# US 9,040,158 B2 · Generic approach for synthesizing asymmetric nanoparticles and nanoassemblies

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- Number: US 9,040,158 B2
- Document ID: US9040158B2
- Status: Granted
- Kind: B2
- Application number: 13/621,992
- Filed: 2012-09-18
- Published: 2014-03-20
- Granted: 2015-05-26
- Earliest claimed: 2012-09-18
- Assignees: Uchicago Argonne, LLC
- Applicants: UChicago Argonne, LLC
- Inventors: Yugang Sun; Yongxing Hu
- Web page: https://patentgrep.com/patent/US9040158B2

## CPC

- H01F 1/0054: {Coated nanoparticles, e.g. nanoparticles coated with organic surfactant}
- B22F 1/054: Nanosized particles
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C22C 2202/02: Magnetic
- Y10S 977/773: Nanoparticle, i.e. structure having three dimensions of 100 nm or less
- Y10S 977/81: Of specified metal or metal alloy composition
- Y10S 977/89: Deposition of materials, e.g. coating, cvd, or ald
- Y10T 428/2991: Coated
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A generic route for synthesis of asymmetric nanostructures. This approach utilizes submicron magnetic particles (Fe3O4—SiO2) as recyclable solid substrates for the assembly of asymmetric nanostructures and purification of the final product. Importantly, an additional SiO2 layer is employed as a mediation layer to allow for selective modification of target nanoparticles. The partially patched nanoparticles are used as building blocks for different kinds of complex asymmetric nanostructures that cannot be fabricated by conventional approaches. The potential applications such as ultra-sensitive substrates for surface enhanced Raman scattering (SERS) have been included.

## Claims

### Claim 1

A method of making asymmetric nanostructures with the use of a colloidal magnetic particle as a reactor, comprising:
providing a superparamagnetic core;
coating the magnetic core with a shell layer;
associating a plurality of a first component with the coated magnetic core;
adding a mediation layer, the thickness of the mediation layer being less than the diameter of at least a subset the plurality of first component, each first component in the subset having an exposed portion outside of the mediation layer;
modifying each exposed portion;
removing the shell layer and mediation layer; and
forming the asymmetric nanostructures, which comprise the first component and a second component.

### Claim 2 (depends on 1)

The method of claim 1, wherein the modifying each first component comprises modifying the exposed portion with a molecule that can specifically bind with the second component.

### Claim 3 (depends on 1)

The method of claim 1, wherein the modifying each first component comprises overgrowing the exposed portion to enlarge each first component in the subset.

### Claim 4 (depends on 1)

The method of claim 1, wherein the mediation layer is amorphous SiO2 with a controlled thickness, such that the modified core comprises a Fe3O4—SiO2 particle formed by a modified Stöber reaction associated with the hydrolysis of tetraethylorthosilicate (TEOS) to coat the Fe3O4 particles with the amorphous SiO2 layer.

### Claim 5 (depends on 4)

The method of claim 4, further comprising modifying the modified core Fe3O4—SiO2 core-shell particles with 3-aminoproplytriethoxysilane (APTS) in an isopropanol solution to graft the SiO2 surface with amino groups (—NH2).

### Claim 6 (depends on 1)

The method of claim 1, wherein the plurality of the first component comprise Au nanoparticles and further wherein the associating of the plurality of the first component comprises bonding.

### Claim 7 (depends on 1)

The method of claim 1, wherein the shell layer and the mediation layer both comprise SiO2.

### Claim 8 (depends on 1)

The method of claim 1, wherein the modifying each first component of the subset comprises overgrowth through electroless plating.

### Claim 9 (depends on 1)

The method of claim 1, wherein the first component and the second component consist of the same material.

### Claim 10 (depends on 1)

The method of claim 1, wherein the first component and the second component consist of different materials.

### Claim 11 (depends on 1)

The method of claim 1, further comprising isolating the core/shell layer/mediation layer/first component particle with a magnetic field prior to modification with the second component.

### Claim 12 (depends on 1)

The method of claim 1, wherein the first component and the second component have different sizes.

### Claim 13 (depends on 1)

The method of claim 1, wherein the mediation layer thickness is between 0% and 99% of each first component in the subset.

### Claim 14

A method of synthesizing nanostructures comprising:
depositing a first SiO2 layer on a magnetic core particle;
attaching a first component to the first SiO2 layer;
depositing a second SiO2 layer, the second SiO2 layer having a thickness less than the diameter of the first component and the first component partially embedded in the second SiO2 layer;
attaching a second component to the first component;
wherein the each of the nanostructures comprise the first component and the second component.

### Claim 15 (depends on 14)

The method of claim 14, wherein prior to attaching a second component, the first component is modified with a linker which can specifically bind with the second component.

### Claim 16 (depends on 14)

The method of claim 14, wherein the second component is attached by plating on exposed portion of the first component.

### Claim 17 (depends on 14)

The method of claim 14, wherein the second SiO2 layer is amorphous, such that the modified core comprises a Fe3O4—SiO2 particle formed by a modified Stöber reaction associated with the hydrolysis of tetraethylorthosilicate (TEOS) to coat the Fe3O4 particles with the amorphous SiO2 layer.

### Claim 18 (depends on 14)

The method of claim 14, wherein the plurality of the first component comprise Au nanoparticles.

### Claim 19 (depends on 14)

The method of claim 14, wherein the first component and the second component consist of the same material.

### Claim 20 (depends on 14)

The method of claim 14, wherein the first component and the second component consist of different materials.