# US 2014/0154713 A1 · Assay method using magnetic silica particles and reagent for said assay method

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- Number: US 2014/0154713 A1
- Document ID: US20140154713A1
- Status: Published application
- Kind: A1
- Application number: 14/123,299
- Filed: 2012-05-31
- Published: 2014-06-05
- Earliest claimed: 2011-06-15
- Assignees: Sanyo Chemical Industries, Ltd.; Wako Pure Chemical Industries, Ltd.
- Inventors: Yusuke Mizuno; Masamitsu Miyamori; Shinjiro Matsuda; Yo Yagura
- Web page: https://patentgrep.com/patent/US20140154713A1

## CPC

- G01N 33/54326: {Magnetic particles}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- C01B 33/18: Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof (preparation of aerogels by dehydrating gels C01B33/158; treatment to enhance the pigmenting or filling properties C09C)
- G01N 33/5434: {using magnetic particle immunoreagent carriers which constitute new materials per se}
- G01N 33/552: Glass or silica
- G01N 33/553: Metal or metal coated
- C01P 2004/64: Nanometer sized, i.e. from 1-100 nanometer
- C01P 2006/42: Magnetic properties
- 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
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

In the method of assaying an analyte in a sample of the present invention, magnetic silica particles are used. The magnetic silica particles include: silica particles containing 60 to 95% by weight of a superparamagnetic metal oxide that has an average particle size of 1 to 15 nm; and the analyte, an analog of the analyte, or a substance capable of specifically binding to the analyte immobilized on the surface of the silica particles.

## Claims

### Claim 1

A method of assaying an analyte in a sample in which magnetic silica particles are used,
the magnetic silica particles comprising:
silica particles containing 60 to 95% by weight of a superparamagnetic metal oxide that has an average particle size of 1 to 15 nm; and
the analyte, an analog of the analyte, or a substance capable of specifically binding to the analyte immobilized on a surface of the silica particles.

### Claim 2 (depends on 1)

The assay method according to claim 1,
wherein the magnetic silica particles comprise an analyte-binding substance that is a substance capable of specifically binding to the analyte and is immobilized on the surface of the silica particles, and
the method comprises:
bringing a sample containing the analyte, the magnetic silica particles, and a labeled analyte-binding substance that is an analyte-binding substance labeled by a label into contact with each other to form a labeled complex that is a complex of the analyte-binding substance, the analyte, and the labeled analyte-binding substance on the magnetic silica particles;
B/F-separating the magnetic silica particles carrying the labeled complex;
measuring the amount of the label in the labeled complex; and
assaying the analyte in the sample based on the resulting amount of the label.

### Claim 3 (depends on 1)

The assay method according to claim 1,
wherein the magnetic silica particles comprise the analyte or the analog of the analyte immobilized on the surface of the silica particles, and
the method comprises:
bringing a sample containing the analyte, a labeled analyte-binding substance that is a substance labeled by a label and is capable of specifically binding to the analyte, and the magnetic silica particles into contact with each other to form a labeled complex that is a complex of the analyte or the analog of the analyte and the labeled analyte-binding substance on the magnetic silica particles;
B/F-separating the magnetic silica particles carrying the labeled complex;
measuring the amount of the label in the labeled complex; and
assaying the analyte in the sample based on the resulting amount of the label.

### Claim 4 (depends on 1)

The assay method according to claim 1,
wherein the magnetic silica particles comprise an analyte-binding substance that is a substance capable of specifically binding to the analyte immobilized on the surface of the silica particles, and
the method comprises:
bringing a sample containing the analyte, a labeled analyte or analog thereof that is an analyte or analog of the analyte labeled by a label, and the magnetic silica particles into contact with each other to form a labeled complex that is a complex of the analyte-binding substance and the labeled analyte or analog on the magnetic silica particles;
B/F-separating the magnetic silica particles carrying the labeled complex;
measuring the amount of the label in the labeled complex; and
assaying the analyte in the sample based on the resulting amount of the label.

### Claim 5 (depends on 2)

The assay method according to claim 2,
wherein the B/F separation is performed utilizing the magnetism of the magnetic silica particles.

### Claim 6 (depends on 1)

The assay method according to claim 1,
wherein the magnetic silica particles have an average particle size of 1 to 5 μm.

### Claim 7 (depends on 1)

The assay method according to claim 1,
wherein the superparamagnetic metal oxide is an iron oxide.

### Claim 8 (depends on 7)

The assay method according to claim 7,
wherein the iron oxide is at least one selected from the group consisting of magnetite, γ-hematite, an intermediate iron oxide between magnetite and α-hematite, and an intermediate iron oxide between γ-hematite and α-hematite.

### Claim 9 (depends on 1)

The assay method according to claim 1,
wherein at least one organic compound selected from the group consisting of glutaraldehyde, albumin, carbodiimide, streptavidin, biotin, and functional group-containing alkylalkoxysilanes is bound to the surface of the magnetic silica particles before the immobilization of the analyte, the analog of the analyte, or the substance capable of specifically binding to the analyte on the surface of the magnetic silica particles.

### Claim 10 (depends on 9)

The assay method according to claim 9,
wherein the functional group of the alkylalkoxysilanes is at least one selected from the group consisting of an amino group, a carboxyl group, a hydroxy group, a mercapto group, and a glycidyloxy group.

### Claim 11 (depends on 1)

The assay method according to claim 1,
wherein the substance capable of specifically binding to the analyte is an antibody against the analyte or the analog of the analyte, an antigen capable of binding to the analyte or the analog of the analyte, or a protein capable of binding to the analyte or the analog of the analyte.

### Claim 12 (depends on 1)

A reagent for the assay method according to claim 1, comprising
magnetic silica particles comprising:
silica particles containing 60 to 95% by weight of a superparamagnetic metal oxide that has an average particle size of 1 to 15 nm; and
an analyte, an analog of the analyte, or a substance capable of specifically binding to the analyte immobilized on a surface of the silica particles.

### Claim 13 (depends on 12)

The reagent according to claim 12,
wherein the magnetic silica particles have an average particle size of 1 to 5 μm.

### Claim 14 (depends on 12)

The reagent according to claim 12,
wherein the superparamagnetic metal oxide is an iron oxide.

### Claim 15 (depends on 14)

The reagent according to claim 14,
wherein the iron oxide is at least one selected from the group consisting of magnetite, γ-hematite, an intermediate iron oxide between magnetite and α-hematite, and an intermediate iron oxide between γ-hematite and α-hematite.

### Claim 16 (depends on 12)

The reagent according to claim 12,
wherein at least one organic compound selected from the group consisting of glutaraldehyde, albumin, carbodiimide, streptavidin, biotin, and functional group-containing alkylalkoxysilanes is bound to the surface of the magnetic silica particles before the immobilization of the analyte, the analog of the analyte, or the substance capable of specifically binding to the analyte on the surface of the magnetic silica particles.

### Claim 17 (depends on 16)

The reagent according to claim 16,
wherein the functional group of the alkylalkoxysilanes is at least one selected from the group consisting of an amino group, a carboxyl group, a hydroxy group, a mercapto group, and a glycidyloxy group.

### Claim 18 (depends on 12)

The reagent according to claim 12,
wherein the substance capable of specifically binding to the analyte is an antibody against the analyte or the analog of the analyte, an antigen capable of binding to the analyte or the analog of the analyte, or a protein capable of binding to the analyte or the analog of the analyte.