# US 2021/0239684 A1 · Target substance separation method and quantification method

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- Number: US 2021/0239684 A1
- Document ID: US20210239684A1
- Status: Published application
- Kind: A1
- Application number: 17/236,705
- Filed: 2021-04-21
- Published: 2021-08-05
- Earliest claimed: 2018-10-26
- Assignees: Terumo Kabushiki Kaisha
- Applicants: Terumo Kabushiki Kaisha
- Inventors: Hiroya SATO
- Web page: https://patentgrep.com/patent/US20210239684A1

## CPC

- G01N 33/537: with separation of immune complex from unbound antigen or antibody
- G01N 33/561: Immunoelectrophoresis
- G01N 27/44726: {using specific dyes, markers or binding molecules}
- G01N 27/44786: {of the magneto-electrophoresis type}
- G01N 33/54326: {Magnetic particles}
- G01N 27/44769: {Continuous electrophoresis, i.e. the sample being continuously introduced, e.g. free flow electrophoresis [FFE]}
- 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)

## Abstract

A method for separating a target substance includes: forming a mixture containing: a target substance-magnetic particle complex that includes: a sample containing a target substance, and magnetic particles to which a first receptor is fixed, wherein the first receptor is adapted to specifically recognize a site of the target substance; and separating the target substance-magnetic particle complex from the mixture by magnetism and electrophoresis.

## Claims

### Claim 1

A method for separating a target substance, the method comprising:
forming a mixture containing:
a target substance-magnetic particle complex that comprises:
a sample containing a target substance, and
magnetic particles to which a first receptor is fixed, wherein the first receptor is adapted to specifically recognize a site of the target substance; and
separating the target substance-magnetic particle complex from the mixture by magnetism and electrophoresis.

### Claim 2 (depends on 1)

The method according to claim 1,
wherein the step of separating the target substance-magnetic particle complex from the mixture comprises:
collecting the target substance-magnetic particle complex at a predetermined position by magnetism, and
subsequently, subjecting the target substance-magnetic particle complex to electrophoresis, whereby the target substance-magnetic particle complex is separated from the mixture.

### Claim 3 (depends on 1)

The method according to claim 1,
wherein the electrophoresis is carrier-free electrophoresis.

### Claim 4 (depends on 1)

The method according to claim 1,
wherein the sample is selected from the group consisting of blood, interstitial fluid, or urine.

### Claim 5

A method for measuring a target substance amount, the method comprising:
forming a mixture containing:
a target substance-magnetic particle-labeled substance complex that comprises:
a sample containing a target substance, and
magnetic particles to which a first receptor is fixed, wherein the first receptor is adapted to specifically recognize a site of the target substance, and
a labeled substance to which a second receptor is fixed, wherein the second receptor is adapted to specifically recognize a site different from the site of the target substance;
separating the target substance-magnetic particle-labeled substance complex from the mixture by magnetism and electrophoresis; and
subsequently, measuring the target substance amount in the sample, which comprises detecting a signal intensity of the target substance-magnetic particle-labeled substance complex.

### Claim 6 (depends on 5)

The method according to claim 5,
wherein the step of separating the target substance-magnetic particle complex from the mixture comprises:
collecting the target substance-magnetic particle complex at a predetermined position by magnetism, and
subsequently, subjecting the target substance-magnetic particle complex to electrophoresis, whereby the target substance-magnetic particle-labeled substance complex and the unreacted second receptor-fixed labeled substance are separated from each other.

### Claim 7 (depends on 5)

The method according to claim 5,
wherein the electrophoresis is carrier-free electrophoresis.

### Claim 8 (depends on 5)

The method according to claim 5,
wherein the target substance amount in the sample is measured based on (i) a previously determined calibration curve of the signal intensity of the target substance-magnetic particle-labeled substance complex with respect to the target substance amount created using a target substance whose amount is known in advance, and (ii) the detected signal intensity of the target substance-magnetic particle-labeled substance complex.

### Claim 9 (depends on 5)

The method according to claim 5,
wherein the labeled substance is at least one selected from the group consisting of a fluorescent substance, a radioactive isotope, an enzyme, or a redox substance.

### Claim 10 (depends on 5)

The method according to claim 5,
wherein the sample is selected from the group consisting of blood, interstitial fluid, or urine.

### Claim 11

An inspection kit for a target-substance-related disease comprising:
magnetic particles to which a first receptor is fixed, wherein the first receptor is adapted to specifically recognize a site of a target substance;
a labeled substance to which a second receptor is fixed, wherein the second receptor is adapted to specifically recognize a site different from the site that is recognized by the target substance; and
a magnet.