Metal-resin composite and use thereof
A metal-resin composite that has a structure in which a plurality of metal particles are fixed to resin particles and, in the range of pH 3 to pH 10, the maximum value of the zeta potential is at least 5 mV and the minimum value is −5 mV or less. In this metal-resin composite, it is preferable that, in the range of pH 3 to pH 10, the difference between the maximum value and the minimum value of the zeta potential is at least 20 mV; and it is further preferable that the point of zero charge of the zeta potential is in the range of pH 3.5 to pH 9.0. This metal-resin composite can be used in immunoassays and in immunoassay reagents as a labeled substance by making antigens or antibodies adhere to the surface of the metal-resin composite.
1 . A metal-resin composite comprising:
resin particles; and
a plurality of metal particles fixed to the resin particles,
wherein,
the resin particles comprise a nitrogen-containing polymer selected from the group consisting of poly-2-vinylpyridine, poly-3-vinylpyridine, and poly-4-vinylpyridine,
the metal particles are particles of gold, platinum, palladium, or an alloy thereof,
the metal particles comprise metal particles that are completely enclosed in each of the resin particles, metal particles having a portion that is embedded in each of the resin particles and a portion that is exposed to an outside of each of the resin particles, and metal particles that are adhered to a surface of the resin particles, and 20 wt % or less of the metal particles are the metal particles that are adhered to the surface of the resin particles,
in a range of pH 3 to pH 10, a maximum value of a zeta potential is 5 mV or higher and a minimum value thereof is −5 mV or lower,
at least one anionic functional group and at least one cationic functional group are present on a surface of each of the resin particles or the metal-resin composite, wherein the at least one anionic functional group is selected from the group consisting of a carboxyl group, a sulfonic acid group and a phosphonic acid group, and the at least one cationic functional group comprises a nitrogen-containing group, and
at least a portion of the metal particles are distributed in a planar direction and in a depth direction in each of the resin particles in a range of the first 50% from the surface of each of the resin particles in a resin particle radius direction.
2 . The metal-resin composite according to claim 1 ,
wherein, in a range of pH 3 to pH 10, a difference between the maximum value and the minimum value of the zeta potential is 20 mV or higher.
3 . The metal-resin composite according to claim 1 ,
wherein a point of zero charge of the zeta potential is in a range of pH 3.5 to pH 9.0.
4 . The metal-resin composite according to claim 1 ,
wherein the average particle size of the metal particles is in a range of 1 nm to 100 nm.
5 . The metal-resin composite according to claim 1 ,
wherein the average particle size of the metal-resin composite is in a range of 30 nm to 1,000 nm.
6 . A labeling substance comprising the metal-resin composite according to claim 1 .
7 . The labeling substance according to claim 6 ,
wherein antigens or antibodies are adhered to the surface of the metal-resin composite and used.
8 . An immunoassay using the labeling substance according to claim 6 .
9 . A reagent for immunological measurement comprising the metal-resin composite according to claim 1 .
10 . An analyte measurement method for detecting or quantifying an analyte included in a sample, the method comprising the following Processes (I) to (III) that are performed using a test strip for lateral flow chromatography that includes a membrane and a determination section in which a capture ligand that specifically binds to the analyte is fixed to the membrane;
Process (I): a process in which the analyte included in the sample is brought into contact with a labeled antibody obtained by labeling an antibody that specifically binds to the analyte with a metal-resin composite;
Process (II): a process in which a composite including the analyte and the labeled antibody formed in Process (I) is brought into contact with the capture ligand in the determination section; and
Process (III): a process in which a color development intensity derived from localized surface plasmon resonance and/or light energy absorption due to electron transition of the metal-resin composite is measured,
wherein the metal-resin composite includes resin particles and a plurality of metal particles fixed to the resin particles, the resin particles comprise a nitrogen-containing polymer selected from the group consisting of poly-2-vinylpyridine, poly-3-vinylpyridine, and poly-4-vinylpyridine, the metal particles are particles of gold, platinum, palladium, or an alloy thereof, the metal particles comprise metal particles that are completely enclosed in each of the resin particles, metal particles having a portion that is embedded in each of the resin particles and a portion that is exposed to an outside of each of the resin particles, and metal particles that are adhered to a surface of the resin particles, and 20 wt % or less of the metal particles are the metal particles that are adhered to the surface of the resin particles, and in a range of pH 3 to pH 10, a maximum value of a zeta potential of the metal-resin composite is 5 mV or higher, and a minimum value thereof is −5 mV or lower,
at least one anionic functional group and at least one cationic functional group are present on a surface of each of the resin particles or the metal-resin composite, wherein the at least one anionic functional group is selected from the group consisting of a carboxyl group, a sulfonic acid group and a phosphonic acid group, and the at least one cationic functional group comprises a nitrogen-containing group, and
at least a portion of the metal particles are distributed in a planar direction and in a depth direction in each of the resin particles in a range of the first 50% from the surface of each of the resin particles in a resin particle radius direction.
11 . An analyte measurement kit for detecting or quantifying an analyte included in a sample, comprising:
a test strip for lateral flow chromatography including a membrane and a determination section in which a capture ligand that specifically binds to the analyte is fixed to the membrane; and
a detection reagent including a labeled antibody obtained by labeling an antibody that specifically binds to the analyte with a metal-resin composite,
wherein the metal-resin composite has a structure in which a plurality of metal particles are fixed to resin particles, the resin particles comprise a nitrogen-containing polymer selected from the group consisting of poly-2-vinylpyridine, poly-3-vinylpyridine, and poly-4-vinylpyridine, the metal particles are particles of gold, platinum, palladium, or an alloy thereof, the metal particles comprise metal particles that are completely enclosed in each of the resin particles, metal particles having a portion that is embedded in each of the resin particles and a portion that is exposed to an outside of each of the resin particles, and metal particles that are adhered to a surface of the resin particles, and 20 wt % or less of the metal particles are the metal particles that are adhered to the surface of the resin particles, and in a range of pH 3 to pH 10, a maximum value of a zeta potential is 5 mV or higher and a minimum value thereof is −5 mV or lower,
at least one anionic functional group and at least one cationic functional group are present on a surface of each of the resin particles or the metal-resin composite, wherein the at least one anionic functional group is selected from the group consisting of a carboxyl group, a sulfonic acid group and a phosphonic acid group, and the at least one cationic functional group comprises a nitrogen-containing group, and
at least a portion of the metal particles are distributed in a planar direction and in a depth direction in each of the resin particles in a range of the first 50% from the surface of each of the resin particles in a resin particle radius direction.
12 . A test strip for lateral flow chromatography for detecting or quantifying an analyte included in a sample, comprising:
a membrane;
a determination section in which a capture ligand that specifically binds to the analyte is fixed to the membrane in a direction in which the sample is developed; and
a reaction section including a labeled antibody obtained by labeling an antibody that specifically binds to the analyte with a metal-resin composite upstream from the determination section,
wherein the metal-resin composite has a structure in which a plurality of metal particles are fixed to resin particles, the resin particles comprise a nitrogen-containing polymer selected from the group consisting of poly-2-vinylpyridine, poly-3-vinylpyridine, and poly-4-vinylpyridine, the metal particles are particles of gold, platinum, palladium, or an alloy thereof, the metal particles comprise metal particles that are completely enclosed in each of the resin particles, metal particles having a portion that is embedded in each of the resin particles and a portion that is exposed to an outside of each of the resin particles, and metal particles that are adhered to a surface of the resin particles, and 20 wt % or less of the metal particles are the metal particles that are adhered to the surface of the resin particles, and in a range of pH 3 to pH 10, a maximum value of a zeta potential is 5 mV or higher and a minimum value thereof is −5 mV or lower,
at least one anionic functional group and at least one cationic functional group are present on a surface of each of the resin particles or the metal-resin composite, wherein the at least one anionic functional group is selected from the group consisting of a carboxyl group, a sulfonic acid group and a phosphonic acid group, and the at least one cationic functional group comprises a nitrogen-containing group, and
at least a portion of the metal particles are distributed in a planar direction and in a depth direction in each of the resin particles in a range of the first 50% from the surface of each of the resin particles in a resin particle radius direction.
13 . The metal-resin composite according to claim 1 ,
wherein all of the metal particles that are completely enclosed in each of the resin particles are distributed in a planar direction and in a depth direction in each of the resin particles in a range of the first 25% from the surface of each of the resin particles in a resin particle radius direction.
14 . The metal-resin composite according to claim 1 ,
wherein the resin particles further comprise divinylbenzene and a polymerizable monomer having a characteristic as a surfactant.
15 . The metal-resin composite according to claim 14 ,
wherein the polymerizable monomer having a characteristic as a surfactant is selected from the group consisting of polyethylene glycol methyl ether methacrylate and polyethylene glycol dimethacrylate.