JP2007108131A - Analyte carrier and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an analyte carrier usable in an analyzer for detecting an extremely micro amount of molecule, and a manufacturing method therefor. <P>SOLUTION: In this analyte carrier, a metal thin wire is exposed partially in structure having a meso-porous substance membrane with a uniform-diametric tubular pore formed on a substrate, and having the metal thin wire in the pore of the meso-porous substance film. This manufacturing method for the analyte carrier has a process for forming on the substrate the meso-porous substance membrane having structure arrayed unidirectionally with the uniform-diametric tubular pore, a process for introducing a solution containing a metal compound into the pore of the meso-porous substance membrane, a process for converting chemically the metal compound to form the metal thin wire in the pore, and a process for removing selectively the meso-porous substance membrane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an analyte carrier used for Raman spectroscopic analysis and a method for producing the same. More specifically, the present invention relates to a surface generated during Raman spectroscopic analysis by forming uniaxially oriented metal wires on a substrate. The present invention relates to an analyte carrier that enhances an enhancing action, and a method for producing the analyte carrier.

Recently, single-molecule spectroscopy using surface-enhanced Raman scattering (SERS: Surface-enhanced Raman Scattering) has attracted attention (see Non-Patent Document 1). This refers to a phenomenon in which the Raman scattering intensity of a substance adsorbed on the surface of a metal electrode, sol, crystal and deposited film, semiconductor, etc. is remarkably enhanced as compared with when the substance is in a single state. In comparison, the scattering intensity is about 10 ⁵ to 10 ⁶ times. The characteristics of SERS are as follows: 1) An enhancement effect appears in metals that can generate localized plasmons, such as gold, silver, copper, platinum, nickel, and the like, and the effect is particularly remarkable in gold and silver. 2) The roughness of the metal surface is involved in the development of SERS, and the effect is enhanced by using a metal with a high specific surface area. It is considered that the excitation of surface plasmons on the metal surface plays an important role. ing.

As a recent new idea regarding the mechanism of SERS, several molecules sandwiched between two silver nanoparticles exhibit a remarkable SERS effect due to an enhanced electric field caused by silver nanoparticles (see Non-Patent Document 2). . This is due to the effect of surface-enhanced resonance Raman scattering that occurs when the SERS condition and the resonance Raman scattering condition overlap, and the Raman scattering intensity increases to about 10 ¹¹ to 10 ¹⁴ times.

In addition, as an example of sensing using SERS and resonance Raman scattering, Non-Patent Document 3 describes polarization by using silver nanowires arranged in one direction using porous alumina prepared by anodization as a template. An example has been reported that enables the detection of trace molecules by SERS spectroscopy.
Hyundai Chemistry September 2003 p. 20-27 Appl. Phys. Lett. 2004, Vol. 83, p. 5557 J. et al. Phys. Chem. B, 2004, Vol. 108, p. 12724

  However, the above reported example had some points to be improved.

  First, regarding Non-Patent Document 2, since the surfaces of two silver nanoparticles facing each other are small, the region of the electric field generated by the interaction between the particles is also narrowed, so that the resulting Raman scattering intensity is also small. There was a problem of becoming smaller. On the other hand, with respect to Non-Patent Document 3, since porous alumina used as a template at the time of producing the wire is dissolved after the nanowire is produced, and the nanowire obtained thereby is dispersed in a solvent and then developed on the substrate, There is a problem that the orientation of is partial and reproducibility is poor. Furthermore, the end of the wire obtained by this method is in the form of particles and aggregates.

  The present invention has been made in view of the above-described contents, and a mesoporous material film having a structure in which tubular pores having a substantially uniform diameter are arranged in a uniaxial direction is formed on a substrate and used as a template. In this method, fine metal wires having uniaxial orientation are formed in the pores, and then a part of the mesoporous material film as a template is selectively removed to partially expose the fine metal wires on the substrate. An analyte carrier and a method for producing the same are provided.

  That is, a first invention according to the present application is an analyte carrier used for Raman spectroscopic analysis, a mesoporous material film having tubular pores of uniform diameter formed on a substrate, and the mesoporous material film In the structure having fine metal wires in the pores, the fine metal wires are partially exposed on the substrate.

  In particular, the mesoporous material film is preferably formed of tubular pores arranged in a uniaxial direction.

  In particular, it is preferable that the fine metal wire has a uniaxial orientation.

  In particular, it is preferable that the metal is Au, Ag, or Pt.

  In particular, the substance constituting the pore wall of the mesoporous material film is silicon dioxide, or an organic group containing one or more carbon atoms, and two or more silicon atoms bonded to the organic group at two or more locations. The organic silica hybrid material is preferably composed of one or more oxygen atoms bonded to the silicon atom.

  The present invention also provides a method for producing the analyte carrier.

  That is, the second invention according to the present application is a method for producing an analyte carrier used for Raman spectroscopic analysis, wherein a mesoporous material film having a structure in which tubular pores having a uniform diameter are arranged in a uniaxial direction is provided on a substrate. A step of introducing a solution containing a metal compound into the pores of the mesoporous material film, a step of chemically changing the metal compound to form a fine metal wire, and the mesoporous material film selectively. It has the process to remove, It is characterized by the above-mentioned.

  In particular, the step of introducing the solution containing the metal compound into the pores of the mesoporous material film includes the step of forming sites for immobilizing anions on the pore surfaces of the mesoporous material film, and the metal in the pores. It is characterized by comprising a step of introducing an anion containing these atoms.

  In particular, the step of forming the site for immobilizing anions on the pore surface of the mesoporous material film contains a silane coupling agent having a cation site, or a metal capable of forming an oxide having a higher isoelectric point than silica. The step of modifying the pore surface with an aqueous solution of a metal salt is preferable.

  According to the present invention, an analyte carrier capable of detecting a trace amount of molecules by Raman spectroscopic analysis can be provided.

  FIG. 1 shows a configuration example of an analyte carrier of the present invention. In FIG. 1, 11 is a substrate, 12 is a mesoporous material film, 13 is a pore, 14 is a pore wall, and 15 is a fine metal wire.

  A mesoporous material film 12 having tubular pores having a honeycomb structure is formed on a substrate 11 having structural anisotropy on the surface. In the mesoporous material film, the tubular pores 13 are particularly preferably arranged in one direction. The pores 13 constituting the mesoporous material film 12 indicate pores having a meso region diameter of 2 nm to 50 nm defined by IUPAC, and from the adsorption isotherm obtained by the gas adsorption method, Berret-Joyner- In the pore size distribution evaluated by the Halenda (BJH) method, 60% or more of pores are included in a range having a width of 10 nm. The range having a width of 10 nm indicates a range where the difference between the minimum value and the maximum value is 10 nm, for example, from 5 nm to 15 nm.

  The pore wall 14 forming the pore 13 is composed of silica or an organic group containing one or more carbon atoms, two or more silicon atoms bonded to the organic group at two or more locations, and one or more bonded to a silicon atom. It is comprised by the organic silica hybrid material which consists of these oxygen atoms. In the organic-silica hybrid material, at least one bond that is not bonded to an organic group is terminated with a silanol group, and many silanol groups are exposed on the pore surface. Can be used as a preferred surface for the formation of the site to be immobilized. However, the substance constituting the pore wall in the present invention is not limited to these.

  Further, fine metal wires 15 are formed in the pores 13. The thin metal wire 15 is made of silver, gold, platinum or the like. In addition, since the fine metal wire is formed using tubular pores as a template, the diameter of the obtained fine metal wire can be adjusted by changing the pore size of the mesoporous material serving as the template.

  Further, in the analyte carrier shown in FIG. 1, by selectively removing the mesoporous material, it is possible to expose a part of the fine metal wire on the substrate, and thereby the analyte adheres to the fine metal wire. It has an easy structure. Further, both ends of the fine metal wires are supported by the mesoporous material film, so that the distance between the fine metal wires is the same as the thickness of the pore wall of the mesoporous material, and it is possible to prevent the fine metal wires from aggregating.

  FIG. 2 is a process diagram showing a method for producing an analyte carrier in the present invention. In FIG. 2, step A is a step of forming a mesoporous material film having a structure in which tubular pores having a uniform diameter are arranged in a uniaxial direction on a substrate, and step B is a step of applying a solution containing a metal compound to the mesoporous material film. The step of introducing into the pores, Step C is a step of chemically changing the metal compound to form a fine metal wire, and Step D is a step of selectively removing the mesoporous material film and exposing the fine metal wire on the substrate. .

The analyte carrier of the present invention and the production method thereof will be described below.
(Step A: Step of forming a mesoporous material film having a structure in which tubular pores having a uniform diameter are arranged in a uniaxial direction on a substrate)
There are various reports on the method for producing a mesoporous material film, which are roughly classified into two methods, a method called a solvent evaporation method and a method based on heterogeneous nucleation-nucleus growth on a substrate. As long as a mesoporous film having a pore structure arranged in a uniaxial direction can be produced, the method is not limited to these methods.

  In the configuration shown in FIG. 1, reference numeral 11 denotes a substrate having structural anisotropy on the surface.

  As a material having structural anisotropy formed on the surface of the substrate, a polymer compound Langmuir-Blodgett film, a polymer compound film subjected to rubbing treatment, or the like is preferably used. JP-A-2001-58812 describes the orientation control of the pores of the mesoporous film using such an anisotropic polymer compound film. However, the method of forming a polymer compound having anisotropy on the surface used in the present invention is not limited to these two methods, and any method that can induce anisotropy is applicable. is there. For example, the provision of anisotropy by irradiation with polarized light can be mentioned. Further, the substrate having anisotropy on the surface applicable to the present invention is not limited to these, and as long as the target structure can be produced, the surface is anisotropic, for example, (110) plane of silicon single crystal. It is also possible to use a crystalline substrate having properties. In this case, the process of forming the polymer compound film on the substrate is not necessary.

  First, a method for manufacturing a substrate will be described. In the present invention, a case where a polymer compound film subjected to rubbing treatment is formed on the surface of a substrate will be described. As the substrate on which the polymer film is formed, any material can be used as long as it can withstand the process for producing a mesoporous material film described later. For example, quartz glass, a silicon substrate, and the like can be favorably applied.

  The rubbing process is a process of applying a polymer coating on a substrate by a technique such as spin coating and rubbing it in one direction with a cloth or the like. The rubbing cloth is wound around a roller, and the rubbing is performed by bringing the rotating roller into contact with the substrate surface and moving the stage to which the substrate is fixed in one direction with respect to the roller.

  The polymer compound subjected to the rubbing treatment is basically limited to the material as long as it can withstand the formation process of the mesoporous material film described later and can control the uniaxial orientation of pores in the mesoporous material film. Polyimide or the like is preferably used.

  Next, a method for producing a mesoporous material film using the above-described method based on heterogeneous nucleation-nuclear growth on a substrate having a structural anisotropy on the surface will be described.

  The silica mesostructure film can be formed by holding the substrate in an aqueous solution containing a surfactant that is an amphiphilic molecule, silicon alkoxide that is a silica source, and an acid that acts as a hydrolysis catalyst. A silica mesostructure film in which surfactant micelles that are aggregates of amphiphilic molecules and hydrolyzed alkoxide precursors that are silica precursors are regularly arranged on the substrate by self-assembly is formed.

  The reaction vessel used for forming the silica mesostructured film by this method is not particularly limited as long as it does not affect the reaction, and a material such as polypropylene or Teflon (registered trademark) can be used. The reaction vessel may be placed in a sealed vessel made of a highly rigid material such as stainless steel so that the reaction vessel is not destroyed even if pressure is applied during the reaction. A substrate holder is placed in the reaction vessel, and the substrate is held by using the substrate holder.

  The reaction solution was adjusted to a pH suitable for formation of the component constituting the target pore wall by adding acid or the like to the surfactant aqueous solution, and ethyl silicate or 1,4-bis (trimethoxysilyl) ethylene was used. A material which becomes the raw material of the material of the desired pore wall is added. In the case of using an alkoxide, an alcohol in which the alcohol produced as a result of hydrolysis is soluble in water is preferably used.

  The surfactant to be used is preferably a cationic surfactant having a hydrophilic group such as ammonium, or a nonionic surfactant having polyethylene oxide as a hydrophilic group. However, usable surfactants are not limited to these. Further, the length of the hydrophobic group and the size of the hydrophilic group of the surfactant molecule to be used are determined according to the pore diameter of the target mesostructure.

  The material constituting the pore wall includes silica or an organic group containing one or more carbon atoms, two or more silicon atoms bonded to the organic group at two or more positions, and one or more oxygen atoms bonded to the silicon atom. An organic silica hybrid material composed of Since silica has a silanol group on its surface, it is possible to suitably produce a site for immobilizing anions on the pore surface. In addition, in the organic silica hybrid material, among the silicon atom bonds, at least one bond that is not bonded to an organic group is terminated with a silanol group, so that many silanol groups are exposed on the pore surface. , And can be used as a preferable surface for forming a site for immobilizing an anion.

  In the present invention, the substrate having structural anisotropy on the surface is put in the precursor solution as described above, and the temperature is optimized for the compound constituting the target pore wall for one day. By holding for about 10 days, a film of a silica mesostructure in which the direction of the tubular pores is controlled can be produced on the substrate.

  The pore structure of the produced silica mesostructured film can be evaluated by out-of-plane X-ray diffraction. Further, by analyzing the structure of this film in more detail by in-plane X-ray diffraction analysis, it is possible to obtain information on a lattice plane that is not horizontal with respect to the substrate, which cannot be observed by the out-of-plane X-ray diffraction method.

  The surfactant is removed from the silica mesostructure produced as described above to obtain a mesoporous silica film. There are various methods for removing the surfactant to make it porous, but any method can be used as long as the organic component can be removed without destroying the pore structure. Is possible. The most commonly used method is a method of firing in an atmosphere containing oxygen. For example, by firing the formed structure in air at 450 degrees for 4 hours, it is possible to completely remove organic components while maintaining the pore structure. There is a method of using a silane coupling agent later when forming a site for immobilizing anions on the pore surface. At that time, it is important that silanol groups exist on the pore surface. . In the firing treatment, it is known that the amount of silanol groups decreases before and after firing. Therefore, it is also possible to use a method of decomposing with a microwave and a method of extracting with a solvent that can remove the surfactant without reducing the amount of silanol groups on the silica surface. However, these methods cannot completely remove the surfactant from the pores as compared with the method by firing. Any method can be used as long as it can remove the surfactant without reducing the amount of silanol groups on the silica surface.

  In addition to the above-described method based on heterogeneous nucleation-nucleus growth on a substrate, a method based on a solvent evaporation method is favorably used for producing a mesoporous material film. This manufacturing method will be described below. This method is a simple method applicable to the production of a wide variety of mesoporous material films, and a precursor solution containing a surfactant and a raw material for pore walls is placed on a substrate having structural anisotropy on the surface. This is a method of performing a reaction such as solvent evaporation, hydrolysis, condensation, etc. after coating or arranging at an arbitrary position on the substrate.

  The precursor solution used in this method is obtained by adding a raw material of a material constituting pore walls to a surfactant solution. As the solvent, alcohols such as ethanol and isopropanol are preferably used. However, the solvent is not limited to these. For example, a mixed solvent of alcohol and water, water, or the like can be used depending on the target pore wall material. An acid may be added as a reaction catalyst.

  The precursor solution having the above-described configuration is applied to a substrate having structural anisotropy on the surface or disposed at an arbitrary position on the substrate. Various methods such as dip coating, spin coating, and mist coating can be used as the application method. In addition to these, any method capable of uniform application can be applied. A general apparatus can be used for spin coating or dip coating, and there is no particular limitation.

  The surfactant is removed from the mesostructured film produced as described above to obtain a mesoporous material film. There are various methods for removing the surfactant to make it porous, but any method can be used as long as the organic component can be removed without destroying the pore structure. Is possible.

(Step B: Step of introducing a solution containing a metal compound into the pores of the mesoporous material film)
In order to form fine metal wires in the pores of a mesoporous material film having a structure in which tubular pores of a uniform diameter are arranged in a uniaxial direction, the mesoporous material film is immersed in a solution containing a metal compound and the inside of the pores. There is a method in which metal-containing ions are formed by introducing metal-containing ions into the metal, and then chemically changing the metal atom-containing ions. In the present invention, gold, silver or platinum is preferable as the metal element constituting the fine metal wire. However, the present invention is not limited to these as long as it can form a target fine metal wire and further generate surface plasmons or localized plasmons. The solvent for dissolving the metal compound may be any solvent that dissolves the metal compound, and more specifically, water, ethanol, and the like.

When producing a fine metal wire such as gold or platinum, an anion containing a metal atom is preferably used. In particular, AuCl ₄ ⁻ and PtCl ₆ ²⁻ are preferable. Usually, since the isoelectric point of silica is about 2, it is difficult to introduce many anions containing metal atoms into the pores. Therefore, in order to introduce more metal atom-containing anions into the pores, it is preferable to form a site for immobilizing the anions in the pores.

  As a method for forming a site for immobilizing anions on the pore surface, a method for modifying the pore surface with a silane coupling agent having a cation site and a metal capable of forming an oxide having a higher isoelectric point than silica are used. A method of modifying the pore surface with an aqueous solution of the contained metal salt is preferably used.

  First, a method for modifying the pore surface with a silane coupling agent having a cation moiety will be described. The silane coupling agent binds to the silanol group on the pore surface to form an anion exchange site. As the silane coupling agent having a cation moiety, those containing an ammonium group, that is, those having positively charged nitrogen are suitable. For example, ammonium hydrochloride such as N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride (TPTCA), 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane Etc. can be used. An anion containing a metal atom is immobilized to a positive charge derived from the cation portion of such a silane coupling agent.

  Next, a method for modifying the pore surface using an aqueous solution of a metal salt containing a metal capable of forming an oxide having an isoelectric point higher than that of silica will be described. Titanium, aluminum, zirconium and tin are preferable as the metal capable of forming an oxide having an isoelectric point higher than that of silica. However, the metal constituting the metal salt is not limited to these as long as it is an aqueous solution of a metal salt capable of forming a site for immobilizing anions by modification of the pore surface. In this method, a substance having a bond between a metal having a higher isoelectric point than silica and oxygen on the pore surface is formed on the pore surface, so that the positive charge density is increased and the anion containing a metal atom is adsorbed. The amount increases.

  Next, an anion containing a metal atom, which is a raw material for the target thin metal wire, is introduced into the site where the formed anion is immobilized. As a method for introducing an anion containing a metal atom into the pore, there is a method of immersing a mesoporous material film having a site for fixing an anion on the pore surface in a solution of a metal compound as a precursor of a metal fine wire. preferable. By repeating the step of immersing the mesoporous material film in the metal compound solution, it becomes possible to introduce more metal fine wire precursors into the pores. Thereby, a fine metal wire corresponding to the length of the tubular pore can be obtained.

Moreover, as a metal compound as a precursor of a metal fine wire, the said metal salt or complex salt can be used, for example.
(Step C: Step of forming a fine metal wire by chemically changing a metal compound)
As a method for converting the metal compound introduced into the pores into a fine metal wire, a method by heat treatment is mainly used. Further, as a method for converting an anion containing a metal atom into a fine metal wire, a method of reducing by heating in a hydrogen atmosphere, a method of reducing with an aqueous sodium borohydride solution, or a method of reducing by light irradiation is preferable. For example, Journal of As described in the American Chemical Society, Vol. 123, p. 3373, when a platinum fine wire was prepared using H ₂ PtCl ₆ as a platinum compound, after being exposed to 20 Torr of water vapor and 100 Torr of methanol vapor for 2 hours, respectively. By irradiating with light using a high-pressure mercury lamp (100 W, 250-600 nm) for 24 hours and further drying under vacuum for 12 hours, it becomes possible to obtain fine metal wires. However, the conversion method to the fine metal wire used in the present invention is not limited to these.
(Step D: Step of selectively removing the mesoporous material film and exposing the fine metal wires on the substrate)
Next, a process D for selectively removing the mesoporous material film and exposing the fine metal wires on the substrate is performed.

  By selectively removing the mesoporous material, it is possible to produce a structure in which the mesoporous material supports only both ends of the fine metal wires as shown in FIG. Further, since the distance between the fine metal wires is the same as the thickness of the pore wall of the mesoporous material, it is possible to prevent the fine metal wires from aggregating.

  As a method for selectively removing the mesoporous material film, a wet etching method is preferably used. Wet etching is a method of dissolving with a chemical solution such as sulfuric acid, nitric acid, phosphoric acid, or hydrofluoric acid.

  The wet etching will be described. First, a photosensitizer is applied to the surface of a mesoporous silica film having fine metal wires in the pores by spin coating. The photosensitive agent applied to the surface is not particularly limited as long as it can be formed on the film, and a positive photosensitive agent is preferably used.

  After film formation, exposure processing is performed through a photomask, and then development processing is performed using a developer. By immersing the film thus patterned in a hydrofluoric acid / ammonium fluoride mixed solution, it becomes possible to selectively etch the mesoporous silica film not covered with the photosensitive agent.

  Next, the photosensitive agent is peeled off. The method for removing the photosensitizer includes a method of washing with an alcohol such as isopropanol, but is not limited thereto as long as the photosensitizer can be removed from the mesoporous material film.

  By performing the above steps, an analyte carrier in which the mesoporous material film is selectively removed on the substrate and the fine metal wires having uniaxial orientation are exposed can be produced.

  An example of an analysis method performed using the analyte carrier having the above-described configuration is a configuration as shown in FIG. In FIG. 3, the laser beam 37 generated from the laser generator 35 is incident from the film surface of the mesoporous material film 32, and the metallic thin line 33 and the molecule 34 to be detected excited by the laser beam cause an enhancing action, thereby enhancing the enhanced Raman. Scattered light 38 is emitted. The Raman scattered light 38 is detected by the photodetector 36. At that time, the electric field region generated between the fine metal wires is very large and has anisotropy. Therefore, it can be obtained by irradiating polarized light in the direction parallel to the orientation direction of the fine metal wires. Anisotropy also occurs in the Raman scattering. When polarized light in a direction perpendicular to the orientation direction of the fine metal wires is incident, a spectrum with a larger intensity can be obtained, which can be a very effective means for detecting a trace molecule.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail using an Example, this invention is not necessarily limited to what was described in the Example.

  In this example, a mesoporous silica film having a pore structure in which tubular mesopores having substantially uniform diameters were arranged in a uniaxial direction, produced by a method based on heterogeneous nucleation-nuclear growth on a substrate surface, This is an example in which, after producing a gold fine wire, mesoporous silica is selectively removed to expose the gold fine wire on the substrate, thereby producing an analyte carrier. As a method for forming a site for immobilizing anions on the pore surface, a method of modifying with a silane coupling agent was used.

  After washing with acetone, isopropyl alcohol, and pure water, an NMP solution of polyamic acid A was applied to a quartz glass substrate whose surface was cleaned in an ozone generator by spin coating, and baked at 200 ° C. for 1 hour. A polyimide A film having the following structure was formed.

  On the other hand, the rubbing process was performed on the conditions as shown in Table 1, and it used as a board | substrate. This substrate is hereinafter referred to as a rubbing treatment substrate.

  It is possible to produce a silica mesostructured film having a pore structure in which tubular mesopores having substantially uniform diameters are arranged in a uniaxial direction by using a substrate subjected to such rubbing treatment. 058812.

The silica mesostructured film is formed on this substrate. As a reaction solution, 6.01 g of polyoxyethylene 10 cetyl ether (C ₁₆ EO ₁₀ ) as a nonionic surfactant was dissolved in 128 ml of pure water, and 20.6 ml of 36 wt. % Concentrated hydrochloric acid was added. To this aqueous solution, 2.20 ml of tetraethoxysilane (TEOS) was added and stirred for 3 minutes to obtain a precursor solution. The composition (molar ratio) of the final precursor solution was TEOS: H ₂ O: HCl: C ₁₆ EO ₁₀ = 0.125: 100: 3: 0.11.

  The rubbing-treated substrate was immersed in this precursor solution with the surface on which the polyimide A film was formed facing downward, and reacted at 80 ° C. for 5 days. After a predetermined reaction time, the substrate immersed in the precursor solution was pulled up, sufficiently washed with pure water, and dried at room temperature.

  As a result of evaluating the produced film by the out-of-plane X-ray diffraction method, a strong diffraction peak attributed to the (100) plane of a hexagonal structure having a plane spacing of 4.8 nm was confirmed. It was confirmed to have an ordered pore structure. Moreover, when evaluated by the in-plane X-ray diffraction method, a strong diffraction peak with a period of 180 ° was confirmed, and it was confirmed that the tubular mesopores had a pore structure arranged in a uniaxial direction.

  The surfactant was decomposed and removed from the produced film by microwave treatment to make it porous. The membrane was immersed in a mixed solution prepared so that the volume ratio of 15M nitric acid and 9.3M hydrogen peroxide was 15: 1, and microwaves with a frequency of 2450 MHz and a voltage of 220 V were irradiated for 5 minutes. It was confirmed by infrared spectrophotometry and the like that the organic component derived from the surfactant did not exist and that silanol groups remained sufficiently in the film after the removal of the surfactant.

  Next, the site | part which fix | immobilizes an anion on the pore surface was formed by the silane coupling agent process. The film is 50 wt. % N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride (TPTCA) in a methanol solution, kept at room temperature for 12 hours, thoroughly washed with pure water, and dried at room temperature. When the treated film was evaluated by infrared spectrophotometry, binding of TPTCA to the silica surface was confirmed. Further, as a result of analysis of the treated film by X-ray diffraction, it was confirmed that both out-of-plane regularity and in-plane regularity were maintained.

The thus obtained, the anions on the surface of the mesopores using mesoporous silica film having a portion to be immobilized, tetrachloroauric acid tetrahydrate (HAuCl 4 · 4H _{2 O)} as the precursor A gold thin wire was prepared. 10 wt. After being immersed in a 1% HAuCl ₄ .4H ₂ O aqueous solution and kept at room temperature for 24 hours, it was thoroughly washed with ethanol and dried at room temperature. By repeating this operation 10 times, a sufficient amount of AuCl ₄ ⁻ was introduced into the mesopores so that a fine metal wire could be formed. A mesoporous silica thin film sufficiently containing AuCl ₄ ^{− in the} pores was immersed in a 0.1 M aqueous sodium borohydride solution to reduce AuCl ₄ ⁻ to produce a gold fine wire.

  Next, the silica as a template was selectively removed from the mesoporous silica film having gold fine wires in the pores. First, a positive photosensitive agent AZ1500 (manufactured by Clariant) was applied by spin coating to the surface of a mesoporous silica film having gold fine wires in the pores. After the film formation, an exposure process for 10 seconds was performed through a photomask, and then a development process was performed using a developer MIF312. The film patterned in this manner was immersed in a hydrofluoric acid / ammonium fluoride mixed solution (1: 5) to selectively etch the mesoporous silica film not covered with the photosensitive agent.

  Next, the photosensitive agent was peeled off by washing with isopropanol. By performing the above steps, it was possible to produce an analyte carrier from which a mesoporous material film was selectively removed and gold fine lines were exposed on the substrate. In the produced gold fine wire, it was confirmed by observation with a transmission electron microscope that a gold fine wire having high linearity, uniform diameter, and long fine wire length was formed.

  A rhodamine 6G dye molecule solution having a concentration of 100 μmol / l is dropped on the analyte carrier, and an argon ion laser having a wavelength of 514.5 nm is irradiated from the analyte carrier surface through a polarizer. Raman scattered light was detected by a detector installed on the side.

  When the polarized light was irradiated in a direction parallel to the long axis direction of the fine gold wire, Raman scattering was hardly confirmed, but when the polarized light was irradiated in the direction perpendicular to the long axis direction of the fine gold wire, It was confirmed that very large surface enhanced Raman scattering (SERS) was generated. Further, it was confirmed that the peak intensity of the Raman spectrum was increased by 10 times or more.

  At this time, for comparison, a similar experiment was performed using a fine gold wire prepared using a mesoporous silica film having no uniaxial orientation as a template, and an analysis using the fine gold wire having the uniaxial orientation produced this time was performed. Comparison with physical support was performed. As a result, the generation of SERS was confirmed in the analyte carrier using a gold fine wire not having uniaxial orientation, but the intensity did not depend on the polarization, and the value was also obtained when the polarization was used. It was small compared.

  As described above, when Raman scattering measurement is performed using a uniaxially oriented gold wire prepared using a mesoporous silica film as a template as an analyte carrier, SERS that depends on the polarization direction is generated. As a result, molecular detection sensitivity Is significantly improved, and a trace amount of molecules can be detected. In addition to the dye molecules as described above, trace amounts of biomolecules such as adenine and guanine and DNA can also be detected.

  This example uses a mesoporous organic silica hybrid membrane having a pore structure in which tubular mesopores having substantially uniform diameters are arranged in a uniaxial direction, which is produced by a dip coating method based on a solvent evaporation method. In this example, after preparing the platinum thin wire, the silica was selectively removed to expose the platinum thin wire on the substrate, thereby preparing the analyte carrier. As a method of forming a site for immobilizing anions on the pore surface, a method of modifying with zirconium oxynitrate was used.

1,4-bis (trimethoxysilyl) ethylene (BTME) was added as a starting material to an ethanol solution containing a predetermined amount of n-hexadecyltrimethylammonium bromide (C ₁₆ TAB) prepared in advance and stirred for 30 minutes. . In order to hydrolyze BTME, hydrochloric acid and water were added to this solution, and a precursor solution was obtained by stirring for 8 hours. The composition (molar ratio) of the precursor solution was set to be BTME: EtOH: H ₂ O: HCl: C ₁₆ TAB = 0.5: 22: 5: 0.004: 0.3014. This precursor solution was applied to the rubbing-treated substrate by a dip coating method at a lifting speed of 2 mm / s and dried in an environmental tester at 25 ° C. and 50% relative humidity for 24 hours.

  When the produced film was evaluated by an out-of-plane X-ray diffraction method, a strong diffraction peak attributed to the (100) plane of a hexagonal structure with a plane spacing of 3.8 nm was confirmed, and this film had a tubular mesopore with a hexagonal structure. It was confirmed to have an ordered pore structure. When this film was evaluated by in-plane X-ray diffraction, a strong diffraction peak with a period of 180 ° was confirmed, and it was confirmed that the membrane had a pore structure in which the tubular mesopores were uniaxially arranged. It was.

  The surfactant was extracted and removed from the prepared membrane with a solvent to make it porous. 36 wt. The membrane was immersed in a mixed solution prepared so that the volume ratio of 1% hydrochloric acid to ethanol was 15: 500, held at 70 ° C. for 12 hours, thoroughly washed with pure water, and dried at room temperature. . The mesoporous organic silica hybrid film after removal of the surfactant is free of organic components derived from the surfactant, has an ethylene group remaining, and has a sufficient silanol group remaining. This was confirmed by infrared spectrophotometry. Further, it was confirmed by nuclear magnetic resonance spectroscopy that the bonds between silicon atoms and carbon atoms were maintained even after removal of the surfactant, and the ethylene groups were uniformly dispersed in the pore walls.

  Next, the site | part which fixes an anion on the pore surface was formed by the zirconium oxynitrate aqueous solution process. When an anion-immobilized site is introduced into pores by treatment with an aqueous zirconium oxynitrate solution, the membrane having an organic group in the pore wall has an advantage that it can be modified more easily than a mesoporous silica membrane. The membrane is 10 wt. After being immersed in a 1% aqueous solution of zirconium oxynitrate and held for 12 hours, it was thoroughly washed with pure water and dried at 100 ° C. for 1 hour. As a result of analyzing the treated film by X-ray diffraction, it was confirmed that both out-of-plane and in-plane regularity was maintained.

There was thus obtained, the use of the mesoporous organosilica hybrid film having a site for immobilizing anions on the surface of the mesopores, hexachloroplatinic acid hexahydrate _{(H 2 PtCl 6 · 6H 2} O) Using platinum as a precursor, platinum fine wires were prepared. 10 wt. % Of _{H 2} PtCl ₆ · 6H 2 was immersed in O solution, was kept at room temperature for 24 hours, ethanol was thoroughly washed and dried at room temperature. By repeating this operation 10 times, a sufficient amount of PtCl ₆ ²⁻ was introduced into the mesopores so that a fine metal wire could be formed. The mesoporous organic silica hybrid membrane that sufficiently contained PtCl ₆ ^{2− in the} mesopores was reduced by heating to 500 ° C. in a hydrogen atmosphere to obtain a platinum fine wire.

  An analyte carrier in which the platinum fine wire is exposed on the substrate can be prepared by selectively removing silica from the film containing the platinum fine wire in the mesopores by the same method as in Example 1. It was possible. In the produced platinum thin wire, it was confirmed by transmission electron microscope observation that a platinum thin wire having high linearity, a uniform diameter, and a long thin wire length was formed.

  A rhodamine 6G dye molecule solution having a concentration of 100 μmol / l is dropped on the analyte carrier, and an argon ion laser having a wavelength of 514.5 nm is irradiated from the analyte carrier surface through a polarizer. Raman scattered light was detected by a detector installed on the side.

  When the polarized light was irradiated in a direction parallel to the long axis direction of the platinum thin wire, Raman scattering was hardly confirmed, but when the polarized light was irradiated in the direction perpendicular to the long axis direction of the platinum thin wire, It was confirmed that very large surface enhanced Raman scattering (SERS) was generated. Further, it was confirmed that the peak intensity of the Raman spectrum was increased by 10 times or more.

  At this time, for comparison, a similar experiment was performed using a platinum fine wire produced using a mesoporous silica film having no uniaxial orientation as a template, and an analysis using the uniaxially oriented platinum fine wire produced this time was performed. Comparison with physical support was performed. As a result, the generation of SERS was confirmed in the analyte carrier using platinum fine wires not having uniaxial orientation, but the intensity did not depend on the polarization, and the value was also obtained when the polarization was used. It was small compared.

  When Raman scattering measurement is performed using a uniaxially oriented platinum fine wire produced using a mesoporous silica film as a template as an analyte carrier as described above, SERS that depends on the polarization direction is generated, resulting in molecular detection sensitivity. Is significantly improved, and a trace amount of molecules can be detected. In addition to the dye molecules as described above, trace amounts of biomolecules such as adenine and guanine and DNA can also be detected.

  This example uses a mesoporous silica film having a pore structure in which tubular mesopores having substantially uniform diameters, which are produced by a dip coating method based on a solvent evaporation method, are arranged in a uniaxial direction. This is an example in which after preparing a silver fine wire, silica was selectively removed to expose the silver fine wire on the substrate, thereby producing an analyte carrier.

Tetraethoxysilane (TEOS) was added as a starting material to an ethanol solution containing a predetermined amount of polyoxyethylene 10 cetyl ether (C ₁₆ EO ₁₀ ) prepared in advance and stirred for 30 minutes. In order to hydrolyze TEOS, hydrochloric acid and water were added to this solution and stirred for 2 hours to obtain a precursor solution. The composition (molar ratio) of the precursor solution was set to be TEOS: EtOH: H ₂ O: HCl: C ₁₆ TAB = 1: 22: 5: 0.004: 0.08.

  This precursor solution was applied to the rubbing-treated substrate by a dip coating method at a lifting speed of 2 mm / s and dried in an environmental tester at 25 ° C. and 50% relative humidity for 24 hours.

  When the produced film was evaluated by an out-of-plane X-ray diffraction method, a strong diffraction peak attributed to the (100) plane of a hexagonal structure with a surface spacing of 4.1 nm was confirmed, and this film had a tubular mesopore having a hexagonal structure. It was confirmed to have an ordered pore structure. When this film was evaluated by in-plane X-ray diffraction, a strong diffraction peak with a period of 180 ° was confirmed, and it was confirmed that the membrane had a pore structure in which the tubular mesopores were uniaxially arranged. It was.

  The produced film was baked at 400 ° C. for 4 hours, so that the surfactant was decomposed and removed to make it porous. It was confirmed by infrared spectrophotometry and the like that the organic component derived from the surfactant was not present in the film after the removal of the surfactant.

Using the mesoporous silica film thus obtained, a silver fine wire was prepared using a silver nitrate solution (weight ratio; ethanol: water = 1: 1) as a precursor. The membrane was immersed in a 0.2M silver nitrate solution and kept at room temperature for 24 hours, and then thoroughly washed with ethanol and purified water and dried at room temperature. By repeating this operation 10 times, a sufficient amount of Ag ⁺ was introduced into the mesopores to form a fine metal wire. The mesoporous silica film that sufficiently contained Ag ⁺ in the mesopores was subjected to reduction treatment by heating in the atmosphere at 300 ° C. for 2 hours to obtain a silver fine wire.

  Next, an analyte carrier in which the silver fine wires are exposed on the substrate is prepared by selectively removing silica from the film containing silver fine wires in the mesopores by the same method as in Example 1. It was possible to do. In the produced silver thin wire, it was confirmed by transmission electron microscope observation that a silver thin wire having high linearity, a uniform diameter, and a long thin wire length was formed.

  A rhodamine 6G dye molecule solution having a concentration of 100 μmol / l is dropped on the analyte carrier, and an argon ion laser having a wavelength of 514.5 nm is irradiated from the analyte carrier surface through a polarizer. Raman scattered light was detected by a detector installed on the side.

  When the polarized light was irradiated in the direction parallel to the long axis direction of the silver thin wire, Raman scattering was hardly confirmed, but when the polarized light was irradiated in the direction perpendicular to the long axis direction of the silver thin wire, It was confirmed that very large surface enhanced Raman scattering (SERS) was generated. Further, it was confirmed that the peak intensity of the Raman spectrum was increased by 10 times or more.

  At this time, for comparison, the same experiment was performed using a silver fine wire produced using a mesoporous silica film having no uniaxial orientation as a template, and the analysis was performed using the silver fine wire having the uniaxial orientation produced this time. Comparison with physical support was performed. As a result, in the analyte carrier using silver thin wires not having uniaxial orientation, the generation of SERS was confirmed, but the intensity did not depend on the polarization, and the value was also obtained when the polarization was used. It was small compared.

  When Raman scattering measurement is performed using a uniaxially oriented silver thin wire produced using a mesoporous silica film as a template as an analyte carrier as described above, SERS depending on the polarization direction is generated, resulting in molecular detection sensitivity. Is significantly improved, and a trace amount of molecules can be detected. In addition to the dye molecules as described above, trace amounts of biomolecules such as adenine and guanine and DNA can also be detected.

[Industrial applicability]
The analyte carrier and the method for producing the same of the present invention can be used in an analysis apparatus for detecting an extremely small amount of molecules.

It is the schematic which shows the structure of the analyte carrier of this invention. It is process drawing which shows an example of the process in the manufacturing method of the analyte carrier of this invention. It is an example of the analysis method using the analyte carrier of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12 Mesoporous material film 13 Pore 14 Pore wall 15 Metal fine wire 31 Substrate 32 Mesoporous material film 33 Metal fine wire 34 Detected molecule 35 Laser generator 36 Photo detector 37 Laser light 38 Raman scattered light

Claims (10)

An analyte carrier for use in Raman spectroscopy, comprising:
A mesoporous material film having tubular pores of uniform diameter formed on a substrate, and a structure having metal fine wires in the pores of the mesoporous material film, wherein the metal wires are partially exposed on the substrate Analyte carrier, characterized in that   2. The analyte carrier according to claim 1, wherein the mesoporous material film comprises tubular pores arranged in a uniaxial direction.   The analyte carrier according to claim 1 or 2, wherein the thin metal wire has a uniaxial orientation.   4. The analyte carrier according to claim 1, wherein the metal is Au, Ag, or Pt.   The analyte carrier according to any one of claims 1 to 4, wherein the substance constituting the pore wall of the mesoporous substance film is silicon dioxide.   The substance constituting the pore wall of the mesoporous material film is bonded to the silicon atom, an organic group containing one or more carbon atoms, two or more silicon atoms bonded to the organic group at two or more locations, and 1 The analyte carrier according to any one of claims 1 to 4, which is an organic silica hybrid material composed of the above oxygen atoms. A method for producing an analyte carrier for use in Raman spectroscopy, comprising:
Forming a mesoporous material film having a structure in which tubular pores of uniform diameter are arranged in a uniaxial direction on a substrate, introducing a solution containing a metal compound into the pores of the mesoporous material film, and A method for producing an analyte carrier, comprising: a step of chemically changing a metal compound to form a fine metal wire; and a step of selectively removing the mesoporous material film. Introducing the solution containing the metal compound into the pores of the mesoporous material film,
8. The method according to claim 7, comprising a step of forming a site for immobilizing an anion on the pore surface of the mesoporous material film, and a step of introducing an anion containing a metal atom into the pore. A method for producing the analyte carrier as described.   The step of forming a site for immobilizing anions on the pore surface of the mesoporous material film is a step of modifying the pore surface using a silane coupling agent having a cation site. A method for producing an analyte carrier according to claim 8.   The step of forming a site for immobilizing anions on the pore surface of the mesoporous material film modifies the pore surface with an aqueous solution of a metal salt containing a metal capable of forming an oxide having a higher isoelectric point than silica. The method for producing an analyte carrier according to claim 7 or 8, wherein the method comprises the steps of:

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