# US 2021/0276095 A1 · Bipyramid-templated synthesis of monodisperse noble metal nanocrystals

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- Number: US 2021/0276095 A1
- Document ID: US20210276095A1
- Status: Published application
- Kind: A1
- Application number: 17/205,140
- Filed: 2021-03-18
- Published: 2021-09-09
- Earliest claimed: 2015-06-08
- Assignees: The University of Chicago
- Applicants: The University of Chicago
- Inventors: Yossi WEIZMANN; Kyle GIBSON; Jung-Hoon LEE; Zoya CHEGLAKOV
- Web page: https://patentgrep.com/patent/US20210276095A1

## CPC

- B22F 9/24: starting from liquid metal compounds, e.g. solutions
- B22F 1/0553: {Complex form nanoparticles, e.g. prism, pyramid, octahedron}
- B82Y 40/00: Manufacture or treatment of nanostructures
- C30B 7/005: {Epitaxial layer growth}
- C30B 7/14: the crystallising materials being formed by chemical reactions in the solution
- C30B 29/02: Elements
- C30B 29/34: Silicates
- C30B 29/52: Alloys
- C30B 29/66: Crystals of complex geometrical shape, e.g. tubes, cylinders
- B22F 1/052: characterised by a mixture of particles of different sizes or by the particle size distribution
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- 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
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR

## Abstract

Methods for forming samples of noble metal bipyramid nanocrystals having very low size and shape polydispersities from samples of mixed noble metal nanocrystals are provided. The samples include those comprising high purity, substantially monodisperse, plasmonic gold bipyramid nanocrystals. Also provided are methods of growing secondary twinned metal nanocrystals using the noble metal bipyramid nanocrystals as seed particles. Like the seed bipyramid nanocrystals from which they are grown, the secondary nanocrystals are twinned nanocrystals and may also be characterized by very low size and shape polydispersities. Secondary twinned nanocrystals grown by these methods include enlarged metal bipyramid nanocrystals and nanocrystals with anisotropic “dumbbell” shapes having a variety of tip geometries. Methods for using noble metal bipyramid nanocrystals as plasmonic heaters to heat reaction solutions via plasmonic-photothermal radiation-to-heat conversion are also provided.

## Claims

### Claim 1

A plurality of bipyramid-shaped noble metal nanocrystals comprising:
a plasmonic noble metal core and a PEGylated silica coating, the bipyramid-shaped noble metal nanocrystals having:
(a) a size polydispersity of less than 10%; and
(b) an ability to absorb light having wavelengths in the range of 400-1200 nm.

### Claim 2 (depends on 1)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 1, wherein the bipyramid-shaped noble metal nanocrystals are penta-twinned bipyramid-shaped noble metal nanocrystals.

### Claim 3 (depends on 2)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 2, wherein the penta-twinned bipyramid-shaped noble metal nanocrystals have an average length lower than 100 nm.

### Claim 4 (depends on 2)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 2, wherein the noble metal is gold.

### Claim 5 (depends on 4)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 4, wherein the penta-twinned bipyramid-shaped gold nanocrystals have an average length in the range from 68.3 nm to 239.7 and an average width in the range from 22.7 nm to 64.5 nm.

### Claim 6 (depends on 4)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 4, wherein the penta-twinned bipyramid-shaped gold nanocrystals have an average length in the range from 65 nm to 95 nm and aspect ratios in the range from 3.0 to 3.4.

### Claim 7 (depends on 6)

The plurality of bipyramid-shaped noble metal nanocrystals of claim 6, wherein the penta-twinned bipyramid-shaped gold nanocrystals have a size polydispersity of less than 8%.

### Claim 8

The plurality of noble metal nanocrystals having a shape selected from the group consisting of: a penta-twinned bifrustum body having a first end capped with a penta-twinned tip structure and a second end capped with a penta-twinned tip structure, with a narrowing between the body and each of the first and second penta-twinned tip structures; a penta-twinned bifrustum body with pyramid shaped ends; a penta-twinned bifrustum body with penta-twinned rod-shaped ends; a penta-twinned bifrustum body with sphere-shaped ends; and
a penta-twinned spherical polyhedron.

### Claim 9

A method for isothermal amplification of nucleic acid molecules, comprising:
preparing a reaction mixture that comprises the nucleic acid molecules, primer nucleic acid strands, free nucleotides, a nucleic acid polymerase, and a plurality of bipyramid-shaped noble metal nanocrystals;
irradiating the reaction mixture under a first pulse length and frequency, with radiation having wavelengths in an infrared region of the electromagnetic spectrum at which said nanocrystals absorb said radiation, thereby heating said reaction mixture to a first temperature for a first time period,
wherein said bipyramid-shaped noble metal nanocrystals are characterized by:
a plasmonic noble metal core and a PEGylated silica coating;
a size polydispersity of less than 10%;
and
an ability to absorb light having wavelengths in the range of 400-1200 nm.

### Claim 10 (depends on 3)

The method of claim 3, wherein said reaction mixture further comprises fluorescent probe molecules that bind to the nucleic acid molecules, and the method further comprising exciting said fluorescent probe molecules and monitoring a resulting fluorescence.

### Claim 11 (depends on 9)

The method of claim 9, wherein the noble metal is gold.

### Claim 12 (depends on 9)

The method of claim 9, wherein the reaction mixture has an optical density of 1 to 5.

### Claim 13 (depends on 9)

The method of claim 9, further comprising, subsequent to said irradiating under a first pulse length and frequency, irradiating said reaction mixture under a second pulse length and frequency, thereby heating said reaction mixture to a second temperature for a second time period, wherein said second temperature is different than said first temperature.

### Claim 14 (depends on 13)

The method of claim 13, wherein said second temperature is lower than said first temperature.

### Claim 15 (depends on 9)

The method of claim 9, wherein the bipyramid-shaped noble metal nanocrystals are penta-twinned bipyramid-shaped noble metal nanocrystals.

### Claim 16 (depends on 15)

The method of claim 15, wherein the penta-twinned bipyramid-shaped noble metal nanocrystals have an average length lower than 100 nm.

### Claim 17 (depends on 15)

The method of claim 15, wherein the noble metal is gold.

### Claim 18 (depends on 17)

The method of claim 17, wherein the penta-twinned bipyramid-shaped gold nanocrystals have an average length in the range from 68.3 nm to 239.7 and an average width in the range from 22.7 nm to 64.5 nm.

### Claim 19 (depends on 17)

The method of claim 17, wherein the penta-twinned bipyramid-shaped gold nanocrystals have an average length in the range from 65 nm to 95 nm and aspect ratios in the range from 3.0 to 3.4.

### Claim 20 (depends on 19)

The method of claim 19, wherein the penta-twinned bipyramid-shaped gold nanocrystals have a size polydispersity of less than 8%.