# US 2022/0034875 A1 · Particle, affinity particle, test reagent, and detection method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0034875 A1 - Document ID: US20220034875A1 - Status: Published application - Kind: A1 - Application number: 17/502,629 - Filed: 2021-10-15 - Published: 2022-02-03 - Earliest claimed: 2019-04-26 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Ryo Natori; Motokazu Kobayashi; Norishige Kakegawa; Fumio Yamauchi; Kengo Kanazaki; Daisuke Sasaguri - Web page: https://patentgrep.com/patent/US20220034875A1 ## CPC - G01N 33/54326: {Magnetic particles} - G01N 33/5434: {using magnetic particle immunoreagent carriers which constitute new materials per se} - C08L 101/02: characterised by the presence of specified groups {, e.g. terminal or pendant functional groups} - G01N 33/553: Metal or metal coated - 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) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract Provided is a magnetic particle excellent in detection speed when a substance to be measured, such as an antigen or an antibody, is detected from a specimen. The particle includes a magnetic particle containing a magnetic material, wherein the magnetic particle has a resin on a surface, wherein the particle has a volume average particle diameter of 0.4 μm or more and 1.5 μm or less, wherein the particle has a density of 5.1 g/cm3 or more and 10.0 g/cm3 or less, and wherein the resin has a functional group capable of binding a ligand. ## Claims ### Claim 1 A particle comprising a magnetic particle containing a magnetic material, wherein the magnetic particle has a resin on a surface, wherein the particle has a volume average particle diameter of 0.4 μm or more and 1.5 μm or less, wherein the particle has a density of 5.1 g/cm3 or more and 10.0 g/cm3 or less, and wherein the resin has a functional group capable of binding a ligand. ### Claim 2 (depends on 1) The particle according to claim 1, wherein the particle has a density of 5.1 g/cm3 or more and 6.5 g/cm3 or less. ### Claim 3 (depends on 1) The particle according to claim 1, wherein the particle has a volume average particle diameter of 0.7 μm or more and 1.2 μm or less. ### Claim 4 (depends on 1) The particle according to claim 1, wherein the particle has a volume average particle diameter of 0.7 μm or more and 0.9 μm or less. ### Claim 5 (depends on 1) The particle according to claim 1, wherein the resin has a weight average molecular weight of 10,000 or more. ### Claim 6 (depends on 1) The particle according to claim 1, wherein the resin has repeating units represented by the following formulae (2) and (3). ### Claim 7 (depends on 1) The particle according to claim 1, wherein the resin has units derived from styrene and acrylic acid. ### Claim 8 (depends on 1) The particle according to claim 1, wherein the particle is used for a specimen test. ### Claim 9 (depends on 1) The particle according to claim 1, wherein a number of the magnetic materials in the magnetic particle is 1, and wherein the magnetic particle contains the magnetic material at a content of 100%. ### Claim 10 (depends on 1) The particle according to claim 1, wherein the magnetic material contains at least one kind selected from the group consisting of: a metal; and a metal oxide. ### Claim 11 (depends on 1) The particle according to claim 1, wherein the magnetic material is at least one kind selected from the group consisting of: iron; nickel; and magnetite. ### Claim 12 (depends on 11) The particle according to claim 11, wherein the magnetic material contains the iron, and wherein the magnetic material contains an iron atom at a content of 80% or more and 100% or less. ### Claim 13 (depends on 11) The particle according to claim 11, wherein the magnetic material contains the nickel, and wherein the magnetic material contains a nickel atom at a content of 80% or more and 100% or less. ### Claim 14 (depends on 1) The particle according to claim 1, wherein the functional group capable of binding a ligand is at least one kind selected from the group consisting of: a carboxyl group; an amino group; a thiol group; an epoxy group; a maleimide group; and a succinimidyl group. ### Claim 15 (depends on 14) The particle according to claim 14, wherein the functional group capable of binding a ligand is the carboxyl group. ### Claim 16 (depends on 1) The particle according to claim 1, wherein the resin has a siloxane bond. ### Claim 17 (depends on 1) An affinity particle comprising the particle of claim 1 and a ligand that binds to the particle. ### Claim 18 (depends on 17) The affinity particle according to claim 17, wherein the ligand is any one of an antibody and an antigen. ### Claim 19 (depends on 17) A test reagent comprising the affinity particle of claim 17 and a dispersion medium for dispersing the affinity particle. ### Claim 20 A method of detecting a substance to be measured contained in a specimen, the method comprising: a first step of adding a specimen containing a substance to be measured and a test reagent containing an affinity particle and a dispersion medium for dispersing the affinity particle into a container having a first ligand immobilized on a lower side in a gravity direction; a second step of applying a magnetic field so that the affinity particle binds to the first ligand via the substance to be measured; and a third step of applying a magnetic field so that the affinity particle free from binding to the first ligand via the substance to be measured is separated away from the first ligand, wherein the affinity particle includes a particle comprising a magnetic particle containing a magnetic material, wherein the magnetic particle has a resin on a surface, wherein the particle has a volume average particle diameter of 0.4 μm or more and 1.5 μm or less, wherein the particle has a density of 5.1 g/cm3 or more and 10.0 g/cm3 or less, and wherein the resin has a functional group capable of binding a ligand, and further wherein the first ligand and the second ligand are each bound to the substance to be measured. ### Claim 21 (depends on 20) The detection method according to claim 20, wherein the first ligand and the second ligand are identical to each other. ### Claim 22 (depends on 20) The detection method according to claim 20, wherein the first ligand and the second ligand are different from each other. ### Claim 23 (depends on 20) The detection method according to claim 20 further comprising detecting a signal from the affinity particle bound to the first ligand via the substance to be measured.