Compound, metal nanoparticle composite using the compound, and method for detecting a target molecule

Abstract

To provide a metal nanoparticle complex that shows an affinity labeling function, a novel compound that has a great ability to modify metal nanoparticles constituting the complex, and a method for detecting a target molecule by using the metal nanoparticle complex.SOLUTION: For example, a compound is shown by the following formula. A metal nanoparticle complex according to an embodiment is a complex of metal nanoparticles, the compound, and a ligand-bearing compound, where the compound and the ligand-bearing compound are bound to the metal nanoparticles.SELECTED DRAWING: None

Description

[Technical Field] 【0001】 This disclosure relates to a compound, a metal nanoparticle composite using the compound, and a method for detecting a target molecule. [Background technology] 【0002】 PEG-lipoic acid derivatives, which are formed by bonding polyethylene glycol (hereinafter also referred to as PEG) to lipoic acid, are known to have high water solubility, excellent metal surface modification ability, and metal nanoparticle stabilization properties. For this reason, PEG-lipoic acid derivatives are used as modifiers and coatings for metal nanoparticles (see, for example, Non-Patent Document 1 and Patent Document 1). 【0003】 PEG lipoic acid derivatives can be covalently bonded to the surface of metal nanoparticles by a suitable metal nanoparticle synthesis reaction or ligand exchange reaction, and depending on the manufacturing conditions, it is possible to obtain metal nanoparticle modifiers in which the PEG lipoic acid derivative is densely modified on a monolayer film (see, for example, Non-Patent Documents 2-4). 【0004】 In recent years, methods have been developed to obtain protein-modified metal nanoparticles by introducing more suitable functional groups (e.g., protein reactive groups) to the PEG-lipoic acid derivatives (see, for example, Non-Patent Document 5). Nanoparticles modified with specific proteins are expected to have applications as detection reagents, diagnostic agents, and drug candidates (see, for example, Non-Patent Document 6). 【0005】 The main examples of protein reactive groups introduced onto metal nanoparticles include amino groups, carboxyl groups, alkyne groups, and azide groups (see, for example, Non-Patent Documents 7-9 and Patent Document 2). All of these protein reactive groups require the addition of reaction reagents, such as activators, to initiate a reaction with proteins. Furthermore, amino groups and carboxyl groups generally do not exhibit substrate selectivity or regioselectivity. [Prior art documents] [Patent Documents] 【0006】 [License 1] U.S. Patent No. 9,446,152 (B2) [License 2] U.S. Patent No. 8,378,075 (B2) [Non-licensed literature] 【0007】 [Non-licensed Document 1] Karakoti et al. Angew. Chem. Int. Ed. 2011, 50, 1980-1994 [Non-licensed Document 2] Susumu et al. Nat. Prot. 2009, 4, 412-423 [Non-licensed Document 3] Sakurai et al. Chem. Sci., 2016,7, 702-706 [Non-licensed Document 4] Sakurai et al, Bioorg. Med. Chem. Lett, 2018 [Non-licensed Document 5] Karakoti et al. Angew. Chem. Int. Ed. 2011, 50, 1980-1994. [Non-licensed Document 6] Saha et al. Chem. Rev. 2012, 112, 5, 2739-2779. [Non-licensed Document 7] Brennan et al. Bioconj. Chem. 2006, 17,1373; Zhang, et al. Langmuir 2010, 26, 10171 [Non-licensed Document 8] Narita et al. Bioorg. Med. Chem. Lett. 2019, 29, 126768 [Non-licensed Document 9] GT Hermanson, Bioconjugate Techniques 2nd Ed. Academic Press. 2008. [Overview of the Initiative] [Problems that the invention aims to solve] 【0008】 Conventional technologies have not been able to select specific amino acid residues as modification sites using metal nanoparticle complexes, nor have they been able to selectively modify specific proteins in a mixed protein solution. In other words, no metal nanoparticle complexes with affinity labeling capabilities capable of inducing crosslinking reactions through covalent bond formation with specific proteins were known. 【0009】 This disclosure aims to provide a metal nanoparticle composite exhibiting affinity labeling function, a novel compound with excellent metal nanoparticle modification ability constituting the composite, and a method for detecting target molecules using the metal nanoparticle composite. [Means for solving the problem] 【0010】 As a result of diligent research, the inventors have found that a metal nanoparticle composite, in which a specific compound and a compound containing a ligand are bound to metal nanoparticles, exhibits affinity labeling functionality. 【0011】 Examples of embodiments of this embodiment are described below. 【0012】 (1) A compound represented by the following general formula (1), (2), or (3). [ka] (In general formula (1), X 1 is O or NH, Y 1 R is O, NH, a group represented by formula (4) below, or a group represented by formula (5) below, 1 (The base is selected from the following formulas (6) to (14) and (20) to (51).) [Chemical formula] (In general formula (2), X 2 is O or NH, Y 2 is O, NH, a group represented by the following formula (4), or a group represented by the following formula (5), and R 2 is a group selected from the following formulas (8) to (19) and (21) to (51).) [Chemical formula] (In general formula (3), n is an integer selected from 1, 2, 4, 5, and 7 to 12, X 3 is O or NH, Y 3 is O, NH, a group represented by the following formula (4), or a group represented by the following formula (5), and R 3 is an electrophilic group.) [Chemical formula] (In formulas (4) and (5), a indicates the bonding site with R 1 , R 2 or R 3 , and b indicates the bonding site with CH2. In formula (5), x is an integer from 1 to 10.) [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] (In formula (10), m is an integer from 1 to 17, in formulas (11), (34), (39), and (40), q is an integer from 0 to 14, and in formulas (29) and (30), r is an integer from 1 to 9.) 【0013】 (2) The said R 3(1) The compound according to (1), wherein n is a group selected from formulas (6) to (51). (3) The compound according to (1) or (2), wherein n is 8 to 12. (4) A complex of metal nanoparticles, a compound described in any of (1) to (3), and a compound having a ligand, A metal nanoparticle composite in which the compound described in any of (1) to (3) above and the compound having the ligand are bound to the metal nanoparticle. (5) A method for detecting a target molecule, comprising the step of bringing the metal nanoparticle composite described in (4) into contact with the sample to form a crosslinked composite between the target molecule in the sample and the metal nanoparticle composite. (6) A high-throughput screening method that includes the target molecule detection method described in (5) as part of a high-throughput screening method. [Effects of the Invention] 【0014】 The method disclosed herein provides a metal nanoparticle composite exhibiting affinity labeling function, a novel compound with excellent metal nanoparticle modification ability constituting the composite, and a method for detecting target molecules using the metal nanoparticle composite. [Modes for carrying out the invention] 【0015】 The present invention will be described in detail below. 【0016】 <Compound> The compounds according to this embodiment are compounds represented by the following general formulas (1), (2), or (3). The compounds according to this embodiment are compounds that constitute the metal nanoparticle composite described later, and by using these compounds, the metal nanoparticle composite described later can exhibit affinity labeling function. The compounds represented by general formulas (1), (2), or (3) have a five-membered ring structure having a disulfide, and can bind to metal nanoparticles by cleaving the disulfide. 【0017】 [ka] 【0018】 (In general formula (1), X 1 is O or NH, Y 1 R is O, NH, a group represented by formula (4) below, or a group represented by formula (5) below, 1 (The base is selected from the following formulas (6) to (14) and (20) to (51).) In general formula (1), R 1 In one preferred embodiment, the group is selected from the following formulas (6) to (14) and (20) to (47). 【0019】 [ka] 【0020】 (In general formula (2), X 2 is O or NH, Y 2 R is O, NH, a group represented by formula (4) below, or a group represented by formula (5) below, 2 (The base is selected from the following formulas (8) to (19) and (21) to (51).) In general formula (2), R 2 In one preferred embodiment, the group is selected from the following formulas (8) to (19) and (21) to (47). 【0021】 [ka] 【0022】 (In general formula (3), n is an integer selected from 1, 2, 4, 5 and 7 to 12, X 3 is O or NH, Y 3 R is O, NH, a group represented by formula (4) below, or a group represented by formula (5) below, 3 (It is an electrophile.) 【0023】 [ka] 【0024】 (In equations (4) and (5), a is R 1 , R 2 or R 3 The bond site is shown, and b is shown as the bond site with CH2. (In equation (5), x is an integer from 1 to 10.) 【0025】 [ka] 【0026】 [ka] 【0027】 [ka] 【0028】 [ka] 【0029】 [ka] 【0030】 (In equation (10), m is an integer between 1 and 17; in equations (11), (34), (39), and (40), q is an integer between 0 and 14; and in equations (29) and (30), r is an integer between 1 and 9.) 【0031】 In general formula (3), the R 3 The group is an electrophile, and in one preferred embodiment, it is a group selected from formulas (6) to (51), and in another preferred embodiment, it is a group selected from formulas (6) to (47). These groups are preferred from the viewpoint of ease of synthesis and from the viewpoint of suitably exhibiting affinity label function. 【0032】 R in general formula (1) 1, R in general formula (2) 2 , and R of general formula (3) 3 These are electrophiles, and the presence of electrophiles allows the metal nanoparticle composite to exhibit affinity labeling functionality. 2 and R 3 In one preferred embodiment, the group is selected from (8), (9), (15), (19), (25), (50), and (51). 1 In one preferred embodiment, the group is selected from (8), (9), (25), (50), and (51). 【0033】 In general formula (3), n is an integer selected from 1, 2, 4, 5, and 7 to 12, and is preferably 8 to 12. Among the compounds represented by general formulas (1), (2), or (3), the compound represented by general formula (3) in which n is 8 to 12 tends to have high dispersibility and water solubility, and as a result it is possible to improve the dispersibility of the metal nanoparticle composite, so it is preferred. 【0034】 X in general formula (1) 1 X in general formula (2) 2 , and X of general formula (3) 3 It is either O or NH. Although it varies depending on the synthesis method, NH is preferred from the viewpoint of ease of synthesis. 【0035】 Y in general formula (1) 1 , Y in general formula (2) 2 , and Y of general formula (3) 3 This group is O, NH, a group represented by formula (4), or a group represented by formula (5). Although it varies depending on the synthesis method, it is preferable from the viewpoint of ease of synthesis that it is NH, a group represented by formula (4), or a group represented by formula (5). 【0036】 In equations (4) and (5), a is R 1 , R 2 or R 3The formula (5) shows the bonding site with CH2, and b shows the bonding site with CH2. In formula (5), x is an integer from 1 to 10. This range is preferred because it offers high dispersibility, water solubility, and rotational freedom. 【0037】 In formula (10), m is an integer from 1 to 17, preferably from 1 to 8. In formulas (11), (34), (39), and (40), q is an integer from 0 to 14, preferably from 1 to 9. In formulas (29) and (30), r is an integer from 1 to 9. These ranges are preferred because they offer high dispersibility, water solubility, and rotational freedom. 【0038】 -Y in general formula (1) 1 -R 1 , -Y of general formula (2) 2 -R 2 , and -Y of general formula (3) 3 -R 3 Examples of structures (combinations) include structures selected from the following groups ((A-1), (A-2), and (A-3), or (A-1) and (A-2)). The following structures are Y 1 , Y 2 , Y 3 However, it is a group represented by formula (4) or formula (5). -Y of general formula (1) 1 -R 1 For example, R 1 Structures that are not groups selected from formulas (6) to (14) and (20) to (51) are excluded, and the -Y of general formula (2) 2 -R 2 For example, R 2 Structures that are not groups selected from equations (8) to (19) and (21) to (51) are excluded. 【0039】 [ka] 【0040】 [ka] 【0041】 In (A-2), x is synonymous with x in equation (5), and q is synonymous with q in equations (11), (34), (39), and (40). 【0042】 [ka] 【0043】 The structures represented by the aforementioned groups ((A-1), (A-2), and (A-3)) are Y 1 , Y 2 , Y 3 However, the group is represented by formula (4) or formula (5), but in the group ((A-1), (A-2), and (A-3)), Y 1 , Y 2 , Y 3 The structure in which is replaced with NH is also the same as the -Y in general formula (1). 1 -R 1 , -Y of general formula (2) 2 -R 2 , and -Y of general formula (3) 3 -R 3 This is a preferred configuration (combination) of the structure. 【0044】 There are no particular restrictions on the synthesis method of compounds represented by general formulas (1), (2), or (3), and they can be synthesized based on known organic synthesis methods. For example, compounds represented by general formulas (1), (2), or (3) can be synthesized by reacting the carboxyl group of α-lipoic acid with the hydroxyl group of polyethylene glycol to obtain lipoic acid to which PEG is attached, and then reacting the hydroxyl group of PEG with a compound having the desired electrophile. Another example is to react the carboxyl group of α-lipoic acid with the amino group of polyethylene glycol modified so that at least one end is an amino group to obtain lipoic acid to which PEG is attached, and then reacting the amino group or hydroxyl group of PEG with a compound having the desired electrophile. 【0045】 <Metal nanoparticle composite> The metal nanoparticle composite according to this embodiment is a composite of the aforementioned compound (the compound described in the <Compound> section above) and a compound having a ligand, wherein the aforementioned compound and the compound having the ligand are bound to the metal nanoparticles. The metal nanoparticle composite according to this embodiment has affinity labeling functionality and can therefore be used in methods for detecting target molecules. The reason the metal nanoparticle composite has affinity labeling functionality is that the ligand binds to the target molecule, for example, forming a bond such as a hydrogen bond, which is not usually a covalent bond, and further, the aforementioned compound R 1 , R 2 , or R 3 However, it is presumed that this is because it is possible to form a covalent bond with the target molecule and create a crosslinked complex between the target molecule and the metal nanoparticle composite. 【0046】 In a metal nanoparticle composite, there are no particular restrictions on the amount of the aforementioned compound bound to the metal nanoparticles, however, the value obtained by dividing the area of ​​the metal nanoparticles by the number of molecules of the aforementioned compound bound to the metal nanoparticles is, for example, 0.24 nm. 2 Preferably, the number of molecules is / or more. 【0047】 In a metal nanoparticle composite, there are no particular restrictions on the amount of compound having a ligand that binds to the metal nanoparticles, however, the value obtained by dividing the area of ​​the metal nanoparticles by the number of molecules of the compound having a ligand that binds to the metal nanoparticles is, for example, 0.24 nm. 2 Preferably, the number of molecules is / or more. 【0048】 (Metal nanoparticles) Examples of metal nanoparticles include gold nanoparticles, silver nanoparticles, platinum nanoparticles, copper nanoparticles, palladium nanoparticles, alloy nanoparticles of these metals, and quantum dots. Colloidal metal nanoparticles may also be used. It is preferable to use particles with a high specific gravity, such as gold nanoparticles, as these particles allow the crosslinked composite to be recovered by simple operations such as centrifugation. 【0049】 The median diameter (D50) of the metal nanoparticles is, for example, between 5 nm and 50 nm, and preferably between 10 nm and 30 nm. The median diameter (D50) of the metal nanoparticles is the particle size that represents the 50% integrated value of the integrated distribution curve measured by dynamic light scattering (DLS). 【0050】 There are no particular restrictions on the quantum dots used; for example, quantum dots containing group II-VI compounds, group III-V compounds, or group IV elements as components (also referred to as "group II-VI quantum dots," "group III-V quantum dots," and "group IV quantum dots," respectively) can be used. 【0051】 Specific examples of quantum dots include, but are not limited to, CdSe, CdS, CdTe, ZnSe, ZnS, ZnTe, InP, InN, InAs, InGaP, GaP, GaAs, PbS, Si, and Ge. 【0052】 It is also possible to use quantum dots in which a shell is placed on top of a quantum dot that has a core as described in the above specific example. Hereafter, when the core is CdSe and the shell is ZnS, quantum dots with a shell will be written as CdSe / ZnS. Examples of quantum dots with a shell include, but are not limited to, CdSe / CdS, CdS / ZnS, InP / ZnS, CdSe / ZnS, InGaP / ZnS, Si / SiO2, Si / ZnS, Ge / GeO2, Ge / ZnS, etc. 【0053】 As metal nanoparticles, those that have been surface-treated with organic compounds or the like may be used, if necessary. 【0054】 (Compounds containing ligands) The ligand-containing compound can be any compound that contains a ligand and is capable of binding to metal nanoparticles; there are no particular restrictions. 【0055】 The ligand is not particularly limited as long as it can specifically bind to the target molecule (a specific bioactive substance) in the sample. In this embodiment, "bioactive substance" is a term that refers to all molecules with physiological functions (e.g., biomolecules). 【0056】 Examples of target molecules include target proteins. Ligands can be any structure that specifically complexes with the target molecule. For example, low molecular weight physiologically active substances can be used as ligands. Examples of target molecule-ligand combinations are shown in Table 1 below. 【0057】 [Table 1] 【0058】 Furthermore, as a combination of a target molecule and a ligand, a specific ligand can be adopted as the ligand, and a substance that specifically complexes with that ligand can be defined as the target molecule. 【0059】 The ligand-containing compound preferably has a functional group for binding to metal nanoparticles. The functional group preferably has a thiol (e.g., alkanethiol) or disulfide. 【0060】 (Method for manufacturing metal nanoparticle composites) There are no particular restrictions on the method for producing the metal nanoparticle composite; it is sufficient to bind the aforementioned compound (the compound described in the <Compounds> section above) and a compound having a ligand to the metal nanoparticles. 【0061】 There are no particular restrictions on the order in which the compounds are bound to the metal nanoparticles. The aforementioned compounds may be bound first, followed by the ligand-containing compounds; the ligand-containing compounds may be bound first, followed by the aforementioned compounds; or the aforementioned compounds and the ligand-containing compounds may be bound simultaneously. 【0062】 Generally, thiols and disulfides are known to readily bind to metal nanoparticles, especially gold nanoparticles. Therefore, the aforementioned compounds can readily bind to metal nanoparticles, and if the ligand-containing compound also contains a thiol or disulfide, the ligand-containing compound can also readily bind to metal nanoparticles. 【0063】 If the metal nanoparticles have difficulty forming bonds with the aforementioned compounds or compounds containing ligands, it is also preferable to pre-treat the surface of the metal nanoparticles to facilitate bond formation. 【0064】 Examples of methods for producing metal nanoparticle composites include: a method in which the aforementioned compound and a ligand-containing compound are mixed in advance, and the resulting mixture is added to a solution (dispersion) containing metal nanoparticles to obtain a metal nanoparticle composite; a method in which the aforementioned compound is added to a solution (dispersion) containing metal nanoparticles, and then a ligand-containing compound is added to obtain a metal nanoparticle composite; and a method in which a ligand-containing compound is added to a solution (dispersion) containing metal nanoparticles, and then the aforementioned compound is added to obtain a metal nanoparticle composite. A specific example of a method for producing metal nanoparticle composites is the method described in the examples. 【0065】 <Method for detecting target molecules> The method for detecting target molecules according to this embodiment is a method for detecting target molecules that includes the step of forming a crosslinked composite between the target molecule in the sample and the metal nanoparticle composite by bringing the aforementioned metal nanoparticle composite into contact with the sample. The step of forming a crosslinked composite between the target molecule in the sample and the metal nanoparticle composite by bringing the metal nanoparticle composite and the sample into contact will also be referred to as the crosslinked composite formation step. 【0066】 There are no particular restrictions on the sample, but typically it is a sample containing the target molecule, a sample expected to contain the target molecule, or a sample for which it is desirable to determine whether or not it contains the target molecule. The target molecule is usually a specific physiologically active substance, such as a target protein. When performing the cross-linking complex formation step, the sample is preferably a liquid (including solutions, dispersions, suspensions, etc.). The sample may be of human origin or of non-human origin. Examples of non-human organisms include mammals (excluding humans), non-mammalian organisms such as birds, fish, insects, plants, algae, and fungi. Examples of mammals (excluding humans) include mice, rats, horses, sheep, pigs, goats, and cattle. Furthermore, the sample may be of non-biological origin. For example, if the target molecule is a synthetic protein, the sample may contain an artificially synthesized synthetic protein. Also, the sample may be a mixed sample containing multiple substances. 【0067】 The sample may be a liquid sample from the start, such as bodily fluids like blood, urine, sweat, or tears, or it may be a sample derived from something other than bodily fluids, such as cells (e.g., animal cells, bacterial cells, plant cells). 【0068】 The sample may be a sample that has been pre-treated to facilitate the cross-linking complex formation process. For example, if the sample is cells, a cell extract may be prepared in advance by pre-treatment, and this cell extract may be used as the sample. 【0069】 The crosslinking composite formation process is typically carried out by adding a metal nanoparticle composite or a dispersion of metal nanoparticle composites to the sample. There are no particular restrictions on the amount of metal nanoparticle composite added, but a crosslinking composite can be suitably formed by adding an excess amount of metal nanoparticle composite that is greater than the amount of target substance expected to be contained in the sample. 【0070】 The cross-linking composite formation process is usually carried out at 4 to 37°C. While this process is usually carried out under atmospheric pressure, it may also be carried out under an inert gas atmosphere such as nitrogen. Furthermore, while this process is usually carried out under normal pressure, it may also be carried out under reduced pressure or under increased pressure. This process is usually carried out for 1 to 24 hours after addition. 【0071】 After the crosslinking complex formation step, the target molecule can be easily detected by performing an optional step. Optional steps include, for example, separating the crosslinked complex from the sample after the crosslinking complex formation step, removing metal nanoparticles from the crosslinked complex, and detecting the target molecule. Washing may be performed as appropriate between each step. 【0072】 Washing can be performed, for example, using a washing buffer. Examples of washing buffers include surfactants and PEG-containing solutions such as PBS (phosphate-buffered saline), TBS (Tris-buffered saline), and HEPES buffer (a buffer for 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid). 【0073】 One step in separating the cross-linked composite from a sample that has undergone the cross-linked composite formation process is to perform centrifugation to separate the cross-linked composite, which has precipitated due to the high specific gravity of the metal nanoparticles, from the supernatant. 【0074】 One step in removing metal nanoparticles from the crosslinked complex is to cleave the binding sites (MS) between the metal nanoparticles and the lipoic acid-derived structure using a buffer containing a reducing agent (e.g., PBS, TBS, HEPES buffer). Examples of reducing agents include dithiothreitol and β-mercaptoethanol. In this step, the efficiency of binding site cleavage can be improved by adding the reducing agent to the crosslinked complex and then maintaining a temperature of, for example, 25-100°C. 【0075】 The process of detecting target molecules includes steps such as analyzing the recovered target molecules by mass spectrometry or by polyacrylamide electrophoresis (SDS-PAGE) to confirm the presence and quantity of the target molecules. 【0076】 <High-throughput screening method> The high-throughput screening method according to this embodiment is a high-throughput screening method that performs the aforementioned target molecule detection method as part of the high-throughput screening method. 【0077】 The aforementioned method for detecting target molecules includes a step of forming a crosslinked composite between the target molecule in the sample and a metal nanoparticle composite. In order to quickly determine the optimal conditions in this step, it is preferable to perform the aforementioned method for detecting target molecules as part of a high-throughput screening method. In the high-throughput screening method, it is preferable to evaluate at least one of the formation rate and the amount of the crosslinked composite. 【0078】 In high-throughput screening methods, for example, a sample is immobilized in a multi-well plate (e.g., a 96-well multi-well plate, a 386-well multi-well plate), and a dispersion of metal nanoparticle composites is added to each well. In this case, by appropriately changing the type and amount of sample immobilized in the wells, the type and amount of metal nanoparticle composites in the dispersion (concentration in the dispersion), the amount of the dispersion, the temperature, the reaction time, etc., it is possible to determine conditions for effectively detecting target molecules, preferably optimal detection conditions. In high-throughput screening methods, the temperature can be 50°C or lower, for example, between 4 and 37°C as mentioned above. 【0079】 In high-throughput screening methods, after performing the crosslinking complex formation step and then washing as appropriate, the formation of the crosslinking complex can be easily confirmed by labeling it with a compound having a tag that specifically binds to the crosslinking complex (for example, the metal nanoparticle complex constituting the crosslinking complex). Examples of tags include fluorescent groups, chemiluminescent enzymes, and dyes. The tagged compound only needs to have a portion that specifically binds to the crosslinking complex (for example, the metal nanoparticle complex constituting the crosslinking complex). Examples of portions that specifically bind to the crosslinking complex (for example, the metal nanoparticle complex constituting the crosslinking complex) include antibodies, avidin, and lectins. As an example, by pre-modifying the metal nanoparticle complex with biotin, HRP (Horseradish Peroxidase)-avidin can be used as the tagged compound. The tagged compound can be appropriately selected depending on the type of ligand constituting the metal nanoparticle complex. By performing fluorescence analysis, colorimetric analysis, etc., depending on the type of tag, the presence or absence or amount of the crosslinking complex can be evaluated. [Examples] 【0080】 The embodiments will be described below with reference to examples, but this disclosure is not limited to these examples. 【0081】 [Synthesis Example 1] Azide-PEG(3)lipoic acid amide (formula (I) below) was synthesized by the following method. 【0082】 [ka] 【0083】 To a solution of α-lipoic acid (134 mg, 0.65 mmol) in dry DMF (N,N-dimethylformamide) (1.5 mL), DIPEA (N,N-diisopropylethylamine) (103 μl, 0.59 mmol), HATU (1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate) (247 mg, 0.65 mmol), and HOAt (1-hydroxy-7-azabenzotriazole) (40.8 mg, 0.30 mmol) were added at room temperature. To this mixture, 11-azido-3,6,9-trioxaundecane-1-amine (128 mg, 0.59 mmol), dissolved in dry DMF (1.5 mL) and DIPEA (103 μl, 0.59 mmol), was added. 【0084】 The reaction mixture was stirred at room temperature for 19 hours. The reaction mixture was concentrated under reduced pressure, then diluted with ethyl acetate (siRNA), and washed with 1 M aqueous HCl, Milli-Q water, 5% aqueous NaHCO3, and brine. The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by flash column chromatography (CH2Cl2 / MeOH / AcOH = 100 / 0 / 0~97 / 3 / 0.1) to obtain azide-PEG(3)lipoic acid amide (formula (I)) (209 mg, 0.51 mmol, 78%) as a yellow liquid. 【0085】 1H NMR (300MHz, CHCl3): δ6.09(s,1H),3.68-3.62(m,10H),3.54(t,J=3.8Hz,2H),3.45(t,J=4.8Hz,2H),3.39(t,J=4.8Hz,2 H),3.21-3.06(m,2H),2.50-2.39(m,1H),2.18(t,J=7.2Hz,2H),1.93-1.84(m,1H),1.72-1.61(m,5H),1.53-1.39(m,2H), 13 C NMR(75MHz,CDCl3):δ172.9,70.5,70.4(×2),70.0,69.9(×2),56.5,50.5,40.1,39.0,38.4,36.2,34.5,28.8,25.3.;HRMS(ESI-TOF) calculated value C 16 H 30 N4NaO4S2(M+Na) + :429.1606 Measured value: 429.1589. 【0086】 [Synthesis Example 2] Amino-PEG(3)lipoic acid amide (formula (II) below) was synthesized by the following method. 【0087】 [ka] 【0088】 Azide-PEG(3)lipoamide (209 mg, 0.51 mmol) dissolved in tetrahydrofuran (6.6 mL) was mixed with triphenylphosphine (262 mg, 0.77 mmol). The mixture was stirred at room temperature for 30 minutes. H2O (0.13 mL) was added, and the reaction mixture was stirred for 17 hours, then concentrated under reduced pressure to obtain amino-PEG(3)lipoamide (formula (II)). 【0089】 LRMS (ESI-TOF), C 16 H 32 N2NaO4S2(M+Na) + Calculated value: 403.1701; Measured value: 403.1556. 【0090】 [Synthesis Example 3] 3-Fluorosulfonylbenzoic acid NHS ester (formula (III) below) was synthesized by the following method. 【0091】 [ka] 【0092】 3-Fluorosulfonylbenzoic acid (10.0 mg, 0.049 mmol) and N-hydroxysuccinimide (6.20 mg, 0.054 mmol) were dissolved in dry CH2Cl2 (150 μL), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (11 mg, 0.059 mmol) was added at 0°C. The reaction mixture was stirred at room temperature for 1 hour. After diluting the solution with ethyl acetate, it was washed with H2O, 10% NH4Cl aqueous solution, and brine. The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain the crude product of 3-fluorosulfonylbenzoic acid NHS ester (formula (III)). 【0093】 [Example 1] Compound 1 (formula (IV) below) was synthesized by the following method. 【0094】 [ka] 【0095】 Triethylamine (TEA) (8 μL, 0.029 mmol) and 3-fluorosulfonylbenzoate NHS ester (10.5 mg) were added at room temperature to a 150 μL dry DMF solution of amino-PEG(3) lipoamide (11.2 mg, 0.029 mmol). 【0096】 The solution was stirred at room temperature for 3 hours. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography (CHCl3 / MeOH = 100 / 0 to 95 / 5) to obtain compound 1 (11.0 mg, 0.019 mmol, yield 66%) as a white solid. 【0097】 1H NMR (400MHz, CDCl3): δ 8.48(s,1H),8.31(d,J=7.9Hz,1H),8.12(d,J=8.3Hz,1H),7.74(t,J=8 .7Hz,1H),7.37(s,1H),6.01(s,1H),3.70-3.62(m,12H),3.55-3.51(m, 2H),3.41-3.37(m,2H),3.20-3.07(m,2H),2.49-2.41(s,1H),2.16(t, J=7.4Hz,2H),1.93-1.85(m,1H),1.70-1.58(m,5H),1.50-1.41(m,2H); 13 C NMR (100MHz, CDCl3): δ 173.0, 164.8, 136.5, 134.8, 133.3, 130.9, 130.2, 127.0, 70.7, 70.6, 70.4, 70.3, 70.2, 69.8, 56.5, 40.3, 40.3, 38.6, 38.5, 36.5, 34.7, 29.0, 25.4; HRMS (ESI-TOF) calculated C 23 H 35 FN2NaO7S3(M+Na) + :589.1488, measured value 589.1510. 【0098】 [Example 2] Compound 2 (formula V below) was synthesized by the following method. 【0099】 【change】 【0100】 Amino-PEG(3) lipoic acid amide (19.0 mg, 0.049 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) (9.3 mg, 0.049 mmol) and 4-dimethylaminopyridine (DMAP) (0.4 mg, 3.4 μmol) were dissolved in dry CH2Cl2 (243 μl), and monomethyl fumarate (7.6 mg, 0.058 mmol) was added. The mixture was stirred at room temperature for 3 hours. The solution was diluted with CH2Cl2, washed with brine, dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by flash column chromatography (CH2Cl2 / MeOH = 100 / 0 to 95 / 5) to obtain Compound 2 (4.9 mg, 0.01 mmol, yield 20%). 【0101】 1 H NMR (300 MHz, CDCl3): δ 7.02 - 6.81 (m, 3H), 6.4 (s, 1H), 3.96 - 3.45 (m, 20H), 3.15 - 3.11 (m, 2H), 2.46 (m, 1H), 2.22 - 2.20 (t, J = 7.6 Hz, 2H), 1.94 - 1.91 (m, 4H), 1.67 (m, 4H), 1.46 (m, 2H); 13 C NMR (100 MHz, CDCl3): δ 173.0, 165.5, 163.8, 130.0, 70.5 (×2), 70.1 (×2), 69.7 (×2), 56.5, 52.2, 40.4, 40.3, 39.2, 38.6, 34.7, 29.0, 25.4; HRMS (ESI-TOF) calculated value C 21 H 36 N2O7S2 (M+Na) + : 515.6395; measured value 515.6340. 【0102】 [Example 3] The above synthesis example and example were carried out in the same manner except that the raw materials were changed, and the following compounds were synthesized. The synthesized compounds are shown in Table 2 below together with the compounds produced in Examples 1 and 2. 【0103】 【Table 2】 【0104】 The compounds 3 to 12 synthesized in Example 3 are as follows. Compound 3: 1 H NMR (300MHz, CDCl3): δ 7.01(s,1H),6.03(s,1H),4.06-4.02(m,2H),3.36-3.44(m,17H),3.20-3.07(m,2H),2.51-2 .41(m,1H),2.18(t,J=7.3Hz,2H),1.98-1.87(m,1H),1.70-1.66(m,4H),1.50-1.45(m,2H); 13 C NMR (100MHz, CDCl3): δ 173.0, 166.6, 70.6 (×2), 70.1 (×2), 69.5 (×2), 56.5, 42.8, 40.3, 39.7, 39.2, 38.6, 36.5, 34.8, 29.0, 25.5; HRMS (ESI-TOF) calculated C 18 H 33 ClN2O5S2(M+Na) + :479.1520; measured value 479.1558. 【0105】 Compound 4: 1 H NMR (300MHz, CDCl3): δ 7.05(s,1H),6.12(s,1H),3.88(d,J=3.1Hz,2H),3.72-3.56(m,12H),3.56-3.42(m,2H),3.40-3.38(m,2H),3 .26-3.07(m,2H),2.51-2.43(m,1H),2.2(t,J=7.6Hz,2H),1.89(m,1H),1.71-1.60(m,5H),1.49-1.41(m,2H); 13 C NMR (100MHz, CDCl3): δ 172.9, 166.1, 70.6, 70.5, 70.3, 70.1, 69.9, 69.5, 56.6, 42.7, 40.3, 39.6, 39.2, 38.6, 36.5, 34.7, 29.0, 25.4; HRMS (ESI-TOF) calculated C 18 H 33 BrN2NaO5S2(M+Na) + :523.0912; measured value 523.0905. 【0106】 Compound 5: 1 H NMR (400MHz, CDCl3): δ 6.27(s,1H),6.22(s,1H),4.41-4.37(m,1H),3.90-3.85(m,1H),3.60-3.51(12H),3.43-3.39(m,4H),3.19-3.04(m,3H),2.82-2.80(t, J=4.4,1H),2.63-2.61(dd,J=2.6,1H),2.46-2.38(m,3H),2.24-2.14(m,4H),1.97-1.86(m,3H),1.71-1.58(m,5H),1.48-1.37(m,2H); 13 C NMR (100MHz, CDCl3): δ 173.1, 172.9, 147.0, 122.1, 70.6 (×2), 70.3 (×2), 70.0, 69.7, 65.0, 56.5, 50.2, 49.4, 44.7, 40.3, 39.2, 38.5, 36.4, 34.7, 33.3, 29.0, 25.0, 24.6; HRMS (ESI-TOF) calculated C 24 H 42 N2NaO 13 S2(M+Na) + :573.2280; measured value 573.2289. 【0107】 Compound 6: 1 H NMR (300MHz, CDCl3): δ6.40(s,1H),6.34(s,1H),4.40-4.36(m,1H),3.91-3.86 (dd,J=6.4,1H),3.62-3.60(m,40H),3.55-3.50(m,4H),3.42-3.39(m,4H),3.1 9-3.04(m,3H),2.82-2.80(t,J=4.35,1H),2.63-2.61(m,1H),2.46-2.37(m,3H ),2.23-2.14(m,4H),1.97-1.83(m,3H),1.73-1.55(m,5H),1.50-1.36(m,2H); 13C NMR (75MHz, CDCl3): δ 172.9, 172.2, 70.6, 70.3, 70.0, 64.9, 56.5, 49.4, 44.8, 40.3, 39.3, 38.5, 36.4, 35.3, 34.7, 33.2, 29.0, 25.5, 20.9; HRMS (ESI-TOF) calculated values ​​C 40 H 74 N2NaO 16 S2(M+Na) + :925.4377; measured value 925.4329. 【0108】 Compound 7: 1 H NMR (400MHz, CDCl3): δ7.50-7.47(d,1H),6.17(s,1H),4.51-4.48(t,J=5.04,2H),4.43-4.39(dd ,J=2.8,1H),3.92-3.84(m,3H),3.60-3.51(m,12H),3.45-3.41(m,2H),3.21-3.06(m,3H),2.84-2 .82(t,J=4.4,1H),2.78-2.74(t,J=7.6,2H),2.64-2.63(dd,J=2.8,1H),2.48-2.41(m,1H),2.19 -2.16(t,J=7.3,2H),2.05-1.98(m,2H),1.93-1.85(m,1H),1.71-1.60(m,5H),1.52-1.39(m,2H); 13 C NMR (100MHz, CDCl3): δ 173.1, 172.9, 147.0, 122.2, 70.6, 70.3, 70.1, 70.0, 65.0, 56.7, 50.2, 49.5, 44.8, 40.4, 39.2, 38.6, 36.5, 34.8, 33.4, 29.0, 25.5, 25.0, 24.7; HRMS (ESI-TOF) calculated C 25 H 42 N4NaO7S2(M+Na) + :597.2393 Measured value: 597.2356. 【0109】 Compound 8: 1H NMR (400MHz, CDCl3): δ7.47(d,1H),6.36(s,1H),4.48-4.46(m,2H),4.39-4.36(dd,J=5.0,1H),3. 90-3.85(dd,J=6.41,1H),3.83-3.81(m,2H),3.62-3.57(m,44H),3.42-3.38(m,2H),3.19-3.04(m, 3H),2.82-2.79(t,J=4.6,1H),2.75-2.72(t,J=7.6,2H),2.72-2.60(m,1H),2.46-2.38(m,1H),2.1 7-2.13(t,J=7.6,2H),2.03-1.95(m,2H),1.91-1.83(m,1H),1.72-1.55(m,5H),1.49-1.37(m,2H); 13 C NMR (100MHz, CDCl3): δ 173.0, 172.9, 146.9, 122.2, 70.6, 70.2, 70.0, 69.6, 64.9, 56.5, 50.2, 49.4, 44.7, 40.3, 39.2, 38.5, 36.3, 34.7, 33.3, 29.0, 25.4, 25.0, 24.6; HRMS (ESI-TOF) calculated value C 41 H 74 N4NaO 15 S2(M+Na) + :949.4490 Measured value: 949.4524. 【0110】 Compound 9: 1 H NMR (300MHz, CDCl3): δ7.78-7.76(d,J=6.9,1H),6.20(s,1H),4.73-4.65(m,J=12.4) ,4.55-4.52(t,J=5.0),3.89-3.83(m,3H),3.62-3.52(m,10H)3.46-3.41(m,3H),3.21 -3.06(m,3H),2.80-2.78(m,1H),2.62-2.60(dd,J=2.75,2.29,1H),2.48-2.40(m,1H ),2.19-2.15(t,J=7.3,2H),1.93-1.85(m,1H),1.75-1.60(m,5H),1.50-1.41(m,2H); 13C NMR (75MHz, CDCl3): δ 172.9, 144.7, 124.0, 71.2, 70.64, 70.58, 70.5, 70.3, 70.0, 69.5, 56.5, 50.8, 50.3, 44.3, 39.2, 40.3, 38.6, 36.4, 34.7, 29.0, 25.5; HRMS (ESI-TOF) calculated C 22 H 38 N4NaO6S2(M+Na) + :541.2130 Measured value: 541.2116. 【0111】 Compound 10: 1 H NMR (400MHz, CDCl3): δ7.47(s,1H),6.36(s,1H),4.72-4.63(m,2H),4.54-4.51(t,J =4.99,2H),3.86-3.80(m,3H),3.64-3.52(m,42H),3.47-3.40(m,1H),3.20-3.05(m ,3H),2.79-2.76(t,J=4.5,1H),2.61-2.59(dd,J=2.4,2.8,1H),2.49-2.39(m,1H), 2.19-2.14(t,J=7.4,2H),1.94-1.83(m,3H),1.72-1.58(m,5H),1.51-1.39(m,2H); 13 C NMR (100MHz, CDCl3): δ 172.9, 144.6, 124.0, 71.2, 70.6, 70.3, 70.0, 69.5, 64.7, 56.5, 50.8, 50.3, 44.3, 40.3, 39.2, 38.6, 36.4, 34.8, 29.0, 25.5; HRMS (ESI-TOF) calculated C 38 H 70 N4NaO 14 S2(M+Na) + :893.4228 Measured value: 893.4258. 【0112】 Compound 11: 1H NMR (300MHz, CDCl3): δ8.30-8.24(m,4H),8.11-8.08(m,2H),7.59-7.51(m,3H),6.33-6.31(m,1H),4.79-4.74(m,2H),4.59-4.53(m,2H),3.91-3.8 4(m,2H),3.72-3.59(m,44H),3.22-3.05(m,2H),2.51-2.37(m,1H),2.2 4-2.14(m,2H),1.90(d,J=2.8Hz,1H),1.74-1.60(m,5H),1.51-1.39(m, 2H); 13 C NMR (75MHz, CDCl3) 172.9, 166.0, 165.6, 144.3, 138.8, 135.2, 130.9, 129.1 (×2), 127.2, 126.9, 123.8, 119.7, 70.6, 70.3, 70.0, 69.5, 56.5, 50.4, 40.3, 39.3, 38.6, 36.4, 34.8, 29.0, 25.5; HRMS (ESI-TOF) calculated value C 49 H 75 N9NaO 13 S2(M+Na) + :1064.4823; measured value: 1064.4775. 【0113】 Compound 12: 1 H NMR (300MHz, CDCl3): δ8.31(d,2H,J=8.3Hz),8.20(d,2H,J=7.6Hz),8.01(d,2H, J=8.3Hz),7.61-7.51(m,3H),6.26(s,1H),4.75(d,2H,J=5.2Hz),4.53(t,3H,J=5 .0Hz),3.87(t,1H,J=5.0Hz),3.63-3.59(m,44H),3.55(s,2H),2.47-2.39(m,1H) ,2.17(t,2H,J=7.6Hz),2.01-1.83(m,2H),1.75-1.60(m,5H),1.49-1.40(m,2H); 13C NMR(75MHz,CDCl3)172.9,166.0,165.6,144.3,138.8,135.2,130.9,129.1(×2),127.2,126.9,123.8, 119.7,70.6,70.3,70.0,69.5,56.5,50.4,40.3,39.3,38.6,36.4,35.8,29.0,25.5;HRMS (ESI-TOF) calculated value C 49 H 75 N9NaO 13 S2(M+Na) + :1048.4323; Measured value:1048.4317. 【0114】 [Example 4] Metal nanoparticle affinity probes (metal nanoparticle composites) were synthesized using the following method. 【0115】 0.5 mg of BSPP (Bis(p-sulfonatophenyl)phenylphosphine dihydrate dipotassium salt) was added to a solution of citric acid-stabilized AuNPs (gold nanoparticles) (12 nm, 18 nM, 1 mL), and the mixture was stirred on a plate shaker at 50°C for 1 hour. The resulting mixture was centrifuged at 18,000 × g at 4°C for 1 hour, and the supernatant was carefully removed. The BSPP-stabilized AuNPs were washed three times with MilliQ water and diluted with MeOH (0.5 mL). 【0116】 A stock solution (total amount of compound 1 and lactose lipoic acid derivative: 18 nmol) was prepared by mixing a 10 mM MeOH solution of compound 1 and a 10 mM MeOH solution of a lactose lipoic acid derivative (a compound containing a ligand) in a 1:2 ratio. 【0117】 The stock solution was added to a MeOH solution of BSPP-stabilized AuNPs (18 pmol), and the mixture was stirred at room temperature for 18 hours. The resulting functionalized AuNPs (metal nanoparticle affinity probes) were washed twice with MeOH / MilliQ water (1 / 1), and then once with MilliQ water. Functionalization of the AuNPs was confirmed by UV-Vis, agarose gel electrophoresis, and MALDI-TOF MS analysis. The functionalized AuNPs are metal nanoparticle complexes in which compound 1 and a ligand-containing compound are bound to the AuNPs. 【0118】 UV-VIS: Functionalized AuNPs had a λmax of 521 nm. Compared to citrate-stabilized AuNPs, which had a λmax of 518 nm, this showed a slightly higher wavelength shift, confirming that they were functionalized. Furthermore, the concentration was calculated from the ratio of the absorbance at 450 nm to the absorbance at the maximum absorption wavelength, based on the method of Haiss et al. (Haiss. W; Thanh. NT K; Aveyard. J and Fernig. D. G, Anal. Chem., 2007, 79, 4215-4221.). MALDI-TOF MS: (Compound 1) [M+Na] + Calculated value 589.15, measured value 589.14 (compound containing ligand) [M+Na] + Calculated value: 676.22, Measured value: 676.21. Electrophoretic analysis: In analysis using a 0.5% agarose gel, the electrophoretic mobility of functionalized AuNPs was lower than that of BSPP-stabilized AuNPs. This suggests that the coating state of the gold nanoparticle surface changed due to functionalization with compound 1, which has a larger molecular weight than BSPP, or with compounds containing ligands. 【0119】 [Example 5] 2 pmol of the functionalized AuNPs (metal nanoparticle affinity probes) obtained in Example 4 were mixed with a HEPES buffer solution (40 μL) containing 4 pmol of the target molecule, lactose-binding protein PNA (Peanut agglutinin), and incubated at 4°C for 2 hours. After incubation, the mixture containing the crosslinked complex of the target molecule and the metal nanoparticle affinity probe was diluted with PBS buffer containing 2% SDS, centrifuged at 18,000 × g at 4°C for 15 minutes, and the supernatant was carefully removed. The mixture was then washed with PBS buffer, and Laemmli buffer containing 10% β-mercaptoethanol was added and heated at 95°C for 5 minutes to cleave and elute the crosslinked structure of the target molecule and compound from the metal nanoparticles. The eluted target molecule was analyzed by SDS-PAGE and fluorescence imaging to confirm that the target molecule was covalently crosslinked with the metal nanoparticle affinity probe, resulting in concentrated purification. 【0120】 In addition, in Example 4, functionalized AuNPs could be obtained similarly even when compound 1 was replaced with compounds 2 to 10. 【0121】 [Example 6] 50 μL of a 10% Protein-free blocking buffer-PBS buffer solution containing 2 pmol each of five functionalized AuNPs (functionalized AuNPs prepared using compounds 1-5) (metal nanoparticle affinity probes) was added to a 96-well multiwell plate immobilized with 10 μg / well of the target molecules: lactose-binding protein PNA, ECA (Erythrina cristagalli: Erythrina cristagalli lectin), and RCA (Ricinus communis Agglutinin: Ricinus communis lectin). The plate was incubated at 4°C for a set period (1, 2, 4, 6, 20 hours). After incubation, the mixture containing the cross-linked complex of the target molecule and the metal nanoparticle affinity probe was washed three times with 10% Protein-free blocking buffer-PBS buffer (300 μL) containing free lactose (final concentration 0.5 M), followed by three more washes with 10% Protein-free blocking buffer-PBS buffer (300 μL). Next, a 10% protein-free blocking buffer-PBS buffer solution (50 μL) containing 20 μg / mL horse radish peroxidase (HRP)-labeled PNA was incubated at 25°C for 1 hour and washed with another 10% protein-free blocking buffer-PBS buffer solution (50 μL). A 1:1 mixed solution (50 μL) of 3,3',5,5'-tetramethylbenzidine (TMB), a substrate of HRP, and hydrogen peroxide was added. After 5 minutes, a 2N sulfuric acid aqueous solution (50 μL) was added to stop the enzymatic reaction, and the amount of cross-linked complex was quantified by measuring the absorbance at 450 nm using a plate reader. This allowed for the analysis of the reaction efficiency of each probe under each reaction condition, and the reaction conditions that maximized the reaction efficiency were determined. 【0122】 All publications, patents, and patent applications cited herein shall be incorporated herein by direct reference. 【0123】 Although this embodiment has been described in detail above, the specific configuration is not limited to this embodiment, and any design changes that do not depart from the gist of this disclosure are also included in this disclosure.

Claims

[Claim 1] A compound represented by the following general formula (1), (2), or (3). 【Chemistry 1】 (In general formula (1), X １ is O or NH, Y １ is O, NH, a group represented by the following formula (4), or a group represented by the following formula (5), R １ (The base is selected from the following formulas (6) to (14), (20) to (28), (31) to (33), (35) to (42), and (44) to (51).) 【Chemistry 2】 (In general formula (2), X ２ is O or NH, Y ２ is O, NH, a group represented by the following formula (4), or a group represented by the following formula (5), R ２ (The base is selected from the following formulas (8) to (19), (21) to (28), (31) to (33), (35) to (42), and (44) to (51).) 【Transformation 3】 (In general formula (3), n is an integer selected from 1, 2, 4, 5, and 7 to 12, and X ３ is O or NH, and Y ３ is O, NH, a group represented by the following formula (4), or a group represented by the following formula (5), and R ３ is a group selected from the following formulas (6) to (28), (31) to (33), (35) to (42), and (44) to (51)) 【Chemistry 4】 (In equations (4) and (5), a is R １ , R ２ or R ３ The linkage site is shown, and b is CH ２ This shows the connection point. (In equation (5), x is an integer from 1 to 10.) 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 (In equation (10), m is an integer from 1 to 17; in equations (11), (34), (39), and (40), q is an integer from 0 to 14; and in equations (29) and (30), r is an integer from 1 to 9.) [Claim 2] The compound according to claim 1, wherein n is 8 to 12. [Claim 3] A complex comprising metal nanoparticles, the compound according to claim 1 or 2, and a compound having a ligand that specifically complexes with a target molecule, A metal nanoparticle composite in which the compound according to claim 1 or 2 and a compound having a ligand that specifically complexes with the target molecule are bound to the metal nanoparticle. [Claim 4] A method for detecting a target molecule, comprising the step of bringing the metal nanoparticle composite described in claim 3 into contact with the sample to form a crosslinked composite between the target molecule in the sample and the metal nanoparticle composite. [Claim 5] A high-throughput screening method comprising performing the target molecule detection method described in claim 4 as part of a high-throughput screening method.

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