JP2025001989A - Functional molded body and production method of the same - Google Patents

Abstract

To provide a functional molded body capable of capturing virus, heavy metal, or the like.SOLUTION: A production method of a functional molded body includes steps of: (A) generating a radical on a surface layer of a substrate by irradiating the substrate with electron beams; (B) reacting the radical on the surface layer of the substrate with a polymer brush monomer having an epoxy group, and subjecting a polymer brush to secondary polymerization to dispose the polymer brush on the surface layer of the substrate; and (C) introducing, to the polymer brush, a functional structure to be a host structure of a host-guest reaction using an introduction substance by reacting the epoxy group of the polymer brush with the introduction substance. The host-guest reaction is any one selected from the group consisting of antibody-antigen reaction, ligand-receptor reaction, and chelate-complex reaction.SELECTED DRAWING: Figure 1

Description

Application for application of Article 30, Paragraph 2 of the Patent Act submitted. Published in the abstracts of the 59th Joint Kyushu Meeting of Chemical-Related Branches, co-hosted by The Agricultural Chemical Society of Japan, Western Japan Branch, The Society of Chemical Engineering, Kyushu Branch, The Chemical Society of Japan, Kyushu Branch, The Society of Synthetic Organic Chemistry, Kyushu Yamaguchi Branch, The Electrochemical Society of Japan, Kyushu Branch, The Japan Society for Analytical Chemistry, Kyushu Branch, The Society of Polymer Science, Kyushu Branch, and The Society of Fiber Science and Technology, Western Branch, on July 2, 2022. Presented at the 59th Joint Kyushu Meeting of Chemical-Related Branches, co-hosted by The Agricultural Chemical Society of Japan, Western Japan Branch, The Society of Chemical Engineering, Kyushu Branch, The Chemical Society of Japan, Kyushu Branch, The Society of Synthetic Organic Chemistry, Kyushu Yamaguchi Branch, The Electrochemical Society of Japan, Kyushu Branch, The Japan Society for Analytical Chemistry, Kyushu Branch, The Society of Polymer Science, Kyushu Branch, and The Society of Fiber Science and Technology, Western Branch, held at the Kitakyushu International Conference Center.

The present invention relates to a functional molded body and a manufacturing method thereof. In particular, the present invention relates to a functional molded body having a polymer brush layer and having functional groups on the polymer brush layer, which is suitable for capturing and concentrating various target substances by the functional groups.

The recent outbreak of COVID-19, which has caused a pandemic, has raised interest in viruses, and sewage surveillance projects to predict the spread of infectious diseases through sewage monitoring are being implemented in Japan and other countries. However, this technique requires concentration of sewage because the amount of coronavirus detected in the feces of infected individuals is low, and there are many issues, such as the time lag between collection and detection and the establishment of operating methods. Virus concentration techniques include (a) the antibody method and (b) the negative charge membrane concentration method.

(a) The antibody method includes active adsorption, in which an antibody that specifically recognizes the target virus is adsorbed onto the surface of a substrate, and passive adsorption, in which the antibody is directly bound to the substrate. The former active adsorption method is driven primarily by electrostatic interactions, and although preparation is easy, it has problems with peeling of the adsorbed antibody and shielding of the antigen-binding site due to structural denaturation. The latter passive adsorption method is a technique in which a substrate having carboxyl or amino groups is brought into an intermediate activated state using a bivalent reagent to form a covalent bond with the target antibody, and does not have the problems of the active adsorption method described above. However, since it is a monolayer adsorption onto the substrate surface, there is a problem in that the antigen concentration rate is low.

(b) The negative charge membrane concentration method involves preparing a membrane that has a positive charge to match the negative charge of the virus, and adsorbing the virus through electrostatic interaction. This method can also be applied to resins and is a very simple method, but it has the problem of poor concentration efficiency because it also adsorbs negatively charged substances other than viruses (e.g. proteins).

Furthermore, in recent years, rapid industrial development in developing countries has led to the emission of heavy metals through the production of non-ferrous metals and the burning of fossil fuels. Heavy metals thus emitted into the environment are polluting water, a resource essential to life. It has been reported that rapid industrial development has had a serious impact on the environment, producing thick smog and polluting the air, water, soil, and agricultural products with heavy metals. In other words, heavy metal pollution occurs not only in water, but also in the soil as it moves through the air and rain.

Among heavy metals, for example, mercury is a harmful pollutant regulated by the US Environmental Protection Agency (EPA), and is known to cause diseases in the brain and nerves due to its toxicity based on bioaccumulation and non-biodegradability. Another threat of mercury pollution is the health damage caused by mercury methylation. Against this background, the Mercury Export Ban Act was established to reduce the use of mercury for commercial purposes worldwide. In other words, technology that can remove mercury contained in wastewater is needed. Chemical precipitation, ion adsorption, membrane filtration, and other wastewater treatment technologies have been applied, but they have problems such as low capacity and low selectivity.

Although expensive equipment is used to analyze hazardous metals such as mercury, there is a growing need for simple on-site measurement. However, there is an issue with measuring with these simple testers, in that the concentrations of the target metals are low, making on-site measurement difficult. For this reason, there is a need to develop pretreatment materials that can recover and concentrate specific hazardous metals.

Methods used to concentrate mercury include (c) activated carbon, (d) solvent extraction, (e) ion exchange resins, and (f) chelating resins.

(c) While activated carbon exhibits a high adsorption capacity for mercury, it has no selectivity, and there are problems in terms of inhibition of concentration by coexisting substances and separation operations after adsorption.
(d) The solvent extraction method uses an extractant having a sulfur-based functional group, which has a high affinity for mercury. Although this method has high selectivity, it has problems such as the need to use a large amount of organic solvent and a separation procedure.
(e) The driving force for concentration using ion exchange resins is electrostatic interaction, and positively charged substances other than mercury are also adsorbed, resulting in a problem of extremely low selectivity.
(f) Chelate resins have sulfur-based functional groups that have a high affinity for mercury fixed inside the resin, and have excellent mercury selectivity. However, since the functional groups exist in a single layer on the pore surface of the resin, there is a problem that a large amount of resin is required to increase the adsorption capacity.

Meanwhile, it has also been considered to provide various physical properties by providing so-called polymer brushes, etc., which are graft-polymerized on the surface of a substrate. For example, Patent Document 1 discloses a method for producing an anion-selective adsorbent porous membrane having neutral hydroxyl groups and anion exchange groups, which is characterized in that a substrate membrane made of a polyolefin or a copolymer of an olefin and a halogenated olefin is irradiated with ionizing radiation, and then glycidyl methacrylate or glycidyl acrylate is grafted in the gas phase, and then, if necessary, epoxy groups are partially ring-opened with an acidic liquid, and then ammonia or an organic amine is added.

Patent Document 2 discloses a method for producing a selectively adsorptive porous membrane in which a porous substrate membrane having a substantially three-dimensional network structure, made of polyolefin, a copolymer of olefin and halogenated olefin, or polyvinylidene fluoride, is irradiated with ionizing radiation, and then a vinyl monomer having an epoxy group is graft-polymerized, and then reacted with alcohols, phenols, or monoamines under alkaline conditions, and the remaining epoxy groups are converted into diols.

Japanese Unexamined Patent Publication No. 2-132132 Japanese Patent Application Publication No. 8-141392

As mentioned above, there are various situations where it may be necessary to capture viruses, heavy metals, etc.

The objective of the present invention is to provide a functional molded body that can capture viruses, heavy metals, etc.

The inventors conducted extensive research to solve the above problems, and discovered that the following invention meets the above objective, leading to the present invention. That is, the present invention relates to the following inventions.

<1> A step (A) of irradiating a substrate with an electron beam to generate radicals on a surface layer of the substrate;
a step (B) of reacting a monomer for polymer brushes having an epoxy group with the radicals of the surface layer of the substrate to secondary polymerize the polymer brushes, thereby providing the polymer brushes on the surface layer of the substrate;
and (C) a step of reacting a substance to be introduced with the epoxy group of the polymer brush to introduce a functional structure to the polymer brush, the functional structure being a host structure for a host-guest reaction using the substance to be introduced,
The method for producing a functional molded article, wherein the host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction.
<2> The method according to <1>, wherein the monomer for the polymer brush is glycidyl methacrylate or glycidyl acrylate.
<3> The method uses a diamine compound, a protein crosslinking agent and a functional substance as the substance to be introduced in the introducing step (C),
The step (C) of introducing includes a step (C-1) of reacting the epoxy group of the polymer brush with a diamine compound to bond an amino group derived from the diamine compound;
a step (C-2) of reacting the protein crosslinking agent that reacts with the amino group;
The method according to <2>, further comprising the step (C-3) of reacting the functional substance with the protein crosslinking agent.
<4> The method according to <3>, wherein the protein crosslinking agent is a bifunctional reagent and/or a dialdehyde compound, and the functional substance is a functional protein.
<5> The method according to <4>, wherein the bifunctional reagent is N-(11-Maleimidoundecanoyloxy)sulfosuccinimide, sodium salt, and the dialdehyde compound is glutaraldehyde.
<6> The method according to <2>, wherein the substance to be introduced is a sulfur-containing amine-based compound having a structure containing an amine and a sulfur atom, and the host structure has a nitrogen atom and a sulfur atom derived from the sulfur-containing amine-based compound.
<7> The method according to <6>, wherein the structure containing a sulfur atom in the sulfur-containing amine compound is any one selected from the group consisting of thiol, sulfide, and dithiocarboxylic acid.
<8> The method according to <7>, wherein the sulfur-containing amine compound is one or more substances selected from the group consisting of 4-imidazoledithiocarboxylic acid, 3-methylthiopropylamine, 2-aminoethanethiol, and 2,2'-thiobisethylamine.
<9> A substrate, a polymer brush layer provided on a surface layer of the substrate, and a functional structure that serves as a host structure for a host-guest reaction and is introduced into the polymer brush layer,
The host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction.

The functional molded article of the present invention can capture viruses, heavy metals, etc.

FIG. 2 is a flow diagram of an example of a method for producing a functional molded article of the present invention. FIG. 1 is a schematic diagram showing a flow of a method for producing a functional molded article according to the present invention. FIG. 1 is a schematic diagram of a test device used in the examples. 1 is an image showing the results of a luminescence test carried out in an example.

The following describes in detail the embodiment of the present invention, but the description of the constituent elements described below is one example (representative example) of the embodiment of the present invention, and the present invention is not limited to the following content as long as the gist of the present invention is not changed. Note that when the expression "~" is used in this specification, it is used as an expression including the numerical values before and after it.

[Method of producing the functional molded article of the present invention]
The method for producing a functional molded body of the present invention includes the steps of: (A) irradiating a substrate with an electron beam to generate radicals on the surface layer of the substrate; (B) reacting a monomer for polymer brush having an epoxy group with the radicals on the surface layer of the substrate to secondary polymerize the polymer brush and provide the polymer brush on the surface layer of the substrate; and (C) reacting a substance for introduction with the epoxy group of the polymer brush to introduce a functional structure to the polymer brush, which is a host structure for a host-guest reaction using the substance for introduction, and the host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction. In the present application, the method for producing a functional molded body of the present invention may be simply referred to as the method for producing the functional molded body of the present invention.

[Functional Molded Article of the Present Invention]
The functional molded article of the present invention has a substrate, a polymer brush layer provided on the surface layer of the substrate, and a functional structure that serves as a host structure for a host-guest reaction introduced into the polymer brush layer, wherein the host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction.

In addition, the functional molded body of the present invention can also be obtained by the manufacturing method of the functional molded body of the present invention in this application, and the corresponding configurations in this application can be used mutually.

Electron beam graft polymerization is a method in which a polymeric material (substrate) is irradiated with an electron beam to dissociate carbon-hydrogen (C-H) bonds, and then vinyl monomers are brought into contact with the generated radicals to cause addition polymerization. The C=C bond in the reacted vinyl monomer is broken, one side bonds with the substrate, and the other side becomes a radical and becomes a new reaction point.

In this way, polymer chains, or graft chains, grow on the substrate through addition polymerization, and new functional groups can be introduced by chemically modifying these chains. In other words, the researchers thought that by introducing molecules containing sulfur atoms, it would be possible to develop a filter that exhibits mercury adsorption properties.

The inventors have targeted mercury as a heavy metal and developed filters and other devices that can recover mercury efficiently and quickly by densely immobilizing molecules containing sulfur atoms, which have a high affinity for mercury, onto a hollow fiber membrane. Based on this knowledge, they have obtained a functional membrane that can capture heavy metals.

Furthermore, the inventors developed a functional material that can capture low concentrations of viruses with high sensitivity and high yield by introducing a bivalent reagent into a flat membrane and immobilizing antibodies to the target virus at a high density, and based on this knowledge, they obtained a functional membrane that can capture viruses.
The present invention is based on these findings.

FIG. 1 is a flow diagram of an example of the method for producing a functional molded article of the present invention.
Step S11 is a process of generating radicals on the surface layer of the substrate.
Step S21 is a process of providing a polymer brush on the surface layer by utilizing radicals on the surface layer.
Step S31 is a process of introducing functional groups into the polymer brush, thereby obtaining a functional molded article having functional groups on the surface layer of the molded article serving as the substrate.

Figure 2 is a schematic diagram showing the flow of the method for producing a functional molded body of the present invention. Here, an electron beam is irradiated onto a film-like substrate made of polyethylene. This generates radicals on the surface layer. A reactive monomer is then secondary polymerized onto these radicals to obtain a polymer brush. By introducing functional groups into this polymer brush, a functional film in which the functional groups are densely arranged can be obtained.

[Step (A) of generating radicals]
The step (A) of generating radicals is a step of generating radicals on the surface layer of the substrate. A resin having a C-H structure is used as the substrate. By irradiating this C-H structure with an electron beam, H atoms are separated and C. radicals are generated on the surface layer of the substrate. The degree of radical generation is appropriately set depending on the shape and physical properties of the substrate, the degree to which the polymer brush is desired to be provided, and the like. The degree of radicalization is set based on the irradiation dose of the electron beam, and the like.

[Substrate]
The functional molded article of the present invention is a molded article having functional groups introduced thereinto as a substrate. The substrate can be any molded article capable of generating radicals by electron beam irradiation and capable of maintaining any shape under the conditions of use. More specifically, the substrate is a molded article of a resin having a C-H structure.

Materials that can be used for the substrate include, for example, polyolefin resins such as polyethylene and polypropylene; polystyrene resins such as polystyrene, acrylonitrile-styrene copolymer (AS resin), and acrylonitrile-butadiene-styrene copolymer (ABS resin); polyvinyl chloride; polyvinylidene chloride; acrylic resins; polyamide; polycarbonate; polyallyl ester; polyimide; polyacetate; polyether ketone, polyether sulfone; polyphenylene oxide, polyphenylene sulfide; cellulose, and the like.

In particular, it is preferable for the material to be versatile, readily available, easy to process, and suitable for generating radicals and secondary polymerization of polymer brushes. Polyethylene is particularly suitable for such purposes.

The shape of the substrate can be any molded object. The shape of the substrate can be any shape suitable for the intended use of the guest substance to be captured, such as planar shapes such as membranes, sheets, and plates, three-dimensional shapes such as hollow fiber membranes, blocks, cylinders, tubes, and containers, and fibrous shapes.

Typical substrates suitable for use in the manufacturing method of the present invention include polyethylene membranes, films, and hollow fiber membranes.

[Electron beam irradiation]
In the manufacturing method of the present invention, the substrate is irradiated with an electron beam to generate radicals. The means for irradiating the electron beam is not particularly limited, and is appropriately selected according to the shape of the substrate and the degree to which the surface layer of the substrate is desired to be radicalized. The electron beam irradiation can be based on the absorbed dose, and can be based on, for example, about 10 kGy to 1,000 kGy, about 50 kGy to 500 kGy, or about 100 kGy to 300 kGy.

[Step (B) of Providing Polymer Brushes]
The step (B) of providing a polymer brush is a step of providing a polymer brush by secondary polymerization of a monomer for polymer brush using radicals on the surface layer of the base material after the step (A).

[Monomer for polymer brushes]
The monomer for the polymer brush is a monomer for forming a polymer brush, and the monomer for the polymer brush is one that leaves an epoxy group when the polymer brush is formed by secondary polymerization.

As a monomer for the polymer brush, for example, a vinyl monomer having an epoxy group can be used. In this case, the vinyl group undergoes secondary polymerization to form a polymer brush, and this polymer brush has an epoxy group.

Specific examples of monomers for polymer brushes include glycidyl methacrylate (GMA) and glycidyl acrylate. In particular, glycidyl methacrylate is suitable for the manufacturing method of the present invention because it forms a polymer brush and has an epoxy group.

[Secondary Polymerization]
The secondary polymerization is a reaction in which a monomer for polymer brushes is polymerized with radicals on the surface layer of a substrate to form a polymer brush. By contacting the substrate in which radicals have been generated with the monomer for polymer brushes, the radicals on the substrate react with the monomer for polymer brushes to cause secondary polymerization, and a polymer brush can be formed on the surface layer of the substrate.

The means for secondary polymerization can be appropriately set according to the shape of the substrate, the degree and state of the radicals, the type of monomer for the polymer brush, etc. In the secondary polymerization, it is possible to adjust the fluidity of the monomer for the polymer brush so that the monomer for the polymer brush has more opportunities to come into contact with the radicals, adjust the surrounding conditions to prevent side reactions and inhibitory reactions, add energy to promote the reaction, etc.

For example, from the viewpoint of fluidity, the monomer for polymer brushes can be used for secondary polymerization as a mixed solution mixed with a solvent as appropriate. From the viewpoint of ambient conditions, the secondary polymerization can be performed under nitrogen replacement or reduced pressure to reduce oxygen and air. Ultrasonic irradiation, heating, shaking, etc. can also be performed as appropriate.

The reaction stops when the monomer for the polymer brush is used up in the secondary polymerization. The conditions until the reaction stops can be controlled by time, but the reaction can also be stopped by changing the conditions to make the reaction less likely by washing, or by understanding the concentration of the monomer for the polymer brush.

[Polymer brush]
The functional molded article of the present invention has a polymer brush on the surface layer of a substrate. The polymer brush is made of a polymer obtained by polymerizing a monomer for the polymer brush, and one end of the main chain of the polymer brush reacts with a radical of the substrate and bonds to the substrate. The increase in the dry weight of the polymer brush before and after secondary polymerization can be used as an indicator of graft polymerization.

[Step (C) of introducing functional groups]
The step (C) of introducing a functional group is a step, which is carried out after the step (B), of introducing a functional structure, which serves as a host structure in a host-guest reaction, into the polymer brush.

[Host-guest reaction]
The host-guest reaction can be any reaction selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction.

[Introduction of host structure]
The introduction of the functional structure that will become the host structure is carried out using an introduction substance. The introduction substance is a substance having a structure that reacts with the epoxy group of the polymer brush. The introduction substance may itself have a functional structure that will become the host structure. Alternatively, as the introduction substance, a bonding compound for reacting with a substance having a functional structure that will become the host structure and a compound having a functional structure that will become the host structure may be used, and these may be reacted in sequence to introduce the functional structure.

[Introduction of host structures using protein cross-linking agents]
A diamine compound, a protein crosslinking agent, and a functional substance are used as the substances to be introduced in the introducing step (C), and the introducing step (C) can include a step (C-1) of reacting the epoxy group of the polymer brush with a diamine compound to bond an amino group derived from the diamine compound, a step (C-2) of reacting the protein crosslinking agent which reacts with the amino group, and a step (C-3) of reacting the functional substance which reacts with the protein crosslinking agent.

In step (C-1), the epoxy groups of the polymer brush are first reacted with a diamine compound such as ethylenediamine, so that the amino groups (amine, -NH ₂ ) introduced into the polymer brush are available for reaction with a protein crosslinking agent in step (C-2).

[Diamine compound]
A diamine compound is a compound having two amino groups in the molecule. Formula (1) is a generalized structural formula of an example of a diamine compound. Formula (1) has two amino groups (-NH ₂ ). R ₁ in formula (1) is a structure that bonds each amine. R ₁ can be, for example, an alkylene group (-C _n H _2n -) having 1 to 12 carbon atoms. R ₁ is preferably an alkylene group having 1 to 8 carbon atoms, and particularly preferably an alkylene group having 2 to 6 carbon atoms. For example, ethylenediamine can be used as the diamine compound.

[Protein crosslinking agent]
Protein crosslinking agents are used to crosslink protein structures. In particular, those that bind to amine structures contained in proteins are used. In the present invention, a protein crosslinking agent is reacted with an amine structure introduced into a primer brush using a diamine compound, and one side of the protein crosslinking agent is bound to the amine structure.

[Bifunctional Reagents]
A bifunctional reagent can be used as the protein crosslinking agent. A bifunctional reagent is a reagent having two functional groups, and is widely used in immunoassays, protein research, and the like. The bifunctional reagent can be an "N-hydroxysuccinimide active ester" (NHS ester), an "N-hydroxysuccinimide active ester containing sulfonic acid" (Sulfo-NHS ester), or a compound having a "maleimide group." NHS ester and Sulfo-NHS ester are sometimes called NHS esters, etc., because they share a portion of their structure. This bifunctional reagent reacts with the amine structure (-NH ₂ ) introduced into the polymer brush and is connected to the polymer brush so as to extend. The NHS ester, etc., or the maleimide group on the other end binds to a protein, such as a primary antibody.

Formula (2-1) and formula (2-2) are generalized structural formulas of examples of bifunctional reagents. Formula (2-1) has a maleimide group and an NHS ester. Formula (2-2) has a maleimide group and a sulfo-NHS ester. Formula (2-1) and formula (2-2) combine different structures, but both may have an NHS ester or the like. In formula (2-1) and formula (2-2), R ₂₁ and R ₂₂ are structures that bond the respective structures.

R ₂₁ and R ₂₂ can each independently be, for example, an alkylene group (-C _n H _2n -) having 1 to 20 carbon atoms. R ₂₁ and R ₂₂ are preferably alkylene groups having 4 to 14 carbon atoms, and particularly preferably alkylene groups having 8 to 12 carbon atoms.

As such a bifunctional reagent, for example, bifunctional reagents such as "Hetero-bifunctional Reagents" and "Homo-bifunctional Reagents" manufactured by Dojindo Chemical Industries, Ltd. can be used.

"Hetero-bifunctional Reagents" is a group of reagents that have an NHS ester (OSu) group that reacts with primary amino groups, and a maleimide group that reacts with thiols (SH groups). "Homo-bifunctional Reagents" is a group of reagents that have two NHS esters. These can be used to bind two proteins that are close to each other, or to make a compound that has an amino group reactive to the amino group. In particular, hetero-bifunctional reagents are preferred, as they are expected to react selectively, with one structure binding to the structure on the polymer brush side and the other binding to a functional protein.

Examples of bifunctional reagents that can be used include "N-(6-Maleimidocaproyloxy)succinimide", "N-(4-Maleimidobutyryloxy)succinimide", "N-(6-Maleimidocaproyloxy)sulfosuccinimide, sodium salt", "N-(4-Maleimidobutyryloxy)sulfosuccinimide, sodium salt", "N-(8-Maleimidocapryloxy)sulfosuccinimide, sodium salt", "N-(11-Maleimidoundecanoyloxy)sulfosuccinimide, sodium salt", and "N-[(4-Maleimidomethyl)cyclohexylcarbonyloxy]sulfosuccinimide, sodium salt". In particular, "N-(11-Maleimidoundecanoyloxy)sulfosuccinimide, sodium salt" (Sulfo-KMUS) is preferred, as it has a long alkyl group and an epoxy group located away from the polymer brush, which is thought to be less likely to cause steric hindrance and easier to attach functional substances.

Bifunctional reagents that can be used include "Bis(sulfosuccinimidyl)suberate, disodium salt", "Dithiobis(succinimidyl undecanoate)", "Dithiobis(succinimidyl hexanoate)", "Dithiobis(succinimidyl propionate)", and "Dithiobis(sulfosuccinimidyl propionate), disodium salt".

[Dialdehyde compounds]
The protein crosslinking agent may be a dialdehyde compound. A dialdehyde compound is a compound having two aldehyde groups in the molecule. Formula (3) is a generalized structural formula of an example of a dialdehyde compound. The structure of formula (3) has two aldehydes. R ₂ in formula (3) is a structure that bonds each aldehyde. R ₃ may be, for example, an alkylene group (-C _n H _2n -) having 1 to 12 carbon atoms. R ₃ is preferably an alkylene group having 1 to 8 carbon atoms, and particularly preferably an alkylene group having 2 to 6 carbon atoms. For example, glutaraldehyde (1,5-pentanedial) may be used as the dialdehyde compound.

The present invention can use a protein crosslinking agent to bind a functional protein to a polymer brush. Examples of such functional proteins include protein G, protein A, protein L, lectins, and antibodies. These functional proteins can also be modified as needed, for example, by adding an antibody or capturing a glycan.

When a bifunctional reagent is used as the protein crosslinking agent, a functional substance that reacts with the bifunctional reagent and has a host structure is also used. Such a functional substance may be a substance with an antibody structure or a substance with a receptor structure.

[antibody]
The antibody may be, for example, an IgG antibody or an immunoglobulin such as IgM, IgA, IgD, or IgE. Furthermore, a secondary antibody or the like may be bound to the antibody.

[Receptor structure]
In addition, a receptor structure of a receptor-ligand reaction may be introduced. The ligand may be a low molecular weight substrate for an enzyme, a hormone, or the like. The receptor structure is a structure corresponding to these ligands. For example, biotin, avidin, or the like may be used.

[Measurement of antibody immobilization]
A molecule having an amino group or a thiol group is reacted with the epoxy group, and then a bivalent reagent is immobilized. An antibody-immobilized membrane can be produced by directly binding an antibody to this bivalent reagent. In the present invention, the antibody is directly bound to a high-concentration polymer brush extending three-dimensionally from a substrate via a bivalent reagent, and therefore the amount of antibody per unit area is high, resulting in a higher amount of virus capture than conventional materials with a monolayer of antibody immobilized thereon.

Since the antibody can be immobilized on the substrate in a three-dimensional layer at a high concentration, the antigen concentration rate per unit area is higher than that of a monolayer antibody. In addition, since the antibody is directly bonded to the polymer brush via a bivalent reagent (crosslinker), denaturation due to electric charge and peeling of the antibody, which occur in active adsorption, are unlikely to occur.
The functional molded article of the present invention can be used, for example, in immunochromatography, PCR, sewer surveillance, and the like, to improve virus concentration efficiency.

Since it can achieve a concentration efficiency far higher than existing virus concentration materials, it is expected to improve the sensitivity of immunochromatography and PCR methods. When applied to sewerage surveillance, it has the potential to become a new concentration material for COVID-19, which has not yet been established. In addition, since multiple antibodies can be immobilized on one type of substrate at once, it is expected to be applied to multiplex analysis of viruses. The technology of the present invention can be applied not only to antibodies and chelating reagents, but also to enzymes, ionic liquids, etc.

After introducing a bivalent reagent into the polymer brush, the antibody of the virus to be concentrated is bound to the bivalent reagent, making it possible to create a material that can efficiently concentrate only specific viruses by taking advantage of the high antigen recognition ability of the antibody.

[Introduction of host structure using sulfur-containing amine compound]
The functional molded article of the present invention can have a substance to be introduced that is a sulfur-containing amine-based compound having a structure containing an amine and a sulfur atom, and a host structure that has a nitrogen atom and a sulfur atom derived from the sulfur-containing amine-based compound.

The structure containing a sulfur atom in the sulfur-containing amine compound can be any one selected from the group consisting of thiol, sulfide, and dithioate. The structure of the amine compound is a primary amine or a secondary amine.

[Thiol]
A thiol has a structure in which the oxygen atom of a hydroxyl group is replaced with a sulfur atom. Formula (4) is a generalized structural formula of a sulfur-containing amine compound having a thiol structure. Formula (4) has a thiol structure. R ₄ in formula (4) is a structure that bonds an amino group with SH. R ₄ can be, for example, an alkylene group having 1 to 12 carbon atoms (-C _n H _2n -). _{R 4} is preferably an alkylene group having 1 to 8 carbon atoms, and particularly preferably an alkylene group having 2 to 6 carbon atoms. For example, 2-aminoethanethiol can be used as this compound.

[Sulfide]
A sulfide is a structure in which divalent sulfur is substituted with two organic groups. Formula (5) is a generalized structural formula of a sulfur-containing amine compound having a sulfide structure. The compound of formula (5) has a sulfide structure. R ₅₁ in formula (5) is one of the organic groups. R ₅₁ can be, for example, an alkyl group (-C _n H _2n+1 ) having 1 to 12 carbon atoms or an alkylene group (-C _n H _2n -) having an amino group at one end. R ₅₁ is preferably an alkyl group or alkylene group having 1 to 8 carbon atoms, and particularly preferably an alkyl group or alkylene group having 2 to 6 carbon atoms. R ₅₂ in formula (5) is a structure in which an amino group and SH are bonded. R ₅₂ can be, for example, an alkylene group (-C _n H _2n -) having 1 to 12 carbon atoms. R ₅₂ is preferably an alkylene group having 1 to 8 carbon atoms, and more preferably an alkylene group having 2 to 6 carbon atoms. As this compound, for example, 3-methylthiopropylamine (MTPA) or 2,2'-thiobisethylamine (TBEA) can be used.

The dithiocarboxylic acid can be, for example, 4-imidazoledithiocarboxylic acid (IDTCA).

[Sulfur-containing amine compounds]
As such a sulfur-containing amine compound, one or more substances selected from the group consisting of 4-imidazoledithiocarboxylic acid (IDTCA), 3-methylthiopropylamine (MTPA), 2-aminoethanethiol (AET), and 2,2'-thiobisethylamine (TBEA) can be used.

For example, the following can be used as a method using a chelate/complex reaction: A chelate molecule having a sulfur atom within the molecule is fixed between the epoxies of a GMA polymer that becomes a polymer brush. Compared to conventional chelate resins in which chelate molecules are arranged in a single layer, the functional molded body of the present invention has chelate molecules fixed at a high density to a high-concentration polymer brush that extends three-dimensionally, resulting in a high adsorption capacity for metals such as mercury per unit area.

In other words, sulfur-based molecules, which have a high affinity for mercury, can be fixed in high concentrations in a three-dimensional layer rather than in a monolayer on the substrate, resulting in a higher adsorption capacity and higher concentration efficiency than existing adsorbents. In addition, the chelate captures heavy metals that form complexes, making it less susceptible to the effects of coexisting substances.

The functional molded body of the present invention can recover metals such as mercury with high efficiency and speed by densely immobilizing molecules containing sulfur atoms that have a high affinity for metals such as mercury on a substrate. This makes it suitable as a pretreatment material for recovering or concentrating specific hazardous metals.

In this way, the functional molded article of the present invention is produced by irradiating a substrate such as a general-purpose resin with an electron beam to generate radicals, which are then brought into contact with a reactive monomer to produce a polymer brush. By introducing appropriate functional groups into this polymer brush, new functionality can be imparted, and the molded article can be used as a molded article that captures various guest substances using a guest-host reaction.

[Uses of functional molded bodies]
The functional molded article of the present invention can be used to capture guest substances in accordance with the host structure. The capture of guest substances can be performed by any method that is suitable for the shape of the substrate and the conditions in which the guest substances are present.
For example, a fluid such as a liquid containing a guest substance is brought into contact with the functional molded body, and the guest substance in the fluid is captured by the host structure of the functional molded body. This contact may be continuous by flowing the fluid, or the functional molded body may be immersed in the fluid. The guest substance captured by the host structure may be appropriately desorbed and collected.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless the gist of the invention is changed.

Example 1 Preparation of a Functional Film for Capturing Mercury A functional molded product having a chelate structure was produced using a sulfur-containing amine compound.

Hollow fiber membrane: Asahi Kasei Chemical Corporation's Micro-The MF (outer diameter 3 mm, inner diameter 2 mm, pore size 0.3 μm) was used as a porous hollow fiber membrane made of polyethylene (PE), a polymer substrate.

The mercury standard solution (Hg 1000) used was from Wako Pure Chemical Industries, Ltd.
N,N-Dimethylformamide (DMF): Wako Pure Chemical Corporation Glycidyl methacrylate (GMA): Wako Pure Chemical Corporation Ethylenediamine (EDA): Wako Pure Chemical Corporation Ethanol (EtOH): Wako Pure Chemical Corporation Methanol (MeOH): Wako Pure Chemical Corporation Ammonia water (NH ₃ ): Wako Pure Chemical Corporation Hydrochloric acid (HCl): Wako Pure Chemical Corporation Nitric acid (HNO ₃ ): Wako Pure Chemical Corporation 2-Aminoethanethiol (AET): Tokyo Chemical Industry Co., Ltd., first class or special grade reagent 2,2'-Thiobisethylamine (TBEA): Tokyo Chemical Industry Co., Ltd., first class or special grade reagent 3-Methylthiopropylamine (MTPA): Tokyo Chemical Industry Co., Ltd., first class or special grade reagent 4-Imidazoledithiocarboxylic acid (IDTCA): Sigma-Aldrich Co. LLC, Santa Cruz Biotechnology, Inc.

[Electron beam graft polymerization]
1) At the Kyushu EB Center of HV Corporation, a PE porous hollow fiber membrane substrate was irradiated with an electron beam at a total dose of 200 kGy to generate radicals.
2) Nitrogen was bubbled through a mixed solution of 10 vol % GMA/MeOH for 1 hour or more to replace oxygen in the solution with nitrogen.
3) The film in which radicals were generated was placed in a vacuumed reaction tube, and then a mixed solution of 10 vol% GMA/MeOH was poured in to immerse the film. Next, the film was irradiated with 40 kHz ultrasonic waves for 1 minute using an ultrasonic cleaner (MCS-6, AS ONE Corporation) (US CLEANER, AS ONE Corporation) to remove air from within the film structure, and then the graft polymerization reaction was carried out while shaking for 10 minutes in a 40°C constant temperature shaking water bath (T-N225, Thomas Scientific Instruments Co., Ltd.).
4) The membrane was then washed twice alternately with DMF and MeOH, rinsed twice with pure water, and placed in an ultrasonic cleaner while immersed in pure water, and dried for 24 hours in a dryer (DNS-600D, Tokyo Rikakikai Co., Ltd.) at 80°C.

The amount of introduced GMA was calculated as the graft ratio using formula (1).
dg [%] = (W1-W0)/W0× 100 (1)
Here, W0 and W1 are the dry weights of the membrane before and after graft polymerization. In this study, a GMA membrane with a graft ratio of about 70% was prepared.

[Introduction of Functional Groups]
The structures of the sulfur-containing molecule and the nitrogen-containing molecule for comparison introduced into the membrane as functional groups are shown in the following formulas: EDA was used as a comparative example that does not contain sulfur atoms.

AET, TBEA, and MTPA were adjusted to 1.5 mol/L using pure water.
About 5 g of IDTCA was dissolved in methanol, filtered, and then concentrated to 25 mL using a rotary evaporator (N-1000V-W, EYELA, Tokyo Rikakikai Co., Ltd.).
The introduction of functional groups was carried out by measuring the weight of the dried GMA film, immersing the GMA film once in EtOH and three times in pure water, and cleaning the film in an ultrasonic cleaner at 25° C. for 15 minutes.
The washed membrane was immersed in the prepared functional group solution and reacted in a windowed thermostatic water bath (TBN302DA, Advantec Co., Ltd.) set at 80° C. to introduce functional groups into the epoxy groups of the GMA.
The IDTCA solution was reacted at 60° C. because the solvent was MeOH. After the introduction of the functional groups, the membrane was immersed in pure water, EtOH, and pure water in that order, washed with an ultrasonic cleaner, and then dried with a dryer.
The IDTCA membrane was immersed in MeOH twice and in pure water three times, washed in an ultrasonic cleaner, and then dried in a dryer. The functional group introduction rate was calculated from the change in membrane weight after drying before and after the introduction of functional groups using the following formula.

Introduction rate (%) = "Difference in membrane weight before and after functional group introduction (g) / GMA membrane weight" x 100

[Mercury adsorption/desorption test]
An arbitrary amount of ethanol was passed through each of the prepared functional group-introduced membranes using a permeation apparatus as outlined in FIG. 3, and then about 10 mL of 0.1 mol/L hydrochloric acid was passed through the membrane to open the unreacted epoxy groups.
Then, pure water was passed through the membrane to wash the inside, and then a mercury solution adjusted to an arbitrary concentration of about pH 1.0 was passed through at 2.5 mL/min to adsorb mercury to the functional group-introduced membrane. After the mercury adsorption was saturated, 20 mL of pure water was passed through, and 25 mL of ammonia water adjusted to pH 10 was passed through to desorb mercury from the membrane. The collected solution was measured with a microwave plasma atomic emission spectrometer (4100MP-AES, Agilent Technologies, Inc.: MP-AES) to calculate the mercury concentration.

The amount of mercury adsorption was calculated using the following formula.
Mercury adsorption amount (mg/g) = "Amount of adsorbed mercury (mg)/Weight of membrane (g)"

The mercury desorption rate was calculated using the following formula.
Mercury desorption rate (%) = "amount of desorbed mercury (mg) / amount of adsorbed mercury (mg)" x 100

[Results and Discussion]
Mercury adsorption and desorption test Adsorption breakthrough curves were obtained when 5 ppm and 10 ppm mercury solutions were passed through the PE membrane and the EDA membrane (introduction rate 77%). The horizontal axis of the adsorption breakthrough curve is the amount of feed liquid relative to the membrane volume, and the vertical axis is the effluent concentration relative to the initial concentration. The amount of mercury adsorbed was 0.31 mg/g for the PE membrane and 0.40 mg/g for the EDA membrane, and almost no mercury was adsorbed by either membrane.

Next, the results were obtained when a 10 ppm mercury solution was passed through an AET membrane with an introduction rate of 63%. The amount of mercury adsorbed was 11.45 mg/g, and the desorption rate was 16.9%. Mercury was not adsorbed by the PE membrane and EDA membrane, which do not have sulfur atoms, whereas mercury was adsorbed by the AET membrane, which does have sulfur atoms, confirming that there is an affinity between sulfur atoms and mercury even within the membrane.

Furthermore, in order to compare the difference between thiol groups and sulfides among molecules having sulfur atoms, a comparison was made between a TBEA membrane and an MTPA membrane. The results were obtained when a 10 ppm mercury solution was passed through a TBEA membrane with a sulfur introduction rate of 36%, and when a 100 ppm mercury solution was passed through an MTPA membrane with a sulfur introduction rate of 68%.

The TBEA membrane had a mercury adsorption amount of 6.69 mg/g and a desorption rate of 18.8%, while the MTPA membrane had a mercury adsorption amount of 86.17 mg/g and a desorption rate of 69.8%, showing that the MTPA membrane had about 13 times the amount of mercury adsorption as the TBEA membrane. This is because the TBEA membrane has amino groups at both ends, which bridge the polymer brushes, and the polymer brushes may have a lower degree of freedom, which may have reduced the frequency factor with mercury, or the polymer brushes may not be able to take a conformation to form a complex with mercury due to the reduced degree of freedom. In addition, the TBEA membrane had about half the introduction rate and adsorption amount of the AET membrane, so if the introduction rates of the AET membrane and the TBEA membrane are the same, it is thought that the mercury adsorption amounts will be about the same.

It was thought that when thiol groups with high affinity for mercury are present in the membrane, as in the AET membrane, the amount of mercury adsorbed would be high, but in fact the results were about the same as with TBEA. Therefore, it was thought that the thiol groups may have reacted nucleophilically with the epoxy groups, so a maleimide solution that reacts specifically with thiol groups was used to confirm the bonding mode with the epoxy groups. When the AET membrane was immersed in the maleimide solution, no maleimide was introduced, suggesting that it is highly likely that both the thiol groups and amino groups in the AET membrane react with the epoxy groups, cross-linking the polymer brushes. Therefore, it is thought that the amounts of adsorption in the AET membrane and the TBEA membrane were about the same.

Next, the results were obtained when a 200 ppm mercury solution was passed through an IDTCA membrane with an introduction rate of 51%. The amount of mercury adsorbed was 66.46 mg/g, and the desorption rate was 28.6%. In addition, when the introduction rate was 66%, the amount of mercury adsorbed was 134.1 mg/g, but it did not break through.

The reason for the high adsorption amount of the IDTCA film is thought to be that the nucleophilicity of dithioates is reduced due to the delocalization of electrons, and the thiol groups do not bond with epoxy groups, while only the imidazole groups undergo a nucleophilic reaction with epoxy groups. Therefore, the degree of freedom of the polymer brush does not decrease, and the frequency factor with mercury does not decrease, which is thought to be why the IDTCA film showed a high adsorption amount. In addition, since it has two sulfur atoms, it is thought to have a high ability to form complexes with mercury. However, while the adsorption amount is high, the desorption rate is less than half that of MTPA. This is thought to be because the bond between the sulfur atoms and mercury is strong due to the presence of two sulfur atoms.

Next, the results were obtained when a 100 ppm mercury solution was passed through an IDTCA membrane with an introduction rate of 33%. The amount of mercury adsorbed was 10.72 mg/g, and the desorption rate was 44.9%, which is 1.6 times higher than the membrane with an introduction rate of 51%. This is thought to be because the lower the introduction rate of IDTCA, the lower the local density of IDTCA in the membrane, making it impossible to take a conformation for complexing with mercury, resulting in a decrease in the amount of adsorption and an improvement in the amount of desorption due to the difficulty in forming a stable complex.

In comparing thiol groups and sulfides, it was found that sulfides showed higher adsorption and desorption rates than the AET and MTPA membranes. However, when the functional groups bridged the polymer brushes, both the adsorption amount and desorption rate became similar to those of thiols.
The results obtained so far are shown in Table 1, which shows the results of adsorption/desorption tests for various functional group membranes.

This article summarizes the main results of developing a filter capable of highly efficient concentration of mercury by introducing molecules containing sulfur atoms into the membrane and selecting functional groups suitable for concentrating mercury. (1) In order to concentrate mercury, functional groups that have sulfur atoms in the molecule and react with epoxy rings at only one end are suitable. (2) When mercury is adsorbed, it is present in large amounts on the inside of the membrane, and when it is desorbed, it moves to the outside and is desorbed after repeated adsorption and desorption.

Example 2: Production of functional membrane for capturing viruses A membranous functional molded article capable of capturing viruses was produced using a bivalent reagent and an IgG antibody.

In the same manner as in Example 1, a polyethylene flat membrane was used instead of the hollow fiber membrane. Glycidyl methacrylate (GMA) was graft-polymerized onto the polyethylene flat membrane irradiated with an electron beam. The shaking time for this graft polymerization was 20 minutes, and the graft ratio of GMA was 200%.
Then, ethylenediamine (EDA) was introduced to obtain an EDA membrane.
Moreover, 2-aminoethanethiol (AET) was introduced instead of EDA to prepare an AET membrane.

Next, the EDA membrane was immersed in an ice bath in a 2 mmol/L aqueous solution of N-(11-Maleimidoundecanoyloxy) sulfosuccinimide (Sulfo-KMUS) to attempt the introduction of a bifunctional reagent.

We also attempted to introduce a bifunctional reagent into the AET membrane by immersing it in a 2 mmol/L DMSO solution of Sulfo-KMUS.

[Results and Discussion]
The functional group introduction into the GMA membrane was calculated to be 56% for the EDA membrane and 46% for the AET membrane. In addition, the introduction rate of the bifunctional reagent into each membrane was 39% for the EDA membrane relative to the weight of the added bifunctional reagent, which was a high introduction rate. This is expected to lead to the realization of a virus capture material. On the other hand, the introduction of functional groups into the AET membrane was confirmed, but did not lead to the introduction of the bifunctional reagent.

[Luminescence test]
Based on this test, IgG immobilization was verified using HRP-anti-IgG, which specifically recognizes the immobilized IgG. Figure 4 shows the results of exposure photography.

The top of Figure 4 shows the state at the time of exposure photography, and identifies the location of the membrane. The bottom of Figure 4 shows the luminescence photographed. (a) is the EDA membrane (membrane up to the point where EDA was introduced). (b) is the bivalent reagent membrane (membrane up to the point where bivalent reagent was introduced). (c) to (e) are membranes in which the amount of IgG solution was changed and IgG was introduced after the bivalent reagent. In (c) to (e), luminescence was confirmed, and it was confirmed that the secondary antibody could be immobilized, as the antibody was successfully introduced.

Example 3 Preparation of Protein G Immobilized Membrane A protein G immobilized membrane was prepared.
[reagent]
Glutaraldehyde: Fujifilm Wako Pure Chemical Industries, Ltd. "25% glutaraldehyde solution, Wako Grade 1"
・Protein G: Fujifilm Wako Pure Chemical Industries, Ltd. "Protein G, recombinant"
・IgG antibody: Fujifilm Wako Pure Chemical Industries, Ltd. "Normal rabbit IgG, whole molecule, purified product"

[Production method]
1) Graft Polymerization of GMA Electron beam graft polymerization was carried out in the same manner as in Example 2 to graft polymerize glycidyl methacrylate (GMA).

2) Introduction of Ethylenediamine Similarly, in the same manner as in Example 2, ethylenediamine was introduced into a graft polymer of glycidyl methacrylate (GMA) to obtain an EDA membrane.

3) Glutaraldehyde introduction Glutaraldehyde was used as a cross-linking agent to bind protein G to amino groups.
The EDA membrane was immersed in a 0.5% by volume aqueous solution of glutaraldehyde (GA) at 25° C. (room temperature) for about one day, and then washed with pure water several times.

4) Protein G adsorption Protein G specifically recognizes and captures IgG antibodies. A 0.1 g/L protein G solution was passed through a cylindrical porous hollow fiber membrane using a batch-type permeation device. The flowing protein G solution was collected, and the amount of protein G adsorbed to the membrane was calculated by absorptiometry. This was continued until the absorbance no longer changed, that is, until the adsorption equilibrium was reached. As a result, the amount of protein G immobilized was 28 (g-protein G/kg-fiber).

5) IgG antibody adsorption A 0.2 g/L IgG antibody solution was run through a batch-type permeation device. The running IgG solution was sampled at regular intervals, and the IgG adsorption behavior to the membrane was evaluated by spectrophotometry. The absorbance decreased over time, confirming that adsorption was progressing, and adsorption was saturated in about 60 minutes, capturing the IgG.

[Example 4] Preparation of lectin-immobilized membrane [Reagents]
Lectin: MP Biomedicals, Inc. "Concanavalin A"
・Glycoprotein: Fujifilm Wako Pure Chemical Industries, Ltd. "Albumin, egg-derived"

A lectin-immobilized membrane was prepared in the same manner as in Example 3. Instead of protein G as in Example 3, a lectin (concanavalin A) was immobilized.

Lectins recognize and capture glycans bound to proteins. The flowing lectin solution was sampled at regular intervals, and the lectin adsorption behavior to the membrane was evaluated by spectrophotometry. In the membrane prepared in this example, the lectin (concanavalin A) captured the glycoprotein (albumin).

It was found that the protein G fixed membrane recognized and adsorbed IgG antibodies, while the lectin (concanavalin A was used in this case) fixed membrane recognized and adsorbed glycoproteins (ovalbumin was used in this case).

The functional molded article of the present invention can be used to adsorb and capture viruses, mercury, etc., and is industrially useful.

Claims (9)

A step (A) of irradiating a substrate with an electron beam to generate radicals on a surface layer of the substrate;
a step (B) of reacting a monomer for polymer brushes having an epoxy group with the radicals of the surface layer of the substrate to secondary polymerize the polymer brushes, thereby providing the polymer brushes on the surface layer of the substrate;
and (C) a step of reacting a substance to be introduced with the epoxy group of the polymer brush to introduce a functional structure to the polymer brush, the functional structure being a host structure for a host-guest reaction using the substance to be introduced,
The method for producing a functional molded article, wherein the host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction. The manufacturing method according to claim 1, wherein the monomer for the polymer brush is glycidyl methacrylate or glycidyl acrylate. The substance to be introduced in the introducing step (C) is a diamine compound, a protein crosslinking agent, and a functional substance,
The step (C) of introducing includes a step (C-1) of reacting the epoxy group of the polymer brush with a diamine compound to bond an amino group derived from the diamine compound;
a step (C-2) of reacting the protein crosslinking agent that reacts with the amino group;
The method according to claim 2, further comprising the step (C-3) of reacting the functional substance that reacts with the protein crosslinking agent. The method according to claim 3, wherein the protein crosslinking agent is a bifunctional reagent and/or a dialdehyde compound, and the functional substance is a functional protein. The method according to claim 4, wherein the bifunctional reagent is N-(11-Maleimidoundecanoyloxy)sulfosuccinimide, sodium salt, and the dialdehyde compound is glutaraldehyde. the substance to be introduced is a sulfur-containing amine compound having a structure containing an amine and a sulfur atom,
The method according to claim 2 , wherein the host structure has a nitrogen atom and a sulfur atom derived from the sulfur-containing amine compound. The method according to claim 6, wherein the structure containing a sulfur atom in the sulfur-containing amine compound is any one selected from the group consisting of thiol, sulfide, and dithiocarboxylic acid. The method according to claim 7, wherein the sulfur-containing amine compound is one or more substances selected from the group consisting of 4-imidazoledithiocarboxylic acid, 3-methylthiopropylamine, 2-aminoethanethiol, and 2,2'-thiobisethylamine. A substrate, a polymer brush layer provided on a surface layer of the substrate, and a functional structure that serves as a host structure for a host-guest reaction and is introduced into the polymer brush layer,
The host-guest reaction is any one selected from the group consisting of an antibody-antigen reaction, a ligand-receptor reaction, and a chelate-complex reaction.

Images