JP6197796B2 - Detection device - Google Patents

Description

  The present invention relates to a detection device that detects the presence or amount of an analyte using surface plasmons.

  Detection devices that detect the presence or amount of an analyte using surface plasmons have been known for some time. As such a detection device, a surface plasmon resonance (SPR) device and a surface plasmon-field enhanced fluorescence spectroscopy (hereinafter abbreviated as “SPFS”) device are used. It has been known. These devices include a prism, a metal thin film formed on one surface of the prism, and a capturing body (for example, an antibody) fixed on the metal thin film. In these apparatuses, surface plasmons are generated in the metal thin film by irradiating the metal thin film with laser light from the inside of the prism. These devices use this surface plasmon to detect the analyte.

  In these apparatuses, it is necessary to scan the incident angle of the laser beam on the metal thin film to determine the incident angle (hereinafter referred to as “resonance angle”) when the surface plasmon resonance is maximized. That is, in the SPR apparatus, in order to detect the analyte by measuring the shift amount of the resonance angle, it is necessary to determine the resonance angle by scanning the incident angle of the laser beam on the metal thin film. Further, in the SPFS apparatus, in order to excite the fluorescent substance with the maximum efficiency and the same energy, it is necessary to determine the resonance angle by scanning the incident angle of the laser beam with respect to the metal thin film.

  When scanning the incident angle of the laser beam on the metal thin film as described above, it is necessary to change only the incident angle without changing the position of the irradiation spot on the metal thin film. However, in these apparatuses, since light is irradiated onto the metal thin film through the prism, it is not easy to change only the incident angle without changing the position of the irradiation spot. Accordingly, means for eliminating the positional deviation of the irradiation spot due to changing the incident angle has been proposed (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses an attenuated total reflection thin film evaluation apparatus that evaluates a metal thin film by irradiating a metal thin film formed on one surface of a triangular prism with a laser beam. Even in the attenuated total reflection thin film evaluation apparatus, it is necessary to scan the incident angle of the laser beam with respect to the metal thin film. In the apparatus described in Patent Document 1, not only the optical axis of the laser beam and the prism are relatively rotated, but also the incident angle is changed by relatively moving the optical axis of the laser beam and the prism. This prevents misalignment of the irradiation spot.

  Patent Document 2 discloses an SPR device having a semi-cylindrical prism. In the apparatus described in Patent Document 2, the position of the irradiation spot is prevented from being changed by changing the incident angle by rotating the laser light source about the central axis of the semi-cylinder.

JP-A-6-288902 JP 2004-354092 A

  The apparatus described in Patent Document 1 has a problem that the configuration is complicated and the manufacturing cost increases because a plurality of drive mechanisms must be provided. The apparatus described in Patent Document 2 has a problem in that since the laser light is perpendicularly incident on the prism surface, the reflected light returns to the light source and the amount of light, wavelength, and the like of the laser light change. Moreover, since the incident surface is a curved surface, the apparatus described in Patent Document 2 has a problem that the incident angle with respect to the prism surface is different between the central portion and the peripheral portion of the laser beam.

  An object of the present invention is a detection device that can change the incident angle without changing the position of the irradiation spot on the metal thin film, and has a simple configuration and does not return reflected light from the prism surface to the light source. Is to provide.

In order to solve the above problems, a detection apparatus according to an embodiment of the present invention is equipped with a detection chip including a prism having an incident surface and a surface on which a metal thin film is formed, and excitation light is transmitted through the incident surface. A detection device for detecting the presence or amount of an analyte by irradiating the metal thin film, a chip holder for holding the detection chip, a light source for emitting the excitation light, and the excitation light An angle adjusting unit that relatively rotates the optical axis of the excitation light and the chip holder in order to irradiate a predetermined position of the metal thin film at a predetermined angle through the incident surface; The angle adjustment unit scans the incident angle of the excitation light with respect to the metal thin film within an angle range including an angle at which an incident angle with respect to the incident surface is not 0 ° and a surface plasmon is generated in the metal thin film, Previous The angle adjustment unit, when scanning the incident angle of the excitation light to the metal thin film, the extension of the excitation light optical axis incident on the incident plane when the minimum angle, the central angle and the maximum angle of the angle range The excitation light incident on the incident surface at the minimum angle and the maximum angle of the angle range from the center of the inscribed circle, with the center of the inscribed circle of the triangle formed surrounded by the line as the center relative around a point located within the circle and the distance to the intersection of the extension line to the radius of the optical axis, and said tip holder and the optical axis of the excitation light, on a virtual plane including the triangle Rotate.

  According to the present invention, since the incident angle can be changed with a simple configuration without changing the position of the irradiation spot on the metal thin film, an apparatus with high detection sensitivity can be manufactured at low cost. Further, according to the present invention, since the reflected light from the prism surface does not return to the light source, the presence or amount of the analyte can be detected with high accuracy.

1 is a schematic diagram illustrating a configuration of an SPFS apparatus according to a first embodiment. It is sectional drawing of a detection chip. 4 is a flowchart illustrating an operation procedure of the SPFS apparatus according to the first embodiment. FIG. 5 is a schematic diagram of a prism for explaining the position of the rotation center of the chip holder in the SPFS device according to the first embodiment. FIG. 6 is a schematic diagram illustrating a configuration of an SPFS apparatus according to a second embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
In the first embodiment, an embodiment of an SPFS apparatus that is a detection apparatus according to the present invention will be described.

  First, an outline of the SPFS apparatus will be described. The SPFS device includes a prism made of a dielectric, a metal thin film formed on one surface of the prism, and a capturing body (for example, an antibody) fixed to a surface of the metal thin film that does not face the prism. If an analyte is present in the sample, the analyte is captured by this capturing body. The captured analyte is labeled with a fluorescent substance. When excitation light (laser light) is irradiated from the inside of the prism onto the metal thin film at an incident angle greater than the critical angle, an evanescent wave is generated. The evanescent wave excites the fluorescent material and emits fluorescence. The SPFS device detects the presence or amount of the analyte by detecting the amount of the fluorescent light.

  FIG. 1 is a schematic diagram illustrating a configuration of an SPFS apparatus 100 according to the first embodiment. As shown in FIG. 1, the SPFS device 100 includes an excitation light emitting unit 110, a base 120, a chip holder 130, a rotary motor 140, and a light detection unit 150. The SPFS device 100 also includes a control unit (not shown) that centrally performs control of each drive unit and quantification of the amount of light received by the light detection unit 150.

  The SPFS device 100 is used with the detection chip 10 mounted on the chip holder 130. As will be described later, the detection chip 10 is disposed on the prism 20 having the incident surface 21, the film formation surface 22, and the emission surface 23, the metal thin film 30 formed on the film formation surface 22, and the film formation surface 22. And a flow path member 40 (see FIG. 2).

  The excitation light emitting unit 110 has a laser diode (hereinafter abbreviated as “LD”) as an excitation light source, and the excitation light α (single mode laser light) is directed toward the incident surface 21 of the detection chip 10 held by the chip holder 130. ). More specifically, the excitation light emitting unit 110 emits only the P wave toward the incident surface 21 so that the excitation light α is totally reflected by the metal thin film 30 included in the detection chip 10. . The excitation light emitting unit 110 includes an LD unit, a first wave adjuster, and a shaping optical system (all not shown).

  The LD unit emits the collimated excitation light α having a constant wavelength and light amount so that the shape of the irradiation spot on the surface of the metal thin film 30 is substantially circular. The LD unit includes an LD as an excitation light source, a collimator that collimates the excitation light α emitted from the LD, and a temperature adjustment circuit for making the light amount of the excitation light α constant. The excitation light α emitted from the LD has a flat outline shape even when collimated. Therefore, the LD is held in a predetermined posture so that the shape of the irradiation spot on the surface of the metal thin film 30 is substantially circular. Further, the wavelength and light amount of the excitation light α emitted from the LD vary depending on the temperature. For this reason, the temperature adjustment circuit monitors the light amount of the light branched from the collimated excitation light α using a photodiode or the like, and adjusts the temperature of the LD so that the wavelength and the light amount of the excitation light α are constant. .

  The first wave adjuster includes a first bandpass filter (hereinafter abbreviated as “BPF1”) and a linear polarization filter (hereinafter abbreviated as “LP”), and harmonizes the light emitted from the LD unit. Since the excitation light α from the LD unit has a slight wavelength distribution width, the BPF 1 turns the excitation light α from the LD unit into narrowband light having only the center wavelength. In addition, since the excitation light α from the LD unit is not completely linearly polarized light, the LP converts the excitation light α from the LD unit into completely linearly polarized light.

  The shaping optical system adjusts the beam diameter, contour shape, and the like of the excitation light α so that the shape of the irradiation spot on the surface of the metal thin film 30 is a circular shape having a predetermined size. The excitation light α emitted from the shaping optical system is applied to the prism 20 included in the detection chip 10. The shaping optical system is, for example, a slit or zoom means.

  The chip holder 130 is held on the base 120 so as to be rotatable about an axis orthogonal to the optical axis of the excitation light α emitted from the excitation light emitting unit 110. The chip holder 130 is connected to the rotation motor 140 and is rotated by the rotation motor 140. The rotary motor 140 is fixed to the base 120. The chip holder 130 and the rotation motor 140 jointly rotate the chip holder 130 (and the detection chip 10) with respect to the optical axis of the excitation light α. That is, in the SPFS device 100 of the present embodiment, the chip holder 130 and the rotation motor 140 function together as an angle adjustment unit that relatively rotates the optical axis of the excitation light α and the chip holder 130. The position of the rotation center of the chip holder 130 will be described in detail later.

  The light detection unit 150 is disposed so as to face the surface of the metal thin film 30 of the detection chip 10 held by the chip holder 130 that does not face the prism 20. More specifically, the light detection unit 150 is disposed on a straight line that passes through the irradiation spot of the excitation light α on the surface of the metal thin film 30 and is perpendicular to the surface of the metal thin film 30. The light detection unit 150 detects light emitted from the surface of the metal thin film 30 that does not face the prism 20. For example, the light detection unit 150 detects fluorescence β emitted from the fluorescent material on the metal thin film 30 and plasmon scattered light from the metal thin film 30. The light detection unit 150 switches the position of the lens barrel 151 including a condensing lens and an imaging lens, the second wave shaper 152 including a second bandpass filter (hereinafter abbreviated as “BPF2”), and the BPF2. A motor 153 and a light receiving sensor 154 are included.

  The condensing lens and the imaging lens included in the lens barrel 151 constitute a conjugate optical system that is not easily affected by stray light. The light traveling between the condenser lens and the imaging lens is substantially parallel light. The condenser lens and the imaging lens form a fluorescent image on the metal thin film 30 on the light receiving surface of the light receiving sensor 154.

  The second wave adjuster 152 is provided in the lens barrel 151 so as to be positioned between the condenser lens and the imaging lens. The BPF 2 blocks light having the wavelength of the excitation light α, so that light other than the fluorescence wavelength (for example, leakage light from the excitation light emitting unit 110, plasmon scattered light, diffused light, etc.) reaches the light receiving sensor 154. To prevent that. That is, the BPF 2 removes a noise component from the light that reaches the light receiving sensor 154, and contributes to improvement in detection accuracy and sensitivity of weak fluorescence. The position of BPF 2 is switched by a switching motor 153. When detecting fluorescence, the BPF 2 is inserted into the lens barrel 151 so as to be positioned on the optical path. On the other hand, when detecting plasmon scattered light, the BPF 2 is retreated from the lens barrel 151 so as to be located outside the optical path.

  The light receiving sensor 154 detects a fluorescent image on the metal thin film 30. For example, the light receiving sensor 154 is a photomultiplier tube with high sensitivity and high S / N ratio. The light receiving sensor 154 may be an avalanche photodiode (APD) or the like. The fluorescence image on the metal thin film 30 also tilts with the rotation of the chip holder 130, but the angle is several degrees, and the fluorescence is emitted from the fluorescent material equally in all directions. Can be ignored.

  Note that the size of the irradiation spot α1 of the excitation light α on one surface (surface facing the prism 20) of the metal thin film 30 is such that the light detection on the other surface (surface facing the light detection unit 150) of the metal thin film 30 is performed. The size is adjusted to be smaller than the size of the measurement region β1 by the unit 150 (see FIG. 2). By doing in this way, even if the irradiation spot α1 is slightly displaced due to the error of each parameter of the prism 20, it is possible to prevent the irradiation spot α1 from deviating from the measurement region β1.

  FIG. 2 is a cross-sectional view of the detection chip 10. As shown in FIG. 2, the detection chip 10 includes a prism 20, a metal thin film 30, and a flow path member 40. The detection chip 10 is replaced whenever an analyte is detected.

  The prism 20 is formed of a transparent resin having a refractive index of about 1.4 to 1.6. The prism 20 may be made of glass. The prism 20 has an incident surface 21 on which the excitation light α from the excitation light emitting unit 110 is incident on the inside of the prism 20 and a film formation surface on which a metal thin film 30 that reflects the excitation light α incident on the inside of the prism 20 is formed. 22 and an emission surface 23 for emitting the excitation light α reflected by the metal thin film 30 to the outside of the prism 20. For example, the angle between the incident surface 21 and the film formation surface 22 and the angle between the film formation surface 22 and the emission surface 23 are both about 80 °.

  The metal thin film 30 is formed on the film formation surface 22 of the prism 20. The metal thin film 30 amplifies the evanescent wave (enhanced electric field) generated by the total reflection of the excitation light α at the interface between the metal thin film 30 and the film formation surface 22. That is, by generating surface plasmon resonance in the metal thin film 30 on the film formation surface 22, the excitation light α is totally reflected on the surface without the metal thin film 30 (film formation surface 22) to generate an evanescent wave. The evanescent wave formed can be amplified.

  The material of the metal thin film 30 is not particularly limited as long as it is a metal that causes surface plasmon resonance. Examples of the material of the metal thin film 30 include gold, silver, copper, aluminum, and alloys thereof. In the present embodiment, the metal thin film 30 is a gold thin film.

  Although not shown in FIG. 2, a capturing body for capturing the analyte is fixed to the surface of the metal thin film 30 that does not face the prism 20. The type of the capturing body is not particularly limited as long as the analyte can be captured. For example, the capture body is an antibody specific for the analyte.

  The flow path member 40 is disposed on the film formation surface 22 of the prism 20. The flow path member 40 forms a flow path 41 through which the sample solution flows together with the film formation surface 22 and the metal thin film 30. Both ends of the channel 41 are connected to an inlet 42 and an outlet 43 formed on the upper surface of the channel member 40, respectively. The flow path member 40 is formed of a transparent resin, and is joined to the prism 20 by adhesion using an adhesive, laser welding, ultrasonic welding, pressure bonding using a clamp member, or the like. The channel 41 is formed such that the region where the metal thin film 30 and the sample are in contact with each other is wider than the measurement region β1 of the light detection unit 150.

  When the detection chip 10 is installed in a preprocessing unit (not shown) of the SPFS device 100, a sample is injected into the flow channel 41. The detection chip 10 into which the sample has been injected is transported to the chip holder 130 after the reaction between the capturing body fixed on the metal thin film 30 and the analyte is completed, and is mounted on the chip holder 130 in a predetermined posture. The

  Next, the detection operation of the SPFS device 100 will be described. FIG. 3 is a flowchart illustrating an example of an operation procedure of the SPFS apparatus 100.

  First, as a preliminary preparation, a sample or the like is injected into the flow channel 41 of the detection chip 10, and an analyte labeled with a fluorescent substance is captured by a capturing body fixed on the metal thin film 30. For example, a sample containing an analyte is injected into the flow path 41 of the detection chip 10. Thereby, at least a part of the analyte in the sample is captured by the capturing body (for example, antibody). Next, the inside of the flow path 41 is washed with a buffer solution or the like to remove substances not captured by the capturing body. Next, a liquid containing another capturing body (for example, a fluorescently labeled antibody) labeled with a fluorescent substance is injected into the channel 41. Thereby, the analyte captured by the capturing body fixed on the metal thin film 30 can be labeled with the fluorescent substance. Finally, the inside of the flow path 41 is washed again with a buffer solution or the like to remove free fluorescent substances. By the above procedure, the analyte labeled with the fluorescent substance can be captured by the capturing body fixed on the metal thin film 30.

  As another advance preparation, the SPFS device 100 is turned on to keep the temperature of the LD in the excitation light emitting unit 110 constant. This is because, as described above, the wavelength and light amount of the excitation light α emitted from the LD vary with temperature. When the wavelength and light quantity of the excitation light α change, the plasmon resonance conditions and the amount of evanescent waves generated also change. Since it takes time until the LD temperature becomes constant, it is preferable to turn on the power supply with a margin.

  After the LD temperature becomes constant, the detection chip 10 is mounted on the chip holder 130 (step S10). As described above, in the detection chip 10, the analyte labeled with the fluorescent substance is captured by the capturing body fixed on the metal thin film 30.

  Next, while irradiating the predetermined position of the metal thin film 30 with the excitation light α, the incident angle of the excitation light α with respect to the metal thin film 30 is scanned to determine the optimum resonance angle (step S20). Specifically, after the BPF 2 in the light detection unit 150 is withdrawn from the optical path, the chip holder 130 is rotated around a rotation center described later while irradiating a predetermined position of the metal thin film 30 with the excitation light α. At this time, the light detection unit 150 detects plasmon scattered light from the metal thin film 30. If necessary, an ND filter may be inserted in the optical path in the light detection unit 150. The SPFS apparatus 100 can change only the incident angle without changing the position of the irradiation spot on the metal thin film 30 by rotating the chip holder 130 around the rotation center described later. The control unit stores the relative rotation angle between the optical axis of the excitation light α and the chip holder 130 and the amount of plasmon scattered light. Furthermore, the control unit determines the relative rotation angle when the amount of plasmon scattered light is maximum as the optimum resonance angle. The control unit rotates and fixes the chip holder 130 so that the incident angle of the excitation light α with respect to the metal thin film 30 becomes the resonance angle determined in step S20 (step S30).

  Next, the amount of fluorescent light at the optimum incident angle set in step S30 is detected (step S40). Specifically, after the BPF 2 in the light detection unit 150 is inserted in the optical path, the fluorescence from the measurement region β1 is measured while irradiating the excitation light α to a predetermined position of the metal thin film 30 at an optimal incident angle. . The control unit stores the detected value and displays it on the display (step S50). Thereafter, the chip holder 130 is returned to the initial position, and a series of measurements is completed (step S60).

  As described above, when the analyte is detected using the SPFS device 100, the tip holder 130 is rotated while irradiating the metal thin film 30 with the excitation light α, and the incident angle of the excitation light α with respect to the metal thin film 30 is determined. Scan (step S20). This step will be described in more detail with reference to FIG.

  Basically, the optimum incident angle (that is, the resonance angle) of the excitation light α with respect to the metal thin film 30 is determined by the configuration of the detection chip 10. Parameters relating to this resonance angle include the refractive index of the prism 20, the refractive index and extinction coefficient of the metal constituting the metal thin film 30, the film thickness of the metal thin film 30, the wavelength of the excitation light α, and the like. However, the resonance angle often deviates slightly from the calculated value due to the type and amount of fluorescent material used during detection, the shape error of the prism 20, and the like. Therefore, it is necessary to determine the true resonance angle by scanning the incident angle within an angle range of less than several degrees on both sides with the calculated value as the center.

  As described above, in the SPFS apparatus 100 of the present embodiment, the chip holder 130 is rotated to scan the incident angle of the excitation light α with respect to the metal thin film 30 (angle A shown in FIG. 4). At this time, the SPFS device 100 does not have an incident angle with respect to the incident surface 21 of 0 °, and includes an angle range including an angle at which surface plasmon is generated in the metal thin film 30 (angle range B shown in FIG. Within the range, the incident angle of the excitation light α with respect to the metal thin film 30 is scanned. The reason why the incident angle with respect to the incident surface 21 is not 0 ° is to prevent the reflected light from the incident surface 21 from returning to the excitation light emitting unit 110. The scanning angle range B is within 10 °, and the incident angle of the excitation light α with respect to the incident surface 21 (angle D shown in FIG. 4) is more than 0 ° and not more than 10 °.

The minimum incident angle of the excitation light α with respect to the incident surface 21 will be examined in more detail. When the beam size of the excitation light α is d and the distance of the LD from the incident surface 21 is L, the minimum incident angle to be avoided is ATRAN (d / 2L). The laser intensity of the excitation light α has a Gaussian distribution. In general, the beam diameter of the Gaussian distributed laser light is 1 / e ² (13.5%) of the center intensity. However, even if the laser intensity is about 0.1% of the central intensity, the influence of the return light appears. Therefore, the minimum incident angle of the excitation light α with respect to the incident surface 21 is Atan (d / L) is preferable. For example, if the minimum incident angle of the excitation light α with respect to the incident surface 21 is 5 °, it is sufficient for practical use (actually, there is no problem even if it is made smaller).

  Further, the SPFS apparatus 100 is incident on the optical axis extension line of the excitation light α incident on the incident surface 21 at the minimum angle in the scanning angle range B and on the incident surface 21 at the maximum angle in the scanning angle range B. The chip holder 130 is rotated around the intersection C with the extension line of the optical axis of the excitation light α. By doing so, the incident angle of the excitation light α with respect to the metal thin film 30 can be changed without changing the position of the irradiation spot α1 on the metal thin film 30 (see FIG. 4). In practice, not only the intersection C but also a point located within 10% of the diameter of the irradiation spot of the excitation light α on the surface of the metal thin film 30 from the intersection C has no major problem.

  The optical axis of the excitation light α at the center angle of the scanning angle range B and the optical axis of the excitation light α at the minimum angle and the maximum angle of the scanning angle range B do not intersect at one point, and are minute triangles. make. In this case, when the center of the inscribed circle of the triangle is the center of rotation, the variation of the irradiation position is the smallest. As the triangle becomes larger, the displacement of the irradiation position also becomes larger. If the irradiation position is deviated due to non-uniformity of residual substances or image plane illuminance distribution of the observation optical system, the amount of fluorescence changes. The deviation of the irradiation position is approximately proportional to the distance between the rotation center and each light beam and the resonance angle. For example, when the resonance angle is 70 °, when the excitation light α moves a predetermined distance in a direction orthogonal to the optical axis, the irradiation position in the surface direction on the surface of the metal thin film 30 moves about three times the predetermined distance. End up. However, the irradiation position is shifted to a range where there is no practical problem by using the rotation point as the intersection C or a point located within 10% of the diameter of the irradiation spot of the excitation light α on the surface of the metal thin film 30 from the intersection C. Can be suppressed. In addition, the above-mentioned triangle can be made small by narrowing the scanning angle range B and bringing it close to the normal line of the incident surface 21.

  Considering the above points, the angle of the incident surface 21 in the detection chip 10 is defined from the resonance angle and the scanning angle range B. Let θ be the angle (small angle) between the optical axis of the excitation light α incident on the prism 20 and the normal line of the incident surface 21 when the amount of surface plasmons generated in the metal thin film 30 is maximized. Here, when approximated as Sinθ≈θ and the refractive index of the prism is 1.5, an angle formed by the optical axis of the excitation light α incident on the prism 20 and the normal line of the incident surface 21 (incident surface 21 The angle of incidence to the angle; the angle D) shown in FIG. 4 is 1.5θ. Since the scanning angle range ± ε of the resonance angle in the prism 20 is also small, the incident angle of the excitation light α with respect to the incident surface 21 at the maximum angle and the minimum angle in the scanning angle range B (angle D shown in FIG. 4) is 1. 5 (θ ± ε). When 1.5 (θ ± ε) includes 0 °, return light is generated. On the other hand, when 1.5 (θ ± ε) is excessively large, the deviation width of the irradiation position becomes large. As described above, from the viewpoint of preventing return light, it is preferable that 1.5 (θ−ε) is equal to or greater than ATAN (d / L) (eg, 5 ° or greater). Since ε ≦ 5 °, the angle θ between the optical axis of the excitation light α in the prism 20 and the normal line of the incident surface 21 at the resonance angle is 8.4 ° or more, and the excitation light α with respect to the incident surface 21 The swing angle range of the incident angle is ± 7.5 ° or less. When the refractive index of the prism is 2.0 (the maximum value of glass), the angle θ formed by the resonance angle and the normal line of the incident surface 21 is 7.5 ° or more, and the swing angle of the incident angle of the excitation light α. The range is ± 10 ° or less (the swing width is 20 ° or less). Therefore, the angle between the optical axis of the excitation light α incident on the prism 20 and the normal line of the incident surface 21 when the amount of surface plasmon generation in the metal thin film 30 is maximum is within a range of 5 to 20 °. Preferably there is.

  As described above, the SPFS device 100 according to the present embodiment has the extension line of the optical axis of the excitation light α incident on the incident surface 21 at the minimum angle in the scanning angle range B and the maximum angle in the scanning angle range B. In order to rotate the chip holder 130 around or near the intersection C with the extension line of the optical axis of the excitation light α incident on the light incident surface 21, the position of the irradiation spot α 1 on the metal thin film 30 is not changed. The incident angle of the excitation light α with respect to the thin film 30 can be changed.

(Embodiment 2)
In the first embodiment, the SPFS device 100 that rotates the chip holder 130 with respect to the optical axis of the excitation light α has been described. However, in the second embodiment, the optical axis of the excitation light α is rotated with respect to the chip holder 130. The SPFS device 200 will be described.

  FIG. 5 is a diagram illustrating a configuration of the SPFS apparatus 200 according to the second embodiment. As shown in FIG. 5, the SPFS device 200 includes an excitation light emitting unit 110, a base 120, a chip holder 210, a rotation lever 220, a rotation motor 230, and a light detection unit 150. The SPFS device 200 also includes a control unit (not shown) that centrally performs control of each drive unit and quantification of the amount of light received by the light detection unit 150. Similar to the SPFS apparatus 100 according to the first embodiment, the SPFS apparatus 200 according to the second embodiment is used with the detection chip 10 mounted on the chip holder 210. Note that the same components as those of the SPFS device 100 according to Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  Unlike the chip holder 130 of the SPFS device 100 according to the first embodiment, the chip holder 210 is fixed to the base 120 so as not to rotate.

  On the other hand, in the SPFS device 200 according to the second embodiment, the rotating lever 220 is rotatable about the axis orthogonal to the optical axis of the excitation light α emitted from the excitation light emitting unit 110 and the base 120 and the chip holder 210. Is held in. The position of the rotation center of the rotation lever 220 is the same as the position of the rotation center of the chip holder 130 of the SPFS device 100 according to the first embodiment. Since the rotation center of the rotation lever 220 is located in the prism 20 of the detection chip 10, the rotation axis of the rotation lever 220 is provided on the outside of the chip holder 210.

  The excitation light emitting unit 110 is fixed to the rotation lever 220 instead of the base 120. The excitation light emitting unit 110 is fixed to the rotation lever 220 so that the optical axis of the excitation light α passes through the rotation center of the rotation lever 220. The rotation lever 220 is connected to the rotation motor 230 and is rotated by the rotation motor 230. The rotary motor 230 is fixed to the base 120. The rotation lever 220 and the rotation motor 230 jointly rotate the optical axis of the excitation light α with respect to the chip holder 210 (and the detection chip 10). That is, in the SPFS device 200 of the present embodiment, the rotary lever 220 and the rotary motor 230 function together as an angle adjustment unit that relatively rotates the optical axis of the excitation light α and the chip holder 210.

  The SPFS apparatus 200 according to the present embodiment is the SPFS apparatus according to the first embodiment, except that the rotating lever 220 (and the excitation light emitting unit 110) is rotated instead of the chip holder 130 (and the detection chip 10). It operates in the same procedure as 100.

  The SPFS device 200 according to the second embodiment has the same effect as the SPFS device 100 according to the first embodiment.

  In addition, although each said embodiment demonstrated the SPFS apparatus, the detection apparatus which concerns on this invention is not limited to a SPFS apparatus. For example, the detection device according to the present invention may be an SPR device. In this case, the SPR device includes a light detection unit that detects excitation light reflected from the metal thin film and emitted from the emission surface.

  This application claims the priority based on Japanese Patent Application No. 2012-251149 of an application on November 15, 2012. The contents described in the application specification and the drawings are all incorporated herein.

  Since the detection apparatus of the present invention can detect the presence or amount of an analyte with high sensitivity and high accuracy, it is useful for clinical examinations, for example.

DESCRIPTION OF SYMBOLS 10 Detection chip | tip 20 Prism 21 Incident surface 22 Film-forming surface 23 Output surface 30 Metal thin film 40 Channel member 41 Channel 42 Inlet 43 Outlet 100,200 SPFS apparatus 110 Excitation light emission part 120 Base 130,210 Chip holder 140 , 230 Rotating motor 150 Photodetector 151 Lens barrel 152 Second wave adjuster 153 Switching motor 154 Light receiving sensor 220 Rotating lever α Excitation light α1 Excitation light irradiation region β Fluorescence β1 Fluorescence measurement region

Claims (7)

Detection that detects the presence or amount of an analyte by mounting a detection chip including a prism having an incident surface and a surface on which a metal thin film is formed, and irradiating the metal thin film with excitation light through the incident surface A device,
A chip holder for holding the detection chip;
A light source that emits the excitation light;
An angle adjusting unit that relatively rotates the optical axis of the excitation light and the chip holder in order to irradiate the excitation light at a predetermined angle to the predetermined position of the metal thin film through the incident surface;
Have
The angle adjustment unit scans the incident angle of the excitation light with respect to the metal thin film within an angle range including an angle at which an incident angle with respect to the incident surface is not 0 ° and a surface plasmon is generated in the metal thin film. ,
When the angle adjustment unit scans the incident angle of the excitation light with respect to the metal thin film , the optical axis of the excitation light incident on the incident surface at the minimum angle, the center angle, and the maximum angle of the angle range. The excitation that is incident on the incident surface at the minimum angle and the maximum angle of the angle range from the center of the inscribed circle, with the center of the inscribed circle of the triangle formed surrounded by the extension line as the center. around a point located within a distance a of a circle radius to the intersection of the extension line of the optical axis of the light, and said tip holder and the optical axis of the excitation light, on a virtual plane including the triangle Rotate relatively,
Detection device. The angle adjustment unit relatively rotates the optical axis of the excitation light and the chip holder on the virtual plane around a point located within the range of the inscribed circle. The detection device described. The detection apparatus according to claim 2, wherein the angle adjustment unit relatively rotates the optical axis of the excitation light and the chip holder on the virtual plane with a center of the inscribed circle as a center. . Said angle adjustment unit, to the extent the incident angle of the excitation light to the incident surface becomes less 10 ° beyond the 0 °, scanning the incident angle of the excitation light, in any one of claims 1 to 3 The detection device described. A detection chip in which the angle between the optical axis of the excitation light incident on the prism and the normal to the incident surface is within a range of 5 to 20 ° when the amount of surface plasmons generated in the metal thin film is maximized The detection device according to claim 1, wherein the detection device is mounted. The detection device according to any one of claims 1 to 5 , further comprising a light detection unit that detects light emitted from a surface of the metal thin film that does not face the prism. 7. The apparatus according to claim 1, further comprising: a light detection unit configured to detect the excitation light reflected by the metal thin film when the excitation light is irradiated onto the metal thin film through the incident surface. The detection device described.

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