JP2012145348A - Optical waveguiding type biochemical sensor chip, biosensor cartridge and biosensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguiding type biochemical sensor chip capable of repeatedly performing high sensitive measurement, a biosensor cartridge and a biosensor system.SOLUTION: According to an embodiment, the optical waveguiding type biochemical sensor chip includes an optical waveguiding part and a sensing part. The optical waveguiding part includes an optical waveguiding layer for guiding light. The sensing part is in contact with a main surface of the optical waveguiding part and includes a sensing material layer. By one reaction of oxidation and reduction corresponding to a specimen introduced into the sensing material layer, a first change is generated in absorption characteristics of the sensing material layer for infiltration light infiltrated into the sensing material layer. By the other reaction of oxidation and reduction caused by voltage applied to the sensing material layer, a second change reversed to the first change is generated in the absorption characteristics.

Description

  Embodiments described herein relate generally to an optical waveguide biochemical sensor chip, a biosensor cartridge, and a biosensor system.

  Development of small and highly sensitive biochemical sensor chips is advancing. For example, in diabetes treatment, it is important to detect glucose with high sensitivity. For this reason, an optical waveguide biochemical sensor chip has been developed.

  Development of a sensor chip that can repeatedly measure a sample such as glucose is desired. This makes it possible to detect the specimen continuously for a certain period. For example, there is a device that measures glucose in tissue fluid with an electrochemical sensor. However, since a sensor in electrochemical measurement has low detection sensitivity, a measurement error may occur when measuring low-concentration glucose in tissue fluid.

JP 2008-209219 A

  Embodiments of the present invention provide an optical waveguide biochemical sensor chip, a biosensor cartridge, and a biosensor system capable of repeatedly measuring with high sensitivity.

  According to an embodiment of the present invention, an optical waveguide biochemical sensor chip including an optical waveguide unit and a sensing unit is provided. The optical waveguide unit includes an optical waveguide layer that guides light. The sensing unit is in contact with the main surface of the optical waveguide unit and includes a sensing material layer. A first change occurs in the absorption characteristic of the sensing material layer with respect to penetrating light penetrating from the main surface into the sensing material layer by one reaction of oxidation and reduction according to the analyte introduced into the sensing material layer. Due to the other reaction of oxidation and reduction due to the voltage applied to the sensing material layer, a second change in the absorption characteristic opposite to the first change occurs.

1 is a schematic cross-sectional view illustrating the configuration of an optical waveguide biochemical sensor chip according to a first embodiment. It is a schematic diagram which illustrates the characteristic of the optical waveguide type biochemical sensor chip concerning a 1st embodiment. FIG. 3A and FIG. 3B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment. FIG. 4A and FIG. 4B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment. FIG. 5A and FIG. 5B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment. FIGS. 6A and 6B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment. FIG. 7A and FIG. 7B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment. FIG. 8A to FIG. 8E are schematic cross-sectional views in order of the processes, illustrating the method for manufacturing the optical waveguide biochemical sensor chip according to the first embodiment. FIG. 9A to FIG. 9F are schematic cross-sectional views in order of the processes, illustrating another method for manufacturing the optical waveguide biochemical sensor chip according to the first embodiment. FIG. 10A to FIG. 10C are schematic cross-sectional views illustrating the configuration and operation of the biosensor cartridge according to the second embodiment. It is a schematic diagram which illustrates the structure of the biosensor system which concerns on 3rd Embodiment. It is a flowchart figure which illustrates operation | movement of the biosensor system which concerns on 3rd Embodiment.

Each embodiment will be described below with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
Note that, in the present specification and each drawing, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating the configuration of an optical waveguide biochemical sensor chip according to the first embodiment.
As shown in FIG. 1, the optical waveguide biochemical sensor chip 110 according to the embodiment includes an optical waveguide unit 10 and a sensing unit 20. Hereinafter, “optical waveguide biochemical sensor chip” may be abbreviated as “sensor chip” as appropriate.

The optical waveguide unit 10 includes an optical waveguide layer 11. The optical waveguide layer 11 guides the light 15.
The optical waveguide unit 10 includes a first main surface 10a and a second main surface 10b. The 2nd main surface 10b is a surface on the opposite side to the 1st main surface 10a. In the specific example, the first main surface 10 a is one main surface of the optical waveguide layer 11. The second main surface 10 b is the other main surface of the optical waveguide layer 11. The light 15 is reflected by the first main surface 10 a and the second main surface 10 b and guided inside the optical waveguide layer 11.

  The sensing unit 20 is in contact with the main surface of the optical waveguide unit 10. Hereinafter, the case where the sensing unit 20 is in contact with the first main surface 10a of the optical waveguide unit 10 will be described. The sensing unit 20 is in contact with the main surface of the optical waveguide layer 11.

  The sensing unit 20 includes a sensing material layer 21. As will be described later, the sensing unit 20 may further include a layer other than the sensing material layer 21.

  A part of the light 15 guided through the optical waveguide layer 11 penetrates the sensing material layer 21. The penetrating light 16 penetrating is evanescent light of the light 15 guided through the optical waveguide layer 11 on the main surface (first main surface 10 a) of the optical waveguide unit 10.

  A voltage can be applied to the sensing unit 20. That is, a voltage can be applied to the sensing material layer 21. For example, the optical waveguide unit 10 (specifically, the optical waveguide layer 11) is conductive. In this case, a voltage is applied to the sensing material layer 21 by applying a voltage between the optical waveguide unit 10 and a counter electrode (not shown). Furthermore, as will be described later, the optical waveguide unit 10 may include a transparent conductive layer provided between the optical waveguide layer 11 and the sensing unit 20. In this case, a voltage is applied to the sensing material layer 21 by applying a voltage between the transparent conductive layer and a counter electrode (not shown).

  The specimen sp is introduced into the sensing material layer 21. The specimen sp is a solution containing, for example, a body fluid. For example, the body fluid includes a test object. The test object is, for example, glucose.

  The sensing material layer 21 includes, for example, a sensing material. The sensing material includes, for example, Prussian blue. The sensing material layer 21 includes a sensing material and a binder in which the sensing material is dispersed. The binder is, for example, a light curable resin (for example, an ultraviolet curable resin).

  The sensing material layer 21 can absorb water. The sensing material layer 21 is insoluble in water. For example, the binder is made of a water-insoluble material while being able to absorb water. For example, hydrogel or the like is used as the binder.

  The sensing unit 20 includes, for example, an enzyme that advances the reaction of the specimen sp. For example, the sensing material layer 21 includes an enzyme that reacts with the analyte sp. When the specimen sp is glucose, the enzyme is, for example, glucose oxidase (GOD). Hereinafter, a case where the specimen sp is glucose and the enzyme is GOD will be described.

For example, the specimen sp is dropped on the sensing unit 20. Thereby, glucose and oxygen introduced into the sensing material layer 21 react with each other by an enzyme, and gluconic acid and hydrogen peroxide (H ₂ O ₂ ) are generated.

When the sensing material contained in the sensing material layer 21 is Prussian blue, for example, the reaction of the first formula occurs.

K ₄ Fe ^(II) ₄ [Fe ^(II) (CN) ₆ ] ₃ (transparent) + 2H ₂ O ₂
→ K ₄ Fe ^(III) [Fe ^(II) (CN) ₆ ] ₃ (blue) + 4OH ⁻ + 4K ⁺ (Formula 1)

As shown in the first formula, the sensing material layer 21 changes from a transparent state to a colored state (blue state). The reaction of the first formula is an oxidation reaction.

A voltage is applied to the sensing material layer 21 in a state where the sensing material layer 21 is in contact with a solution containing, for example, K (potassium) ions (for example, a KCl solution). Thereby, the reaction of the second formula occurs.

K ₄ Fe ^(III) [Fe ^(II) (CN) ₆ ] ₃ (blue) + 4K ⁺ + 4e ⁻
→ K ₄ Fe ^(II) ₄ [Fe ^(II) (CN) ₆ ] ₃ (transparent) (Formula 2)

As shown in the second formula, the sensing material layer 21 changes from a colored state (blue state) to a transparent state. The reaction of the second formula is a reduction reaction.

  The reaction of the second formula is the opposite reaction to the reaction of the first formula. That is, a reversible reaction occurs in the sensing material layer 21.

The reaction of the first formula is a reaction based on hydrogen peroxide (H ₂ O ₂ ) generated by the specimen sp. Therefore, the reaction of the first formula is a reaction according to the specimen sp introduced into the sensing material layer 21. For example, when the amount of the specimen sp is large (concentration is high), a large amount of reaction of the first formula occurs. For this reason, the degree of coloring of the sensing material layer 21 is high. That is, the color of the sensing material layer 21 becomes darker.

  Then, the absorption of the sensing material layer 21 with respect to the penetrating light 16 is changed by the reaction of the first formula. That is, in the transparent state on the left side of the first expression, the absorption with respect to the penetrating light 16 is small. In the blue state on the right side of the second equation, the absorption with respect to the penetrating light 16 is large.

  The intensity of the outgoing light 17 emitted from the optical waveguide layer 11 changes due to the change in the light absorption characteristics before and after the reaction of the first equation. Due to the change of the emitted light 17, the specimen sp (for example, the amount and concentration of the specimen sp) can be detected with high accuracy.

  And the state of the sensing material layer 21 returns to the original state on the left side of the first equation by the reaction of the second equation. Thereby, the sensor chip 110 can be used repeatedly.

  Thus, the penetrating light that permeates the sensing material layer 21 from the main surface (first main surface 10a) of the optical waveguide unit 10 by one reaction of oxidation and reduction according to the specimen sp introduced into the sensing material layer 21. A first change occurs in the absorption characteristics of the sensing material layer 21 with respect to 16. That is, the absorption rate of the sensing material layer 21 with respect to the penetrating light 16 increases or decreases. By detecting this first change, the specimen sp can be detected.

  Then, due to the other reaction of oxidation and reduction due to the voltage applied to the sensing material layer 21, a second change opposite to the first change occurs in the absorption characteristics. That is, when the absorption rate of the sensing material layer 21 with respect to the penetrating light 16 increases in the first change, the absorption rate decreases as the second change. On the other hand, when the absorption rate of the sensing material layer 21 with respect to the penetrating light 16 decreases in the first change, the absorption rate increases as a second change. By this second change, the state of the sensing material layer 21 returns to the original state.

  The oxidation reaction of the first formula (one reaction of oxidation and reduction) and the reduction reaction of the second formula (the other reaction of oxidation and reduction) are opposite to each other. That is, in the sensor chip 110, a reversible reaction occurs.

  As described above, the above-described one of the oxidation and reduction reactions (the reaction of the first formula) according to the specimen sp is performed between the enzyme (for example, glucose oxidase) included in the sensing unit 20 and the specimen sp (for example, glucose). The reaction product can include a reaction between a sensing material (for example, Prussian blue) included in the sensing unit 20 (specifically, the sensing material layer 21). This product is, for example, hydrogen peroxide.

  In the sensing material layer 21, one of oxidation and reduction reactions according to the specimen sp introduced into the sensing material layer 21 occurs, so that the absorption characteristic of the sensing material layer 21 with respect to the penetrating light 16 depends on the specimen sp. The state changes from the first state (transparent state) to the second state (colored state). In the sensing material layer 21, the other reaction of oxidation and reduction occurs due to the voltage applied to the sensing material layer 21, and the absorption characteristics change from the second state to the first state. The absorption characteristic of the sensing material layer 21 with respect to the penetrating light 16 changes reversibly according to the specimen sp.

  Thereby, an optical waveguide type biochemical sensor chip capable of repeatedly measuring with high sensitivity can be provided.

  As a sensor chip using Prussian blue, a current detection type sensor chip can be considered. In this case, the specimen sp is detected by the change in current in the Prussian blue reaction corresponding to the specimen sp. In the current detection type sensor chip, the detection accuracy is low.

  On the other hand, since the sensor chip 110 according to the embodiment is an optical waveguide sensor chip, the detection accuracy is high.

FIG. 2 is a schematic view illustrating characteristics of the optical waveguide biochemical sensor chip according to the first embodiment.
As shown in FIG. 2, the angle between the axis of the light 15 guided through the optical waveguide layer 11 and the normal line of the first major surface 10a is defined as θ. The refractive index of the optical waveguide layer 11, _{n 1.} The refractive index of the sensing material layer 21 (sensing section 20) and _{n 2.} Let λ be the wavelength of the light 15. At this time, the penetration distance dp of the penetrating light 16 (evanescent light) penetrating from the first main surface 10a of the optical waveguide unit 10 into the sensing material layer 21 is expressed by the following third formula.

dp = λ · (n ₁ ² sin ² θ−n ₂ ² ) ^1/2 / 2π (3rd formula)

In the embodiment, the thickness of the sensing material layer 21 is desirably equal to or less than the penetration distance dp. If the thickness of the sensing material layer 21 is thicker than the penetration distance dp, the portion of the sensing material layer 21 that is thicker than the penetration distance dp does not contribute to the detection of the analyte sp. By setting the thickness of the sensing material layer 21 to be equal to or less than the penetration distance dp, the detection accuracy of the specimen sp is improved.

  Thus, the thickness of the sensing material layer 21 is desirably equal to or less than the evanescent distance of the evanescent light penetrating from the main surface (first main surface 10a) of the optical waveguide unit 10 into the sensing unit 20.

FIG. 3A and FIG. 3B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment.
3A is a plan view, and FIG. 3B is a cross-sectional view taken along line A1-A2 of FIG. 3A. As shown in FIGS. 3A and 3B, the sensor chip 121 according to the embodiment further includes a substrate unit 30 in addition to the optical waveguide unit 10 and the sensing unit 20.

  The substrate unit 30 is provided on the opposite side of the optical waveguide unit 10 from the sensing unit 20. That is, the optical waveguide unit 10 is disposed between the substrate unit 30 and the sensing unit 20.

The substrate unit 30 includes a substrate 33, a first deflection unit 31, and a second deflection unit 32.
The substrate 33 is disposed to face the optical waveguide layer 11. The first deflection unit 31 is provided on the substrate 33 and faces the optical waveguide layer 11. The first deflection unit 31 changes the traveling direction of the light 14 incident on the substrate 33 and causes the light to enter the optical waveguide layer 11. Thereby, the light 15 based on the incident light 14 is guided inside the optical waveguide layer 11. The light 14 is, for example, laser light.

  The second deflection unit 32 is provided on the substrate 33 and faces the optical waveguide layer 11. The second deflecting unit 32 emits the light 15 guided through the optical waveguide layer 11 from the optical waveguide layer 11. Thereby, the emitted light 17 is emitted from the optical waveguide layer 11.

  As the substrate 33, for example, a glass substrate can be used. However, any material can be used for the substrate 33. For the substrate 33, for example, a resin material may be used. However, it is desirable to use a glass substrate as the substrate 33 from the viewpoint of dimensional accuracy and surface roughness.

  In the sensor chip 121, the light 14 may be incident obliquely from the first main surface 10 a side, and the light 15 may be guided in the optical waveguide layer 11. In this case, a material that is reflective to the light 15 may be used for the substrate 33.

  For example, the refractive index of the substrate 33 is lower than the refractive index of the optical waveguide layer 11. When resin is used for the optical waveguide layer 11, the refractive index of the optical waveguide layer 11 is, for example, about 1.49 to 1.70. When glass (for example, non-alkali glass) is used for the substrate 33, the refractive index of the substrate 33 is 1.515, for example.

  The first deflecting unit 31 and the second deflecting unit 32 may include a diffraction grating. For the diffraction grating, for example, a material having a refractive index different from that of the substrate 33 can be used. For example, the diffraction grating is provided by processing a titanium oxide film formed on the substrate 33 into a predetermined shape. Specifically, the pitch of the diffraction grating is, for example, 0.9 μm or more and 1.1 μm or less.

  For example, the first deflection unit 31 and the second deflection unit 32 are provided on one surface of the substrate 33 (for example, the upper surface facing the optical waveguide layer 11). At least a part of the optical waveguide layer 11 is provided between at least a part of the first deflection part 31 and at least a part of the second deflection part 32 in the direction from the first deflection part 31 to the second deflection part 32. It is done.

  When the first deflection unit 31 and the second deflection unit 32 are provided on the upper surface of the substrate 33, the light 14 enters from the lower surface of the substrate. The light 14 that has passed through the substrate 33 enters the first deflecting unit 31, changes the traveling direction of the light 14, and enters the optical waveguide layer 11.

  Further, for example, when the first deflection unit 31 and the second deflection unit 32 are provided on the upper surface of the substrate 33, the light 14 may be incident from the upper surface of the substrate. Also in this case, the light 14 enters the first deflecting unit 31, the traveling direction of the light 14 changes, and enters the optical waveguide layer 11.

  In this specific example, the optical waveguide layer 11 is conductive. In this case, the voltage for performing the reaction of the second formula is applied to the sensing material layer 21 by the optical waveguide layer 11. That is, a voltage is applied to the sensing material layer 21 using the optical waveguide layer 11 as one electrode and a counter electrode described later as the other electrode.

  In the sensor chip 121, the sensing material layer 21 of the sensing unit 20 includes a sensing material (for example, Prussian blue), an enzyme, and a binder. That is, the sensing material layer 21 includes an enzyme that reacts with the specimen sp.

FIG. 4A and FIG. 4B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment.
4A is a plan view, and FIG. 4B is a cross-sectional view taken along line A1-A2 of FIG. 4A. As shown in FIG. 4A and FIG. 4B, the sensor chip 122 according to the embodiment also includes the substrate unit 30 in addition to the optical waveguide unit 10 and the sensing unit 20. The optical waveguide unit 10 further includes a transparent conductive layer 12 in addition to the optical waveguide layer 11.

  The transparent conductive layer 12 is provided between the optical waveguide layer 11 and the sensing unit 20. The transparent conductive layer 12 is transmissive to the penetrating light 16. That is, the transparent conductive layer 12 is transparent to light having the wavelength of the light 15.

  The voltage for carrying out the reaction of the second formula is applied to the sensing material layer 21 by the transparent conductive layer 12. That is, a voltage is applied to the sensing material layer 21 using the transparent conductive layer 12 as one electrode and a counter electrode described later as the other electrode.

  The transparent conductive layer 12 includes an oxide containing at least one element selected from the group consisting of In, Sn, Zn, and Ti. For the transparent conductive layer 12, for example, ITO (Indium Tin Oxide) can be used. When ITO is used for the transparent conductive layer 12, the refractive index of the transparent conductive layer 12 is 2.06. For example, the refractive index of the transparent conductive layer 12 is higher than the refractive index of the optical waveguide layer 11.

  In the optical waveguide unit 10, for example, the transparent conductive layer 12 can guide the light 15 together with the optical waveguide layer 11.

  That is, the main surface (first main surface 10 a) of the optical waveguide unit 10 can be the main surface of the transparent conductive layer 12. Then, a first change and a second change occur in the absorption characteristics of the sensing material layer 21 with respect to the penetrating light 16 penetrating the sensing material layer 21 from the main surface (first main surface 10a) of the transparent conductive layer 12.

  Also in the sensor chip 122, the sensing material layer 21 includes a sensing material, an enzyme, and a binder. That is, the sensing material layer 21 includes an enzyme that reacts with the specimen sp.

In general, when the transparent conductive layer 12 is thin, the sheet resistance increases. In order to effectively carry out the reaction of the second formula, it is desirable that the sheet resistance is low. From a practical viewpoint, the thickness of the transparent conductive layer 12 is preferably 150 nanometers (nm) or more. Thereby, sheet resistance falls. Thereby, the reaction of the second formula can be carried out effectively.
The number of reflections of the light 15 on the main surface of the transparent conductive layer 12 depends on, for example, the thickness of the optical waveguide layer 11 and the transparent conductive layer 12. In general, light propagating through a planar optical waveguide layer is attenuated by scattering at the interface between the optical waveguide layer and the upper and lower layers. When the optical waveguide layer is too thin, the number of reflections increases, and as a result, the emitted light intensity decreases. As a result, it becomes easy to be affected by noise due to disturbance light, fluctuation of the measurement system, and the like. In the configuration illustrated in FIGS. 4A and 4B, the above-described problem does not occur unless the optical waveguide layer 11 is excessively thinned. However, if the transparent conductive layer 12 is excessively thick, the optical path length of the light 15 becomes long, so that the number of reflections of the light 15 on the main surface of the transparent conductive layer 12 decreases. Thereby, since the generation amount of the penetrating light 16 is reduced, the detection sensitivity is lowered. Therefore, the thickness of the transparent conductive layer 12 is desirably 1 μm or less.

  As in the sensor chip 121 illustrated in FIG. 3, when the optical waveguide layer 11 is conductive and a voltage is applied to the sensing material layer 21 by the optical waveguide layer 11, the thickness of the optical waveguide layer 11 is 150 nm or more. However, it is desirable. Thereby, sheet resistance falls and reaction of the 2nd formula can be carried out effectively. When the optical waveguide layer 11 is too thin, the intensity of the light 17 is lowered due to the influence of scattering due to the increase in the number of reflections, and the influence of noise is generated. For this reason, the thickness of the optical waveguide layer 11 is desirably 10 μm or more.

FIG. 5A and FIG. 5B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment.
FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view taken along line A1-A2 of FIG. As shown in FIGS. 5A and 5B, in the sensor chip 123 according to the embodiment, the sensing unit 20 further includes an enzyme layer 22 in addition to the sensing material layer 21. The enzyme layer 22 is laminated on the sensing material layer 21. The enzyme layer 22 includes an enzyme that reacts with the specimen sp. Thereby, the reaction of the first formula occurs. Thereby, the above operation is performed.

  The sensing material layer 21 includes a sensing material (for example, Prussian blue) and a binder. The enzyme layer 22 can include an enzyme and a binder.

  In this specific example, the sensing material layer 21 is disposed between the enzyme layer 22 and the optical waveguide unit 10. The sensing material layer 21 is disposed on the optical waveguide unit 10 side. That is, the sensing material layer 21 is disposed in the vicinity of or in contact with the optical waveguide unit 10. Thereby, the change of the absorption characteristic in the sensing material layer 21 becomes easy to detect. Thereby, detection sensitivity can be improved. Moreover, reversible responsiveness can be improved.

FIGS. 6A and 6B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment.
6A is a plan view, and FIG. 6B is a cross-sectional view taken along line A1-A2 of FIG. 6A. As shown in FIGS. 6A and 6B, in the sensor chip 124 according to the embodiment, the sensing unit 20 includes a sensing material layer 21 and an enzyme layer 22. Further, the optical waveguide unit 10 includes an optical waveguide layer 11 and a transparent conductive layer 12.

FIG. 7A and FIG. 7B are schematic views illustrating the configuration of another optical waveguide biochemical sensor chip according to the first embodiment.
FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line A1-A2 of FIG. 7A. As shown in FIG. 7A and FIG. 7B, the sensor chip 125 according to the embodiment is not provided with the substrate portion 30.

  The end surface of the optical waveguide layer 11 of the optical waveguide unit 10 (surface connected to the first main surface 10a and the second main surface 10b) is inclined with respect to the main surface (first main surface 10a). Thereby, for example, the light 14 enters the inside of the optical waveguide layer 11 from one end face of the optical waveguide layer 11. Then, for example, light 15 guided through the optical waveguide layer 11 is emitted as outgoing light 17 from another end face of the optical waveguide layer 11. And the change of the light absorption characteristic in the sensing material layer 21 is detected.

  In this example, the transparent conductive layer 12 is provided in the optical waveguide unit 10, but the transparent conductive layer 12 may be omitted. In this example, the sensing layer 20 is not provided with the enzyme layer 22, but the sensing unit 20 may further include the enzyme layer 22.

  Also in the sensor chips 121 to 125, it is possible to provide an optical waveguide biochemical sensor chip that can be repeatedly measured with high sensitivity.

  The absorption wavelength band of the sensing material layer 21 can include the wavelength of the light 15. For example, the absorption wavelength band of the sensing material layer is 625 nm or more and 650 or less. For example, the wavelength of the light 15 is not less than 625 nm and not more than 650 nm.

  In the embodiment, the sensing material layer 21 includes Prussian blue. However, the embodiment is not limited to this. That is, a first change occurs in the absorption characteristic of the sensing material layer 21 with respect to the penetrating light 16 due to one reaction of oxidation and reduction according to the analyte introduced into the sensing material layer 21, and the voltage applied to the sensing material layer 21. The sensing material layer 21 can include any material that causes a second change in the absorption characteristics opposite to the first change due to the other reaction of oxidation and reduction due to.

  Sensing material layer 21 is Prussian blue, 3,3 ', 5,5'-tetramethylbenzine (TMBZ), o-phenylenediamine (OPD), o-tolidine, N, N'-Bis (2-hydroxy-3-surufopropyl) Tolicine, disodium salt, tetrahydrate (SAT-3) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid ammonium salt (ABTS) can be included.

Hereinafter, an example of a manufacturing method of the sensor chip according to the embodiment will be described.
FIG. 8A to FIG. 8E are schematic cross-sectional views in order of the processes, illustrating the method for manufacturing the optical waveguide biochemical sensor chip according to the first embodiment.
These drawings show an example of a method for manufacturing the sensor chip 122.

  As shown in FIG. 8A, a film that becomes the first deflection unit 31 and the second deflection unit 32 is formed on the substrate 33, for example. As this film, for example, a titanium oxide film is used. For example, sputtering is used to form the titanium oxide film. Then, this film is processed into a predetermined shape by lithography and etching. Thereby, the 1st deflection | deviation part 31 and the 2nd deflection | deviation part 32 are formed. For example, RIE (Reactive Ion Etching) is used for this etching. Thereafter, the mask material used in the etching is removed.

  As shown in FIG. 8B, the optical waveguide layer 11 is formed on the substrate 33, the first deflection unit 31, and the second deflection unit 32. Specifically, for example, an organic film to be the optical waveguide layer 11 is applied and cured.

  As shown in FIG. 8C, the transparent conductive layer 12 is formed on the optical waveguide layer 11. Specifically, for example, an ITO film to be the transparent conductive layer 12 is formed by a method such as vacuum deposition and sputtering.

  As shown in FIG. 8D, a sensing material film 21f to be the sensing material layer 21 is formed. In this example, the sensing material film 21f includes Prussian blue, an enzyme, and a binder. An ultraviolet curable resin is used for the binder. A solution containing these is applied by, for example, a spinner. Thereby, the sensing material film 21f is formed.

  As shown in FIG. 8E, the sensing material layer 21f is exposed and developed using a mask having a predetermined shape, and the sensing material layer 21 is obtained.

Then, a reduction process is performed on the sensing material layer 21. That is, the reaction of the second formula is performed. Thereby, the sensing material layer 21 becomes transparent. As a result, the sensing material layer 21 is in a state where the specimen sp can be detected.
In this way, the sensor chip 122 is obtained.

FIG. 9A to FIG. 9F are schematic cross-sectional views in order of the processes, illustrating another method for manufacturing the optical waveguide biochemical sensor chip according to the first embodiment.
These drawings show an example of a manufacturing method of the sensor chip 124.

  As shown in FIG. 9A, for example, a film that becomes the first deflection unit 31 and the second deflection unit 32 is formed on the substrate 33. As illustrated in FIG. 9B, the optical waveguide layer 11 is formed on the substrate 33, the first deflection unit 31, and the second deflection unit 32. As shown in FIG. 9C, a transparent conductive layer 12 (for example, an ITO film) is formed on the optical waveguide layer 11.

  As illustrated in FIG. 9D, a mask film 20 r that covers a region of the transparent conductive layer 12 where the sensing unit 20 is not provided is formed. A region not covered with the mask film 20r is a sensing region. For example, an arbitrary coating method such as a screen printing method is used for forming the mask film 20r.

  As shown in FIG. 9E, Prussian blue is electrodeposited. Thereby, the sensing material layer 21 is formed. Thereafter, a reduction process is performed.

As shown in FIG. 9F, the enzyme layer 22 is formed on the sensing material layer 21. For example, the enzyme layer 22 is formed by applying and curing a solution containing an enzyme and a binder, for example, with a spinner.
In this way, the sensor chip 124 is obtained.

(Second Embodiment)
The second embodiment is a biosensor cartridge using the optical waveguide biochemical sensor chip according to the first embodiment. Hereinafter, the case where the biosensor cartridge includes the sensor chip 122 will be described. The embodiment is not limited to this, and any of the sensor chips according to the first embodiment and any modified sensor chip can be used.

FIG. 10A to FIG. 10C are schematic cross-sectional views illustrating the configuration and operation of the biosensor cartridge according to the second embodiment.
As shown in FIG. 10A, the biosensor cartridge 210 according to this embodiment includes an optical waveguide biochemical sensor chip (for example, sensor chip 122), a counter electrode 40, and a housing according to the first embodiment. 50.

  The counter electrode 40 is separated from the sensing unit 20. The counter electrode 40 is disposed, for example, on the opposite side of the sensing unit 20 from the optical waveguide unit 10. That is, the sensing unit 20 is disposed between the counter electrode 40 and the optical waveguide unit 10. The counter electrode 40 faces the sensing unit 20.

The housing 50 holds the sensor chip 122 and the counter electrode 40.
For example, the housing 50 includes a facing portion 54 and a side portion 53. The facing unit 54 is provided above the sensing unit 20. The counter electrode 40 is disposed on the lower surface of the facing portion 54 (the surface facing the sensing portion 20). The side portion 53 is provided on a portion of the optical waveguide portion 10 around the sensing portion 20. In this specific example, the side portion 53 is provided with a through electrode 55. The through electrode 55 penetrates the side portion 53 and is electrically connected to the transparent conductive layer 12. When the optical waveguide layer 11 is conductive, the through electrode 55 may be electrically connected to the optical waveguide layer 11.

  For the counter electrode 40 and the through electrode 55, for example, at least one of gold, platinum, and carbon is used. This improves the chemical stability of these electrodes. For example, a black resin molded body is used for the housing 50. By using a black resin, it is possible to suppress the influence of ambient light during measurement.

  FIG. 10A illustrates one state when the specimen sp is detected. FIG. 10B illustrates another state at the time of detection of the specimen sp. FIG. 10C is an initialization in which the detection of the specimen sp is completed and the sensing material layer 21 returns to the state before the detection. The state is illustrated.

  As illustrated in FIG. 10A, the sample liquid spl including the sample sp can flow into the space 50 s between the sensing unit 20 and the counter electrode 40.

  For example, the housing 50 includes an inflow port 51 through which the sample liquid spl flows into the space 50s and an outflow port 52 through which the sample liquid spl flows out of the space 50s. The specimen sp (for example, glucose) in the specimen liquid spl that has flowed from the inflow port 51 is introduced into the sensing material layer 21. Thereby, the reaction of the first formula occurs.

  In the state illustrated in FIG. 10B, the concentration of the sample sp in the sample liquid spl is higher than that in the state illustrated in FIG. For this reason, more reactions of the first formula occur.

  For this reason, the light absorption rate of the sensing material layer 21 in the state illustrated in FIG. 10B is higher than the light absorption rate of the sensing material layer 21 in the state illustrated in FIG. This difference in light absorption is detected by measuring the intensity of the outgoing light 17. Thereby, the specimen sp can be detected with high accuracy.

  As shown in FIG. 10C, when the detection of the specimen sp is completed, the specimen liquid spl is discharged from the outlet 52 and washed. Then, for example, a KCl solution is caused to flow into the space 50 s between the sensing unit 20 and the counter electrode 40. That is, the reaction solution 57 (for example, KCl solution) used for the other reaction (for example, the reaction of the second formula) of oxidation and reduction by voltage can flow into the space 50s between the sensing unit 20 and the counter electrode 40. is there.

  A power source 58 is connected to the counter electrode 40 and the transparent conductive layer 12 through the through electrode 55. When the optical waveguide layer 11 is conductive, a power source 58 is connected to the counter electrode 40 and the optical waveguide layer 11 through the through electrode 55.

  A voltage is applied to the sensing material layer 21 in a state where the sensing material layer 21 is in contact with, for example, a reaction solution 57 (for example, KCl solution) containing K (potassium) ions. Thereby, the reaction of the second formula occurs. Thereby, the sensing material layer 21 returns to the initial state.

  And the reaction liquid 57 is discharged | emitted from the outflow port 52, for example. Then, the sample liquid spl is caused to flow again into the space 50 s between the sensing unit 20 and the counter electrode 40. Then, the detection of the specimen sp is performed again.

  As described above, the biosensor cartridge 210 according to the embodiment can repeatedly measure with high sensitivity.

  Thus, the sample liquid spl containing the sample sp can flow into the space 50 s between the sensing unit 20 and the counter electrode 40. Furthermore, the reaction solution 57 used for the other reaction of oxidation and reduction by voltage (for example, the reaction of the second formula) can flow into the space 50s. For example, the housing 50 includes an inflow port 51 through which the sample liquid spl flows into the space 50s and an outflow port 52 through which the sample liquid spl flows out of the space 50s. One of the inflow port 51 and the outflow port 52 allows the reaction solution 57 to flow into the space 50s, and the other of the inflow port 51 and the outflow port 52 causes the reaction solution 57 to flow out of the space 50s.

(Third embodiment)
The third embodiment is a biosensor system using the biosensor cartridge according to the third embodiment. Hereinafter, the case where the biosensor system includes the biosensor cartridge 210 will be described.

FIG. 11 is a schematic view illustrating the configuration of the biosensor system according to the third embodiment.
As shown in FIG. 11, the biosensor system 310 according to the present embodiment includes the biosensor cartridge 210 according to the second embodiment, the light source 61, the photodetector 62, the sample liquid supply unit 70, and the reaction. A liquid supply unit 80 and a power source 58 are provided. In this example, the sensor chip 122 is used in the biosensor cartridge 210. The embodiment is not limited to this, and any sensor chip according to the first embodiment and any of its modifications can be used.

  The light source 61 generates light 14 (light 15) guided to the optical waveguide layer 11. As the light source 61, for example, a laser diode or the like is used.

  The photodetector 62 detects the light 15 (emitted light 17) guided to the optical waveguide layer 11. A photodiode or the like is used for the photodetector 62.

  The sample liquid supply unit 70 is connected to the biosensor cartridge 210. The sample liquid supply unit 70 supplies the sample liquid spl to the space 50 s between the sensing unit 20 and the counter electrode 40. The sample liquid supply unit 70 includes, for example, a sample liquid tank 71 and a sample liquid pipe 72. The sample liquid tank 71 stores the sample liquid spl. The sample liquid pipe 72 connects the sample liquid tank 71 and the inflow port 51. The sample liquid spl can flow into the space 50s from the inlet 51.

  The reaction solution supply unit 80 is connected to the biosensor cartridge 210. The reaction liquid supply unit 80 supplies the reaction liquid 57 (for example, KCl solution) used in the other reaction (for example, the reaction of the second formula) of oxidation and reduction by voltage to the space 50s. The reaction liquid supply unit 80 includes, for example, a reaction liquid tank 81 and a reaction liquid pipe 82. The reaction liquid tank 81 stores the reaction liquid 57. The reaction liquid pipe 82 connects the reaction liquid tank 81 and, for example, the inlet 51. The reaction liquid 57 can flow into the space 50 s from the inflow port 51. The reaction liquid pipe 82 may connect the reaction liquid tank 81 and an inlet different from the inlet 51.

  The power source 58 is electrically connected to the optical waveguide unit 10 and the counter electrode 40. In this specific example, the power source 58 is electrically connected to the optical waveguide unit 10 through the through electrode 55. Specifically, the power source 58 is electrically connected to the transparent conductive layer 12. When the optical waveguide layer 11 is conductive, the power source 58 may be electrically connected to the optical waveguide layer 11.

  As illustrated in FIG. 11, the biosensor system 310 may further include a solution discharge unit 90 and a control unit 95.

  The solution discharge unit 90 is connected to the biosensor cartridge 210. The solution discharger 90 discharges at least one of the sample liquid spl and the reaction liquid 57 from the space 50s. The solution discharge unit 90 includes, for example, a solution tank 91 and a discharge pipe 92. The solution tank 91 stores at least one of the discharged sample liquid spl and reaction liquid 57. The discharge pipe 92 connects the solution tank 91 and, for example, the outlet 52. At least one of the sample liquid spl and the reaction liquid 57 can flow out from the outflow port 52.

  The control unit 95 controls at least one of the specimen liquid supply unit 70 and the reaction liquid supply unit 80. Specifically, the control unit 95 controls the supply of the sample liquid spl to the space 50 s of the sample liquid supply unit 70 and the supply of the reaction liquid 57 to the space 50 s of the reaction liquid supply unit 80. That is, the operation described with reference to FIGS. 10A to 10C is performed.

  The control unit 95 can communicate with the sample liquid supply unit 70 and the reaction liquid supply unit 80 by a wired or wireless system.

  The control unit 95 may be included in the biosensor system 310. The embodiment is not limited thereto, and the control unit 95 may be provided separately from the biosensor system 310, and communication between the control unit 95 and the biosensor system 310 may be performed by an arbitrary method.

  The control unit 95 may further control the photodetector 62 and the power source 58.

Hereinafter, an example of the operation of the control unit 95 will be described.
FIG. 12 is a flowchart illustrating the operation of the biosensor system according to the third embodiment.
As illustrated in FIG. 12, the control unit 95 causes the sample liquid supply unit 70 to supply the sample liquid spl to the space 50s (step S110). Thereby, for example, the reaction of the first formula occurs.

Further, the control unit 95 causes the photodetector 62 to detect the absorption characteristic of the sensing material layer 21 with respect to the light (penetrated light 16) by the supplied specimen liquid spl (step S120). Absorption characteristics corresponding to the reaction of the first equation are detected. Note that the photodetector 62 may always detect the light absorption characteristics of the sensing material layer 21.
Further, the control unit 95 can obtain the detection result of the absorption characteristic by the photodetector 62.

  After detecting the absorption characteristic (step S120), the control unit 95 causes the reaction solution supply unit 80 to supply the reaction solution 57 to the space 50s (step S130).

  The controller 95 may discharge the sample liquid spl from the space 50s between step S120 and step S130. This operation is performed by, for example, the solution discharge unit 90. The control unit 95 can further control the operation of the solution discharge unit 90 at this time.

  The controller 95 applies a voltage to the sensing unit 20 via the counter electrode 40 in a state where the reaction liquid 57 is introduced into the space 50s (step S140). That is, for example, the control unit 95 turns on the power supply 58 and applies a voltage between, for example, the transparent conductive layer 12 and the counter electrode 40. Thereby, for example, the reaction of the second formula occurs. Thereby, the sensing material layer 21 returns to the original state.

  Further, after the voltage application (step S140), the control unit 95 causes the sample liquid supply unit 70 to further supply the sample liquid spl to the space 50s (second step S110).

  Then, the control unit 95 causes the photodetector 62 to further detect the light absorption characteristic of the sensing material layer 21 by the supplied specimen liquid spl (second time step S120).

  Thus, according to the biosensor system 310 according to the embodiment, a biosensor system capable of repeated highly sensitive measurements can be provided.

  Note that steps S110 to S140 may be performed at the same time as technically possible. For example, the photodetector 62 may always detect the light absorption characteristics of the sensing material layer 21.

  In the above, the reaction liquid 57 may be discharged from the space 50s between step S140 and the second step S110. This operation is performed by, for example, the solution discharge unit 90. The control unit 95 can further control the operation of the solution discharge unit 90 at this time.

  In the present embodiment, the wavelength of the light 15 (light 14) generated by the light source 61 and guided to the optical waveguide layer 11 is included in the absorption wavelength band of the sensing material layer 21. For example, the wavelength of the light 15 (light 14) generated by the light source 61 and guided to the optical waveguide layer 11 is 625 nm or more and 650 nm or less, and the absorption wavelength band of the sensing material layer 21 is 625 nm or more and 650 nm or less. Thereby, detection with high sensitivity becomes possible.

  According to the embodiments, an optical waveguide biochemical sensor chip, a biosensor cartridge, and a biosensor system capable of repeatedly measuring with high sensitivity are provided.

  In the present specification, “vertical” and “parallel” include not only strictly vertical and strictly parallel, but also include, for example, variations in the manufacturing process, and may be substantially vertical and substantially parallel. It ’s fine.

The embodiments of the present invention have been described above with reference to specific examples. However, embodiments of the present invention are not limited to these specific examples. For example, an optical waveguide part, an optical waveguide layer, a transparent conductive layer, a sensing part, a sensing material layer, a sensing material, an enzyme layer, an enzyme, a binder, a substrate part, a substrate, a deflection part, etc. included in the optical waveguide biochemical sensor chip, Each element such as a counter electrode, a housing and a through electrode included in the biosensor cartridge, and a light source, a photodetector, a sample liquid supply unit, a reaction liquid supply unit, a power source, a solution discharge unit, and a control unit included in the biosensor system With respect to the specific configuration, as long as a person skilled in the art can carry out the present invention in a similar manner and appropriately obtain the same effect by appropriately selecting from the well-known ranges, it is included in the scope of the present invention.
Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, based on the optical waveguide biochemical sensor chip, biosensor cartridge, and biosensor system described above as embodiments of the present invention, all optical waveguide biochemical sensors that can be implemented by a person skilled in the art with appropriate design changes A chip, a biosensor cartridge and a biosensor system are also within the scope of the present invention as long as they include the gist of the present invention.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Optical waveguide part, 10a ... 1st main surface, 10b ... 2nd main surface, 11 ... Optical waveguide layer, 12 ... Transparent conductive layer, 14, 15 ... Light, 16 ... Penetrating light, 17 ... Outgoing light, 20 ... Sensing part, 20r ... mask film, 21 ... sensing material layer, 21f ... sensing material film, 22 ... enzyme layer, 30 ... substrate part, 31 ... first deflection part, 32 ... second deflection part, 33 ... substrate, 40 ... Counter electrode, 50 ... Housing, 51 ... Inlet, 52 ... Outlet, 53 ... Side, 54 ... Opposite part, 55 ... Through electrode, 57 ... Reaction liquid, 58 ... Power source, 61 ... Light source, 62 ... Photodetector 70 ... Sample liquid supply section, 71 ... Sample liquid tank, 72 ... Sample liquid pipe, 80 ... Reaction liquid supply section, 81 ... Reaction liquid tank, 82 ... Reaction liquid pipe, 90 ... Solution discharge section, 91 ... Solution tank, 92 ... Exhaust piping 95 ... control unit, 110,121～125 ... optical waveguide type biochemical sensor chip (sensor chip), 210 ... biosensor cartridge, 310 ... biosensor system, dp ... penetration distance, sp ... specimen, spl ... specimen liquid

Claims (24)

An optical waveguide including an optical waveguide layer for guiding light;
A sensing part in contact with the main surface of the optical waveguide part and including a sensing material layer;
With
By one reaction of oxidation and reduction according to the analyte introduced into the sensing material layer, a first change occurs in the absorption characteristics of the sensing material layer with respect to penetrating light penetrating from the main surface into the sensing material layer,
An optical waveguide biochemical sensor chip characterized in that a second change opposite to the first change occurs in the absorption characteristics due to the other reaction of oxidation and reduction by a voltage applied to the sensing material layer. When the absorption characteristic of the sensing material layer increases in the first change, the absorption characteristic of the sensing material layer decreases as the second change,
2. The optical waveguide biochemical sensor according to claim 1, wherein when the absorption characteristic of the sensing material layer decreases in the first change, the absorption characteristic of the sensing material layer increases as the second change. Chip. Said one reaction of oxidation and reduction according to said analyte is:
3. The optical waveguide type according to claim 1, comprising a reaction of a product of a reaction between an enzyme included in the sensing unit and the specimen, and a sensing material included in the sensing unit. Biochemical sensor chip. The optical waveguide layer is electrically conductive;
The optical waveguide biochemical sensor chip according to any one of claims 1 to 3, wherein the voltage is applied to the sensing material layer by the optical waveguide layer. The optical waveguide unit includes a transparent conductive layer that is provided between the optical waveguide layer and the sensing unit and is transmissive to the penetrating light.
The optical waveguide biochemical sensor chip according to claim 1, wherein the voltage is applied to the sensing material layer by the transparent conductive layer.   6. The optical waveguide biochemical sensor chip according to claim 5, wherein the transparent conductive layer has a thickness of 150 nanometers or more.   The optical waveguide biochemical sensor chip according to claim 1, wherein the penetrating light is evanescent light on the main surface of the light guided through the optical waveguide layer.   8. The optical waveguide biochemical sensor chip according to claim 7, wherein a thickness of the sensing material layer is equal to or less than an evanescent distance of the evanescent light penetrating from the main surface into the sensing unit.   The optical waveguide biochemical sensor chip according to any one of claims 1 to 8, wherein the sensing material layer includes an enzyme that reacts with the analyte. The sensing unit is
The optical waveguide biochemical sensor chip according to any one of claims 1 to 8, further comprising an enzyme layer that is laminated on the sensing material layer and includes an enzyme that reacts with the analyte.   The optical waveguide biochemical sensor chip according to claim 10, wherein the sensing material layer is disposed between the enzyme layer and the optical waveguide unit. It further comprises a substrate part,
The optical waveguide unit is disposed between the substrate unit and the sensing unit,
The substrate portion is
A substrate,
A first deflecting unit provided on the substrate, facing the optical waveguide layer, and changing the traveling direction of light incident on the substrate to be incident on the optical waveguide layer;
A second deflecting unit provided on the substrate, facing the optical waveguide layer, and emitting light guided through the optical waveguide layer from the optical waveguide layer;
The optical waveguide biochemical sensor chip according to claim 1, comprising:   The optical waveguide biochemical sensor chip according to claim 12, wherein the first deflection unit and the second deflection unit include a diffraction grating.   The optical waveguide biochemical sensor chip according to claim 1, wherein the sensing material layer includes Prussian blue.   The optical waveguide biochemical sensor chip according to claim 1, wherein the sensing material layer includes a sensing material and a binder in which the sensing material is dispersed. The optical waveguide biochemical sensor chip according to any one of claims 1 to 15,
A counter electrode spaced apart from the sensing unit;
A housing for holding the optical waveguide biochemical sensor chip and the counter electrode;
With
The sample liquid containing the sample can flow into the space between the sensing unit and the counter electrode,
The biosensor cartridge according to claim 1, wherein a reaction solution used for the other reaction of oxidation and reduction by the voltage can flow into the space.   The biosensor cartridge according to claim 16, wherein the housing includes an inflow port through which the sample liquid flows into the space and an outflow port through which the sample liquid flows out of the space. One of the inflow port and the outflow port allows the reaction solution to flow into the space,
The biosensor cartridge according to claim 17, wherein the other of the inflow port and the outflow port allows the reaction solution to flow out of the space. The biosensor cartridge according to any one of claims 16 to 18,
A light source for generating the light guided to the optical waveguide layer;
A photodetector for detecting the light guided to the optical waveguide layer;
A sample liquid supply unit connected to the biosensor cartridge and supplying the sample liquid to the space;
A reaction liquid supply unit connected to the biosensor cartridge and supplying a reaction liquid used in the other reaction of the oxidation and reduction by the voltage to the space;
A power source electrically connected to the optical waveguide section and the counter electrode;
A biosensor system comprising:   The control unit for controlling the supply of the sample liquid to the space of the sample liquid supply unit and the supply of the reaction liquid to the space of the reaction liquid supply unit. 19. The biosensor system according to 19. The controller is
Causing the sample liquid supply unit to perform the supply of the sample liquid to the space;
Causing the photodetector to detect the absorption characteristic of the sensing material layer with respect to the light by the supplied specimen liquid;
After the detection of the absorption characteristics, the reaction solution supply unit is configured to supply the reaction solution to the space,
21. The biosensor system according to claim 20, wherein the voltage is applied to the sensing unit via the counter electrode in a state where the reaction solution is introduced into the space. The controller is
After the application of the voltage, the sample liquid supply unit further performs the supply of the sample liquid to the space,
The biosensor system according to claim 21, wherein the photodetector further detects the absorption characteristic of the sensing material layer with respect to the light by the supplied specimen liquid.   23. The wavelength of the light generated by the light source and guided to the optical waveguide layer is included in an absorption wavelength band of the sensing material layer. Biosensor system.   The wavelength of the light generated by the light source and guided to the optical waveguide layer is from 625 nanometers to 650 nanometers, and the absorption wavelength band of the sensing material layer is from 625 nanometers to 650 nanometers. 24. The biosensor system according to any one of claims 19 to 23, wherein:

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