Measuring sheet, measuring device and measuring method

Abstract

Embodiments of the present disclosure provide a measurement sheet (1). The measurement sheet may include a propagation layer (2) configured to allow light to propagate in a propagation direction, an introduction portion (3) configured to introduce the light into the propagation layer, an exit portion (4) configured to exit the light from the propagation layer; and a coating layer (5) configured to be formed on a surface (2A) of the propagation layer. The length of a forming area of the coating layer in the propagation direction increases or decreases along a direction perpendicular to the propagation direction. The length of the formation region of the coating layer may be modified with a ligand (82) that reacts with an analyte on the surface of the propagation layer at least in an exposed region exposed from the coating layer.

Description

Technical Field

[0001] The present disclosure generally relates to biosensors, and more particularly to a measurement sheet, a measurement device, and a measurement method for measuring a change in a light pattern. Background Art

[0002] A biosensor is an analytical device that combines a biological component with a physicochemical detector to detect and measure the presence of a specific biological or chemical substance. These devices are designed to convert a biological reaction into a measurable signal, enabling the quantification of various analytes in a sample. Biosensors are applied in various fields including medical diagnosis, environmental monitoring, food safety, and the like.

[0003] In one example, a biosensor can be used to analyze the interaction between chemical substances (e.g., biomolecules). The types of biosensors can include, for example, an optical waveguide-based biosensor, a surface plasmon resonance-based biosensor, and a Mach-Zehnder interference-based biosensor.

[0004] Traditionally, an optical waveguide-based biosensor (PTL1, hereinafter also referred to as an optical waveguide type measurement sheet or a measurement sheet) can use an optical waveguide to detect a substance (i.e., an analyte) and a reactant (i.e., a ligand) that reacts with the analyte that can be formed on the surface of a propagation layer where light propagates. In the optical waveguide type measurement sheet, the presence or absence and the concentration of the analyte can be estimated based on a change in the pattern of light derived from the propagation layer and using the difference in the amount of phase change between a ligand-fixed region and a ligand-unfixed region of the light propagating in the propagation layer.

[0005] In addition, in some other conventional cases, an optical waveguide type biosensor (PTL2) can use a coloring agent and detect a change in the intensity of the propagating light due to light absorption and scattering.

[0006] However, conventional biosensors, particularly optical waveguide type biosensors, cannot perform measurements accurately and reliably. Therefore, it is necessary to improve the performance of the optical waveguide type measurement sheet or biosensor in terms of measurement reproducibility and measurement reliability.

[0007] PTL 1: PCT Patent Application No. WO2019 / 044418

[0008] PTL 2: Japanese Patent Application No. JP2012-78185 Summary of the Invention

[0009] A first aspect of the present disclosure relates to a measurement sheet. The measurement sheet includes a propagation layer configured to allow light to propagate in a propagation direction. The measurement sheet may further include an introduction portion [introduction coupler] configured to introduce the light into the propagation layer. The measurement sheet may further include an exit portion [exit coupler] configured to exit the light from the propagation layer. The measurement sheet may further include a coating layer formed on a surface of the propagation layer. The coating layer increases or decreases a length of a coating formation region in the propagation direction in a direction perpendicular to the propagation direction. Further, a ligand reacts with an analyte on the surface of the propagation layer at least in an exposed region exposed from the coating layer.

[0010] According to one embodiment, the measurement sheet may further include a ligand layer formed by modifying the ligand on the surface of the propagation layer in the exposed region.

[0011] According to one embodiment, a first refractive index of the coating layer is less than a second refractive index of the propagation layer and greater than a third refractive index of the ligand layer.

[0012] According to one embodiment, the coating layer is configured to be formed between the introduction portion and the exit portion of the measurement sheet.

[0013] According to one embodiment, the coating layer is configured to be formed on at least one of the introduction portion or the exit portion of the measurement sheet.

[0014] According to one embodiment, the coating layer is further configured to continuously increase or decrease the length of the coating formation region in the propagation direction in a direction perpendicular to the propagation direction.

[0015] According to one embodiment, the coating layer is further configured to linearly increase or decrease the length of the coating formation region in the propagation direction in a direction perpendicular to the propagation direction.

[0016] According to one embodiment, a thickness of the coating layer is equal to or greater than an attenuation length of evanescent light penetrating from the surface of the propagation layer to a medium on a side of the coating layer.

[0017] According to one embodiment, the coating layer is formed of silica.

[0018] According to one embodiment, the coating layer is formed of a mixture of silica and a metal oxide.

[0019] According to one embodiment, the coating layer is formed of a mixture of silica and alumina (Al2O3).

[0020] According to one embodiment, the measurement sheet may further include a property adjustment film provided on the surface of the coating layer.

[0021] According to one embodiment, the characteristics adjustment film is formed of a metal oxide.

[0022] According to one embodiment, the reaction between the analyte and the ligand causes a change in the refractive index around the propagation layer, and thus a change in the phase distribution of the light.

[0023] On the other hand, a measuring device is provided. The measuring device includes a measuring sheet. The measuring sheet includes: a propagation layer configured to allow light to propagate along a propagation direction; an introduction portion configured to introduce the light into the propagation layer; an exit portion configured to emit the light from the propagation layer; and a coating layer configured to be formed on the surface of the propagation layer. The coating layer increases or decreases the length of the coating formation area in the propagation direction in a direction perpendicular to the propagation direction. In addition, the ligand reacts with the analyte on the surface of the propagation layer at least in the exposed area exposed from the coating layer. The measuring device may also include a light source configured to introduce the light into the introduction portion of the measuring sheet. The measuring device also includes a photodetector configured to receive the light emitted from the exit portion of the measuring sheet. The measuring device also includes a control unit (controller) configured to analyze the pattern change of the light received by the photodetector, the pattern changing based on the reaction between the analyte and the ligand of the measuring sheet.

[0024] According to an embodiment, the control unit is further configured to analyze changes in the propagation direction of the light.

[0025] In another aspect, a measurement method is provided. The measurement method includes introducing light into a propagation layer. The measurement method also includes causing the light to be totally reflected in the propagation layer, wherein the propagation layer has a surface, and a ligand reactive with an analyte is formed in an exposed area exposed from a coating layer formed on the surface of the propagation layer. The measurement method also includes guiding the light out of the propagation layer. The coating layer increases or decreases the length of the coating formation area in the propagation direction in a direction perpendicular to the propagation direction.

[0026] According to one embodiment, the measurement method further comprises analyzing a pattern change of the light derived from the propagation layer. The pattern change is caused by a reaction between the analyte and the ligand of the measurement patch.

[0027] According to one embodiment, the measuring method further comprises analyzing changes in the traveling direction of the light derived from the propagation layer.

[0028] According to one embodiment, the first refractive index of the coating is less than the second refractive index of the propagation layer and greater than the third refractive index of the ligand layer, and the ligand layer is formed by modifying the surface of the propagation layer in the exposed area with a ligand. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Embodiments of the present disclosure are shown in the drawings in an illustrative rather than restrictive manner, where the same reference numerals represent the same elements, and wherein:

[0030] Figure 1(A) to 1(C) Different views showing a schematic structure of a measurement sheet according to embodiments of the present disclosure are shown;

[0031] Figure 2(A) and 2(B) A top view and a cross-sectional view showing the schematic structure of the measurement sheet according to different embodiments of the present disclosure are shown respectively;

[0032] Figure 3 A schematic diagram of a configuration of a measurement device including the measurement sheet according to an embodiment of the present disclosure is shown;

[0033] Figure 4(A) to 4(C) A graph showing a signal measured by the measurement sheet according to an embodiment of the present disclosure is shown;

[0034] Figure 5 A flowchart of a measurement method according to an embodiment of the present disclosure is shown;

[0035] Figure 6(A) to 6(E) A graph showing variants of a planar shape of a coating layer in the measurement sheet according to an embodiment of the present disclosure is shown;

[0036] Figure 7 A performance evaluation result of the measurement sheet according to an embodiment of the present disclosure is shown;

[0037] Figure 8(A) and 8(B) A schematic structure of a conventional measurement sheet according to an embodiment is shown; and

[0038] Figure 9(A)-9(C) Different methods of forming a ligand layer having a specific planar shape in a conventional measurement sheet according to an embodiment are shown.

[0039] EFFECT

[0040] The object of the present invention is to provide an optical waveguide type measurement sheet, a measurement device, and a measurement method that can further improve measurement reproducibility and measurement reliability and further reduce the manufacturing process cost. DETAILED DESCRIPTION

[0041] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that in the following description and drawings, the same reference signs denote the same or similar components, and thus repeated descriptions of the same or similar components are omitted.

[0042] In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, systems and methods are shown only in block diagram form in order to avoid obscuring the gist of the present disclosure.

[0043] Some embodiments of the present disclosure will now be described more fully with reference to the accompanying drawings, in which some, but not all, embodiments of the present disclosure are shown. In fact, the various embodiments of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The same reference numerals always denote the same elements. Additionally, references to "one embodiment" in this specification mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present disclosure. The phrase "in one embodiment" as used throughout the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to a separate or alternative embodiment mutually exclusive of other embodiments. Furthermore, the term "a" as used herein does not denote a limitation of quantity, but rather denotes the presence of at least one of the referenced item. In addition, various features that some embodiments may have and other embodiments may not have are described. Similarly, various requirements that some embodiments may have and other embodiments may not have are also described.

[0044] The embodiments described herein are for illustrative purposes only and there may be many variations. It should be understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the present disclosure. Additionally, it should be understood that the language and terminology used herein are for the purpose of description and should not be regarded as limiting. Any headings used in this specification are for convenience only and have no legal or limiting effect. Various components related to the present disclosure will now be briefly discussed with reference to FIGS. 1 through 9. Reference will be made to the accompanying drawings showing various embodiments of a measurement sheet, wherein the measurement sheet includes a coating layer modified due to a reaction between a ligand and an analyte.

[0045] Measurement sheet

[0046] Figure 1(A) to 1(C)Different views of the schematic structure of the measuring piece 1 according to various embodiments of the present disclosure are shown. For example, Figure 1(A) shows a side view of the measuring piece 1 according to one embodiment. In addition, Figures 1(B) and 1(C) show side views of the measuring piece 1 according to one embodiment.

[0047] Figure 2(A) and 2(B) The schematic structure of the measuring piece 1 according to one embodiment is shown. For example, Fig. 2(A) shows a top view of the measuring piece 1 according to one embodiment. Fig. 2(B) shows a cross-sectional view of the measuring piece 1 according to one embodiment.

[0048] refer to Figure 1(A) to 1(C) and Figure 2(B) to 2(B) , the top surface direction (thickness direction) of the measurement piece 1 is defined as the Z-axis direction, the propagation direction of light in the measurement piece 1 is defined as the Y-axis direction, and the vertical direction perpendicular to the propagation direction is defined as the X-axis direction. In addition, one surface of the measurement piece 1 means the top surface or the bottom surface, and two surfaces means the top surface and the bottom surface.

[0049] According to some embodiments of the present disclosure, some configurations are omitted for the convenience of drawing, and the size ratios of the illustrated configurations are emphasized.

[0050] The measuring piece 1 includes a propagation layer 2. The propagation layer 2 is configured to allow light to propagate in a propagation direction. In addition, the measuring piece 1 includes an introduction part [introduction coupler] 3 and an emission part [exit coupler] 4. In one example, the introduction part 3 is configured to introduce light into the propagation layer 2. In addition, the emission part 4 is configured to emit light from the propagation layer 2.

[0051] In FIG. 2(A) and FIG. 2(B), the propagation layer 2 is drawn along the X-axis and Y-axis directions in the figure in such a manner that the measuring sheet 1 can be used for measurement.

[0052] According to one embodiment of the present disclosure, reference is made to Figure 1(A) to 1(C) The measurement piece 1 is summarized.

[0053] Figure 1(A) to 1(C) A side view and a perspective view showing a schematic structure of a measurement sheet 1 according to an embodiment. As shown in FIG. 1(A) and FIG. 1(B), the measurement sheet 1 may include a propagation layer 2 through which light propagates, an introduction portion 3 for introducing light into the propagation layer 2, an emission portion 4 for guiding light out of the propagation layer 2, and a coating layer 5 formed on the surface of the propagation layer 2. In one example, the coating layer 5 is formed on the surface of the propagation layer 2 in a specific planar shape.

[0054] In one example, the measurement sheet 1 is designed to have a ligand (such as an antibody) on the surface of the propagation layer 2 that can react with an analyte (such as an antigen) in the object to be measured (such as a sample). For example, such a reaction between the ligand and the analyte can form a ligand layer 6 on the surface of the propagation layer 2.

[0055] Referring to FIGS. 1(B) and 1(C), the ligand layer 6 is uniformly formed on the surface 2A of the propagation layer 2 and the surface 5A of the coating layer 5. It should be noted that the propagation layer 2 is located below the coating layer 5, that is, a formation region of the coating is formed on the propagation layer 2, so that the formation region of the coating forms the coating layer 5.

[0056] For example, the coating layer 5 is formed in a specific planar shape on the surface of the propagation layer 2. In one embodiment, the ligand layer 6 can be formed on the entire surface of the surface 2A of the propagation layer 2 and the surface 5A of the coating layer 5. In another embodiment, the ligand layer 6 can be formed at least on a region (referred to as an exposed region) of the surface 2A of the propagation layer 2. The exposed region is exposed from the coating layer 5.

[0057] In one example, the reaction (or binding) between the ligand and the analyte, the bulk effect, and non-specific adsorption can occur on the entire surface of the ligand layer 6. In addition, the coating layer 5 can be formed with a thickness that attenuates the evanescent light, so that the evanescent light penetrating from inside the propagation layer 2 and moving towards the ligand in the ligand layer 6 may be attenuated and difficult to be sensed.

[0058] To overcome the above problems, the measurement sheet 1 can be used to sense the reaction, the bulk effect, and non-specific adsorption between the ligand and the analyte only on the surface 2A of the propagation layer 2 in the exposed region exposed from the coating layer 5. Therefore, due to the thickness formed by the coating layer 5 that attenuates the evanescent light, even if the ligand layer 6 is formed on the entire surfaces 2A and 5A of the propagation layer 2 and the coating layer 5, the reaction, the bulk effect, and non-specific adsorption between the ligand and the analyte can be sensed only on the surface 2A of the propagation layer 2 in the exposed region exposed from the coating layer 5. In one example, due to the reaction (binding) between the analyte and the ligand, the refractive indices of the propagation layer 2 and the coating layer 5 may change. As a result, on the surface 2A of the propagation layer 2 where the ligand layer 6 is formed, the phase distribution in the X-axis direction and the Y-axis direction of the propagation direction of light changes. Therefore, the measurement sheet 1 can be used as a measurement sheet for estimating the presence or concentration of the analyte.

[0059] According to one embodiment, the coating layer 5 is formed in a specific planar shape on the surface 2A of the propagation layer 2 in the measurement sheet 1. Thus, even if the ligand layer 6 is uniformly formed on the entire surfaces 2A and 5A of the propagation layer 2 and the coating layer 5, respectively, the ligand layer 6 is formed in a specific planar shape on the surface 2A of the propagation layer 2 in the exposed area exposed from the coating layer 5. The pattern of the specific planar shape is opposite to the planar shape of the coating layer 5. Further, the formation of the coating layer 5 can be performed by, for example, vapor deposition without considering a wet process. Thereby, the measurement reproducibility can be improved and the manufacturing cost of the measurement sheet 1 can be reduced. Therefore, the measurement sheet 1 of the present disclosure can improve the measurement reproducibility and measurement accuracy of the measurement sheet based on an optical waveguide.

[0060] According to some embodiments, each part of the measurement sheet 1 can be described with reference to FIGS. 1 and 2.

[0061] In one embodiment, the propagation layer 2 is planar. For example, light can be introduced into the propagation layer 2 from the introduction part 3 such that the light is totally reflected on the upper and lower surfaces of the propagation layer 2. Further, the light can be led out from the exit part 4.

[0062] According to the present invention, a deposited film (the refractive index of which is, for example, about 2.07 depending on the wavelength of light) can be used in the propagation layer 2. The deposited film can be made of, for example, metal oxides such as titanium dioxide (TiO2) and tantalum pentoxide (Ta2O5). In one embodiment, the material for manufacturing the propagation layer 2 may include, in addition to metal oxides, dielectrics such as acrylic resin, glass, polyvinyl alcohol, polyvinyl chloride, silicone resin, or polystyrene. Further, the thickness of the propagation layer 2 can vary, for example, in the Z-axis direction, and the length of the propagation layer 2 can vary, for example, in the X-axis and Y-axis directions. For example, the thickness can vary from about 50 nanometers (nm) to about 100 nm. Further, the length of the propagation layer 2 in the Y-axis direction can be, for example, 4 millimeters (mm); and the length of the propagation layer 2 in the X-axis direction can be in the range of, for example, 270 micrometers (μm) to 600 μm. In one example, using a dielectric such as acrylic resin, glass, polyvinyl alcohol, polyvinyl chloride, silicone resin, or polystyrene as the material for the propagation layer 2 can enable the propagation layer 2 itself to have the ability to act as a substrate. Thus, the substrate 7 can be omitted. This reduces the manufacturing cost of the measurement sheet 1.

[0063] In another embodiment, the introduction portion 3 and the exit portion 4 may be provided in the propagation layer 2. Further, the introduction portion 3 and the exit portion 4 may use a diffraction grating. In one example, the diffraction grating may be fabricated using a nanoimprint method. In addition to the diffraction grating, a prism, for example, may also be used to fabricate the introduction portion 3 and the exit portion 4. In one embodiment, the introduction portion 3 and the exit portion 4 may be provided on the lower surface of the propagation layer 2. However, in some embodiments, the introduction portion 3 and the exit portion 4 may be provided on the upper surface rather than the lower surface of the propagation layer 2.

[0064] Further, the coating layer 5 may be formed in a specific planar shape on the surface 2A of the propagation layer 2. The coating layer 5 may at least need to be formed between the introduction portion 3 and the exit portion 4 of the measurement sheet 1. In some embodiments, as shown in FIGS. 1(A) and 2(A), the coating layer 5 may be formed on the introduction portion 3 and the exit portion 4 of the measurement sheet 1. Further, in some embodiments, the coating layer 5 may be formed on the introduction portion 3 or the exit portion 4.

[0065] In one example, the specific planar shape of the coating layer 5 may be the length in the exposed area where the coating layer 5 is formed with the coating. Additionally, the specific planar shape of the coating layer 5 is a shape in which the formation area of the coating extends in the light propagation direction (Y-axis direction) and increases or decreases in a direction perpendicular to the propagation direction (X-axis direction). It can be noted that a part of the specific planar shape of the coating layer 5 may also include the part that increases or decreases, or the entire specific planar shape may increase or decrease. Including the part that increases or decreases in the part of the specific planar shape means that the specific planar shape is, for example, a parallelogram or a trapezoid. For example, the parallelogram or trapezoid includes a part that increases or decreases in the part of the shape and has a fixed length. The entire specific planar shape increasing or decreasing refers to a specific planar shape that is, for example, a right triangle. The right triangle may include such an increasing or decreasing part throughout the shape. For example, the specific planar shape may be a right triangle as shown in FIG. 1(B).

[0066] In an exemplary embodiment, the thickness of the coating layer 5 may be equal to or greater than the evanescent light leakage length that penetrates the medium from the surface 2A of the propagation layer 2 toward the coating layer 5 side. For example, the evanescent light leakage length may refer to the distance at which the evanescent light decays and loses its energy.

[0067] In one example, the wavelength of the evanescent light is about 520 nm. Accordingly, the thickness of the coating layer 5 can be equal to or greater than the penetration length of the evanescent light. For example, the thickness of the coating layer 5 (referred to as "d") can be about 132 nm or greater, and more preferably, the thickness of d can be about 250 nm or greater. Theoretically, the first refractive index of the coating layer 5 is lower than the second refractive index of the propagation layer 2. In addition, the first refractive index of the coating layer 5 can be equal to or substantially equal to the third refractive index of the ligand layer 6.

[0068] It should be noted that the refractive index of the highly stable transparent material can be higher than the third refractive index of the ligand layer 6. Therefore, considering stability, the material of the coating layer 5 with a refractive index lower than that of the propagation layer 2 and higher than that of the ligand layer 6 may be optimal for the measurement sheet 1.

[0069] In one example, in the case of using silica to make the coating layer 5, a vapor deposition film mainly composed of metal oxides can be used to manufacture the propagation layer 2. Additionally, the thickness of the coating layer 5 is specifically described based on the calculation of the penetration distance of the evanescent light. The penetration distance of the evanescent light can refer to the length at which the amplitude of the light is 1 / e (intensity is 1 / e 2 ). The e (energy) can refer to the energy of a single photon of the light. In addition, the penetration (sometimes referred to as "leaching") distance of the evanescent light can be calculated based on the first refractive index of the coating layer 5, the second refractive index of the propagation layer 2, the wavelength of the light propagating into the propagation layer 2, and the propagation angle (also referred to as "Φ") of the light propagating through the propagation layer 2. Here, the propagation angle Φ is the angle between the axis perpendicular to the interface between the propagation layer 2 and the coating layer 5 (such as the Z-axis in FIG. 1) and the direction in which the light travels in the propagation layer 2 (i.e., the propagation direction).

[0070] In an exemplary scenario, the second refractive index of the propagation layer 2 is 2.037, the first refractive index of the coating layer 5 formed thereon can be 1.46, the wavelength of the light in vacuum is 520 nm, and the propagation Φ of the light propagating through the propagation layer 2 is 51.3°. In this case, the calculated penetration distance of the evanescent light is 132.0 nm. Since the region within the length / distance of the penetration distance may become the light absorption region, the film thickness of the coating layer 5 can be greater than or equal to 132.0 nm. In another exemplary scenario, the second refractive index of the propagation layer 2 is 1.987, the first refractive index of the coating layer 5 is 1.45, the wavelength of the light in vacuum is 810 nm, and the propagation angle Φ of the light propagating through the propagation layer 2 is 52.8°. At this time, the calculated penetration distance of the evanescent light is 203.6 nm. Subsequently, the region within this distance may become the light absorption region, and the film thickness of the coating layer 5 can be greater than or equal to 203.6 nm.

[0071] According to another embodiment, silica (with a refractive index of approximately 1.47) can be used to fabricate the coating layer 5. The silica can be formed on the surface 2A of the propagation layer 2 by chemical vapor deposition. In one embodiment, a metal mask can be used to form the planar shape of the coating layer 5 into a right triangle as shown in FIG. 1(B). A metal mask with, for example, a right triangle hole having the shape of the coating layer 5 can be fabricated, and during deposition, the areas other than the coating layer 5 can be masked with the metal mask to form the coating layer 5 into a right triangle. In addition, during the deposition process, the temperature rise is less and the adhesion to the propagation layer 2 is high, resulting in less peeling in the salt solution. Therefore, silica is suitable as the deposition material for the coating layer 5. In addition to using silica as the material for the coating layer 5, metal oxides such as alumina (Al2O3), fluorine-based low refractive index materials (with a refractive index of approximately 1.33 to 1.38), or mixtures of these materials can also be used to fabricate the coating layer 5. In one embodiment, a mixture of silica and a metal oxide mainly composed of silica (such as Al2O3) can be used to fabricate the coating layer 5. For example, magnesium fluoride (MgF2) or thiolate (R)(Na5Al3F 14 ) can be used as the fluorine-based low refractive index material for the coating layer 5.

[0072] In an exemplary embodiment, a property adjustment film (not shown in the figure) can also be formed on the surface 5A of the coating layer 5. The property adjustment film can be formed using, for example, the above-mentioned metal oxides. By further coating and forming the property adjustment film on the surface 5A of the coating layer 5, the properties of the exposed area and the coating layer 5 can be made closer, and the same surface treatment can be further applied. This can improve the measurement stability and measurement accuracy of the measurement sheet 1.

[0073] In one embodiment, a ligand layer 6 can be formed on the surface 2A of the propagation layer 2. In this regard, the ligand can be a substance that specifically reacts or binds with the analyte. The analyte can be the detected substance in the object to be measured (such as a sample). In addition, the ligand layer 6 can be uniformly formed on the surface 2A of the propagation layer 2 and the surface 5A of the coating layer 5, respectively. Alternatively, the ligand layer 6 can also be formed only on the surface 5A of the coating layer 5. However, the ligand layer 6 needs to be formed at least on the surface 2A of the propagation layer 2 in the exposed area exposed from the coating layer 5, that is, on the exposed area on the propagation layer 2 and the surface 5A of the coating layer 5. In one example, the planar shape of the coating layer 5 is a right triangle. In addition, between the introduction part 3 and the exit part 4, the planar shape of the ligand layer 6 in the area formed on the surface 2A of the propagation layer 2 in the exposed area exposed from the coating layer 5 is also a right triangle. Here, the refractive index of the ligand layer 6 can be, for example, approximately 1.33.

[0074] Therefore, on the surface 2A of the propagation layer 2 in the exposed area exposed from the coating layer 5, the ligand layer 6 is formed in a specific planar shape. The pattern of the specific planar shape is inverted from the specific planar shape of the coating layer 5. In the ligand layer 6, the content of the ligand in the light propagation direction (e.g., the Y-axis direction) can monotonically change in the direction (X-axis direction) perpendicular to the propagation direction on the formation area of the coating on the surface 2A of the propagation layer 2. Thus, on the surface 2A of the propagation layer 2 formed with the ligand layer 6, the phase distribution of the light propagating in the Y-axis direction can change in the X-axis direction. The phase distribution can change based on the change in refractive index caused by the reaction (or binding) between the analyte and the ligand. Further, the content of the ligand can be calculated by multiplying the ligand content density per unit length in the light propagation direction by the length of the ligand layer 6 in the light propagation direction.

[0075] In one embodiment, a transparent substrate 7 with an arbitrary structure can be provided on the lower surface of the propagation layer 2. For example, glass (with a refractive index of about 1.47 to 1.48) can be used to fabricate the substrate 7. In another embodiment, the measurement sheet 1 can further include an intermediate layer, such as a fluororesin, located between the lower surface of the propagation layer 2 and the transparent substrate 7.

[0076] Reference Figure 2(A) and 2(B) , a top view and a cross-section showing the schematic structure of the measurement sheet 1 are shown. According to one embodiment, reference Figure 2(A) and 2(B) will describe a mode in which the measurement sheet 1 can be used for measurement.

[0077] When using the measurement sheet 1 for measurement, a ligand 82 can be modified on the surface of the propagation layer 2 to form the ligand layer 6 on the surface 2A of the propagation layer 2. For example, a substrate 8 with a concave cross-section can be provided on the upper surface of the measurement sheet 1 to cover the propagation layer 2 formed with the ligand layer 6. In addition, a flow channel 9 can be provided between the substrate 8 and the ligand layer 6, as shown by the dashed line in the cross-section of FIG. 2(B).

[0078] During operation, a solution of the object or sample to be measured flows into the flow channel 9. In addition, the measurement sheet 1 can be used to measure the analyte contained in the object.

[0079] According to one embodiment, the light introduced into the propagation layer 2 through the introduction portion 3 can propagate in the Y-axis direction in the propagation layer 2. In addition, the introduced light can be derived from the propagation layer 2 through the exit portion 4. When propagating in the Y-axis direction in the propagation layer 2, the light may be affected by the second refractive index of the propagation layer 2. In addition, the affected light may be changed due to the reaction between the analyte in the solution of the object (to be measured) flowing in the flow channel 9 and the ligand 82 in the ligand layer 6. In the measurement sheet 1, the ligand layer 6 can be formed on the surface 2A of the propagation layer 2 such that the length of the ligand layer 6 in the light propagation direction (Y-axis direction) increases or decreases in the direction (X-axis direction) perpendicular to the propagation direction. Thus, due to the influence of the change in the refractive index of the light propagating in the Y-axis direction on the surface 2A of the propagation layer 2 on which the ligand layer 6 is formed, the phase distribution in the X-axis direction changes.

[0080] FIG. 2(B) is a cross-sectional view of the measurement sheet 1 along the axis 2B shown in FIG. 2(A). In the cross-sectional view of FIG. 2(B), the reaction, the bulk effect, and the non-specific adsorption between the ligand 82 and the analyte can be sensed on the surface 2A of the propagation layer 2 on which the ligand layer 6 is formed (for example, the left side of FIG. 2(B)).

[0081] Measurement device

[0082] Figure 3 is a schematic diagram of the configuration of a measurement device 10 including the measurement sheet 1 according to one embodiment. The measurement device 10 may include: a first light source 11A and a second light source 11B (collectively referred to as the light source 11), which can emit light that propagates through the introduction portion 3 of the measurement sheet 1; a first photodetector 12A and a second photodetector 12B (collectively referred to as the photodetector 12), which can receive the light derived from the introduction portion 4 of the measurement sheet 1; and a control unit (controller) 13, which can analyze the change in the pattern (for example, the intensity distribution) of the light received by the photodetector 12. The pattern of the light received by the photodetector 12 can change based on the contact between the solution of the object to be measured and the measurement sheet 1, and the contact causes a reaction between the ligand 82 and the analyte of the object. In addition, the measurement device 10 may further include a measurement unit (light intensity sensor) 14, which can acquire the intensity information of the light received by each light receiving element of the photodetector 12.

[0083] The control unit 13 and the measurement unit 14 can be configured in hardware using, for example, an application-specific integrated circuit (IC), or implemented in software using an information processing device such as a general-purpose computer, a smartphone, or a tablet terminal. For example, the control unit 13 and the measurement unit 14 can be a computer including a CPU, a RAM, a ROM, a non-volatile memory, an input / output interface, etc. For example, the CPU of the processing circuit 10 executes information processing according to a program loaded from the ROM or the non-volatile memory into the RAM.

[0084] In one example, the measuring device 10 may include two sets of measuring sheets 1 (illustrated as measuring sheet 1A and measuring sheet 1B), a light source 11, and at least one photodetector 12. And the measuring device 10. The measuring device 10 can acquire measurement signals of two lines. For example, a first signal (line 1) from the area where the ligand layer 6 is formed, and a second signal (line 2) from the area where the ligand layer 6 is not formed. In the measuring sheet 1A for line 1, the ligand layer 6 can be uniformly formed on the surface 2A of the propagation layer 2 and the coating layer 5. In addition, in the measuring sheet 1B for line 2, the ligand layer 6 may not be formed. The second signal of line 2 can be described as a reference signal for subtracting the effects of the bulk effect and non-specific adsorption from the first signal of line 1.

[0085] In another embodiment, the measuring device 10 may have one measuring sheet 1, at least one light source 11, and at least one photodetector 12. In this case, two measuring lines, that is, two optical waveguide type biosensors, can be fabricated on one substrate 7, and the two-line measurement signals as described above, that is, line 1 and line 2, can be acquired from each of the two measuring lines. The light emitted from one of the light sources 11 can be split and further injected into each of the two measuring lines. In addition, the light derived from each of the two measuring lines can be received by one of the photodetectors 12, such as the first photodetector 12A or the second photodetector 12B.

[0086] In the following description, the measuring sheet with the symbol 1A refers to the measuring sheet for line 1, the measuring sheet with the symbol 1B refers to the measuring sheet for line 2, and the measuring sheet with the symbol 1 refers to the measuring sheet that includes both line 1 and line 2. For the measuring sheet 1 (1A, 1B), the meanings of the symbols A and B are the same as those in the light source 11 (11A, 11B) and the photodetector 12 (12A, 12B).

[0087] The measuring sheet 1 that includes both line 1 and line 2 can be placed at a predetermined position in the measuring device 10. The light emitted from the light source 11 can be introduced into the propagation layer 2 from the lower surface of the measuring sheet 1 through the introduction portion 3. In addition, the light can be totally reflected inside the propagation layer 2, and can be derived from the propagation layer 2 through the exit portion 4 from the lower surface of the measuring sheet 1 and received by the photodetector 12.

[0088] The light source 11 having a light source 11A corresponding to line 1 and a light source 11B corresponding to line 2 can emit visible light having a wavelength of, for example, about 650 nm. The wavelength range of the light emitted by the light source 11 can be, for example, in the range of 450 nm to 2000 nm. Preferably, the light emitted by the light source 11 can be a Gaussian beam. The Gaussian beam is suitable for detecting changes in the light pattern (or intensity distribution) because the general shape of the light pattern can remain unchanged as the light propagates. In one example, the light emitted by the light source is a continuous wave. Although the embodiments of the present disclosure describe that the Gaussian beam is Gaussian distributed in two dimensions in the X-axis direction and the Z-axis direction, this should not be construed as a limitation. In one example, the Gaussian beam is Gaussian distributed at least in the X-axis direction. For example, the light source 11 can be a semiconductor laser-based device, which can be used to generate a Gaussian beam. In addition, the light source 11A for line 1 and the light source 11B for line 2 can emit light of the same wavelength.

[0089] In addition, the photodetectors 12 (12A, 12B) receive the light derived from the exit portion 4. The photodetectors 12 can be composed of light receiving elements arranged in one dimension or two dimensions. The photodetectors 12 can use various image sensors, such as a charge-coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor.

[0090] In one embodiment, the control unit 13 is configured to analyze the change in the peak angle of the light received by the photodetector 12. The control unit 13 can include an arithmetic unit (not shown in the figure) such as a CPU and a storage device (not shown in the figure) such as a memory, for example, a single-board computer such as a Raspberry Pi(R) or an Arduino(R).

[0091] In one embodiment, the measurement unit 14 acquires the intensity information of the light received by each light receiving element of the photodetector 12. The acquired intensity information is transmitted to the control unit 13. The measurement unit 14 can include an application specific integrated circuit (IC).

[0092] Further, referring to FIGS. 1 to Figure 3 describe the function of the measuring device 10.

[0093] The light emitted from the light source 11 can be further introduced into the introduction portion 3 of the measurement sheet 1. The introduced light further propagates while undergoing total internal reflection within the propagation layer 2. The amount of phase shift during total internal reflection of the light can depend on the magnitude of the refractive index of the surrounding material in contact with the propagation layer 2. As shown in FIGS. 1(B), 1(C), and 2(B), there exist on the surface 2A a region where the ligand layer 6 is in contact with the propagation layer 2 and an exposed region where the coating layer 5 is in contact with the propagation layer 2. Further, the ligand layer 6 is formed on top of the coating layer 5. The amount of phase shift of the total internal reflection of the light depends on the refractive index within the penetration region of the evanescent light. In the region of the surface 2A of the propagation layer 2, the refractive index of the region where the ligand layer 6 is in contact with the propagation layer 2 can be equal to the third refractive index (about 1.33) of the ligand layer 6, while the refractive index of the exposed region forming the coating layer 5 is the first refractive index (about 1.47) of the coating layer. Therefore, when the light undergoes total internal reflection, the amount of phase shift on the surface of the propagation layer 2 may be different in the region where the ligand layer 6 is in contact with the propagation layer 2 and in the exposed region where the coating layer 5 is in contact with the propagation layer 2 on the surface 2A.

[0094] Accordingly, the light propagating in the Y-axis direction between the introduction portion 3 and the exit portion 4 in the propagation layer 2 can change the phase distribution in the X-axis direction along with the planar shape of the ligand layer 6 in the region formed on the surface 2A of the propagation layer 2, such that the length of the region where the light propagates in the Y-axis direction increases or decreases in the X-axis direction. Therefore, the phase distribution of the light derived from the exit portion 4 may also be inclined in the X-axis direction, and the propagation direction of the light can be changed. In the configuration shown in FIG. 2, since the first refractive index of the coating layer 5 is higher than the third refractive index of the ligand layer 6, the traveling direction or propagation direction of the light is inclined toward the positive direction of the X-axis. Further, since the refractive index of the region 2A can increase based on the reaction between the ligand 82 and the analyte in the (to-be-measured) object and a part of the to-be-measured object is replaced by the analyte, the propagation direction of the light can be changed, for example, in the negative direction of the X-axis. In another embodiment, the third refractive index of the ligand layer 6 can also increase due to the bulk effect or non-specific adsorption, thereby further reversing the propagation direction of the light toward the negative direction of the X-axis.

[0095] Therefore, the measuring device 10 can use the photodetectors 12 (the first photodetector 12A and the second photodetector 12B) to receive the light derived from the exit portion 4 in the far field (or through a Fourier transform lens) for the region (line 1) where the ligand layer 6 is formed and the region (line 2) where the ligand layer 6 is not formed, respectively. In addition, the measuring device 10 can use the measuring unit 14 to measure the angular change at which the light intensity reaches a peak. The change in the peak angle can be the same phenomenon as the change in the propagation direction of the light. The angular change when the intensity reaches a peak can correspond to the change in the propagation direction of the light. The peak angular change measured by the measuring unit 14 can be fed to the control unit 13 to record the change accordingly in the storage device (memory) of the control unit 13. The control unit 13 may also include an arithmetic unit (CPU or central processing unit), which can subtract the graph of the peak angular change of line 2 from the graph of the peak angular change of line 1. For this purpose, based on the determined change in the subtracted graph being, for example, higher than a predetermined threshold, the reaction between the ligand 82 and the analyte in the ligand layer 6 can be confirmed. Alternatively, the control unit 13 can estimate the concentration or kinetic parameters of the analyte based on the shape of the subtracted graph. Thus, the control unit 13 can perform an analysis process to analyze the change in the pattern of the light. The control unit 13 can also perform an analysis process to analyze the change in the propagation direction of the light. Thus, the measuring device 10 can be used as a measuring device to estimate the presence or absence of the analyte and its concentration or kinetic parameters.

[0096] Figure 4(A)-4(C) The signals measured by the measurement sheet 1 according to one embodiment are shown. As shown in FIG. 4(A), in the measurement sheet 1A of line 1, the ligand layer 6 can be uniformly formed on the surface 2A of the propagation layer 2 and the surface 5B of the coating layer 5. However, in the measurement sheet 1B of line 2, the ligand layer 6 may not be formed. FIG. 4(B) schematically shows the change in the refractive index of the measurement signals of line 1 and line 2, respectively. FIG. 4(C) schematically shows the difference between the measurement signals of line 1 and line 2 shown in FIG. 4(B). Referring to FIG. 4(B), for the case where the ligand layer 6 is formed on the surface of the measurement sheet 1A, the measurement signal from line 1 contains information 71 about the desired reaction (e.g., the antigen-antibody reaction between the ligand 82 and the analyte) and non-specific adsorption, as well as information 73 about the bulk effect. In addition, for the case where the ligand layer is not formed on the surface of the measurement sheet 1B, the measurement signal from line 2 contains only information 72 about non-specific adsorption and information 73 about the bulk effect.

[0097] In one example, a conventional measurement sheet may only acquire a signal corresponding to the differential signal shown in FIG. 4(C). However, when the influence of the bulk effect shown by signal 73 or the influence of non-specific adsorption shown by signal 72 is large, a component that cannot be canceled by subtracting the measurement signals may be generated, and this uncancelable component is a factor that reduces the reliability of measurement data when using a conventional measurement sheet. The details of the conventional measurement sheet are described in connection with FIGS. 8 and 9, for example.

[0098] Referring to FIG. 4(C), the component shown by signal 79 may be a component that cannot be canceled due to the bulk effect, and the component that cannot be canceled due to non-specific adsorption is included in the component shown by signal 70 between signals 79. The dashed line represents the ideal analyte-ligand response. Therefore, although it is desirable to obtain the magnitude of the influence caused by the bulk effect and the magnitude of the influence caused by non-specific adsorption as an index for improving the reliability of measurement data, a conventional measurement sheet may not be able to obtain them.

[0099] In one example, the measurement sheet 1B corresponding to line 2 may not detect the bulk effect and non-specific adsorption on the surface 5A of the coating layer 5 of the measurement sheet 1B. Therefore, the measurement result reflects the bulk effect and non-specific adsorption on the surface 2A of the propagation layer 2 in the exposed area exposed from the coating layer 5. Therefore, a measurement result reflecting the bulk effect and non-specific adsorption can be obtained only from line 2, and the measurement signal from line 2 can be used as an index for the reliability of measurement data.

[0100] On the other hand, the measurement result of the measurement sheet 1A corresponding to line 1 can reflect the ligand-analyte reaction, the bulk effect in the exposed area exposed from the coating layer 5, and non-specific adsorption based on the presence of the ligand layer 6 on the measurement sheet 1A. According to one embodiment, as shown in FIG. 4(C), a differential signal between the measurement signals of line 1 and line 2 can be obtained, and the measurement sheet 1 can operate with further improved measurement reliability.

[0101] Measurement method

[0102] Figure 5 is a flowchart of a measurement method according to one embodiment. In one example, the measurement sheet 1 can be used for measurement by total reflection of light in the propagation layer 2 having a coating layer 5 with a specific planar shape formed on the surface.

[0103] In order to perform measurement, two measurement pieces corresponding to line 1 and line 2 may be prepared. In the measurement piece 1A for line 1, the ligand layer 6 is uniformly formed on the surface 2A of the propagation layer 2 and the surface 5A of the coating layer 5. In the measurement piece 1B for line 2, no ligand layer is formed. Next, for each of the two measurement pieces 1A and 1B, the upper surface of the measurement piece 1 may be covered with a substrate 8 having a concave cross-section, and a flow channel 9 may be provided between the upper surface of the measurement piece 1 and the substrate 8. The two measurement pieces 1A and 1B may be prepared in this way (e.g., the measurement piece 1A is for line 1, and the measurement piece 1B is for line 2), and placed as follows. Figure 3 At a predetermined position in the measuring device 10 shown. The following steps S1 to S3 are performed for each of the two measuring pieces 1A and 1B for line 1 and line 2. In the two measuring pieces 1A and 1B for line 1 and line 2, the measuring piece 1A of line 1 may be formed with a ligand layer 6, and the analyte in the measurement object solution may react with the ligand 82 in the ligand layer 6. The measuring piece 1B of line 2 may not be formed with a ligand layer, and the measuring piece 1B may be used as a reference.

[0104] In step S1, the measurement of the propagation direction of light can be started. In addition, the propagation direction can be acquired and plotted in real time. On the surface of the propagation layer 2, a ligand layer 6 that reacts with the analyte in the object to be measured can be formed. The measurement of the propagation direction can be performed by introducing light into the propagation layer 2 via the introduction portion 3 of the measurement sheet 1. Then, the peak position of the intensity of the light totally reflected in the propagation layer 2 can be measured using the photodetector 12. Afterwards, the light can be derived from the propagation layer 2 through the emission portion 4. Here, the amount of change in the propagation or travel direction of the light (indicating the peak angle) roughly matches the value obtained by dividing the distance between the measurement sheet 1 and the photodetector 12 by the amount of change in the peak position on the photodetector 12.

[0105] In step S2, the object to be measured is brought into contact with the measuring sheet 1. Contact with the object to be measured is established by bringing the object to be measured containing the analyte into contact with the upper surface of the measuring sheet 1. Usually, a buffer is brought into contact with the measuring sheet 1 before and after contact with the object to be measured. The reason for bringing the buffer into contact with the object to be measured before the measuring sheet 1 is brought into contact with the measuring object is that if the object to be measured is brought into contact with the measuring sheet 1 without being brought into contact with the buffer, the influence of the refractive index of the object solution itself and the influence of the volume change of the support material, etc., will be reflected in the measurement signal. If a dissociated measurement signal is also obtained, the buffer is brought into contact with the object to be measured after the object to be measured is brought into contact with the measuring sheet 1 to improve the accuracy of subsequent analysis.

[0106] In the case of having multiple measurement objects, step S2 can be repeated multiple times. Further, when step S2 is repeated multiple times, regeneration is performed as an optional process. Regeneration can be carried out by exposing the measurement sheet 1 to an acidic solution with a pH value, for example, of 3 - 1 to dissociate the ligand 82 and the analyte in a short time. In addition, when it is confirmed that the analyte dissociates rapidly, regeneration can be omitted.

[0107] In step S3, the measurement and plotting of the light propagation direction can be carried out. In addition, in step S4 (comparison step), the graph of the peak angle change obtained from the measurement sheet 1A for line 1 can be subtracted from the graph of the peak angle change obtained from the reference measurement sheet 1B for line 2 to obtain a graph as shown in, for example, FIG. 4(C). In this way, the measurement result from the reference measurement sheet 1B is compared with the measurement result of the measurement sheet 1A.

[0108] From the graph of FIG. 4(C) obtained by subtraction, the reaction between the ligand 82 in the ligand layer 6 and the analyte (i.e., the analyte present in the object to be measured) can be confirmed. For example, when the change in the signal is higher than a predetermined threshold, the reaction can be determined. Alternatively, the concentration or kinetic parameters of the analyte can be estimated based on the curve shape of the signal in FIG. 4(C). Therefore, according to the measurement method in one embodiment, the presence or absence of the analyte can be determined using the measurement sheet 1, or the concentration or kinetic parameters of the analyte can be estimated.

[0109] In addition, in step S4, based on the measurement signal obtained from the reference sheet 1B for line 2, the bulk effect amount and the non - specific adsorption amount as described in reference FIG. 4(C) can be estimated. Thus, the reliability of the measurement result can be evaluated using the measurement signal from line 2.

[0110] In the measurement using the measurement sheet 1, the number of internal reflections of light in the propagation layer 2 can be adjusted by changing the length of the measurement sheet 1 in the Y - axis direction. Therefore, the sensitivity of the measurement sheet 1 can be changed. For example, the longer the length of the measurement sheet 1 in the Y - axis direction, the more times the light can be reflected. Thus, the sensitivity of the measurement sheet 1 is improved.

[0111] In the measurement using the measurement sheet 1, the change amount of the peak angle may not change according to the change in the output intensity of the light source 11. This enables stable measurement using the measurement sheet 1 even if the operation of the light source 11 is somewhat unstable.

[0112] Other forms

[0113] Although the present disclosure has been described above according to specific embodiments, the present disclosure is not limited to the above - described embodiments.

[0114] In the above - described embodiments, as Figure 1(A) to 1(C) AndFigure 2(A) and 2(B) As shown in 2(B) , the planar shape of the coating layer 5 is a right triangle, and the ligand layer 6 in the portion formed on the surface 2A of the propagation layer 2 in the region exposed from the coating layer 5 also has a right triangular planar shape. However, the planar shape of the coating layer 5 is not limited to the exemplified right triangle, and the planar shape of the ligand layer 6 in the portion formed on the surface 2A of the propagation layer 2 in the region exposed from the coating layer 5 is also not limited to the exemplified right triangle. As shown in FIG. 6, the planar shape of the coating layer 5 may include a shape in which the length in the light propagation direction (Y-axis direction) increases or decreases along a direction (X-axis direction) perpendicular to the propagation direction. That is, the length of the formation region of the coating may include a shape in which the length in the propagation direction (Y-axis direction) increases or decreases along a direction (X-axis direction) perpendicular to the propagation direction. The increased or decreased portion may be included as a part of a specific planar shape, or may increase or decrease throughout the specific planar shape. Therefore, the planar shape of the ligand layer 6 in the portion formed on the surface 2A of the propagation layer 2 in the region exposed from the coating layer 5 may also include a shape in which the length in the light propagation direction (Y-axis direction) increases or decreases along a direction (X-axis direction) perpendicular to the propagation direction.

[0115] Figure 6(A) to Figure 6(E) FIG. 6 shows a diagram of a variant of the planar shape of the coating layer 5 in the measurement sheet 1 according to an embodiment. The planar shape of the coating layer 5 shown in FIG. 6(A) may be an isosceles triangle, and the length in the propagation direction (Y-axis direction) may continuously and linearly extend along a direction (X-axis direction) perpendicular to the light propagation direction. In this example, the ligand layer 6 is uniformly formed on the surface 2A. The planar shape of the ligand layer 6 in the portion formed on the surface 2A of the propagation layer 2 in the region exposed from the coating layer 5 becomes a shape of two right triangles facing each other, and the ligand content in the light propagation direction continuously and linearly changes along the vertical direction.

[0116] As shown in FIG. 6(B), the planar shape of the coating layer 5 may be a shape of two right triangles arranged side by side, and the length in the light propagation direction (Y-axis direction) may continuously and linearly become longer along a direction (X-axis direction) perpendicular to the light propagation direction. In one example, the ligand layer 6 is uniformly formed on the surface 2A. The planar shape of the ligand layer 6 in the portion formed on the surface 2A of the propagation layer 2 in the region exposed from the coating layer 5 may also become a shape of two right triangles arranged side by side, and the ligand content in the light propagation direction may continuously linearly change along the vertical direction.

[0117] In the patterns shown in FIGS. 6(A) and 6(B) for example, since the phase distribution of the light derived from the emission portion 4 is similar to the patterns shown in FIGS. 1 and 2 for example, it can be expected that Figure 1(A) to 1(C)and the effects similar to the patterns shown in FIGS. 2(A) and 2(B). Here, in the pattern shown in FIG. 6(A), the ratio of the change amount of the peak angle with respect to the refractive index change increases more than that in the pattern shown in Figure 1(A) to 1(C) This is beneficial for resisting noises such as vibrations. In the pattern shown in FIG. 6(A), based on the confirmed propagation process of the propagating light and the existence range on the X-axis in the exit portion 4 being smaller than that in Figure 1(A) to 1(C) shown, the width of the flow path 9 shown in FIGS. 2(A) and 2(B) in the X-axis direction can be narrower, so that more accurate measurement can be further achieved. In addition, by tilting the incident direction of the light source in the negative direction of the X-axis in FIG. 6(A), the propagation process of the propagating light and the existence range on the X-axis in the exit portion 4 can be made smaller, and the width of the flow path 9 in the X-axis direction can be made narrower. It should be noted that a similar effect can be obtained when changing the arrangement of the coating layer 5 in FIG. 6(A) with the surface 2A of the propagation layer 2 in the area exposed from the coating layer 5.

[0118] More specifically, for example, there are the following three indicators (referred to as the first indicator, the second indicator, and the third indicator) as the performance indicators of the measurement sheet 1. According to the pattern shown in FIG. 6(A), the first indicator and the third indicator can be improved.

[0119] The first indicator can indicate the amount of angle change / refractive index change. For example, the larger the amount of angle change, the more sensitive it is to angle change noises such as vibrations.

[0120] The second indicator can indicate the angle change / beam width and refractive index change. For example, the larger the angle change, the more sensitive it is to intensity change noises such as electrical noises.

[0121] The third indicator can indicate the narrowness of the beam range in the waveguide. For example, the narrower the channel, the more accurate the measurement.

[0122] In the planar shape of the coating layer 5 shown in FIG. 6(C) for example, the length in the light propagation direction (Y-axis direction) can be continuously and non-linearly lengthened along the direction perpendicular to the light propagation direction (X-axis direction). In the example of FIG. 6(C), when the ligand layer 6 is uniformly formed on the surface, the ligand content varies continuously and non-linearly in the portion of the ligand layer 6 formed on the surface 2A of the propagation layer 2 in the area exposed from the coating layer 5 along the perpendicular direction. In this case, the diffusion angle of the light changes with the change of the light propagation direction. Therefore, elements other than the light propagation direction may also change.

[0123] The planar shape of the coating layer 5 shown in Fig. 6(D) may be stepped, and the length in the light propagation direction (Y-axis direction) changes discontinuously in the direction perpendicular to the light propagation direction (X-axis direction). At this time, diffracted light will appear, and the traveling directions and intensity ratios of diffracted lights of each order may change.

[0124] Figure 1(A) to 1(C) 、 Figure 2A The examples shown in Fig. 2(B), Fig. 6(A), Fig. 6(B), Fig. 6(C) and Fig. 6(D) are examples where the density of the ligand layer 6 is constant and the length in the light propagation direction (Y-axis direction) changes monotonically in the perpendicular direction. Figure 1(A) to 1(C) 、 Figure 2A The examples shown in Fig. 2(B), Fig. 6(A), Fig. 6(B) and Fig. 6(C) are examples where the density of the ligand layer is constant and the length in the light propagation direction (Y-axis direction) changes continuously in the perpendicular direction. Figure 1(A) to 1(C) 、 Figure 2A The examples shown in Fig. 2(B), Fig. 6(A) and Fig. 6(B) are examples where the density of the ligand layer is constant and the length in the light propagation direction (Y-axis direction) changes linearly in the perpendicular direction.

[0125] The planar shape of the coating layer 5 shown in Fig. 6(E) may also be outside an isosceles triangle, and the length in the light propagation direction (Y-axis direction) decreases continuously and linearly, and then increases continuously and linearly in the direction perpendicular to the light propagation direction (X-axis direction). Since the refractive index of the coating layer 5 is generally much larger than that of the ligand layer 6, in this case, the light derived from the exit portion 4 can be divided into two parts, and the difference in peak angles of the two parts of light can be obtained, which is beneficial for eliminating noise caused by vibrations and the like.

[0126] It should be noted that Figure 1(A) to 1(C) 、 Figure 2A and the various planar shapes of the coating layer 5 exemplified in Fig. 2(B) and Figure 6(A) to 6(E) can be inverted along the X-axis, further inverted along the Y-axis, and further inverted between the region of the coating layer 5 and the region of the propagation layer 2, and combinations of the above inversions can be made, and similar effects can be obtained from these planar shapes.

[0127] In the above embodiments, examples of antigens and antibodies are shown as the combination of the analyte and the ligand, but the combination is not limited thereto. The combination of the analyte and the ligand may also include enzyme and substrate, hormone and receptor, DNA (deoxyribonucleic acid) complement. Even in these cases, the phase shift amount of total internal reflection of light is different between the surface 2A of the propagation layer 2 in the exposed region exposed from the coating layer 5 and the region where the coating layer 5 is formed, and the phase shift amount in the region of the surface 2A of the propagation layer 2 in the exposed region exposed from the coating layer 5 may change due to the combination of the analyte and the ligand.

[0128] In the measuring device 10 in the above-described embodiment and the measuring method using the measuring sheet 1, the binding reaction of biomolecules is taken as an example. However, even if it is not the binding reaction of the biomolecules exemplified, if the reaction involves a change in refractive index, it can also be applied. As an example, the measuring device 10 in the above-described embodiment and the measuring method using the measuring sheet 1 can be applied to a gas sensor or the like. In this case, a gas can be used as an analyte, and a chemical substance whose refractive index changes when reacting with the gas can be used as a ligand.

[0129] Example

[0130] Examples of the present disclosure are given below to further clarify the features explained in the present disclosure.

[0131] In one example, the performance of the measuring sheet made based on the measuring sheet 1 is evaluated. The performance is evaluated by changing the salt concentration of the buffer solution flowing over the top surface of the measuring sheet 1 and observing the change in the peak position of the light received by the receiver or the photodetector 12 using the measuring device 10. A graph of the observation results is as Figure 7 shown.

[0132] Figure 7 A graph showing the performance evaluation results of the measuring sheet 1 according to an embodiment is shown. Based on determining the change time of the salt concentration in the buffer solution, the peak position of the observed light can change at multiple times (e.g., about 1700 seconds, about 2700 seconds, and about 3600 seconds). This can confirm that the bulk effect as the influence of the refractive index of the buffer solution can be observed in the manufactured measuring sheet 1.

[0133] In another example, a numerical simulation is performed on the relationship between the sensitivity of the refractive index at the surface 5A of the coating layer 5 and the thickness of the coating layer 5. The numerical simulation is performed assuming that silica (SiO2) is used as the coating layer 5 for light having a wavelength of about 520 nm and for light of the total reflection propagation layer 2 having a wavelength of about 810 nm, respectively. For the light incident on the introduction portion of the measuring sheet 1, as shown in FIG. 1(A), the light having an electric field in the Z-axis direction is defined as P-polarized light, and the light having an electric field in the X-axis direction is defined as S-polarized light. It should be noted that since the coupling efficiency with the propagation layer is higher at the introduction portion, it is more sensitive and practical to use P-polarized light for the incident light. When using P-polarized light, the optimum thickness of the propagation layer is slightly less than twice the thickness of S-polarized light. The conditions and results of this numerical simulation are shown in Tables 1 and 2, for example.

[0134]

Table 1

[0135]

[0136]

Table 2

[0137]

[0138] According to the conclusions drawn from Table 1 and Table 2, when the SiO2 coating layer is thicker, the evanescent light penetrating from the inside of the propagation layer 2 to the ligand layer 6 on the surface of the coating layer 5 attenuates more. Therefore, it is preferred that the sensitivity of the refractive index change on the surface of the coating layer is small. In actual use, a refractive index sensitivity of about 1% is sufficient. From the numerical simulation results shown in Table 2, it can be seen that for a wavelength of 520 nm, the thickness of the SiO2 coating layer is preferably about 250 nm or more, and for a wavelength of 810 nm, the thickness of the SiO2 coating layer is preferably about 400 nm or more.

[0139] Figure 8(A) and 8(B) is a schematic structural diagram of the measurement sheet 91 in Patent Document 1 according to an embodiment. As shown in the side view of FIG. 8(A) and the perspective view of FIG. 8(B), the measurement sheet 91 in Patent Document 1 is equipped with a propagation layer 92 for light propagation, an introduction part 93 for introducing light into the propagation layer 92, an exit part 94 for extracting light from the propagation layer 92, and a ligand layer 96, and the region of the ligand layer 96 is formed in a specific planar shape on the surface of the propagation layer 92. Specifically, as shown in FIG. 8(B), the region of the ligand layer 96 is formed in a planar shape (such as a right triangle) such that the length of the ligand layer 96 in the light propagation direction (the Y-axis direction in the figure) increases or decreases in the direction perpendicular to the propagation direction (the X-axis direction in the figure). The transparent substrate 97 provided on the lower surface of the propagation layer 92 has an arbitrary structure.

[0140] Figure 9(A) to 9(C) Shows three methods for forming a ligand layer with a specific planar shape in the measurement sheet in Patent Document 1 according to an embodiment. There are three methods for forming such a ligand layer 96 with a specific planar shape, for example, as shown in FIG. 9. The first method is to uniformly form the scaffold material 81 on the surface of the propagation layer 92, and then use a mask 89 and a ligand solution 80 to pattern the ligand 82 into the above specific planar shape, as shown in FIG. 9(A). The second method is to use a mask 89 to pattern the scaffold material 81 into the above specific planar shape when forming the scaffold material 81 on the surface of the propagation layer 92. As shown in FIG. 9(B), the scaffold material 81 is pre-patterned into the above specific planar shape, so when the scaffold material 81 comes into contact with the ligand solution 80, the ligand 82 is formed into this specific planar shape. The third method is that after uniformly forming the scaffold material 81 on the surface of the propagation layer 92, use a mask 89 and a blocking solution to pre-block the binding sites 83 of the scaffold material 81 in the region with this specific planar shape. As shown in FIG. 9(C), the binding sites 83 of the scaffold material 81 in the region with this specific planar shape are in a state 84 where they may not bind to the ligand 82.

[0141] Since the three methods for forming the ligand layer 96 into a specific planar shape are all wet processes, the repeatability of this process is not high and the cost is relatively high. When forming the ligand layer 96 with the above-mentioned specific planar shape, it is necessary to further improve the repeatability of the process and reduce the cost. As the repeatability of the process improves, the measurement repeatability and measurement accuracy also improve.

[0142] In addition, the magnitudes of the influence of the refractive index of the object to be measured (also known as the bulk effect) and the influence of non-specific adsorption are known as indicators of the reliability of the measurement results in the optical waveguide type measurement sheet. However, in the measurement sheet 91 in Patent Document 1, it is impossible to directly measure the magnitude of the influence of these bulk effects or the magnitude of the influence of non-specific adsorption. In order to improve the reliability of the measurement results, it is necessary to directly measure the magnitude of the influence of these bulk effects or the magnitude of the influence of non-specific adsorption.

[0143] The embodiments of the present disclosure described with reference to FIGS. 1 to 7 are intended to overcome the above-mentioned disadvantages related to conventional optical waveguide type measurement sheets. The present disclosure provides a measurement sheet that accurately and reliably measures the presence or absence of an analyte, its concentration, and / or kinetics by using a coating layer in which the length in the propagation direction in the formation region of the coating increases or decreases in a direction perpendicular to the propagation direction.

[0144] The above description has described embodiments of the present disclosure. With the help of the teachings presented in the foregoing description and the related drawings, those skilled in the art will think of many modifications and other embodiments of the disclosure herein. Therefore, it should be understood that the present disclosure is not limited to the specific embodiments disclosed, and the modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the related drawings describe the exemplary embodiments in the context of certain exemplary combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions can be provided in alternative embodiments without departing from the scope of the appended claims. In this regard, for example, combinations different from those explicitly described above are also contemplated, as may be described in certain of the appended claims. Although specific terms are used herein, they are used only in a general and descriptive sense and not for purposes of limitation.

[0145] List of reference numerals

[0146] 1 Measurement sheet

[0147] 2 Propagation layer

[0148] 3 Introduction part [input coupler]

[0149] 4 Output part [output coupler]

[0150] 5 Coating layer

[0151] 6 Ligand layer

[0152] 7 Substrate

[0153] 8 Substrate material

[0154] 9 Flow channel

[0155] 10 Measuring device

[0156] 11, 11A, 11B Light source

[0157] 12, 12A, 12B Photoelectric detector

[0158] 13 Control unit [Controller]

[0159] 14 Measuring unit [Light intensity sensor]

[0160] 80 Ligand solution

[0161] 81 Bracket material

[0162] 82 Ligand

[0163] 83 Binding site

[0164] 89 Mask

[0165] 91 Conventional measurement sheet

[0166] 92 Propagation layer in the conventional measurement sheet

[0167] 93 Introduction part in the conventional measurement sheet

[0168] 94 Exit part in the conventional measurement sheet

[0169] 96 Ligand layer in the conventional measurement sheet

[0170] 97 Substrate in the conventional measurement sheet

Claims

1. A measurement sheet (1), comprising: A propagation layer (2) configured to allow light to propagate in a propagation direction; An introduction part (3) configured to introduce the light into the propagation layer; An exit part (4) configured to exit the light from the propagation layer; A coating layer (5) configured to be formed on a surface (2A) of the propagation layer, and the coating layer is further configured to increase or decrease a length in the propagation direction of a formation region of the coating along a direction perpendicular to the propagation direction; And A ligand (82) configured to react with an analyte on the surface of the propagation layer at least in an exposed region exposed from the coating layer.

2. The measurement sheet (1) according to claim 1, further comprising: A ligand layer (6) formed by modifying the ligand on the surface (2A) of the propagation layer (2) in the exposed region.

3. The measurement sheet (1) according to claim 2, wherein A first refractive index of the coating layer (5) is less than a second refractive index of the propagation layer (2) and greater than a third refractive index of the ligand layer (6).

4. The measurement sheet (1) according to any one of claims 1 to 3, wherein The coating layer (5) is configured to be formed between the introduction part (3) and the exit part (4) of the measurement sheet.

5. The measurement sheet according to any one of claims 1 to 4, wherein The coating layer is configured to be formed on at least one of the introduction part or the exit part of the measurement sheet.

6. The measurement sheet (1) according to any one of claims 1 to 5, wherein The coating layer (5) is further configured to continuously increase or decrease the length in the propagation direction of the formation region of the coating along a direction perpendicular to the propagation direction.

7. The measurement sheet (1) according to any one of claims 1 to 6, wherein The coating layer (5) is further configured to linearly increase or decrease the length in the propagation direction of the formation region of the coating along a direction perpendicular to the propagation direction.

8. The measurement sheet (1) according to any one of claims 1 to 7, wherein A thickness of the coating layer (5) is equal to or greater than an attenuation length of evanescent light penetrating from the surface (2A) of the propagation layer (2) to a medium on one side of the coating layer.

9. The measurement sheet (1) according to any one of claims 1 to 8, wherein The coating layer (5) is formed of silica.

10. The measurement sheet (1) according to any one of claims 1 to 9, wherein The coating layer (5) is formed of a mixture of silica and a metal oxide.

11. The measurement sheet (1) according to any one of claims 1 to 10, wherein The coating layer (5) is formed of a mixture of silica and alumina, i.e., Al2O3.

12. The measurement sheet (1) according to any one of claims 1 - 11, further comprising: A characteristic adjustment film provided on a surface (5A) of the coating layer (5).

13. The measurement sheet (1) according to claim 12, wherein The characteristics adjustment film is formed of a metal oxide.

14. The measuring sheet (1) according to any one of claims 1 to 13, wherein: Due to the change in the refractive index of the surroundings of the propagation layer (2) caused by the reaction between the analyte and the ligand, the phase distribution of the light changes.

15. A measuring device (10), comprising: Measuring piece (1), The measuring sheet comprises: a propagation layer (2) configured to allow light to propagate in a propagation direction; an introducing portion (3) configured to introduce the light into the propagation layer; An output portion (4) configured to output the light from the transmission layer; a coating layer (5) configured to be formed on the surface (2A) of the propagation layer, the coating layer being further configured to increase or decrease the length of a coating formation region in the propagation direction along a direction perpendicular to the propagation direction; and a ligand (82) configured to react with an analyte on the surface of the propagation layer at least in an exposed region emerging from the coating layer; a light source (11) configured to introduce the light into the introduction portion of the measurement sheet; a photodetector (12) configured to receive the light emitted from the emission portion of the measurement sheet; and A control unit (13) is configured to analyze a change in a pattern of the light received by the photodetector, the pattern changing based on a reaction between the analyte and the ligand of the measurement patch.

16. The measuring device (10) according to claim 15, wherein: The control unit (13) is further configured to analyze changes in the propagation direction of the light.

17. A measurement method comprising: Introducing light into a propagation layer (2); causing the light to be totally reflected in the propagation layer, the propagation layer having a surface (2A), wherein a ligand (82) reactive with an analyte is formed in an exposed region exposed from a coating layer (5) formed on the surface of the propagation layer; as well as The light is guided out of the propagation layer, wherein the length of a formation region of the paint in the paint layer in the propagation direction increases or decreases along a direction perpendicular to the propagation direction.

18. The measuring method according to claim 17, further comprising: Analyzing the pattern changes of the light derived from the propagation layer (2), wherein: The pattern change is caused by the reaction between the analyte and the ligand (82) of the measurement sheet (1).

19. The measurement method according to claim 17 or 18, further comprising: A change in the traveling direction of the light derived from the propagation layer is analyzed.

20. The measuring method according to any one of claims 17 to 19, wherein: The first refractive index of the coating layer (5) is smaller than the second refractive index of the propagation layer (2) and larger than the third refractive index of the ligand layer (6) formed by modifying the surface (2A) of the propagation layer in the exposed area using a ligand (82).

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