JP2015064205A - Localized plasmon resonance chip and localized plasmon resonance biosensor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a localized plasmon resonance chip that solely requires a small number of measurements and increases the detection accuracy.SOLUTION: The localized plasmon resonance biosensor 10 is divided into a plurality of square primary measurement regions S of several hundreds nm to several μm and a plurality of reference measurement regions R. In each primary measurement region S undergoing an antibody antigen reaction, a non-tabular gold (Au) layer GS of a nanometer order for generating a strong plasmon resonance in the X direction is formed along the X direction. In each reference measurement region R that does not undergo an antibody antigen reaction, a non-tabular gold (Au) layer GR of a nanometer order for generating a strong plasmon resonance in the Y direction is formed along the Y direction.

Description

  The present invention relates to a localized plasmon resonance (LPR) chip used for medical diagnosis, medical examination, food inspection, and the like, and a localized plasmon resonance biosensor using the same.

  In recent years, surface plasmon resonance (SPR) biosensors with a Kretschmann arrangement using prisms have been developed as small-sized, low-cost, high-speed sensing biosensors in medical diagnosis, medical examination, food inspection, and the like.

  Furthermore, recently, a localized plasmon resonance (LPR) biosensor not using a prism has been attracting attention as a biosensor for high-sensitivity sensing. Conventional localized plasmon resonance biosensors include a transmission type shown in FIGS. 8 and 9, and a reflection type shown in FIGS.

  In FIG. 8, 101 is a light source, 102 is a collimator lens, 103 is a localized plasmon resonance chip having a surface plasmon resonance unit 103a, 104 is a measuring device including a spectroscope and a multi-channel analyzer and configured by a microcomputer. In this case, the light L1 from the light source 101 is converted into parallel light by the collimator lens 102 and vertically transmitted through the localized plasmon resonance chip 103, and the measurement apparatus 104 transmits the localized plasmon from the light L1 transmitted through the localized plasmon resonance chip 103. The absorption spectrum of the resonance chip 103 is measured. That is, the refractive index (dielectric constant) change of the medium in the vicinity of the surface plasmon resonance portion 103a of the localized plasmon resonance chip 103 can be detected with high accuracy by the shift amount dS1 of the absorption peak wavelength of the absorption spectrum S1 shown in FIG. (Reference: Fig. 2 of Patent Document 1, Fig. 1 of Non-Patent Document 1).

  On the other hand, in FIG. 10, 201 is a light source, 202 is a collimator lens, 203 is a beam splitter, 204 is a localized plasmon resonance chip having a surface plasmon resonance part 204a, 205 includes a spectroscope and a multichannel analyzer, and is constituted by a microcomputer. Measuring device. In this case, the light L2 from the light source 201 is converted into parallel light by the collimator lens 202, is transmitted through the beam splitter 203, is reflected by the localized plasmon resonance chip 204, is further reflected by the beam splitter 203, and enters the measuring device 205. . In the measuring device 205, the reflected light spectrum of the localized plasmon resonance chip 204 is measured from the light L2 reflected by the localized plasmon resonance chip 204. That is, the change in the refractive index (dielectric constant) of the medium in the vicinity of the surface plasmon resonance portion 204a of the localized plasmon resonance chip 204 can be detected with high accuracy by the shift amount dS2 of the reflection dip wavelength of the reflected light spectrum S2 shown in FIG. Reference: FIG. 1 of Patent Document 1).

  The medium in the vicinity of the surface plasmon resonance parts 103a and 204a is initially a sensor substance such as an antibody that specifically binds to a target substance such as an antigen, and the sensor substance is fixed to the surface plasmon resonance parts 103a and 204a in advance. Has been. After the target substance is bonded to the sensor substance, the medium becomes the sensor substance plus the target substance. Therefore, the refractive index (dielectric constant) of the medium changes before and after the bonding. As a result, the target substance can be quantitatively detected with high accuracy by detecting the change in the refractive index (dielectric constant) of the medium with high accuracy.

  In any of the localized plasmon resonance biosensors of FIGS. 8 and 10, the lights L1 and L2 are directly incident perpendicularly to the surface plasmon resonance portions 103a and 204a of the localized plasmon resonance chips 103 and 204. In the surface plasmon resonance biosensor, light is incident obliquely on the bottom surface of the prism. Therefore, the localized plasmon resonance biosensor is superior to the surface plasmon resonance biosensor in terms of miniaturization.

  The surface plasmon resonance portions 103a and 204a of the localized plasmon resonance chips 103 and 204 shown in FIGS. 8 and 10 are made of a metal nano thin film layer or a metal nano particle layer made of a metal such as Au, Ag, Cu, or Al. For example, the metal nano thin film layer is manufactured by forming a metal thin film having a through hole on a transparent substrate by using a nanoimprint technique or a lithography technique (see Patent Document 2). In addition, the metal nanoparticle layer is dispersed and deposited on a smooth glass substrate via a dielectric such as a silane coupling agent by electrophoretic deposition (EPD) method. In this case, each particle of the metal nanoparticle layer is spherical and rod-shaped. Shape, triangular shape, and other polygonal shapes (see Non-Patent Document 2). Further, the ceramic nanoparticles are formed as a single layer on the gold layer, and the ceramic nanoparticles are coated in a cap shape with gold (see Non-Patent Document 3). Furthermore, a submicron-order structure is formed using a special material, and gold is deposited on the structure (see Patent Document 1).

WO2011 / 121857A1 JP 2003-270132 A

Yuichi Tomaru et al., “Localized plasmon sensor using porous alumina substrate”, Fujifilm Research & Development, No.53-2008, pp.34-37 Masaaki Kurita, “Precious Metals Used in Localized Plasmon Resonance Biosensors and Their Applications”, Surface Technology, Vol.62, No.6, 2011, pp.28-30 Anal. Chem. 78, pp. 6415-6475, 2006

  However, since the above-mentioned conventional localized plasmon resonance chip serves both as a reference measurement and a main measurement, there are the following problems.

  First, a local plasmon resonance chip to which a sensor substance such as an antibody is fixed is set as the local plasmon resonance biosensor of FIG. 8 or FIG. 10, and a reference absorption peak wavelength or reflection dip wavelength is measured (referred to as reference measurement). ), Remove the localized plasmon resonance chip from the localized plasmon resonance sensor, attach an antigen such as a virus, which is the target substance, to the localized plasmon resonance chip, wash it, and reset it to the localized plasmon resonance sensor. Measure the absorption peak wavelength or reflection dip wavelength for main measurement (referred to as main measurement). Thereby, the shift amount is obtained. Therefore, there is a problem that the number of times of measurement is two and the working time is long.

  Second, if the setting position of the local plasmon resonance chip at the time of the reference measurement and the setting position of the local plasmon resonance chip at the time of the main measurement do not match, the absorption peak for the main measurement with respect to the reference absorption peak wavelength or the reflection dip wavelength The measurement error of the wavelength or the reflection dip wavelength becomes large, and as a result, there is a problem that the detection accuracy of the target substance expressed by the difference, that is, the shift amount is lowered. 8 and FIG. 10, halogen lamps and light emitting diode (LED) elements are used as the light sources 101 and 201. If the light sources 101 and 201 are not stable, the ambient temperature environment changes, etc., as described above. Since the reference measurement and the main measurement are different, the emission spectra of the light sources 101 and 201 themselves change, so that the measurement error described above also increases, and as a result, the difference, that is, the shift amount is expressed as a result. There exists a subject that the detection accuracy of a substance falls.

  In order to solve the above-mentioned problem, a localized plasmon resonance biosensor according to the present invention is formed on a substrate divided into a main measurement region and a reference measurement region, and on the main measurement region of the substrate, in a first direction. A first non-planar metal layer of nanometer order for generating strong plasmon resonance, a sensor material layer formed on the first non-plate metal layer, and a reference measurement region of the substrate. A nanometer-order second non-plate-like metal layer for generating strong plasmon resonance in a second direction different from the first direction, and a sensor material layer provided on the second non-plate-like metal layer And a masking layer for compensating the dielectric constant. Thus, in this measurement region, the medium before the target substance binding (for example, before the antigen-antibody reaction) is the sensor substance layer, and the medium after the target substance binding (for example after the antigen-antibody reaction) is the sensor substance layer plus the target substance. Therefore, the refractive index (dielectric constant) of the medium in this measurement region changes. On the other hand, in the reference measurement region, the medium before binding of the target substance (for example, before the antigen-antibody reaction) is a masking layer, and the medium after binding of the target substance (for example, after the antigen-antibody reaction) is also a masking layer. The refractive index (dielectric constant) of the medium in the measurement region does not change. In addition, the polarization direction of the transmitted light or reflected light in the main measurement region is the first direction, and the polarization direction of the transmitted light or reflected light in the reference measurement region is the second direction. Both of these use, for example, a polarization beam splitter. Can be identified.

  A transmission type localized plasmon resonance sensor according to the present invention includes a light source, the above-described localized plasmon resonance chip for receiving light from the light source, polarized light in a first direction transmitted through the localized plasmon resonance chip, and A polarization beam splitter for separating polarized light in a second direction different from the first direction, an absorption peak wavelength of an absorption spectrum of polarized light in the first direction from the polarization beam splitter, and an absorption spectrum of polarized light in the second direction. And a measuring device that quantitatively measures the target substance of the localized plasmon resonance chip based on the shift amount with respect to the absorption peak wavelength.

  Further, the reflective localized plasmon resonance sensor according to the present invention includes a light source, the above-described localized plasmon resonance chip for receiving light from the light source, polarized light in a first direction reflected from the localized plasmon resonance chip, and A polarization beam splitter for separating polarized light in a second direction different from the first direction, a reflected dip wavelength of reflected light spectrum of polarized light in the first direction from the polarized beam splitter, and reflected light of polarized light in the second direction And a measuring device that quantitatively measures the target substance of the medium of the localized plasmon resonance chip by the shift amount of the reflection dip wavelength of the spectrum.

  According to the present invention, the refractive index (dielectric constant) of the medium in the measurement region changes before and after the binding of the target substance, and thus a shift amount occurs in the absorption peak wavelength of the absorption spectrum or the reflection dip wavelength of the reflected light spectrum. To do. In contrast, the refractive index (dielectric constant) of the medium in the reference measurement region does not change before and after the target substance is bonded, and therefore no shift occurs in the absorption peak wavelength of the absorption spectrum or the reflection dip wavelength of the reflected light spectrum. . As a result, the measurement of the absorption peak wavelength or reflected dip wavelength of the absorption spectrum in the main measurement region and the absorption peak wavelength or reflected light spectrum of the absorption spectrum in the reference measurement region is performed by one measurement after binding of the target substance. By obtaining the reflection dip wavelength and calculating the shift amount which is the difference, the target substance can be detected quantitatively with high accuracy. In other words, the target substance can be detected quantitatively with high accuracy in one measurement, and work efficiency can be improved.

  In addition, since the reference measurement and the main measurement are performed at the same time, there is no measurement error of the main absorption peak wavelength or the reflection dip wavelength with respect to the reference absorption peak wavelength or the reflection dip wavelength. Detection accuracy can be improved.

1 is a top view showing a first embodiment of a localized plasmon resonance chip according to the present invention. FIG. 2 is a cross-sectional view taken along the line II of FIG. 1 showing a first example of the localized plasmon resonance chip of FIG. FIG. 4 is a cross-sectional view taken along the line II of FIG. 1 showing a second example of the localized plasmon resonance chip of FIG. It is a top view which shows 2nd Embodiment of the localized plasmon resonance chip | tip concerning this invention. FIG. 5 is a cross-sectional view taken along line VV of FIG. 4 illustrating an example of the localized plasmon resonance chip of FIG. It is a figure which shows the transmission type local plasmon resonance biosensor which concerns on this invention. It is a figure which shows the reflection type localized plasmon resonance biosensor which concerns on this invention. It is a figure which shows the conventional transmission type | mold local plasmon resonance biosensor. It is a graph which shows the absorption spectrum obtained with the measuring apparatus of FIG. It is a figure which shows the conventional reflection type localized plasmon resonance biosensor. It is a graph which shows the reflected light spectrum obtained with the measuring apparatus of FIG.

  FIG. 1 is a top view showing a first embodiment of a localized plasmon resonance chip according to the present invention.

  In FIG. 1, the localized plasmon resonance biosensor 10 is divided into a plurality of square main measurement (sensing) regions S and a plurality of reference measurement (reference) regions R of several 100 nm to several μm. In this case, preferably, the main measurement areas S and the reference measurement areas R are alternately arranged so that a plurality of main measurement areas S and reference measurement areas R are simultaneously irradiated by one light measurement spot having a diameter of 3 mm × several tens of mm. To. Each side of the main measurement region S (reference measurement region R) is set to be twice or more the size of the target substance, for example, the size of influenza virus of 90 to 120 nm.

  In each main measurement region S, a nanometer-order non-tabular gold (Au) layer GS for generating strong plasmon resonance in the X direction is formed along the X direction. Although not shown in FIG. 1, an antibody described later is applied as a sensor substance layer on the non-planar Au layer GS.

On the other hand, in each reference measurement region R, a non-tabular gold (Au) layer GR of nanometer order for generating strong plasmon resonance in the Y direction is formed along the Y direction. Although not shown in FIG. 1, a masking layer having a dielectric constant equivalent to that of an antibody described later is formed on the non-planar Au layer GR. The masking layer is made of, for example, silicon oxide (SiO ₂ ), an organic material, or an inorganic material that does not serve as an antibody.

  The non-planar Au layers GS and GR are Au nano thin film layers having a thickness of 10 to 100 nm or Au particle layers having a spherical diameter of 10 to 200 nm, as will be described later.

  Hereinafter, an example of the localized plasmon resonance biosensor of FIG. 1 will be described.

  FIG. 2 is a cross-sectional view taken along the line II of FIG. 1 showing a first example of the localized plasmon resonance sensor of FIG.

  In FIG. 2A, a gold (Au) nano thin film layer 2 having a thickness of 10 nm to 100 nm is formed on a substrate 1 made of glass, polyethylene terephthalate (PET) or the like, and a spherical diameter of 10 nm is formed thereon. A dielectric nanoparticle layer 3 composed of particles of ˜200 nm is arranged, and a gold (Au) nano thin film layer 4 having a thickness of 10 nm to 100 nm as a non-tabular Au layer GS, GR is formed thereon. Furthermore, the antibody 5 is applied as a sensor material layer on the Au nano thin film layer 4 in the measurement region S, while the antibody 5 has a dielectric constant corresponding to the dielectric constant of the antibody 5 on the Au nano thin film layer 4 in the reference measurement region R. A masking layer 6 having a dielectric constant is formed. Reference numeral 7 denotes an antigen as a target substance bound to the antibody 5. That is, the main measurement region S is a region that receives an antigen-antibody reaction, and the reference measurement region R is a region that does not receive an antigen-antibody reaction.

  The respective particles of the dielectric nanoparticle layer 3 in the measurement region S are arranged close to each other with a gap number of nm or less along the X direction, and in the Y direction, are equal to or larger than the diameter of the particles of the dielectric nanoparticle layer 3. It is arranged with a gap. In addition, the particles of the dielectric nanoparticle layer 3 in the reference measurement region R are arranged close to each other with a gap number of nm or less along the Y direction, and the diameter of the dielectric nanoparticle layer 3 is equal to or smaller than that of the dielectric nanoparticle layer 3 in the X direction. It arrange | positions with the above clearance gap.

  In FIG. 2A, due to the presence of the dielectric nanoparticle layer 3, the Au nano thin film layer 4 has a non-plate shape, that is, an uneven shape in the X direction or the Y direction, and causes localized plasmon resonance. Further, although the Au nano thin film layer 2 has a flat plate shape, it interacts with the localized plasmon resonance of the Au nano thin film layer 4 through the dielectric nanoparticle layer 3 to cause localized plasmon resonance.

  In FIG. 2B, the Au nano thin film layer 2 in FIG. 2A is deleted, and the dielectric nanoparticle layer 3 is directly disposed on the substrate 1.

  The dielectric nanoparticle layer 3 in FIGS. 2A and 2B has an action of amplifying the electric field generated by surface plasmon resonance, and therefore increases the absorption peak of the developed absorption spectrum or the reflection dip of the reflected light spectrum. it can.

  2A and 2B, the Au nano thin film layer 2 and the Au nano thin film layer 4 cause surface plasmon resonance with light in the ultraviolet to near infrared region. In this case, since these Au nano thin film layers are made of one kind of metal, that is, Au, as described later, one absorption peak wavelength is expressed in the absorption spectrum, or one reflection dip wavelength is expressed in the reflected light spectrum.

  Also in FIG. 2B, the Au nano thin film layer 4 causing surface plasmon resonance is made of one kind of metal, that is, Au, so that one absorption peak wavelength is expressed in the absorption spectrum or the reflected light spectrum. To develop one reflection dip wavelength. However, since the Au nano thin film layer 2 does not exist, the absorption peak or reflection dip that appears is slightly reduced.

  FIG. 3 is a cross-sectional view taken along the line II of FIG. 1 showing a second example of the localized plasmon resonance chip of FIG.

  In FIG. 3A, a gold (Au) nano thin film layer 2 having a thickness of 10 nm to 100 nm is formed on a substrate 1, and a non-tabular Au layer made of particles having a spherical diameter of 10 nm to 200 nm is formed thereon. A gold (Au) nanoparticle layer 3 ′ as GS and GR is disposed. Further, as in FIG. 2A, the antibody 5 is applied as a sensor material layer on the Au nanoparticle layer 3 ′ in the measurement region S, while the Au nanoparticle layer 3 ′ in the reference measurement region R is applied. A masking layer 6 having a dielectric constant corresponding to the dielectric constant of the antibody 5 is formed thereon. Reference numeral 7 denotes an antigen as a target substance bound to the antibody 5. That is, also in this case, the main measurement region S is a region that receives an antigen-antibody reaction, and the reference measurement region R is a region that does not receive an antigen-antibody reaction.

  The particles of the Au nanoparticle layer 3 ′ in the measurement region S are arranged close to each other with a gap number of nm or less along the X direction, and the diameter of the Au nanoparticle layer 3 ′ is equal to or larger than the diameter of the Au nanoparticle layer 3 ′ in the Y direction. It is arranged with a gap. Further, each particle of the Au nanoparticle layer 3 ′ in the reference measurement region R is arranged close to the gap number of nm or less along the Y direction, and the diameter of the Au nanoparticle layer 3 ′ is equal to or equal to the diameter of the Au nanoparticle layer 3 ′ in the X direction. It arrange | positions with the above clearance gap.

  In FIG. 3A, the Au nanoparticle layer 3 'is non-planar, and therefore causes localized plasmon resonance. Further, although the Au nano thin film layer 2 has a flat plate shape, it interacts with the Au nano particle layer 3 'to cause localized plasmon resonance.

  In FIG. 3 (B) showing a modified example of FIG. 3 (A), the Au nano thin film layer 2 of FIG. 3 (A) is deleted, and the Au nano particle layer 3 ′ is directly formed on the substrate 1. Deploy.

  3A and 3B, the Au nano thin film layer 2 and the Au nano particle layer 3 'cause surface plasmon resonance with light in the ultraviolet to near infrared region. In this case, since these nano thin film layer and nano particle layer are made of one kind of metal, that is, Au, as described later, one absorption peak wavelength is expressed in the absorption spectrum, or one reflection dip wavelength is set in the reflected light spectrum. To express.

  Also in FIG. 3B, since the Au nanoparticle layer 3 ′ causing surface plasmon resonance is made of one kind of metal, that is, Au, one absorption peak wavelength is also expressed in the absorption spectrum, or reflected light. Develop one reflection dip wavelength in the spectrum. However, since the Au nano thin film layer 2 does not exist, the absorption peak or reflection dip that appears is slightly reduced.

  In the first embodiment described above, the nano thin film layers 2 and 4 may be other than Au, for example, Ag, Cu, or Al. Further, the particles of the dielectric nanoparticle layer 3 and the Au nanoparticle layer 3 ′ do not need to be in close contact with each other, and may be several nm apart as described above. Furthermore, the dielectric nanoparticle layer 3 and the Au nanoparticle layer 3 ′ may have a rod shape other than a spherical shape, a triangular shape, or other polygonal shapes.

  FIG. 4 is a top view showing a second embodiment of the localized plasmon resonance chip according to the present invention.

  In FIG. 4, the localized plasmon resonance biosensor 20 is divided into a plurality of square main measurement regions S and a plurality of reference measurement regions R, which are several hundred nm to several μm in the same manner as the localized plasmon resonance biosensor 10 of FIG. 1. Has been. Also in this case, preferably, the main measurement areas S and the reference measurement areas R are alternately arranged, and a plurality of main measurement areas S and reference measurement areas R are simultaneously irradiated by a single light measurement spot having a diameter of 3 mm to several tens of mm. Like that. In addition, each side of the main measurement region S (reference measurement region R) is set to at least twice the size of the target substance.

  In each measurement region S, a plurality of recesses 1aS having a depth of 10 to several hundreds of nm and a diameter of 10 to 200 nm for generating strong plasmon resonance along the X direction are close to each other with a gap of several nm or less along the X direction. Is formed. In this case, each recess 1aS is formed with a gap equal to or larger than the diameter of the recess 1aS in the Y direction.

  On the other hand, in each reference measurement region R, a plurality of recesses 1aR having a depth of 10 to several 100 nm and a diameter of 10 to 200 nm for generating strong plasmon resonance along the Y direction have a gap number of nm or less along the Y direction. Are formed in close proximity. In this case, each recess 1aR is formed with a gap equal to or larger than the diameter of the recess 1aR in the X direction.

  5 is a cross-sectional view taken along line VV in FIG. 4 showing details of the localized plasmon resonance sensor in FIG.

  As shown in FIG. 5A, an Au nano thin film layer 4 'having a thickness of 10 to 100 nm is formed on the sidewalls of the recesses 1aS and 1aR.

  Further, the antibody 5 is applied as a sensor material layer on the Au nano thin film layer 4 ′ in the measurement region S, while the dielectric constant of the antibody 5 is applied on the Au nano thin film layer 4 ′ in the reference measurement region R. A masking layer 6 having a corresponding dielectric constant is formed. Reference numeral 7 denotes an antigen as a target substance bound to the antibody 5. That is, also in this case, the main measurement region S is a region that receives an antigen-antibody reaction, and the reference measurement region R is a region that does not receive an antigen-antibody reaction.

  In FIG. 5A, due to the presence of the recesses 1aS and 1aR, the Au nano thin film layer 4 'has a non-plate shape, that is, an uneven shape in the X direction or the Y direction, and causes localized plasmon resonance.

  In FIG. 5B, the Au nano thin film layer 4 'shown in FIG. 5A is also formed at the bottom of the recesses 1aS and 1aR. Also in this case, the Au nano thin film layer 4 'operates in the same manner as in the case of FIG. 5A, and there is no problem.

  Note that the recesses 1aS and 1aR in FIGS. 5A and 5B are formed using an electron beam irradiation technique, a nanoimprint technique, or the like.

  Also in FIG. 5, the Au nano thin film layer 4 ′ causing surface plasmon resonance is made of one kind of metal, that is, Au, so that one absorption peak wavelength is developed in the absorption spectrum or one in the reflected light spectrum. A reflection dip wavelength is developed.

  FIG. 6 is a diagram showing a transmission type localized plasmon resonance biosensor using the localized plasmon resonance chip of FIGS.

  6, the localized plasmon resonance chip 10 (20) of FIG. 1 (FIG. 4) is adopted instead of the localized plasmon resonance chip 103 in FIG. 8, and measurement is performed with the localized plasmon resonance chip 10 (20). A polarizing beam splitter 105 is provided between the apparatus 104 and the apparatus 104. The polarizing beam splitter 105 emits a p-polarized beam parallel to the incident beam and an s-polarized beam orthogonal thereto.

  In FIG. 6, the light L1 from the light source 101 is collimated by the collimator lens 102 and enters the localized plasmon resonance chip 10 (20) perpendicularly. At this time, the main measurement region S of the localized plasmon resonance chip 10 (20) generates strong plasmon resonance in the X direction (longitudinal direction) and emits a light beam in the X direction (vertical direction), that is, a p-polarized beam. The reference measurement region R of the localized plasmon resonance chip 10 (20) generates strong plasmon resonance in the Y direction (lateral direction) and emits a light beam in the Y direction (lateral direction), that is, an s-polarized beam. Accordingly, the polarization beam splitter 105 emits the p-polarized beam from the localized plasmon resonance chip 10 (20) to the measuring device 104 as a parallel p-polarized beam, and the s-polarized beam from the localized plasmon resonance chip 10 (20). Are output to the measuring device 104 as orthogonal s-polarized beams. As a result, the measuring device 104 calculates the shift amount by subtracting the absorption peak wavelength of the transmitted light spectrum of the s-polarized beam from the absorption peak wavelength of the transmitted light spectrum of the p-polarized beam, and the localized plasmon resonance chip 10 (20). The change in the refractive index (dielectric constant) of the medium can be detected with high accuracy.

  As described above, in the transmission type local plasmon resonance sensor of FIG. 6, the refractive index (dielectric constant) of the medium changes only by setting the local plasmon resonance chip 10 (20) of FIG. 1 (FIG. 4) once. In other words, a target substance such as an antigen can be detected quantitatively with high accuracy.

  FIG. 7 is a diagram showing a reflective localized plasmon resonance biosensor using the localized plasmon resonance chip of FIGS.

  7, the localized plasmon resonance chip 10 (20) of FIG. 1 (FIG. 4) is adopted instead of the localized plasmon resonance chip 204 in FIG. 10, and the localization is replaced with the beam splitter 203. A polarizing beam splitter 206 is provided between the plasmon resonance chip 10 (20) and the measuring device 205. The polarization beam splitter 206 emits a p-polarized beam parallel to the incident beam and an s-polarized beam orthogonal thereto.

  In FIG. 7, the light L2 from the light source 201 is collimated by the collimator lens 102 and is incident on the localized plasmon resonance chip 10 (20) obliquely. At this time, the main measurement region S of the localized plasmon resonance chip 10 (20) generates strong plasmon resonance in the X direction (longitudinal direction) and emits a light beam in the X direction (vertical direction), that is, a p-polarized beam. The reference measurement region R of the localized plasmon resonance chip 10 (20) generates strong plasmon resonance in the Y direction (lateral direction) and emits a light beam in the Y direction (lateral direction), that is, an s-polarized beam. Therefore, the polarization beam splitter 206 emits the p-polarized beam from the localized plasmon resonance chip 10 (20) to the measuring device 205 as a parallel p-polarized beam, and the s-polarized beam from the localized plasmon resonance chip 10 (20). Are output to the measuring device 205 as orthogonal s-polarized beams. As a result, the measuring device 205 calculates the shift amount by subtracting the reflection dip wavelength of the reflected light spectrum of the s-polarized beam from the reflection dip wavelength of the reflected light spectrum of the p-polarized beam, and the localized plasmon resonance chip 10 (20). The change in the refractive index (dielectric constant) of the medium can be detected with high accuracy.

  As described above, also in the reflection type localized plasmon resonance sensor of FIG. 7, the refractive index (dielectric constant) of the medium changes only by setting the localized plasmon resonance chip 10 (20) of FIG. 1 (FIG. 4) once. In other words, a target substance such as an antigen can be detected quantitatively with high accuracy.

  Note that the X direction and the Y direction in the above-described embodiment are not necessarily orthogonal to each other, and the X direction and the Y direction can distinguish the polarization from the main measurement region S and the polarization from the reference measurement region R. It only has to intersect at an angle of about.

  The above-mentioned localized plasmon resonance chip can be manufactured not only by a lithography technique, an electron beam irradiation technique, a nanoimprint technique, etc., but also by a self-alignment function of porous alumina (refer to Non-Patent Document 1, etc.).

  The nanometer order in the present invention means a thickness of 10 nm to 100 nm in the case of a thin film layer, and in the case of particles, a sphere diameter, a length of a long side of a rod or a length of a triangle of 10 nm to 200 nm. means.

  It should be noted that the present invention can be applied to any modifications within the obvious range of the first and second embodiments described above.

  The localized plasmon resonance biosensor having the localized plasmon resonance chip according to the present invention can be used for security (explosives, narcotics) in addition to the above-described medical diagnosis, health check, food inspection, and the like. Further, in addition to the quantification of the target substance in the antigen-antibody reaction, it can be used for quantification of a specific substance in selective binding of DNA or the like.

1: Substrate 1a: Recess 2: Au nano thin film layer 3: Dielectric nano particle layer 3 ′: Au nano particle layer 4, 4 ′: Au nano thin film layer 10, 20: Localized plasmon resonance chip
S: Main measurement area
R: Reference measurement area
GS; GR: non-planar gold (Au) layer 101: light source 102: collimator lens 103: localized plasmon resonance chip 103a: surface plasmon resonance unit 104: measuring device 105: polarization beam splitter 201: light source 202: collimator lens 203: Beam splitter 204: Localized plasmon resonance chip 204a: Surface plasmon resonance unit 205: Measuring device 206: Polarizing beam splitter
S0: Light source spectrum
S1: Absorption spectrum
S2: Reflected light spectrum
L1, L2: Light

Claims (10)

A substrate divided into a main measurement area and a reference measurement area;
A first non-planar metal layer on the order of nanometers formed on the main measurement region of the substrate for generating strong plasmon resonance in a first direction;
A sensor material layer formed on the first non-planar metal layer;
A second non-planar metal layer on the order of nanometers formed on the reference measurement region of the substrate for generating strong plasmon resonance in a second direction different from the first direction;
A localized plasmon resonance chip comprising: a masking layer provided on the second non-planar metal layer for compensating the dielectric constant of the sensor material layer.   The localized plasmon resonance chip according to claim 1, wherein the main measurement region and the reference measurement region are alternately arranged. The first and second non-planar metal layers include a metal thin film layer,
Furthermore, comprising a dielectric particle layer of nanometer order disposed between the substrate and the metal thin film layer,
Each particle of the dielectric particle layer in the main measurement region is disposed close to the first direction,
3. The localized plasmon resonance chip according to claim 1, wherein each particle of the dielectric particle layer in the reference measurement region is disposed adjacently along the second direction.   The localized plasmon resonance chip according to claim 3, further comprising a nanometer-order flat metal thin film layer disposed between the substrate and the dielectric particle layer. The first and second non-planar metal layers are nanometer-order metal particle layers;
Each particle of the metal particle layer in the main measurement region is disposed close to the first direction,
3. The localized plasmon resonance chip according to claim 1, wherein each particle of the metal particle layer in the reference measurement region is disposed adjacently along the second direction.   The localized plasmon resonance chip according to claim 5, further comprising a nanometer-order flat metal thin film layer disposed between the substrate and the metal particle layer. A recess is formed in the substrate at a depth of several tens to several hundreds of nanometers,
The first and second non-planar metal layers comprise a metal thin film layer formed on the side wall of the recess of the substrate,
The recesses of the substrate in the main measurement region are arranged close to each other along the first direction;
3. The localized plasmon resonance chip according to claim 1, wherein the concave portion of the substrate in the reference measurement region is disposed adjacently along the second direction.   The localized plasmon resonance chip according to claim 8, wherein the metal thin film layer is further formed at a bottom of the concave portion of the substrate. A light source;
The localized plasmon resonance chip according to claim 1 for receiving light from the light source;
A polarization beam splitter for separating polarized light in a first direction transmitted through the localized plasmon resonance chip and polarized light in a second direction different from the first direction;
The target substance of the localized plasmon resonance chip is determined by the shift amount between the absorption peak wavelength of the absorption spectrum of the polarized light in the first direction and the absorption peak wavelength of the polarized light spectrum in the second direction from the polarizing beam splitter. A transmission type local plasmon resonance sensor comprising: a measurement device for quantitative measurement. A light source;
The localized plasmon resonance chip according to claim 1 for receiving light from the light source;
A polarization beam splitter for separating polarized light in a first direction reflected from the localized plasmon resonance chip and polarized light in a second direction different from the first direction;
The medium of the localized plasmon resonance chip according to the shift amount of the reflected dip wavelength of the reflected light spectrum of the polarized light in the first direction from the polarized beam splitter and the reflected dip wavelength of the reflected light spectrum of the polarized light in the second direction. A reflection type local plasmon resonance sensor comprising a measuring device for quantitatively detecting a target substance.

Images