Fluorescence detection device

Abstract

Provided is a fluorescence detection device having improved fluorescence detection sensitivity. The fluorescence detection device includes: a light source that irradiates a sample with excitation light in a circularly polarized light state; a cholesterol liquid crystal layer that transmits fluorescence emitted by the excitation light to the sample and reflects the excitation light; and a detection circuit that detects the fluorescence transmitted through the cholesterol liquid crystal layer.

Description

Technical Field

[0001] The present disclosure relates to a fluorescence detection device. Background Art

[0002] The fluorescence detection device of Patent Document 1 includes an optical system having a dichroic mirror, and detects fluorescence reflected from a sample.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-321753 Summary of the invention

[0006] In the fluorescence detection device of Patent Document 1, further performance of removing excitation light without requiring a dichroic mirror is sought.

[0007] An object of the present disclosure is to provide a fluorescence detection device with improved fluorescence detection sensitivity.

[0008] A fluorescence detection device of one embodiment of the present invention includes: a light source that irradiates a sample with excitation light in a circularly polarized light state; a cholesterol liquid crystal layer that transmits fluorescence emitted by the sample through the excitation light and reflects the excitation light; and a detection circuit that detects the fluorescence transmitted through the cholesterol liquid crystal layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram showing the fluorescence detection device according to the first embodiment.

[0010] Figure 2 1 is a cross-sectional view schematically illustrating the cholesteric liquid crystal layer according to Embodiment 1.

[0011] Figure 3 This is a plan view schematically illustrating the first layer and the seventh layer of the cholesteric liquid crystal layer according to Embodiment 1.

[0012] Figure 4 This is a plan view schematically illustrating the second layer of the cholesteric liquid crystal layer of Embodiment 1.

[0013] Figure 5 This is a plan view schematically illustrating the third layer of the cholesteric liquid crystal layer of Embodiment 1.

[0014] Figure 6 This is a plan view schematically illustrating the fourth layer of the cholesteric liquid crystal layer of Embodiment 1.

[0015] Figure 7 This is a plan view schematically illustrating the fifth layer of the cholesteric liquid crystal layer of Embodiment 1.

[0016] Figure 8 This is a plan view schematically illustrating the sixth layer of the cholesteric liquid crystal layer of Embodiment 1.

[0017] Fig. 9 This is an explanatory diagram for explaining the relationship between excitation light and reflected light.

[0018] Fig.10 It is a schematic diagram showing a fluorescence detection device of a comparative example.

[0019] Fig.11 It is a schematic diagram showing a fluorescence detection device according to Embodiment 2.

[0020] Fig.12 It is a schematic diagram showing a fluorescence detection device according to Embodiment 3.

[0021] Fig.13 It is a schematic diagram showing a fluorescence detection device according to a fourth embodiment.

[0022] Fig.14 This is an explanatory diagram showing the relationship between the wavelength characteristics of the excitation light reflected by the first liquid crystal layer and the wavelength characteristics of the excitation light reflected by the second liquid crystal layer in Embodiment 4.

[0023] The mode (implementation mode) for implementing the present disclosure is described in detail with reference to the accompanying drawings. The present disclosure is not limited by the contents described in the following implementation modes. In addition, the structural elements described below include elements that are easily conceivable to those skilled in the art and elements that are substantially the same. Moreover, the structural elements described below can be appropriately combined. In addition, the disclosed content is only an example, and for those skilled in the art, appropriate changes that can be easily conceived of while maintaining the gist of the present disclosure are of course included in the scope of the present disclosure. In addition, in order to make the description clearer, there are cases where the drawings schematically indicate the width, thickness, shape, etc. of each part compared to the actual state, but this is only an example and does not limit the interpretation of the present disclosure. In addition, in the present disclosure and the drawings, sometimes the same elements as those described in the drawings that have appeared are marked with the same figure numerals, and detailed descriptions are appropriately omitted.

[0024] In the present embodiment and the claims, when expressing a state in which other structures are arranged on a certain structure, the case merely expressed as "on..." includes both the case in which the other structures are arranged directly above the certain structure in a manner of contacting the certain structure and the case in which the other structures are arranged above the certain structure via other structures, unless otherwise specified.

[0025] (Implementation Method 1)

[0026] Figure 1 This is a schematic diagram showing the fluorescence detection device according to the first embodiment. Figure 21 is a cross-sectional view schematically illustrating the cholesteric liquid crystal layer according to Embodiment 1. Figure 3 This is a plan view schematically illustrating the first layer and the seventh layer of the cholesteric liquid crystal layer according to Embodiment 1. Figure 4 This is a plan view schematically illustrating the second layer of the cholesteric liquid crystal layer of Embodiment 1. Figure 5 This is a plan view schematically illustrating the third layer of the cholesteric liquid crystal layer of Embodiment 1. Figure 6 This is a plan view schematically illustrating the fourth layer of the cholesteric liquid crystal layer of Embodiment 1. Figure 7 This is a plan view schematically illustrating the fifth layer of the cholesteric liquid crystal layer of Embodiment 1. Figure 8 Schematic diagram of the sixth layer of the cholesterol liquid crystal layer of Embodiment 1. Figure 1 As shown, the fluorescence detection device 1 includes a light source 60, a cholesteric liquid crystal layer 10, a light-transmitting substrate 20, a sample holding portion 30, and a detection circuit 50 in a light-shielded space.

[0027] When the fluorescence detection device 1 irradiates the sample 31 with the excitation light L11 of a predetermined wavelength, the substance in the sample 31 is excited to generate fluorescence L13 having a spectral characteristic with a peak wavelength slightly shifted from the wavelength of the excitation light. The fluorescence detection device 1 can observe the intensity of the fluorescence L13 and the emission intensity distribution of the fluorescence L13.

[0028] The light-transmitting substrate 20 is an insulating base material, and for example, glass or resin material is used.

[0029] The cholesterol liquid crystal layer 10 has a liquid crystal layer 16 formed on a light-transmitting substrate 20 via an alignment film 15. The alignment film 15 is made of polyimide or the like, and has been subjected to a rubbing treatment or a photo-alignment treatment. A cholesterol liquid crystal is a liquid crystal in which elongated liquid crystal molecules are arranged with their long axes aligned in a plane, and the liquid crystal molecules LC spiral as they move in a direction perpendicular to the plane of the light-transmitting substrate 20. Specifically, Figure 2 The first layer LC1, the second layer LC2, the third layer LC3, the fourth layer LC4, the fifth layer LC5, the sixth layer LC6 and the seventh layer LC7 are shown as Figures 3 to 8 The liquid crystal molecules LC rotate as shown. According to each 1 / 2 pitch p of the spiral, the long axis direction of the liquid crystal molecules LC is aligned, so Figure 3 As shown, the long axis direction of the liquid crystal molecules LC in the first layer LC1 and the long axis direction of the liquid crystal molecules LC in the seventh layer LC7 are in the same direction.

[0030] Fig. 9 1 is an explanatory diagram for explaining the relationship between the excitation light and the reflected light. In the cholesterol liquid crystal layer 10, the cholesterol liquid crystal reflects light of a predetermined wavelength having circularly polarized light, the rotation direction of which is the same as the rotation direction of the helix. Fig. 9As shown, the excitation light L11 incident on the cholesterol liquid crystal layer 10 is reflected according to the same condition as the Bragg law shown in equation (1).

[0031] 2×(p / 2)×n×sinθ=m×λ · · · (1)

[0032] Here, m is the number of reflections, λ is the reflection wavelength, p is the pitch of the helix, n is the refractive index, and θ is the angle between the incident direction of the excitation light and the reflection surface BL.

[0033] The sample holder 30 is light-transmissive and holds the sample 31. The sample holder 30 is preferably made of a transparent material that does not emit fluorescence, such as silicon nitride (SiN). However, the sample holder 30 may be omitted in the present embodiment.

[0034] The light source 60 includes a light emitter 61, a polarizing plate 62, and a quarter wave plate 63. The light emitter 61 is a light emitting element that emits light by oscillating a predetermined excitation light. The polarizing plate 62 converts the light from the light emitter 61 into a linearly polarized light state. The quarter wave plate 63 converts the light from the polarizing plate 62 into an excitation light L11 in a circularly polarized light state.

[0035] The detection circuit 50 is a charge coupled device (CCD) and an imaging circuit. The detection circuit 50 can detect the intensity of fluorescence and the emission intensity distribution of fluorescence.

[0036] like Fig. 9 As shown, in accordance with the Bragg law, the excitation light L11 incident from the light source 60 is selectively reflected to become the reflected light L12. For example, when a plurality of liquid crystal molecules rotate clockwise, the cholesterol liquid crystal layer 10 reflects the right circularly polarized light having a wavelength corresponding to the pitch p in the excitation light L11 to become the reflected light L12. On the other hand, when a plurality of liquid crystal molecules rotate counterclockwise, the cholesterol liquid crystal layer 10 reflects the left circularly polarized light having a wavelength corresponding to the pitch p in the excitation light L11 to become the reflected light L12.

[0037] The cholesteric liquid crystal layer 10 is manufactured by selecting a liquid crystal material and a chiral agent corresponding to the wavelength of the excitation light.

[0038] Fig.10 It is a schematic diagram showing a fluorescence detection device of a comparative example. Fig.10 The fluorescence detection device 1a of the comparative example shown in FIG. Figure 1 Compared with the fluorescence detection device 1 shown, the cholesteric liquid crystal layer 10 is not included. Fig.10 In the fluorescence detection device 1 a of the comparative example shown, a sample holding portion 30 is stacked on a light-transmitting substrate 20 .

[0039] When the fluorescence detection device 1a of the comparative example irradiates the sample 31 with excitation light L21 of a predetermined wavelength, the substance in the sample is excited to emit fluorescence having a spectral characteristic with a peak wavelength slightly shifted from the wavelength of the excitation light. In the fluorescence detection device 1a, fluorescence L22 including noise of the excitation light reaches the detection circuit 50.

[0040] On the other hand, in the fluorescence detection device 1 according to the first embodiment, the cholesteric liquid crystal layer 10 selectively reflects the excitation light L11 to make it the reflected light L12 .

[0041] As described above, the fluorescence detection device 1 of the first embodiment includes: the light source 60 that irradiates the sample 31 with the excitation light L11 in the circularly polarized light state; the cholesterol liquid crystal layer 10 that transmits the fluorescence L13 emitted by the sample 31 through the excitation light L11 and reflects the excitation light L11; and the detection circuit that detects the fluorescence L13 transmitted through the cholesterol liquid crystal layer 10. Thus, the excitation light L11 can be selectively reflected to become the reflected light L12, and the excitation light L11 reaching the detection circuit 50 can be suppressed. As a result, the detection sensitivity of the fluorescence L13 detected by the detection circuit 50 is improved.

[0042] (Implementation Method 2)

[0043] Fig.11 2 is a schematic diagram showing a fluorescence detection device according to Embodiment 2. In the following description, the same components as those described in the above embodiment are denoted by the same reference numerals, and duplicate description is omitted.

[0044] The fluorescence detection device 1A includes a light source 60 , a cholesteric liquid crystal layer 10 , a light-transmitting substrate 20 , a sample holding portion 30 , and a detection circuit 50 in a light-shielded space.

[0045] like Fig.11 As shown, in the fluorescence detection device 1A of the second embodiment, the light source 60 includes a light emitter 64 and a quarter wave plate 63. The light emitter 64 emits linearly polarized laser light. The quarter wave plate 63 converts the light from the light emitter 64 into circularly polarized excitation light L11.

[0046] (Implementation 3)

[0047] Fig.12 Schematic diagram showing a fluorescence detection device according to Embodiment 3. In the following description, the same components as those described in the above embodiment are denoted by the same reference numerals, and duplicate description is omitted.

[0048] The fluorescence detection device 1B includes a light source 60, a cholesterol liquid crystal layer 10, a light-transmitting substrate 20, a sample holding portion 30, a detection circuit 50, and a lens 70 in a light-shielded space. Fig.12 As shown, in the fluorescence detection device 1B of the third embodiment, a lens 70 for focusing fluorescence from the sample 31 is further provided between the cholesteric liquid crystal layer 10 and the detection circuit 50 .

[0049] Thus, the collection efficiency of the fluorescence L13 by the lens 70 is improved.

[0050] (Implementation 4)

[0051] Fig.13 It is a schematic diagram showing a fluorescence detection device according to a fourth embodiment. Fig.14 This is an explanatory diagram showing the relationship between the wavelength characteristics of the excitation light reflected at the first liquid crystal layer and the wavelength characteristics of the excitation light reflected at the second liquid crystal layer in Embodiment 4. In addition, in the following description, the same reference numerals are attached to the same structural elements as those described in the above embodiments, and repeated descriptions are omitted.

[0052] As described above, in the fluorescence detection device 1 of the first embodiment, the excitation light L11 incident from the light source 60 selectively becomes the reflected light L12 according to the Bragg law and is reflected by the cholesterol liquid crystal layer 10. Therefore, if the incident angle from the light source 60 is staggered, the excitation light L11 is easily incident on the detection circuit 50. In contrast, the fluorescence detection device 1C of the fourth embodiment has a plurality of liquid crystal layers having different reflection bands, and thus the excitation light L11 can be reflected even if the incident angle of the excitation light L11 is slightly tilted, and the guaranteed range of the incident angle of the excitation light L11 can be expanded.

[0053] The fluorescence detection device 1C has a light source 60, a cholesterol liquid crystal layer 10, a light-transmitting substrate 20, a sample holding portion 30, and a detection circuit 50 in a light-shielded space. Specifically, the cholesterol liquid crystal layer 10 of embodiment 4 includes a first liquid crystal layer 11 and a second liquid crystal layer 12, the first liquid crystal layer 11 has a first helical pitch, and the second liquid crystal layer 12 has a second helical pitch that is different from the first helical pitch. The first liquid crystal layer 11 is formed on an orientation film 15. The second liquid crystal layer 12 is formed on the first liquid crystal layer 11. The first helical pitch of the helix of the first liquid crystal layer 11 and the second helical pitch of the helix of the second liquid crystal layer 12 are made different by changing a chiral agent or the like. As Fig.14 As shown, the wavelength characteristics C11 of the excitation light reflected by the first liquid crystal layer 11 and the wavelength characteristics C12 of the excitation light reflected by the second liquid crystal layer 12 are shifted. In addition, the cholesterol liquid crystal layer 10 may include three or more liquid crystal layers having different helical pitches.

[0054] For example, Fig.13 As shown, if the position is shifted from the position of the light source 60 to the position of the light source 60A rotated in the direction R, the first liquid crystal layer 11 cannot reflect the excitation light L11 of the light source 60A, but the second liquid crystal layer 12 can reflect the excitation light L11 of the light source 60A.

[0055] The above describes the preferred embodiments of the present disclosure, but the present disclosure is not limited to such embodiments. The contents disclosed in the embodiments are only examples, and various changes can be made without departing from the main purpose of the present disclosure. Appropriate changes made without departing from the main purpose of the present disclosure are of course also within the technical scope of the present disclosure. Without departing from the gist of the above-mentioned embodiments and variations, at least one of the various omissions, substitutions and changes of the structural elements can be made.

[0056] Description of Reference Numerals

[0057] 1. 1A, 1B, 1C, 1a Fluorescence detection device

[0058] 10 Cholesteric Liquid Crystal Layer

[0059] 111st liquid crystal layer

[0060] 12 Second liquid crystal layer

[0061] 15 Oriented film

[0062] 16 Liquid crystal layer

[0063] 20 Translucent substrate

[0064] 30 Sample holding unit

[0065] 31 samples

[0066] 50 Detection circuit

[0067] 60, 60A light source

[0068] 61, 64 Luminous body

[0069] 62 Polarizer

[0070] 63 1 / 4 wave plate

[0071] 70 lens

[0072] L11, L21 excitation light

[0073] L12 reflected light

[0074] L13, L22 fluorescence.

Claims

1. A fluorescence detection device, wherein: include: A light source, which irradiates the sample with circularly polarized excitation light; a cholesterol liquid crystal layer that transmits the fluorescence emitted by the sample through the excitation light and reflects the excitation light; and A detection circuit detects the fluorescence transmitted through the cholesteric liquid crystal layer.

2. The fluorescence detection device according to claim 1, wherein: The light source includes: a light emitter; a polarizer that converts the light of the light emitter into a linearly polarized light state; and a quarter wave plate that converts the light in the linearly polarized light state emitted from the polarizer into the excitation light in the circularly polarized light state.

3. The fluorescence detection device according to claim 1, wherein: The invention further comprises a light-transmitting substrate on which the cholesteric liquid crystal layer is formed.

4. The fluorescence detection device according to claim 1, wherein: The cholesteric liquid crystal layer includes a first liquid crystal layer and a second liquid crystal layer. The first liquid crystal layer has a first helical pitch, and the second liquid crystal layer has a second helical pitch different from the first helical pitch.

5. The fluorescence detection device according to any one of claims 1 to 4, wherein: A lens for focusing the fluorescence is further provided between the cholesteric liquid crystal layer and the detection circuit.

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