JP5268102B2 - SPR measurement chip with droplet shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily changing SPR measurement chips by optimizing the shape of a refractive index matching sheet integrally formed with a transparent substrate or by optimizing the shape of the transparent substrate to solve existing problems in an SPR optical system wherein air bubbles liable to get in the transparent substrate make measurement difficult when sticking it fast to the matching sheet, the transparent substrate is not stabilized when sticking it fast thereto, and the like. <P>SOLUTION: This chip for SPR measurement is used in an SPR optical system 210. This chip includes a transparent substrate 205 comprising a metallic thin film for SPR measurement, and further, a transparent elastic adhesive sheet 206 on a surface of the transparent substrate 205 on the opposite side of the thin film. The adhesive sheet 206 has a liquid drop shape swelling from the end of the sheet toward the middle. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a chip for SPR measurement used for measurement using a surface plasmon resonance (SPR) phenomenon in which a specific substance in a solution to be measured is quantitatively or qualitatively measured using an optical system.

  For surface plasmon resonance measurement, a prism, a transparent substrate having the same refractive index as that of the prism having a metal thin film, and an adhesive layer for optically bonding the prism and the transparent substrate are required. A refractive index matching oil is usually used for the adhesive layer, and the transparent substrate is replaced for each measurement.

A cross-sectional view of a configuration example of the conventional SPR optical system described above is shown in FIG.
In FIG. 1, the SPR optical system 100 includes a light source 101, a lens 102, a prism 103, a light receiving element 104, a matching oil 105, and a transparent substrate 106 having a metal thin film. The SPR optical system 110 shows a state where the transparent substrate 106 is bonded to the prism 103 via the matching oil 105.

  However, the refractive index matching oil 105 remains on the prism, and it is necessary to clean the prism 103 every time the transparent substrate 106 is replaced. In order to save time and effort, instead of oil, a sheet whose refractive index is matched is used. However, bubbles are likely to enter during close contact, making measurement difficult. There are disadvantages that the transparent substrate is not stable when in close contact, and the transparent substrate 106 is in close contact with the prism 103, which takes time to replace.

  Patent Document 1 introduces a system that uses a refractive index matching transparent film instead of refractive index matching oil and does not require cleaning on the prism when replacing the glass substrate. However, there has been a problem that a refractive index matching transparent film has to be installed between the glass substrate and the prism, and bubbles are likely to enter at that time.

  Further, Patent Document 2 describes an invention in which an optical interface plate is installed between a prism and a measurement chip. However, there is a problem that not only the number of parts increases but also the shape thereof is complicated.

Japanese Patent No. 3356212 Japanese Patent No. 3294605

  The present invention solves the above-mentioned problems by optimizing the shape of the refractive index matching sheet integrally formed on the transparent substrate in the SPR optical system, or by optimizing the shape of the transparent substrate. An object is to provide a method capable of exchanging measurement chips.

In order to solve the above problems, a surface plasmon resonance measurement chip according to the present invention is transparent on a transparent substrate having a metal thin film for surface plasmon resonance measurement, and on a surface of the transparent substrate opposite to the metal thin film. further comprising an elastic pressure-sensitive adhesive sheet, the transparent elastic adhesive sheet, possess from the edge of the sheet raised drop shape toward the center, and the said transparent substrate is a drop shape only one side of the surface opposite The transparent elastic adhesive sheet is divided into a plurality of portions covering an optical path necessary for measurement of the transparent substrate .

  Moreover, the said transparent elastic adhesive sheet may be formed in the hollow provided in the surface on the opposite side to the said metal thin film of the said transparent substrate.

  The transparent elastic adhesive sheet may be a self-curing material that does not erode the transparent substrate.

  Moreover, you may provide the spacer which prescribes | regulates the distance of the said prism and the said transparent substrate in parts other than the said transparent elastic adhesive sheet of the said transparent substrate.

  In addition, a protective release sheet may be attached to the transparent elastic adhesive sheet before use.

  According to the present invention, in the SPR optical system, by optimizing the shape of the refractive index matching sheet integrally formed on the transparent substrate, or by optimizing the shape of the transparent substrate, air bubbles enter when the transparent substrate is in close contact. It is possible to provide a technique that can easily replace the SPR measurement chip by solving the conventional problems such as easy measurement and difficulty of the measurement, and instability of the transparent substrate when closely attached.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 shows a cross-sectional view of a configuration example of an SPR optical system using the refractive index matching sheet of the present invention.
In FIG. 2, the SPR optical system 200 includes a light source 201, a lens 202, a prism 203, a light receiving element 204, a transparent substrate 205 having a metal thin film, and a refractive index matching sheet 206. The SPR optical system 210 shows a state in which the transparent substrate 205 is bonded to the prism 203 via the refractive index matching sheet 206.

  A refractive index matching sheet 206 having a droplet shape is formed on the back side of the transparent substrate 205 on which the metal thin film is formed. The refractive index matching sheet 206 is directly applied to the transparent substrate 205 and has a droplet shape. Due to this droplet shape, when the transparent substrate 205 is brought into close contact with the prism 203, it is gradually brought into close contact from the central portion of the refractive index matching sheet 206, and bubbles are pushed out.

  Furthermore, the material of the refractive index matching sheet 206 is a silicon polymer, and has properties such as rubber or gel. When the close contact is released, the refractive index matching sheet 206 attempts to return to the original shape. Therefore, the contact surface with the prism 203 is naturally reduced, and the transparent substrate 205 can be easily replaced.

  The refractive index matching sheet 206 is formed by directly applying a sheet material to the transparent substrate 205, and the shape is determined by the affinity of the material with the transparent substrate 205, the surface tension, and the dropping amount. If the affinity with the transparent substrate 205 is low, the sheet material will be repelled, resulting in polka dots. Therefore, it is necessary to select a material with high affinity to some extent. When the transparent substrate 205 is made of glass or plastic, a silicon polymer is suitable.

  The amount by which the sheet material is dropped on the transparent substrate 205 depends on the design of the SPR device. Since the light from the light source 201 is designed to focus on the surface of the transparent substrate 205, the focal position exists upward from the upper surface of the prism 203. Since the distance must be the thickness when the transparent substrate 205 and the refractive index matching sheet 206 are pressure-bonded, the coating amount needs to be accurately controlled.

  Further, in order to obtain an optimal droplet shape, the area to be applied and the amount to be applied must be controlled. If the application area is too small and the application amount is too large, a semi-circular shape is formed, so that the area in contact with the prism 203 at the time of pressure bonding becomes small. If you try to force the pressure in that state, you will have to press it with a considerable pressure. However, the above problem can be accurately controlled by using a precision pump, and does not become an important problem.

  In the simplest shape, a refractive index matching sheet 206 having a droplet shape is formed on the entire surface of the transparent substrate 205. However, in this shape, there is a possibility that the transparent substrate 205 is inclined at the time of close contact. In view of this, a shape in which two portions are applied as in the SPR optical system 300 shown in FIG. 3 can be considered.

  In the shape shown in FIG. 3, the close contact portion with the prism 303 is divided into two or more portions, and the tilt at the close contact of the transparent substrate 305 can be suppressed. In this case, one of the two places where the refractive index matching sheet 306 is applied is an optical path of incident light to the transparent substrate 305 and the other is an optical path of outgoing light. Therefore, the shape to be applied must be designed to cover the two optical paths.

  In order to fabricate the refractive index matching sheet 306 having the shape as described above, various methods such as a method of applying to the transparent substrate 305 using a mask and a method of using screen printing can be considered. It is also conceivable to change the shape of the transparent substrate 401 as in the SPR measurement chip 400 shown in FIG.

  In FIG. 4, the transparent substrate 401 has a shape in which the portion to which the sheet material is applied is depressed in advance, and the sheet material does not spread further. Further, the convex portion of this shape plays a role of a spacer when the refractive index matching sheet 402 is crimped and crushed when the transparent substrate 401 is closely attached to the prism 303, and has a function of controlling the thickness when the transparent substrate 401 is crimped. It is also possible to

  In addition, in order to control the thickness of the silicon rubber during crimping, it is possible to install a separate spacer on the transparent substrate where there is no refractive index matching sheet. In order to prevent scratches and the like, a sheet-like protective tape is applied before use, and the protective tape is peeled off immediately before use so that a normal and scratch-free sheet can be pressure-bonded to the prism 303 at all times. It is also possible.

  In the SPR optical system, the prism material is BK7 (refractive index = 1.51) glass, and the transparent substrate is 16 × 16 × 0.5 mm BK7 glass. On one surface of the transparent substrate, a gold thin film (47 nm) was formed by vapor deposition using titanium as an adhesive layer (2 to 3 nm).

  A transparent silicon rubber having a refractive index of 1.52 after curing with a two-component mixed type was spotted with a pipette on the surface opposite to the gold thin film, and extended to the whole. The resin amount was adjusted so that the thickness of the refractive index matching sheet after curing was 0.5 mm. After the resin is applied, it has a droplet shape due to surface tension.

  The substrate after the application of the silicon resin was allowed to stand at room temperature or cured by heating to produce a refractive index matching sheet integrated SPR measurement chip. The prepared SPR measuring chip with integrated refractive index matching sheet was placed in an SPR optical system as shown in FIG. 5 and applied with a weight from above to be brought into close contact with the prism, and SPR was measured.

  In FIG. 5, the SPR optical system 500 includes a light source 501, a spherical lens A502, a cylindrical lens A503, a prism 504, a cylindrical lens B505, a polarizer 506, a spherical lens B507, and a photodetector 508. , A refractive index matching sheet 509, a transparent substrate 510, and a metal thin film 511.

  An image for confirming SPR measurement under the above-described conditions is shown in FIG. Water was dropped as a sample on the gold thin film. In FIG. 6, the horizontal axis corresponds to the SPR angle direction, and the vertical direction corresponds to the focal line direction on the chip. It can be seen that because of the reflected light phenomenon due to the SPR phenomenon, a dark line can be confirmed on the left side of the image and good measurement can be performed.

  The prism material was BK7, and 16 × 16 × 1 mm BK7 glass was used for the transparent substrate. A gold thin film (47 nm) was formed on one surface of the transparent substrate by sputtering using titanium as an adhesive layer (2 to 3 nm).

  On the surface opposite to the gold thin film, transparent silicon rubber having a refractive index after curing of 1.51 was applied by a doctor blade method so as to have a film thickness of 0.1 mm. Thereafter, it was cured by heating to produce a refractive index matching sheet. The application shape of the transparent silicon gel was set as an application shape 700 shown in FIG.

  The manufactured refractive index matching sheet integrated SPR measurement chip was measured by the same SPR optical system as in Example 1. An image obtained by measuring the SPR of water under these conditions is shown in FIG. From FIG. 8, it can be seen that the SPR measurement chip of the present invention can be used in the same manner as when the refractive index matching oil is used.

  The prism material was BK7, and the transparent substrate was a plastic made of cyclic polyolefin with a thickness of 1 mm. On one surface of the transparent substrate, a gold thin film (47 nm) was formed by vapor deposition using titanium as an adhesive layer (2 to 3 nm).

  A transparent silicon rubber having a refractive index of 1.53 after curing was spotted on the surface opposite to the gold thin film and extended to the whole surface. The resin amount was adjusted so that the thickness of the refractive index matching sheet after curing was 0.1 mm. The shape in which the resin is applied is the same as in Example 2.

  The chip produced above is installed in the same optical system as in Example 1, and an image in which SPR is confirmed is shown in FIG. 9, and a graph is shown in FIG. 9 and 10, it can be seen that the SPR measurement chip of the present invention can be used as in the case of using the refractive index matching oil.

  The prism material was BK7, and the transparent substrate was a plastic made of cyclic polyolefin with a thickness of 1 mm. On one surface of the transparent substrate, a gold thin film (47 nm) was formed by vapor deposition using titanium as an adhesive layer (2 to 3 nm).

  A transparent silicon rubber having a refractive index of 1.53 after curing was dropped onto the surface opposite to the gold thin film and applied. The thickness of the refractive index matching sheet after curing was set to 0.1 mm. The produced SPR measurement chip was measured by the same SPR optical system as in Example 1. FIG. 11 is an image for confirming the SPR measurement of water.

  Furthermore, the antigen-antibody reaction was confirmed with the measurement chip similarly produced. The prepared refractive index matching sheet-integrated SPR measurement chip was provided with two channels, Anti-IgG was immobilized and BSA blocked on one side, and only the BSA blocking was performed on the other side as a reference channel. The chip was placed in an SPR optical system, and a 100 ng / ml IgG solution was allowed to flow as a sample. The measurement result at this time is shown in FIG. From FIG. 12, when 100 ng / ml IgG was flowed at 1000 sec, an increase in signal was confirmed by the antigen-antibody reaction.

  As described above, according to the SPR measurement chip of the present invention, it is possible to obtain performance equivalent to the method used in combination of glass and matching oil in measurement of optical characteristics and actual antigen-antibody reaction, and the like. The substrate can be easily attached and detached.

It is sectional drawing which shows the structure of the conventional SPR optical measurement system. It is sectional drawing which shows the structure of the SPR optical system using the chip | tip for SPR measurement by one Embodiment of this invention. It is sectional drawing which shows the structure of the SPR optical system using the chip | tip for SPR measurement by another embodiment of this invention. It is sectional drawing and the top view of the chip | tip for SPR measurement by another embodiment of this invention. It is a figure which shows the structure of the SPR optical system using the chip | tip for SPR measurement concerning Example 1 of this invention. It is a figure which shows the image which confirms SPR measurement using the chip | tip for SPR measurement which concerns on Example 1 of this invention. It is a figure which shows the application | coating shape of the transparent silicon gel of the chip | tip for SPR measurement which concerns on Example 2 of this invention. It is a figure which shows the image which confirms SPR measurement using the chip | tip for SPR measurement which concerns on Example 2 of this invention. It is a figure which shows the image which confirms SPR measurement using the chip | tip for SPR measurement which concerns on Example 3 of this invention. It is a figure which shows the graph which confirms SPR measurement using the chip | tip for SPR measurement which concerns on Example 3 of this invention. It is a figure which shows the image which confirms SPR measurement using the chip | tip for SPR measurement which concerns on Example 4 of this invention. It is a figure which shows the image which confirms the antibody antigen reaction using the chip | tip for SPR measurement which concerns on Example 4 of this invention.

Explanation of symbols

200, 210, 300, 310 SPR optical system 201, 301, 501 Light source 202, 302 Lens 203, 303, 504 Prism 204, 304, 508 Light receiving element 205, 305, 401, 510, 701 Transparent substrate 206, 306, 402, 509, 702 Refractive index matching sheet 502 Spherical lens A
503 Cylindrical lens A
505 Cylindrical lens B
506 Polarizer 507 Spherical lens B
511 Metal thin film

Claims (5)

A transparent substrate having a metal thin film for surface plasmon resonance measurement;
On the surface of the transparent substrate opposite to the metal thin film, a transparent elastic adhesive sheet is provided,
The transparent elastic pressure-sensitive adhesive sheet has a droplet shape that rises from the edge of the sheet toward the center, and has a droplet shape only on one side of the surface opposite to the transparent substrate,
The surface plasmon resonance measurement chip according to claim 1, wherein the transparent elastic adhesive sheet is divided into a plurality of portions covering an optical path necessary for measurement of the transparent substrate .   The surface plasmon resonance measurement chip according to claim 1, wherein the transparent elastic adhesive sheet is formed in a recess provided on a surface of the transparent substrate opposite to the metal thin film.   2. The surface plasmon resonance measurement chip according to claim 1, wherein the transparent elastic adhesive sheet is a self-curing material that does not erode the transparent substrate.   2. The surface plasmon resonance measurement chip according to claim 1, wherein a spacer for defining a distance between the prism and the transparent substrate is provided on a portion of the transparent substrate other than the transparent elastic adhesive sheet.   The surface plasmon resonance measurement chip according to claim 1, wherein a protective release sheet is attached to the transparent elastic adhesive sheet before use.