"FIG. 4 is a flow diagram illustrating a process of fabricating a diamond-metal conjugate in accordance with another embodiment of the disclosed subject matter.

"FIG. 5 is a flow diagram illustrating a process of fabricating a diamond-metal conjugate in accordance with another embodiment of the disclosed subject matter.

"FIG. 6 is a flow diagram illustrating a method for imaging a characteristic of a sample in accordance with an embodiment of the disclosed subject matter.

"FIG. 7 is a flow diagram illustrating a method for imaging a characteristic of a sample in accordance with another embodiment of the disclosed subject matter.

"FIG. 8 is a schematic diagram of a system for imaging a characteristic of a sample in accordance with another embodiment of the disclosed subject matter.

"Throughout the drawings, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the disclosed subject matter will now be described in detail with reference to the Figs., it is done so in connection with the illustrative embodiments."

For additional information on this patent application, see: ENGLUND, Dirk R. Conjugates of Nano-Diamond and Magnetic Or Metallic Particles. Filed January 8, 2014 and posted July 17, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5044&p=101&f=G&l=50&d=PG01&S1=20140710.PD.&OS=PD/20140710&RS=PD/20140710

Keywords for this news article include: Emerging Technologies, Nanoparticle, Nanotechnology, Nitrogen, The Trustees of Columbia University in the City of New York.

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Source: Politics & Government Week


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