JP6954626B2 - SPR sensor chip, SPR sensor, and sample analysis method - Google Patents

Description

The present invention relates to an SPR sensor chip, an SPR sensor, and a method for analyzing a sample.

The operating principle of the sensor using Surface Plasmon Resonance (SPR) is as follows. For example, in the case of a prism type SPR sensor, the metal layer is irradiated with light through the prism, and an evanescent wave is generated in the vicinity of the metal layer. On the other hand, surface plasmons are simultaneously generated on the surface of the metal layer by irradiation with light. When a predetermined resonance condition is met, the evanescent wave and the surface plasmon resonate (that is, surface plasmon resonance occurs), and the amount of light reflected decreases. The angle of incidence at the interface between the prism and the metal layer when the amount of light reflected is the minimum is called the resonance angle. Resonance conditions in surface plasmon resonance include, for example, conditions such as the incident angle of light, the wavelength of light, and the permittivity of the medium around the metal layer.

Therefore, a sample is provided by providing a reaction film that specifically reacts with a specific molecule on the surface of the sensor, irradiating the interface between the reaction film and the device with laser light while changing the incident angle, and measuring the intensity of the reflected light. A measuring device for analyzing the above is disclosed (for example, Patent Document 1). In Patent Document 1, when the reaction membrane and the molecule are adsorbed, the dielectric constant of the medium changes. Since the resonance angle changes as the dielectric constant changes, it is possible to detect a specific molecule by detecting the change in the resonance angle.

Japanese Unexamined Patent Publication No. 2011-180110

However, in the past, molecules bound to the reaction membrane were desorbed from the reaction membrane by a chemical reaction. Therefore, it takes a long time to desorb a molecule from the reaction membrane and make it possible to detect the next molecule. Therefore, the SPR sensor has a problem that it is difficult to use it in an environment such as a robot where a quick response is required.

An object of the present invention is to provide an SPR sensor chip, an SPR sensor, and a sample analysis method capable of rapid analysis.

The SPR sensor chip according to the present invention has a base portion made of silicon (Si), an SPR portion provided on the surface of the base portion and generating plasmon resonance by incident light, and the SPR portion for physical energy. The base portion has a thickness (T) of at least a part of a portion in contact with the SPR portion having a thickness (T) of 1 μm or less, and the coupling release portion is provided on the base portion. Ru comprising a piezoelectric vibrating the base.
Further, the SPR sensor chip according to the present invention has a base portion made of silicon (Si), an SPR portion provided on the surface of the base portion and generating plasmon resonance by incident light, and physical energy. The base portion is provided with a bond release portion to be applied to the SPR portion, the thickness (T) of at least a part of the portion in contact with the SPR portion is 1 μm or less, and the bond release portion is the said portion of the base portion. A SAW oscillator provided on the surface and generating a surface wave on the surface of the base is provided.

The SPR sensor according to the present invention includes the SPR sensor chip, a light emitting unit that irradiates the incident light toward the SPR unit, and a detection unit that detects an SPR response.

The sample analysis method according to the present invention is a sample analysis method using an SPR portion that generates plasmon resonance due to incident light, and is a portion formed of silicon (Si) and in contact with the SPR portion. The step of arranging the sample in the SPR portion provided on the surface of the base portion having at least a part of the thickness (T) of 1 μm or less, the step of irradiating the incident light toward the SPR portion, and the SPR response. It has a step of detecting and a step of applying physical energy to the SPR portion by vibrating the base portion using a piezoelectric material provided on the base portion.
Further, the sample analysis method according to the present invention is a sample analysis method using an SPR portion that generates plasmon resonance due to incident light, and is formed of silicon (Si) and is in contact with the SPR portion. A step of arranging a sample in the SPR portion provided on the surface of a base portion having a thickness (T) of at least a part of the portion of 1 μm or less, a step of irradiating the incident light toward the SPR portion, and an SPR. It has a step of detecting a response and a step of generating a surface wave on the surface of the base portion by using a SAW oscillator provided on the surface of the base portion to apply physical energy to the SPR portion.

According to the present invention, by applying physical energy at the bond release portion, the substance to be detected can be desorbed faster than before, so that the next analysis is completed after one analysis is completed. The time required to start the analysis can be shortened, and the analysis can be performed quickly.

It is a block diagram which shows the structure of the SPR sensor which concerns on 1st Embodiment. It is a vertical cross-sectional view which shows the schematic structure of the SPR sensor chip which concerns on 1st Embodiment. It is a schematic diagram provided for the explanation of the sample used for the evaluation of the SPR sensor chip which concerns on 1st Embodiment. It is the SEM image of the substrate used for the evaluation of the SPR sensor chip which concerns on 1st Embodiment, FIG. 4A is an image before applying vibration, and FIG. 4B is an image after applying vibration. It is a graph which shows the evaluation result of the SPR sensor chip which concerns on 1st Embodiment. It is a vertical cross-sectional view which shows the schematic structure of the SPR sensor chip which concerns on the modification (1) of 1st Embodiment. It is a vertical cross-sectional view which shows the schematic structure of the SPR sensor chip which concerns on the modification (2) of 1st Embodiment. It is a vertical cross-sectional view which shows the schematic structure of the SPR sensor chip which concerns on the modification (3) of 1st Embodiment. It is a vertical sectional view which shows the schematic structure of the SPR sensor chip which concerns on 2nd Embodiment. It is a vertical sectional view which shows the schematic structure of the SPR sensor chip which concerns on 3rd Embodiment. It is a vertical cross-sectional view which shows the schematic structure of the SPR sensor chip which concerns on the modification of 3rd Embodiment. It is a vertical sectional view which shows the schematic structure of the SPR sensor chip which concerns on 4th Embodiment. FIG. 13A is a schematic view for explaining the usage state of the SPR sensor chip according to the modified example. FIG. 13A shows the incident light having the wavelength or the incident angle selected, and FIG. 13B shows the incident light having the wavelength or the incident angle not selected. It is a figure of the case. It is a graph which is provided for the explanation of FIG. 13, FIG. 14A is a graph corresponding to FIG. 13A, and FIG. 14B is a graph corresponding to FIG. 13B.

The SPR sensor chip according to the present invention is provided on a base made of silicon (Si), an SPR portion provided on the surface of the base and generating plasmon resonance by incident light, and a physical portion provided on the base. It is provided with a coupling release portion that applies target energy to the SPR portion. By applying physical energy to the SPR unit, the SPR sensor chip can desorb the substance to be detected bound to the surface of the SPR unit. Therefore, since the SPR sensor chip can desorb the substance to be detected faster than the conventional one, a quick response is possible accordingly.

The SPR sensor chip includes a case where incident light is incident from the back surface side of the base portion and a case where incident light is incident from the front surface side with respect to the SPR portion provided on the surface of the base portion. This includes a case where incident light is incident from the back surface side of the base portion, a case where a prism is provided on the back surface side of the base portion, and a case where the SPR portion has a grating structure.

The incident light is not particularly limited when it is incident from the front surface of the base, and when it is incident from the back surface side of the base, it is preferable to use infrared light transmitted through the base formed of silicon (Si). Visible light can be used as the incident light by setting the thickness of the base to a predetermined thickness or less even when the light is incident from the back surface side of the base.

The SPR sensor includes an SPR sensor chip, a light emitting unit that irradiates the incident light toward the SPR unit, and a detection unit that detects an SPR response. The detection unit includes a case where the SPR response is acquired electrically and a case where the SPR response is acquired optically.

Glucose and ions can be applied as the substance to be detected. Further, as the substance to be detected, a taste substance can also be applied. A taste substance is a chemical substance that can be recognized as a taste by humans and animals, and includes types such as salty taste, acidity, sweetness, bitterness, and umami.

Physical energy includes at least one of mechanical energy, thermal energy, electrical energy, and light energy. Specific examples include tension, compression, vibration, ultrasonic waves, surface acoustic waves, heating, electric fields, magnetic fields, and electromagnetic waves (light).

1. 1. 1st Embodiment (overall configuration)
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings. The SPR sensor 10 shown in FIG. 1 includes an SPR sensor chip 12A, a light emitting unit 14, and a current detecting unit 16 as a detecting unit. The SPR sensor chip 12A has an SPR unit 18 and a coupling release unit 20. In the case of the present embodiment, the SPR sensor 10 further includes a control unit 26 and an operation unit 28.

The control unit 26 is electrically connected to the SPR sensor chip 12A, the light emitting unit 14, the current detection unit 16, and the operation unit 28. The control unit 26 reads out application programs such as a basic program and an arithmetic processing program stored in advance, and controls the entire SPR sensor 10 according to these various programs. The control unit 26 can execute a plurality of programs (application programs, etc.) in parallel.

The light emitting unit 14 is fixed to a base (not shown) and is optically connected to the SPR sensor chip 12A. Upon receiving the irradiation signal output by the control unit 26, the light emitting unit 14 irradiates the SPR unit 18 with infrared light at a constant incident angle. The infrared light emitted by the light emitting unit 14 is preferably light having a wavelength in the range of 1 μm to 10 μm that passes through Si. As the light emitting unit 14, a laser diode for irradiating monochromatic light or an LED can be used. For example, it is more preferable to use a light source having a center wavelength of 1.31 μm or 1.55 μm because the range of selection of optical components is widened. ..

A chopper 22 may be provided between the light emitting unit 14 and the SPR sensor chip 12A. When the chopper 22 receives the modulation signal output by the control unit 26, the chopper periodically chops the light emitted from the light emitting unit 14 to alternately repeat lighting and extinguishing to modulate the chopper. The light emitted from the light emitting unit 14 is incident on the SPR unit 18 in a state where the amount of light is changed in a pulse shape by the chopper 22.

The current detection unit 16 is electrically connected to the SPR sensor chip 12A, and detects the current value of the SPR unit 18 as an SPR response. When the chopper 22 is used, the current detection unit 16 preferably has a lock-in amplifier 24. The lock-in amplifier 24 can remove noise from the SPR response by receiving a reference signal synchronized with the chopping modulation signal from the control unit 26 and detecting a frequency component equal to the reference signal. The current detection unit 16 is electrically connected to the control unit 26. The current detection unit 16 generates a detection signal corresponding to the detected current value and outputs the detection signal to the control unit 26.

The operation unit 28 has an input unit 30 and a display unit 32. The input unit 30 may be any device as long as it can input data, and is, for example, a touch panel, a keyboard, or the like. The operator can input characters, numbers, symbols, etc. using the input unit 30. When the input unit 30 is operated by an operator, the input unit 30 generates a signal corresponding to the operation. Then, the generated signal is input to the control unit 26 as an instruction of the operator.

The display unit 32 may be any device as long as it can display an image, an image, or the like, and is, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display. The display unit 32 displays detection values, graphs, and the like according to the detection data supplied from the control unit 26. Further, the display unit 32 may be an output device that prints an image, an image, characters, or the like on a display medium such as paper.

The SPR sensor chip 12A will be described with reference to FIG. The SPR sensor chip 12A includes a base 34 made of silicon (Si). An SPR portion 18 and a coupling release portion 20 are provided on the surface 36 of the base portion 34. For the base 34, for example, N-type silicon doped with P (phosphorus) can be used. The doping amount of P is not particularly limited, but for example, it is preferable to adjust the resistivity of the base 34 to be about 10 to 20 Ωcm. The base 34 is provided with an electrode 38 and is electrically connected to the current detection unit 16 through wiring.

The base 34 has a prism 35 integrally formed on the back surface 37 side. The angle formed by the front surface 36 and the back surface (hereinafter, also referred to as “incident surface”) 37 facing the surface 36 is defined as the apex angle θ. Since the critical angle is 22.3 degrees, it is necessary to inject light at about 22.3 degrees with respect to the surface 36 in order to induce SPR. Therefore, it is most preferable to irradiate light from the light emitting unit 14 in a direction perpendicular to the incident surface 37 having an apex angle θ of 22.3 degrees because the reflection of light on the incident surface 37 is minimized. The apex angle θ is not limited to 22.3 degrees, but if it is 5.6 degrees to 39.0 degrees, it is about 22 with respect to the surface 36 by adjusting the direction of the light emitted by the light emitting unit 14. Light can be incident at 3 degrees to induce SPR. The apex angle θ is more preferably 14.3 degrees to 30.3 degrees because the reflection of light on the incident surface 37 can be suppressed. The prism 35 may be a Fresnel lens type. The base 34 is not limited to the case where the prism 35 is integrally formed, and for example, a glass prism may be fixed to the back surface parallel to the front surface and integrally formed.

To form the base 34, for example, after selectively forming a photoresist mask on the back surface 37, an incident surface is formed at a predetermined angle by anisotropic dry etching. Then, by removing the photoresist mask, the prism 35 can be integrally formed on the back surface 37 of the base portion 34.

The SPR unit 18 has a metal layer 42 and a recognition layer 44 formed on the surface of the metal layer 42. The metal layer 42 is Schottky-bonded to the surface 36, and is formed of, for example, gold (Au), silver (Ag), or copper (Cu). The thickness of the metal layer 42 is not particularly limited, but can be, for example, 50 nm to 200 nm. The metal layer 42 is provided with an electrode 39 and is electrically connected to the current detection unit 16 through wiring. Through wiring, the base 34 and the metal layer 42 are connected in series.

To perform a Schottky bond between the metal layer 42 and the surface 36, for example, the surface 36 is washed with hydrofluoric acid, a piranha solution, a surfactant, or the like, or plasma-treated with oxygen, and then the metal layer is subjected to a vapor deposition method. Form 42. After vapor deposition, it is annealed at 100 to 200 ° C. for 10 minutes to 3 hours. By forming the metal layer 42 on the surface 36 by the above procedure, a good Schottky joint can be obtained.

It is preferable to provide an electron barrier layer (not shown) between the metal layer 42 and the base 34. The electron barrier layer can be formed of titanium (Ti), molybdenum (Mo), or platinum (Pt). The thickness of the electron barrier layer is not particularly limited, but can be, for example, 1 nm to 10 nm.

The recognition layer 44 specifically binds to the substance to be detected 56 contained in the sample 54. In the case of the present embodiment, the recognition layer 44 can use a self-assembled monolayer of phenylboronic acid-thiol (16-amino-1-hexadecanethiol, 10-carboxy-1-decanethiol) that binds to glucose. The self-assembled monolayer can be formed on the surface of the metal layer 42, for example, by immersing the metal layer 42 in a solution containing phenylboronic acid-thiol.

The bond release unit 20 detaches the detection target substance 56 bound to the recognition layer 44 by applying mechanical energy to the SPR unit 18. In the case of the present embodiment, the coupling release portion 20 includes a piezoelectric body 50 that vibrates in the direction perpendicular to the surface of the SPR portion 18 (longitudinal direction), and a pair of electrodes 48 provided on both sides of the piezoelectric body 50 in the thickness direction. , 52, and are fixed on both sides with the SPR portion 18 of the surface 36 interposed therebetween, via the insulator 46. The piezoelectric body 50 can be formed of, for example, a piezo element or barium strontium titanate (Ba _x Sr _(1-x) TiO ₃ ; BST, 0 <x <1). The electrodes 48 and 52 are electrically connected to the control unit 26 via wiring, and vibrate in the thickness direction when a predetermined voltage is applied.

(Action and effect)
Next, the operation and effect of the SPR sensor 10 of the present embodiment will be described. First, the SPR sensor chip 12A is irradiated with infrared light from the light emitting unit 14 arranged on the back surface 37 side of the base 34 toward the incident surface 37. The infrared light emitted from the light emitting unit 14 passes through the prism 35 and is incident on the metal layer 42 as incident light. The incident light enters the surface 36 at an angle exceeding the critical angle and is totally reflected. The incident light generates an evanescent wave at the interface between the surface 36 and the metal layer 42, and free electrons in the metal layer 42 obtain energy from the evanescent wave, thereby inducing SPR, which is a dense wave of electrons. The movement of the free electrons is detected by the current detection unit 16 as a current value. It is considered that the current value includes the current due to the flow of electrons from the metal layer 42 to the base 34 when the forward potential difference between the metal layer 42 and the base 34 exceeds the threshold value due to SPR. ..

In this state, the sample 54 containing the substance to be detected 56 is brought into contact with the surface of the SPR unit 18. The dielectric constant of the recognition layer 44 changes when the substance 56 to be detected contained in the sample 54 specifically binds to the recognition layer 44. Then, the resonance condition changes, and the movement of the free electron changes as the energy received decreases. The current detection unit 16 detects a change in the movement of free electrons as a change in the current value by the current detection unit 16, generates a detection signal, and inputs the detection signal to the control unit 26. The change in the current value also includes a change in the current value flowing from the metal layer 42 to the base 34 due to a change in the potential difference between the metal layer 42 and the base 34 due to the change in the dielectric constant of the recognition layer 44. It is considered to be included.

The control unit 26 analyzes the substance to be detected 56 based on the detection signal, and displays the analysis result on the display unit 32. The SPR sensor 10 can analyze the substance to be detected 56 contained in the sample 54 by detecting the change in the dielectric constant of the recognition layer 44 as the change in the current value by the current detection unit 16.

After the analysis of the substance to be detected 56, the control unit 26 supplies a predetermined voltage to the piezoelectric body 50 to vibrate the piezoelectric body 50 in a state where the SPR unit 18 is immersed in a cleaning liquid (for example, water) as needed. The vibration of the piezoelectric body 50 is transmitted to the SPR unit 18 through the base unit 34. Due to the vibration, the substance 56 to be detected bound to the recognition layer 44 is separated from the recognition layer 44. The SPR sensor 10 can analyze another sample by desorbing the substance 56 to be detected from the recognition layer 44, washing it with water or the like as necessary, and then drying it.

Since the SPR sensor 10 of the present embodiment can desorb the substance to be detected faster than the conventional one by applying mechanical energy at the coupling release unit 20, one analysis is completed by that amount. Therefore, the time until the next analysis is started can be shortened, and the analysis can be performed quickly.

Since the SPR sensor 10 electrically detects the SPR response, the actuator for scanning the incident light can be omitted as compared with the case of optically detecting the SPR response, so that the size can be reduced.

The SPR sensor 10 can detect the SPR response electrically with high efficiency because the metal layer 42 is Schottky-bonded to the surface 36. By providing an electron barrier layer between the metal layer 42 and the surface 36, the SPR response can be detected more efficiently.

The SPR sensor 10 can detect the SPR response more efficiently by modulating the light emitted from the light emitting unit 14 by the chopper 22 and removing noise from the SPR response by the lock-in amplifier 24.

A sample was actually prepared, and it was verified that the substance 56 to be detected could be desorbed from the recognition layer 44. The sample was prepared by the following procedure. First, Au nanoparticles having a diameter of 400 nm are immersed in a solution prepared by dissolving 1 mM 10-carboxy-1-decanethiol in DMF (N, N-dimethylformamide) for 2 hours to form Au nanoparticles. Au particles coated with SAM (Self-Assembled Monolayer) carboxylic acid were formed.

An Au / Cr / glass wafer having a thickness of 200 nm / 5 nm / 400 μm was immersed in a solution of 1 mM 16-amino-1-hexadecanethiol in DMF for 2 hours, and the amino acid SAM was coated on the Au layer. A substrate was formed.

Au in a solution prepared by adding 4 mM EDC (Ethylene dichloride) and 1 mM NHS (N-Hydroxysuccinimide) to a MES (Methyl ethylsulfonate) buffer (pH 6.0). The particles and the substrate were immersed for 1 hour to bind Au particles 43 to the amino acid SAM44 on the substrate (FIG. 3). Three samples were obtained by the above procedure.

A piezo element was attached to the bottom surface of the sample via double-sided tape. A piezo element was driven at a frequency of 10 kHz with 20 μl of pure water dropped on the surface of the substrate, and vibration was applied. The input voltage to the piezo element is 5,10,15 kV for each sample, and the density of Au particles is measured by SEM (Scanning Electron Microscope) at intervals of 10 seconds, 20 seconds, and 30 seconds after the vibration is started. confirmed. The results are shown in FIGS. 4A, 4B, and 5.

FIG. 4A is an image of the surface of the substrate before applying vibration, and the white dots observed in the image are Au particles 43. FIG. 4B is an image at the same position on the substrate surface of the same sample as in FIG. 4A after applying a voltage of 15 V to the piezo element and applying vibration for a total of 60 seconds. It was confirmed that the Au particles 43 on the substrate 42 ^{decreased from 2.0 × 10 −2} [pieces / μm ² ] to 4.2 × 10 ^-4 [pieces / μm ^{2] by applying vibration.} From this, it was confirmed that the molecule can be physically desorbed from the recognition layer by vibration.

In FIG. 5, the horizontal axis represents the length of vibration time (s), and the vertical axis represents the residual ratio (%) of Au particles on the substrate. According to this result, it was confirmed that the residual rate can be reduced by applying vibration for at least 10 seconds or more, and the residual rate can be further reduced by increasing the input voltage.

(Modification example)
In the case of the above embodiment, the case where the coupling release portion 20 is fixed on both sides of the SPR portion 18 of the surface 36 via the insulator 46 has been described, but the present invention is not limited to this. For example, the coupling release portion 20 of the SPR sensor chip 12B shown in FIG. 6 is fixed to the back surface 37 side. The SPR sensor chip 12B shown in this figure can obtain the same effect as that of the above embodiment by providing the coupling release portion 20. Further, the coupling release portion 20 may be provided on the surface 36 by sandwiching the piezoelectric body 50 between the electrodes 48 and 52 in parallel with the surface 36.

In the case of the above embodiment, the case where the prism 35 is formed on the back surface 37 side of the base portion 34 has been described, but the present invention is not limited to this. For example, the SPR unit 60 of the SPR sensor chip 12C shown in FIG. 7 has a diffraction grating surface. The diffraction grating surface is formed on the surface of the SPR portion 60 with concave portions 64 and convex portions 62 alternately and at a predetermined pitch. In the case of the present embodiment, the concave portions 64 and the convex portions 62 are alternately formed on the surface 36, and the metal layer 65 is provided with a constant thickness along the surface 36, and the concave portions are formed on the surface of the metal layer 65. Convex parts are formed alternately. A recognition layer 44 is formed along the surface of the metal layer 65. The back surface 59 of the base 58 is not formed with a prism and is substantially parallel to the front surface 36.

The SPR sensor chip 12C operates in the same manner as in the above embodiment. That is, the SPR unit 60 brings the incident light into a close field on the diffraction grating surface and induces SPR. For example, a case where near-infrared light having a wavelength of 1.55 μm is used will be described. When the sample 54 is an aqueous solution, when the period of the diffraction grating surface is 1.17 μm, 2.34 μm, 3.50 μm, and 4.67 μm, the light emitting portion 14 irradiates the back surface 59 substantially perpendicularly. In order, the first-order diffracted light, the second-order diffracted light, the third-order diffracted light, and the fourth-order diffracted light are combined with the SPR to induce the SPR.

In this state, the sample 54 containing the substance to be detected 56 is brought into contact with the surface of the SPR unit 60. The dielectric constant of the recognition layer 44 changes when the substance 56 to be detected contained in the sample 54 specifically binds to the recognition layer 44. Then, the resonance condition changes, and the movement of the free electron changes as the energy received decreases. The current detection unit 16 detects a change in the movement of free electrons as a change in the current value by the current detection unit 16, generates a detection signal, and inputs the detection signal to the control unit 26. The SPR sensor can analyze the substance to be detected 56 contained in the sample 54 by detecting the change in the movement of free electrons as a change in the current value by the current detection unit 16. Since the SPR sensor chip 12C does not use the prism 35, the device can be made smaller and lighter.

In the case of the above embodiment, the case where the piezoelectric body 50 of the coupling release portion 20 vibrates in the vertical direction (longitudinal direction) with respect to the surface of the SPR portion 18 has been described, but the present invention is not limited thereto. The SPR sensor chip 12D shown in FIG. 8 has a SAW (surface acoustic wave) oscillator 66 as a coupling release portion 20. The SAW oscillator 66 is a blind electrode and is provided on the surface 36 of the base 34. The SAW oscillator 66 is electrically connected to the control unit 26, and when a predetermined voltage is applied, it generates a surface wave and applies mechanical energy to the SPR unit 18. By providing the SPR sensor chip 12D shown in this figure with the SAW oscillator 66, the same effect as that of the above embodiment can be obtained.

2. Second Embodiment The second embodiment will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The SPR sensor chip 12E shown in this figure includes a base 58, an SPR unit 60 having a diffraction grating surface, and a case 70. The case 70 has a pedestal portion 71 that holds the base portion 58 and the SPR portion 60, and a flow path forming portion 73 that has a flow path 72 that leads to the surface of the SPR portion 60.

The flow path 72 supplies the sample 54 to the surface of the SPR unit 60 by a capillary phenomenon. The distance H between the inner wall of the flow path 72 and the surface of the SPR portion 60 is preferably 1 mm or less. The flow path forming portion 73 can be formed of, for example, plastic. The flow path forming portion 73 has an incident window 74 at a position corresponding to the SPR portion 60. The incident window 74 has a glass plate fitted in a through hole provided in the ceiling portion of the flow path forming portion 73. The incident window 74 receives the light emitted from the light emitting unit 14 arranged on the SPR unit 60 side. The distance H is preferably more than 1 mm on the entrance side (“IN” in the figure), and the ceiling portion on the entrance side is SPR so that the distance H linearly decreases from the entrance side toward the SPR portion 60. It is preferable that the portion 60 is inclined. The inclination allows the sample 54 to be more easily moved to the surface of the SPR unit 60.

The flow path 72 is provided with an ultrasonic vibrator (not shown) as a coupling release portion 20. The ultrasonic vibrator applies ultrasonic waves to the sample 54 and the cleaning liquid flowing through the flow path 72.

Next, the operation and effect of the SPR sensor of the present embodiment will be described. First, the SPR sensor chip 12E is irradiated with light substantially perpendicularly to the surface of the SPR unit 60 from the light emitting unit 14 arranged on the SPR unit 60 side. The light is not limited to infrared light, but may be visible light. The light is preferably monochromatic light. The light emitted by the light emitting unit 14 enters the SPR unit 60 through the incident window 74 and the flow path 72. The SPR unit 60 brings the incident light into a close field on the diffraction grating surface to induce SPR. The movement of free electrons in the metal layer 65 is detected by the current detection unit 16 as a current value.

In this state, the sample 54 containing the substance to be detected 56 is supplied to the flow path 72, and the sample 54 is brought into contact with the SPR unit 60. The dielectric constant of the recognition layer 44 changes when the substance 56 to be detected contained in the sample 54 specifically binds to the recognition layer 44. Then, the resonance condition changes, and the movement of the free electron changes as the energy received decreases. The SPR sensor can analyze the substance to be detected 56 contained in the sample 54 by detecting the change in the movement of free electrons as a change in the current value by the current detection unit 16.

After the analysis of the substance to be detected 56, the control unit 26 outputs a predetermined desorption signal to an ultrasonic vibrator (not shown) in a state where the sample 54 in the flow path 72 is replaced with a cleaning liquid (for example, water) as needed. And vibrate the vibrator. The vibration is transmitted to the SPR unit 60 through the cleaning liquid. Due to the vibration, the substance 56 to be detected bound to the recognition layer 44 is separated from the recognition layer 44. The SPR sensor can analyze another sample 54 by desorbing the substance 56 to be detected from the recognition layer 44 and further supplying water or the like to the flow path 72 as needed to wash the SPR unit 60. ..

Since the SPR sensor of the present embodiment can desorb the substance to be detected faster than the conventional one by applying mechanical energy to the SPR unit 60 via the cleaning liquid with an ultrasonic vibrator, the first embodiment described above. The same effect as the morphology can be obtained. The piezoelectric body may be fixed to the flow path 72 near the SPR portion 60 as a coupling release portion.

Since the SPR sensor chip 12E induces SPR by the light radiated from the SPR unit 60 side to the SPR unit 60, the SPR sensor chip 12E is not limited to infrared light, and various types of light can be used. Since the ceiling portion of the SPR sensor chip 12E on the inlet side is inclined toward the SPR portion 60, the sample 54 can be more reliably supplied to the surface of the SPR portion 60 by the capillary phenomenon.

3. 3. Third Embodiment The third embodiment will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The coupling release portion 76 of the SPR sensor chip 12F shown in this figure includes an electrode 80 that generates an electric field between the SPR sensor chip 12F and the metal layer 42. The electrode 80 is provided on the surface 36 at a predetermined distance from the metal layer 42. Although not shown in this figure, the metal layer 42 and the base 34 are electrically connected to the current detection unit.

For the recognition layer 81 of the SPR unit 18, an ion exchange membrane that adsorbs ions can be used. As the ion exchange membrane, for example, Nafion (registered trademark), Flemion (registered trademark), Celemion (registered trademark) and the like can be used.

The electrode 80 and the metal layer 42 are connected to the power supply through wiring. By applying a DC voltage between the electrode 80 and the metal layer 42, an electric field E is formed between the electrode 80 and the metal layer 42. The detection target substance 56 bound to the recognition layer 44 is desorbed from the recognition layer 81 by the electric field E. The SPR sensor can analyze another sample 54 by desorbing the substance 56 to be detected from the recognition layer 81 and further supplying water or the like as necessary to wash the SPR unit 18. Since the SPR sensor chip 12F desorbs the detection target substance 56 bound to the recognition layer 81 from the recognition layer 81 more quickly by the electric field E, the same effect as that of the first embodiment can be obtained.

In the case of the third embodiment, the case where the electrode 80 is provided on the surface 36 has been described, but the present invention is not limited to this. For example, the SPR sensor chip 12G shown in FIG. 11 is provided with an electrode 80 facing the SPR unit 18 with the flow path 77 interposed therebetween. The SPR sensor chip 12G has a flow path forming portion 78 in which a flow path 77 leading to the surface of the SPR portion 18 is formed. The electrode 80 is provided on the ceiling portion of the flow path forming portion 78 facing the SPR portion 18. The electrode 80 and the metal layer 42 are connected to the power supply through wiring. By applying a DC voltage between the electrode 80 and the metal layer 42, an electric field E is formed between the electrode 80 and the metal layer 42 orthogonal to the flow path 77. Since the SPR sensor chip 12G desorbs the detection target substance 56 bound to the recognition layer 81 from the recognition layer 81 more quickly by the electric field E, the same effect as that of the first embodiment can be obtained.

4. Fourth Embodiment The fourth embodiment will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The SPR sensor chip 12H shown in this figure includes a base 82 made of Si, an SPR portion 18 provided on the surface of the base 82, a coupling release portion 20, and a prism integrally provided on the back surface of the base 82. It is equipped with 84.

The thickness T of at least a part of the base portion 82 in contact with the SPR portion 18 is 1 μm or less. In the case of this figure, the base portion 82 is formed with a hole 88 having a bottom portion 86 on the back surface side corresponding to the SPR portion 18. The thickness T of the bottom portion 86 is 1 μm or less.

The hole 88 is filled with matching oil and is sealed by a prism 84. The matching oil preferably has a refractive index close to that of Si. The prism 84 is made of glass or plastic. The apex angle θ of the prism 84 is preferably 30 to 60 degrees. As the plastic, for example, polyethylene, polypropylene, ABS resin, polyamide, or polycarbonate can be used.

The SPR sensor chip 12H operates in the same manner as in the first embodiment. First, the SPR sensor chip 12H is irradiated with light from a light emitting unit 14 arranged on the back surface side of the base 82 at a constant incident angle. The light emitting unit 14 preferably irradiates light at 72 degrees with respect to the direction perpendicular to the surface 36. Since the thickness T of the portion of the Si base 82 in contact with the SPR portion 18 is 1 μm or less, not only infrared light but also visible light is transmitted. Therefore, the light emitted by the light emitting unit 14 is not limited to infrared light, but may be visible light.

The infrared light emitted from the light emitting unit 14 passes through the prism 84 and the matching oil in this order from the incident surface 85, passes through the bottom portion 86 of the hole, and is incident on the metal layer 42 as incident light. The incident light enters the surface 36 at an angle exceeding the critical angle and is totally reflected. The incident light generates an evanescent wave at the interface between the surface 36 and the metal layer 42, and free electrons obtain energy from the evanescent wave to induce SPR. By detecting the movement of the free electrons as a current value by the current detection unit 16, the substance 56 to be detected contained in the sample 54 can be analyzed.

If the thickness of the Si base 34 is 1 μm or less, not only infrared light but also visible light is transmitted. Therefore, since the SPR sensor can inject the incident light into the SPR unit 18 from the portion having a thickness of 1 μm or less, the selectivity of the light emitting unit 14 can be expanded.

5. Modifications The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the gist of the present invention.

The incident light will be described with reference to FIGS. 13A and 13B and FIGS. 14A and 14B. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. In FIGS. 14A and 14B, the vertical axis represents the current value detected by the current detection unit 16, and the horizontal axis represents the incident angle or wavelength of the incident light. In the case of the above embodiment, as shown in FIG. 13A, the case where the light emitting unit 14 irradiates monochromatic light has been described. The resonance angle become incident light conditions when (incident angle or wavelength) theta ₁ and the detected relationship between the current value I ₁ and the curve of n _1. On the other hand, when the condition of the incident light _{deviates to θ 2} , the peak of the incident light is steep, so that _{the light component of θ 1} contained in the incident light is small, and the detected current value drops to _{I 2.} Resulting in. When the condition of the incident light _{deviates to θ 3} , the detected current value further decreases to _{I 3.}

On the other hand, as shown in FIG. 13B, the light emitting unit 14 of this modified example irradiates broad infrared light including a plurality of incident angles or a plurality of wavelengths. In this case, with respect to the condition (angle of incidence or wavelength) theta ₁ of the incident light as the resonance angle, _two conditions of the incident light _theta, even deviate the theta _3, because the peak is gentle, included in the theta _2, theta ₃ The light component of θ ₁ is larger than that of monochromatic light. Therefore, the current values I ₄ and I ₅ detected when the conditions of the incident light _{deviate to θ 2} and θ ₃ are larger than _{the current values I 2} and I ₃ in the case of monochromatic light.

When irradiating light from the light emitting unit 14 without changing the incident angle, when the condition of the incident light deviates from the condition of the resonance angle by using broad light containing a plurality of incident angles or a plurality of wavelengths. Even if there is, the substance 56 to be detected can be analyzed more reliably. That is, in the case of this modification, the selectivity of the detection condition can be expanded.

In the cases of the first, third, and fourth embodiments, it is preferable to provide an antireflection film on the incident surface. By providing the antireflection film on the incident surface, it is possible to easily obtain conditions for suppressing reflection on the incident surface and inducing SPR.

In the above embodiment, the SPR sensor chips may be arranged in a plurality of arrays. In the case of the first to third embodiments, a plurality of SPR portions are formed on the Si substrate, a prism is integrally formed on the back surface of the Si substrate by anisotropic dry etching, and the prism is cut out to a predetermined size to produce the prism. Therefore, mass productivity can be improved.

In the case of the fourth embodiment, mass productivity is improved by forming a plurality of SPR portions on the Si substrate, fixing a plastic prism on the back surface of the Si substrate, and cutting out the Si substrate to a predetermined size. Can be done. In particular, polyethylene, polypropylene, ABS resin, polyamide, and polycarbonate are excellent in releasability and are therefore suitable for injection molding.

The coupling release portion may be provided with an electric heater at the base, and the SPR portion may be heated by the electric heater to desorb the substance to be detected from the recognition layer.

The base may include a resin base and fine particles of silicon dispersed in the resin base. Such a base can be formed by dispersing silicon fine particles in a resin and performing injection molding. Further, it can be formed by dispersing silicon fine particles in the resin using an ultraviolet curable resin and irradiating the resin with ultraviolet rays. The base according to this modification can simplify the manufacturing process and reduce the cost as compared with forming from a silicon substrate.

The base may be formed of a medium having a specific high refractive index by a structure called a metamaterial. The metamaterial can be formed, for example, by diffusing fine particles of metal or high dielectric material. If the size of the unit structure of the metamaterial is an order of magnitude smaller than the wavelength, it can be regarded as a homogeneous high refractive index material.

Although the case where the control unit 26 and the operation unit 28 are provided has been described, the present invention is not limited to this, and the control unit 26 and the operation unit 28 may be omitted as appropriate. For example, the SPR sensor may be mounted on the robot, and in that case, it may be operated by the control unit and the operation unit of the robot.

θ Apex angle 10 SPR sensor 12A to 12H SPR sensor chip 14 Light emitting unit 16 Current detection unit (detection unit)
18, 60 SPR part 20, 76 Decoupling part 34, 58, 82 Base part 35, 84 Prism 36 Front side 37 Back side 54 Sample 56 Detectable substance 72 Flow path 73 Flow path forming part 74 Incident window

Claims (8)

With a base made of silicon (Si),
An SPR portion provided on the surface of the base portion and generating plasmon resonance by incident light, and an SPR portion.
It is provided with a coupling release portion that applies physical energy to the SPR portion .
The thickness (T) of at least a part of the base portion in contact with the SPR portion is 1 μm or less.
The coupling release portion includes a piezoelectric body provided at the base portion and vibrating the base portion.
SPR sensor chip. With a base made of silicon (Si),
An SPR portion provided on the surface of the base portion and generating plasmon resonance by incident light, and an SPR portion.
With the uncoupling part that applies physical energy to the SPR part
With
The thickness (T) of at least a part of the base portion in contact with the SPR portion is 1 μm or less.
The disconnection portion includes a SAW oscillator provided on the surface of the base portion and generating a surface wave on the surface of the base portion.
SPR sensor chip. The SPR sensor chip according to claim 1 or 2 , wherein the base is a prism having an angle formed by the front surface and the back surface facing the front surface of 5.6 degrees to 39.0 degrees. The SPR sensor chip according to claim 1 or 2 , wherein the SPR portion has a diffraction grating surface in which concave portions and convex portions are formed alternately at a predetermined pitch on the surface. A flow path forming portion having a flow path leading to the surface of the SPR portion is provided.
The SPR sensor chip according to claim 1 or 2 , wherein the flow path forming portion has an incident window that receives the incident light. The SPR sensor chip according to any one of claims 1 to 5,
A light emitting unit that irradiates the incident light toward the SPR unit,
An SPR sensor including a detection unit that detects an SPR response. This is a sample analysis method using the SPR section that generates plasmon resonance due to the incident light.
A step of arranging a sample on the SPR portion provided on the surface of a base portion having a thickness (T) of at least a part (T) of a portion formed of silicon (Si) and in contact with the SPR portion of 1 μm or less.
The step of irradiating the incident light toward the SPR unit and
Steps to detect SPR response and
A method for analyzing a sample, which comprises a step of vibrating the base portion using a piezoelectric material provided on the base portion to apply physical energy to the SPR portion. This is a sample analysis method using the SPR section that generates plasmon resonance due to the incident light.
A step of arranging a sample on the SPR portion provided on the surface of a base portion having a thickness (T) of at least a part (T) of a portion formed of silicon (Si) and in contact with the SPR portion of 1 μm or less.
The step of irradiating the incident light toward the SPR unit and
Steps to detect SPR response and
A step of generating a surface wave on the surface of the base portion by using a SAW oscillator provided on the surface of the base portion to apply physical energy to the SPR portion.
A method for analyzing a sample having.

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