JP2011179978A - Spr sensor cell and spr sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an SPR sensor cell and an SPR sensor with superior accuracy of detection. <P>SOLUTION: The SPR sensor cell 1 includes an optical waveguide 2 including an under cladding layer 3 and a core layer 4 formed on the under cladding layer 3 to have a predetermined thickness. A sample is placed at the SPR sensor cell 1. A metal thin film 6 is formed on the core layer 4 throughout from the upper position in the thickness direction to the lowest position in the thickness direction of the core layer 4 to be in contact with the sample. The SPR sensor 11 includes the SPR sensor cell 1. According to the SPR sensor cell 1 and the SPR sensor 11, the accuracy of detection can be improved with a simple structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an SPR sensor cell and an SPR sensor, and more particularly, to an SPR sensor cell including an optical waveguide and an SPR sensor including the SPR sensor cell.

  Conventionally, in fields such as chemical analysis and biochemical analysis, SPR (Surface Plasmon Resonance) sensors including optical fibers have been used.

  In an SPR sensor including an optical fiber, a metal thin film is formed on the outer peripheral surface of the tip portion of the optical fiber, an analysis sample is fixed, and light is introduced into the optical fiber. Then, light of a specific wavelength in the introduced light generates surface plasmon resonance in the metal thin film, and attenuates the light intensity.

  In such an SPR sensor, the wavelength for generating surface plasmon resonance usually varies depending on the refractive index of the analysis sample fixed to the optical fiber.

  Therefore, if the wavelength at which the light intensity attenuates after the occurrence of surface plasmon resonance is measured, the wavelength at which the surface plasmon resonance is generated can be identified, and if it is detected that the attenuation wavelength has changed, the surface plasmon resonance is detected. Since it can be confirmed that the wavelength to be generated has changed, a change in the refractive index of the analysis sample can be confirmed.

  As a result, such an SPR sensor can be used for various chemical analysis and biochemical analysis such as measurement of sample concentration and detection of immune reaction.

  For example, when the sample is a solution, the refractive index of the sample (solution) depends on the concentration of the solution. Therefore, in the SPR sensor in which the sample (solution) is in contact with the metal thin film, the concentration of the sample can be detected by measuring the refractive index of the sample (solution), and the refractive index has changed. By confirming, it can be confirmed that the concentration of the sample (solution) has changed.

  In the analysis of immune reaction, for example, an antibody is immobilized on a metal thin film of an optical fiber in an SPR sensor via a dielectric film, a specimen is brought into contact with the antibody, and surface plasmon resonance is generated. At this time, if the antibody and the specimen undergo an immunoreaction, the refractive index of the sample changes. Therefore, by confirming that the refractive index of the sample has changed before and after contact between the antibody and the specimen, the antibody and specimen Can be judged to have immunoreacted.

  However, the SPR sensor provided with such an optical fiber has a problem that it is difficult to form a metal thin film and to fix an analysis sample because the tip of the optical fiber has a fine cylindrical shape.

  In order to solve such a problem, for example, a core through which light passes and a clad covering the core are provided, and a through hole is formed at a predetermined position of the clad up to the surface of the core. An SPR sensor cell in which a metal thin film is formed on the surface of a core at a corresponding position has been proposed (see, for example, Patent Document 1).

  According to this SPR sensor cell, it is easy to form a metal thin film for generating surface plasmon resonance on the core surface and fix the analysis sample to the surface.

JP 2000-19100 A

  However, in the SPR sensor cell described in Patent Document 1, since the metal thin film is formed only on the upper surface of the core facing the through-hole of the clad, the contact area between the analysis sample and the metal thin film is small, and the concentration and change of the analysis sample And the like cannot be detected with high accuracy.

  An object of the present invention is to provide an SPR sensor cell and an SPR sensor excellent in detection accuracy.

  In order to achieve the above object, an SPR sensor cell of the present invention is an SPR sensor cell in which a sample is disposed, and includes an undercladding layer and a core layer formed with a predetermined thickness on the undercladding layer. A waveguide is provided, and a metal thin film is formed on the core layer from the top to the bottom in the thickness direction of the core layer so as to be in contact with the sample.

  According to such an SPR sensor cell, since the metal thin film is formed not only from the uppermost layer in the thickness direction of the core layer but also from the uppermost layer to the lowermost layer, the contact area between the sample and the metal thin film can be increased. . Therefore, if such an SPR sensor cell is used, it is possible to accurately detect the concentration or change of the sample.

  In the SPR sensor cell of the present invention, it is preferable that the core layer has a substantially rectangular shape in cross section, and the metal thin film is formed on an upper surface and both side surfaces of the core layer.

  If the core layer has a substantially rectangular shape in cross section, the surface area of the core layer and the metal thin film can be increased, so that the contact area between the sample and the metal thin film can be further increased, and detection in the SPR sensor cell is possible. The accuracy can be further improved.

  In the SPR sensor cell of the present invention, it is preferable that the optical waveguide further includes an over clad layer formed on the under clad layer so as to surround the sample in contact with the metal thin film.

  If the over clad layer is formed so as to surround the sample in contact with the metal thin film, the sample can be easily disposed on the surface of the metal thin film, so that the workability can be improved.

  In addition, an SPR sensor of the present invention includes the above SPR sensor cell.

  In this SPR sensor, since the SPR sensor cell having a large contact area between the sample and the metal thin film is used, it is possible to accurately detect the concentration and change of the sample.

  According to the SPR sensor cell and the SPR sensor of the present invention, detection accuracy can be improved with a simple configuration.

Fig.1 (a) is a schematic perspective view which shows one Embodiment of the SPR sensor cell of this invention, FIG.1 (b) is AA sectional drawing of the SPR sensor cell shown to Fig.1 (a). 2A and 2B are process diagrams showing a method of manufacturing the SPR sensor cell shown in FIG. 1, wherein FIG. 2A is a process of forming an under cladding layer on a substrate, and FIG. 2B is a core. FIG. 2C shows a step of forming a layer on the under-cladding layer. FIG. 2D shows a step of forming an over-cladding layer on the under-cladding layer. FIG. 2D shows a thickness of the core layer. FIG. 2E shows a process of forming the base material from the top in the direction to the bottom, and the process of removing the substrate. FIG. 3 is a schematic sectional side view showing an embodiment of the SPR sensor of the present invention. FIG. 4 (a) is a schematic perspective view showing another embodiment of the SPR sensor cell of the present invention (a form in which a plurality of core layers are formed), and FIG. 4 (b) is a diagram of the SPR sensor cell shown in FIG. 4 (a). It is BB sectional drawing. FIG. 5 is a cross-sectional view of an essential part of another embodiment of the SPR sensor cell of the present invention (a form in which the core layer is substantially semicircular in sectional view). FIG. 6 is a cross-sectional view of an essential part of another embodiment of the SPR sensor cell of the present invention (a form in which the core layer has a substantially convex shape in cross section).

  Fig.1 (a) is a schematic perspective view which shows one Embodiment of the SPR sensor cell of this invention, FIG.1 (b) is AA sectional drawing of the SPR sensor cell shown to Fig.1 (a).

  1A and 1B, an SPR sensor cell 1 is formed in a substantially rectangular flat plate shape in plan view, and includes an optical waveguide 2 and a base material 10 (see a two-dot chain line) provided as necessary. I have. Further, as will be described in detail later, a sample to be analyzed by the SPR sensor 11 is disposed in the SPR sensor cell 1.

  The optical waveguide 2 is formed in a substantially rectangular flat plate shape in plan view, and includes an under cladding layer 3, a core layer 4, and an over cladding layer 5.

  The under-cladding layer 3 is formed in a substantially rectangular flat plate shape in plan view that is substantially the same as that in the optical waveguide 2 with a predetermined thickness.

  The core layer 4 has a predetermined thickness on the under-cladding layer 3 (one side in the thickness direction, the same applies hereinafter), and has a predetermined cross-sectional view extending in the longitudinal direction at the center in the width direction perpendicular to the longitudinal direction of the under-cladding layer 3. It is formed in a substantially rectangular shape (square column shape).

  The core layer 4 is formed such that its longitudinal length is substantially the same as the longitudinal length of the under cladding layer 3, and its lower surface (the other side surface in the thickness direction) is in contact with the under cladding layer 3. In addition, the both ends in the longitudinal direction are arranged so as to be flush with the both ends in the longitudinal direction of the under cladding layer 3.

  Moreover, although the longitudinal direction both ends of the core layer 4 are mentioned later in detail, it is set as the connection part for optically connecting to the light source 12 and the optical measuring device 13. FIG.

  The over clad layer 5 is formed on the under clad layer 3 in a rectangular frame shape in a plan view in which an opening 7 is formed at a substantially central portion in a plan view so as to surround a sample in contact with a metal thin film 6 (described later). Has been.

  The over cladding layer 5 is formed so that the outer periphery thereof is substantially the same as the outer periphery of the under cladding layer 3 in plan view, and covers the surfaces (upper surface and both side surfaces) of both ends in the longitudinal direction of the core layer 4. Are arranged to be.

  The opening 7 is formed through the over cladding layer 5 in the thickness direction so as to have a substantially rectangular shape in plan view at the central portion of the over cladding layer 5 in plan view. A rectangular frame-like weir portion 8 for arranging the sample is formed on the outer peripheral portion of the upper surface from the over clad layer 5, and the sample surrounded by the weir portion 8 is formed at a substantially central portion in the plan view. An accommodating portion 9 for accommodating is defined.

  In such an optical waveguide 2, a metal thin film 6 is provided on the core layer 4.

  The metal thin film 6 is continuously formed on the surface of the core layer 4 arranged in the accommodating portion 9 so as to come into contact with the sample from the uppermost to the lowermost in the thickness direction of the core layer 4.

  More specifically, the metal thin film 6 is covered with the upper surface and both side surfaces of the core layer 4 exposed from the over cladding layer 5 (that is, the contact surface of the core layer 4 with the under cladding layer 3 and the over cladding layer 5). The surface is continuously formed on the surface excluding the surface to be formed.

  In addition, the metal thin film 6 may be further formed on the upper surface of the under cladding layer 3 exposed from the over cladding layer 5 as necessary (see a two-dot chain line shown in FIG. 1B).

  In FIG. 1A and FIG. 1B, the base material 10 (refer to the two-dot chain line) is formed in a substantially rectangular flat plate shape in plan view that is substantially the same as that in the optical waveguide 2 as necessary. Provided on the bottom surface. Thereby, the base material 10 supports the optical waveguide 2 from the lower side.

  FIG. 2 is a process diagram showing a method of manufacturing the SPR sensor cell shown in FIG.

  Next, a method for manufacturing the SPR sensor cell 1 will be described with reference to FIG.

  In this method, first, as shown in FIG. 2A, a base material 10 is prepared, and then an under cladding layer 3 is formed on the base material 10.

  The base material 10 has a flat plate shape. As a material for forming the base material 10, for example, a ceramic material such as silicon or glass, for example, a metal material such as copper, aluminum, stainless steel, or an iron alloy, for example, polyimide, Examples thereof include resin materials such as glass-epoxy and polyethylene terephthalate (PET). Preferably, a ceramic material is used. The thickness of the base material 10 is 10-5000 micrometers, for example, Preferably, it is 10-1500 micrometers.

  Examples of the material for forming the undercladding layer 3 include polyimide resin, polyamide resin, silicone resin, epoxy resin, acrylic resin, and fluorinated modified products, deuterated modified products, and fluorene modified products. Resin material is mentioned. These resin materials are preferably used as a photosensitive resin by blending a photosensitive agent.

  In order to form the under clad layer 3 on the base material 10, for example, the above-described resin varnish (resin solution) is prepared, and the varnish is formed on the base material 10 by, for example, casting, spin coater or the like. After coating, it is dried and heated if necessary. In the case where a photosensitive resin is used, it is exposed through a photomask after application and drying of the varnish, and if necessary, it is heated after exposure, developed, and then heated.

  The thickness of the under cladding layer 3 formed in this way is, for example, 5 to 200 μm. Moreover, the refractive index of the under clad layer 3 is 1.42 or more and less than 1.55, for example.

  Next, in this method, as shown in FIG. 2B, the core layer 4 is formed on the under cladding layer 3 in the above-described pattern.

  As a material for forming the core layer 4, a resin material having a refractive index higher than that of the resin material of the under cladding layer 3 can be given. As such a resin material, the same resin material as the above is mentioned, for example.

  In order to form the core layer 4, for example, the above-described resin varnish (resin solution) is prepared, and the varnish is applied to the surface of the under cladding layer 3 in the above-described pattern, and then dried and cured as necessary. Let When a photosensitive resin is used, after applying and drying the varnish, it is exposed through a photomask, and if necessary, heated after exposure, developed, and then heated.

  The thickness of the core layer 4 thus formed is, for example, 5 to 100 μm, and the width is, for example, 5 to 100 μm. Moreover, the refractive index of the core layer 4 is set higher than the refractive index of the under clad layer 3, for example, 1.44 or more and 1.65 or less.

  Next, in this method, as shown in FIG. 2C, the over clad layer 5 is formed on the under clad layer 3 with the above-described pattern.

  That is, in this method, the over-cladding layer 5 is formed on the under-cladding layer 3 in the shape of a rectangular frame in plan view having the opening 7, covering both ends in the longitudinal direction of the core layer 4 and in the middle of the longitudinal direction. Arrange to expose. Thereby, the weir part 8 is formed in the outer peripheral part of the upper surface of the under clad layer 3, and the accommodating part 9 for accommodating the sample is defined.

  As a material for forming the over clad layer 5, the same resin material as the above under clad layer 3 is used.

  In order to form the over clad layer 5, for example, the above-described resin varnish (resin solution) is prepared, and the varnish is applied to the surface of the under-cladding layer 3 in the above-described pattern, and then dried. Harden. When a photosensitive resin is used, after applying and drying the varnish, it is exposed through a photomask, and if necessary, heated after exposure, developed, and then heated.

  The thickness of the over clad layer 5 formed in this way is, for example, 5 to 100 μm, and the thickness from the surface of the core layer 4 of the over clad layer 5 at both longitudinal ends of the core layer 4 is For example, it is 1 to 50 μm, preferably 5 to 20 μm. Further, the refractive index of the over cladding layer 5 is set lower than the refractive index of the core layer 4, for example, the same as the refractive index of the under cladding layer 3.

  Further, in such an overcladding layer 5, the size and shape of the opening 7 are not particularly limited, and are appropriately determined according to the type and application of the sample. In order to reduce the size of the SPR sensor cell 1, the opening 7 is preferably formed small.

  Next, in this method, as shown in FIG. 2 (d), the metal thin film 6 is continuously formed from the upper surface (uppermost) in the thickness direction of the core layer 4 to both side surfaces (lowermost).

  Examples of the metal material for forming the metal thin film 6 include gold, silver, and platinum.

  In order to form the metal thin film 6, for example, first, a resist having a reverse pattern of the pattern of the metal thin film 6 is formed, and the periphery of the portion where the metal thin film 6 is formed is masked. Thereafter, the metal thin film 6 is formed on the surface (upper surface and both side surfaces) of the core layer 4 exposed from the resist, for example, by a deposition method such as a vacuum deposition method, an ion plating method, or a sputtering method.

  In order to continuously form the metal thin film 6 on the upper surface and both side surfaces of the core layer 4, for example, the above-described metal material is vapor-deposited from diagonally above both side surfaces of the core layer 4.

  More specifically, in this method, the above-described metal material is used on both sides in the width direction plane including the axis S along the thickness direction (vertical direction) passing through the center in the width direction of the core layer 4 (both sides on both sides of the core layer 4). ) With respect to the axis S, for example, is deposited at an angle θ of ± 15 to 45 °, preferably ± 20 to 30 °.

  Thereafter, the resist is removed by etching or peeling.

  If necessary, the metal thin film 6 can also be formed on the upper surface of the under cladding layer 3 exposed from the over cladding layer 5 (see the two-dot chain line shown in FIG. 1B).

  The metal thin film 6 thus formed has a thickness of, for example, 40 to 70 nm, preferably 50 to 60 nm.

  In this way, the under cladding layer 3, the core layer 4 and the over cladding layer 5 are sequentially laminated on the base material 10, and the metal thin film 6 is exposed on the top surface and both side surfaces of the core layer 4 exposed from the over cladding layer 5. By forming it, the optical waveguide 2 can be formed.

  Further, in this method, as shown in FIG. 2E, the base material 10 can be removed by etching, peeling, or the like, if necessary.

  And the SPR sensor cell 1 provided with the optical waveguide 2 can be manufactured by forming the optical waveguide 2 in this way. In the SPR sensor cell 1, the sample is accommodated (arranged) in the accommodating portion 9, so that the metal thin film 6 exposed in the accommodating portion 9 comes into contact with the sample.

  According to such an SPR sensor cell 1, the metal thin film 6 is formed not only from the uppermost layer in the thickness direction of the core layer 4 but also from the uppermost layer to the lowermost layer, so that the contact area between the sample and the metal thin film 6 is increased. can do. Therefore, if such an SPR sensor cell 1 is used, it is possible to accurately detect the concentration and change of the sample.

  Further, if the core layer 4 has a substantially rectangular shape in cross section, the surface area of the core layer 4 and the metal thin film 6 can be increased, so that the contact area between the sample and the metal thin film 6 can be further increased. The detection accuracy in the SPR sensor cell 1 can be further improved.

  Furthermore, since the over clad layer 5 is formed so as to surround the sample in contact with the metal thin film 6, the sample can be easily disposed on the surface of the metal thin film 6, thereby improving workability. Can do.

  FIG. 3 is a schematic sectional side view showing an embodiment of the SPR sensor of the present invention. In addition, about the member corresponding to each above-mentioned part, the same referential mark is attached | subjected in each following figure, and the detailed description is abbreviate | omitted.

  Next, the SPR sensor 11 including the SPR sensor cell 1 will be described with reference to FIG.

  In FIG. 3, the SPR sensor 11 includes a light source 12, an optical measuring instrument 13, and the SPR sensor cell 1 described above.

  The light source 12 is a known light source such as a white light source or a monochromatic light source, and is connected to an optical fiber 15 via an optical connector 14. The optical fiber 15 is connected to the SPR sensor cell 1 via an optical fiber block 16. It is connected to one end portion in the longitudinal direction of (core layer 4).

  Further, an optical fiber 18 is connected to the other end portion in the longitudinal direction of the SPR sensor cell 1 (core layer 4) via an optical fiber block 17, and this optical fiber 18 is optically measured via an optical connector 19. Connected to the device 13.

  Although not shown, the optical measuring instrument 13 is connected to a known arithmetic processing unit, and can display, store and process data.

  In such an SPR sensor 11, the SPR sensor cell 1 is fixed by a known sensor cell fixing device (not shown). The sensor cell fixing device (not shown) is movable along a predetermined direction (for example, the width direction of the SPR sensor cell 1), whereby the SPR sensor cell 1 is disposed at an arbitrary position.

  The optical fibers 15 and 18 are fixed to optical fiber fixing devices 20 and 21, respectively.

  The optical fiber fixing devices 20 and 21 are fixed on a known 6-axis moving stage (not shown), and the longitudinal direction, width direction (direction perpendicular to the longitudinal direction and the horizontal direction), and thickness direction of the optical fiber. It is movable in (a direction orthogonal to the longitudinal direction and the direction perpendicular to the longitudinal direction) and a rotational direction (three directions) about each of these directions (three directions).

  According to such an SPR sensor 11, the light source 12, the optical fiber 15, the SPR sensor cell 1 (core layer 4), the optical fiber 18, and the optical measuring instrument 13 can be arranged on one axis so as to transmit these. Light can be introduced from the light source 12.

  In this SPR sensor 11, since the SPR sensor cell 1 having a large contact area between the sample and the metal thin film 6 is used, the concentration and change of the sample can be accurately detected.

  Hereinafter, one usage mode of the SPR sensor 11 will be described.

  In this aspect, for example, first, a sample is accommodated (arranged) in the accommodating portion 9 of the SPR sensor cell 1 shown in FIG. 3, and the sample and the metal thin film 6 are brought into contact with each other. Next, predetermined light from the light source 12 is introduced into the SPR sensor cell 1 (core layer 4) through the optical fiber 15 (see arrow L1 shown in FIG. 3).

  The light introduced into the SPR sensor cell 1 (core layer 4) is totally reflected in the core layer 4 and passes through the SPR sensor cell 1 (core layer 4) while generating surface plasmon resonance in the metal thin film 6.

  Thereafter, in the SPR sensor 11, the light transmitted through the SPR sensor cell 1 (core layer 4) is introduced into the optical measuring instrument 13 through the optical fiber 18 (see arrow L2 shown in FIG. 3).

  In the SPR sensor 11, the light introduced into the optical measuring instrument 13 has attenuated light intensity at a wavelength that causes surface plasmon resonance in the core layer 4.

  Since the wavelength for generating surface plasmon resonance depends on the refractive index of the sample accommodated (arranged) in the SPR sensor cell 1, by detecting the attenuation of the light intensity of the light introduced into the optical measuring instrument 13, A change in the refractive index of the sample can be detected.

  More specifically, for example, when a white light source is used as the light source 12, the optical measuring instrument 13 measures the wavelength at which the light intensity attenuates after transmission through the SPR sensor cell 1 (the wavelength that generates surface plasmon resonance), If it is detected that the attenuation wavelength has changed, the change in the refractive index of the sample can be confirmed.

  Further, for example, when a monochromatic light source is used as the light source 12, the optical measuring instrument 13 measures the change (degree of attenuation) of the monochromatic light after transmission through the SPR sensor cell 1, and the degree of attenuation is measured. If the change is detected, it can be confirmed that the wavelength for generating the surface plasmon resonance has changed, and the change in the refractive index of the sample can be confirmed as described above.

  Therefore, such an SPR sensor 11 can be used for various chemical analyzes and biochemical analyzes such as measurement of sample concentration and detection of immune reaction.

  More specifically, for example, when the sample is a solution, since the refractive index of the sample (solution) depends on the concentration of the solution, the SPR sensor 11 in which the sample (solution) is brought into contact with the metal thin film 6. If the refractive index of the sample (solution) is detected, the concentration of the sample can be measured. Moreover, if it detects that the refractive index of the sample (solution) has changed, it can be confirmed that the concentration of the sample (solution) has changed.

  In detecting an immune reaction, for example, an antibody is fixed on the metal thin film 6 of the SPR sensor cell 1 via a dielectric film, and a specimen is brought into contact with the antibody. At this time, since the refractive index of the sample changes if the antibody and the specimen undergo an immunoreaction, by detecting that the refractive index of the sample changes before and after contact between the antibody and the specimen, the antibody and the specimen are immune. It can be judged that it reacted.

  And according to such SPR sensor cell 1 and SPR sensor 11, improvement in detection accuracy can be aimed at by simple composition.

  FIG. 4A is a schematic perspective view showing another embodiment of the SPR sensor cell of the present invention, and FIG. 4B is a cross-sectional view of the SPR sensor cell shown in FIG.

  In the above description, one core layer 4 is formed in the SPR sensor cell 1. However, the number of core layers 4 is not particularly limited, and a plurality of (for example, three) core layers 4 may be formed.

  4A and 4B, the SPR sensor cell 1 includes an optical waveguide 2 and a base material 10 (see a two-dot chain line) provided as necessary. The optical waveguide 2 includes an under cladding layer. 3. A plurality of (three) core layers 4 and an over clad layer 5 are provided.

  A plurality of (three) core layers 4 are formed on the under-cladding layer 3 in a substantially rectangular shape (square prism shape) in a cross-sectional view extending in the longitudinal direction and spaced apart from each other in the width direction.

  When the optical waveguide 2 includes a plurality of (for example, three) core layers 4, the sample can be analyzed simultaneously a plurality of times by the SPR sensor 11 including the SPR sensor cell 1, so that the analysis efficiency can be improved.

  FIG. 5 is a cross-sectional view of a main part of another embodiment of the SPR sensor cell according to the present invention (the core layer has a substantially semicircular shape in cross section), and FIG. 6 shows another embodiment (core of the SPR sensor cell of the present invention). It is principal part sectional drawing of the form whose layer is a cross-sectional view substantially convex shape.

  Further, in the above description, the core layer 4 is formed in a substantially rectangular shape (square column shape) in a cross-sectional view extending in the longitudinal direction, but the shape of the core layer 4 is not particularly limited, and the core layer 4 is For example, it can be formed in an arbitrary shape such as a substantially semicircular shape (semi-cylindrical shape) shown in FIG. 5 and a substantially convex shape (convex column shape) shown in FIG.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples and comparative examples.

Example 1
A 4-inch silicon wafer was prepared as a substrate (base material), and an under cladding layer having a thickness of 25 μm was formed on the substrate (base material) using a photosensitive epoxy resin (see FIG. 2A).

  Next, using a photosensitive epoxy resin having a higher refractive index than that used for forming the undercladding layer, a linear (square columnar) core layer having a thickness of 50 μm and a width of 50 μm is formed on the undercladding layer. It formed (refer FIG.2 (b)).

  Thereafter, an over clad layer having a thickness of 70 μm was formed in the above-described pattern using the same photosensitive epoxy resin as that used for forming the under clad layer. An opening was formed in a part of the overcladding layer so that the core layer was exposed 8 mm in the length in the longitudinal direction (see FIG. 2C).

  Then, gold was deposited on the surface (upper surface and both side surfaces) of the core layer exposed from the opening and the upper surface of the under cladding layer to form a metal thin film having a thickness of 50 nm (see FIG. 2D).

  In forming the metal thin film, from the both sides in the width direction plane (both sides of the core layer 4) including the axis S along the thickness direction (vertical direction) passing through the center of the core layer 4 in the width direction, the axis S In contrast, gold was deposited at an angle of ± 25 ° (ie, from two directions of + 25 ° and −25 ° angles).

  Thereby, the SPR sensor cell provided with the optical waveguide was formed.

Example 2
An SPR sensor cell including an optical waveguide was formed in the same manner as in Example 1 except that the core layer was 20 μm thick and 20 μm wide.

Comparative Example 1
± 0 ° with respect to the axis S from both sides of the plane in the width direction (both sides of the core layer 4) including the axis S along the thickness direction (vertical direction) passing through the center in the width direction of the core layer 4 (Ie, from one side in the thickness direction of the core layer), and the metal thin film was not formed on the side surface of the core layer, but only on the upper surface of the core layer. An SPR sensor cell having an optical waveguide was formed.

Comparative Example 2
± 0 ° with respect to the axis S from both sides of the plane in the width direction (both sides of the core layer 4) including the axis S along the thickness direction (vertical direction) passing through the center in the width direction of the core layer 4 (Ie, from one side in the thickness direction of the core layer), and the metal thin film was not formed on the side surface of the core layer, but only on the upper surface of the core layer. An SPR sensor cell having an optical waveguide was formed.

Evaluation The SPR sensor cell obtained by each Example and each comparative example was fixed to the SPR sensor (see FIG. 3).

  Thereafter, 50 μL of four types of glucose aqueous solutions (concentrations: 5% by weight, 10% by weight, 20% by weight, 30% by weight) having different concentrations as samples are introduced into the opening of the SPR sensor cell, and a wavelength of 650 nm is introduced from one end of the core layer. And the intensity of the light emitted from the other end was measured. And the transmittance | permeability (%) when the intensity | strength of light in the state without glucose aqueous solution was set to 100% was calculated | required.

  Then, using the glucose concentration of the glucose aqueous solution as the X-axis and the transmittance as the Y-axis, the relationship was plotted on the XY coordinates to create a calibration curve, and the slope and correlation coefficient were obtained. The values are shown in Table 1. In addition, it shows that a detection sensitivity is so high that inclination is large, and a detection accuracy is so high that a correlation coefficient is close to one.

Results Each example in which a metal thin film was formed on the upper surface and both side surfaces of the core layer had a larger slope and a correlation coefficient close to 1 compared to each comparative example in which a metal thin film was formed only on the upper surface of the core layer. Met.

DESCRIPTION OF SYMBOLS 1 SPR sensor cell 2 Optical waveguide 3 Under clad layer 4 Core layer 5 Over clad layer 6 Metal thin film 7 Opening part 8 Weir part 9 Housing part 10 Base material 11 SPR sensor

Claims (4)

An SPR sensor cell in which a sample is placed,
An optical waveguide comprising an undercladding layer and a core layer formed with a predetermined thickness on the undercladding layer,
The SPR sensor cell according to claim 1, wherein a metal thin film is formed on the core layer from the top to the bottom in the thickness direction of the core layer so as to come into contact with the sample. The core layer has a substantially rectangular shape in sectional view,
The SPR sensor cell according to claim 1, wherein the metal thin film is formed on an upper surface and both side surfaces of the core layer.   3. The SPR sensor cell according to claim 1, wherein the optical waveguide further includes an over clad layer formed on the under clad layer so as to surround the sample in contact with the metal thin film. 4. . An SPR sensor comprising the SPR sensor cell according to claim 1.

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