JP2011107071A - Optical waveguide type biosensor and biosensor system including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biosensor which can enhance detection sensitivity. <P>SOLUTION: The optical waveguide type biosensor 10 includes: a substrate 1; a clad 2; a core 3; and an opening 4. The clad 2 is formed on the substrate 1. The core 3 includes a Mach-Zehnder type core and is formed within the clad 2. Then, a partial region 321 of the core 3 includes an antibody. The opening 4 is provided in the clad 2 while abutting on the partial region 321 doped with the antibody in the core 3. Thus, the partial region 321 is exposed to the outside via the opening 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a Mach-Zehnder optical waveguide biosensor and a biosensor system including the same.

  There is a need for a system that quickly and easily measures a sensing object.For example, in the medical and welfare fields, from the viewpoint of environmental management in a facility, prevention of virus / bacterial infection, etc. Realization of a system aiming at high precision and multipoint is desired.

  On the other hand, as a technique for detecting a sensing object, a technique using an optical waveguide has been studied. For example, an antibody is immobilized on the tip of an optical fiber cladding, an optical waveguide core, or the surface of an optical waveguide cladding, and the like. An optical biosensor that detects the presence of an antigen from a change in refractive index based on an adivine-biotin bond, which is easy to handle and is frequently used as a model for binding between biological substances, is known. (Non-Patent Document 1). From this experimental result, a similar test method for antigen-antibody reaction can be achieved.

H. Tazawa et al, Applied Physics Letters, 91, 113901 (2007).

  However, the conventional optical biosensor has a problem that a change in light intensity generated due to an antigen-antibody reaction is small and sufficient detection sensitivity cannot be obtained.

  Therefore, the present invention has been made to solve such a problem, and an object thereof is to provide a biosensor capable of increasing detection sensitivity.

  Another object of the present invention is to provide a biosensor system including a detection unit that can increase detection sensitivity.

  According to this invention, the optical waveguide biosensor includes a substrate, a clad, and a core. The clad is formed on the substrate and is made of sol-gel glass. The core is formed in the clad and is made of sol-gel glass. The core includes first to fourth cores. The third core is connected to the first and second cores. The fourth core has a shape symmetrical to the third core with respect to the axes of the first and second cores, is connected to the first and second cores, and includes an antibody. And the area | region containing the antibody of a 4th core is exposed outside via the opening part provided in the clad.

  Preferably, the optical waveguide biosensor further includes a flow path. The flow path is provided in the clad in contact with the opening and allows water to flow.

  Preferably, the antibody contained in the fourth core is determined according to the type of antigen that is the detection target.

  According to the invention, the biosensor system includes a plurality of optical waveguide biosensors, an optical fiber, an optical pulse light source, a plurality of fiber Bragg gratings, and a detector. Each of the plurality of optical waveguide biosensors detects an antigen. The optical fiber optically connects a plurality of optical waveguide biosensors in series. The optical pulse light source is connected to one end of the optical fiber and emits a plurality of pulse lights having different wavelengths. The plurality of fiber Bragg gratings are provided in the optical fiber corresponding to the plurality of optical waveguide biosensors, and each reflects interference light in the corresponding optical waveguide biosensor. The detector detects a plurality of reflected lights reflected by the plurality of fiber Bragg gratings, and detects the presence or absence of an antigen-antibody reaction in the optical waveguide biosensor based on the detection result. Each of the plurality of optical waveguide biosensors includes a substrate, a clad, and a core. The clad is formed on the substrate and is made of sol-gel glass. The core is formed in the clad and is made of sol-gel glass. The core includes first to fourth cores. The third core is connected to the first and second cores. The fourth core has a shape symmetrical to the third core with respect to the axes of the first and second cores, is connected to the first and second cores, and includes an antibody. The region containing the antibody of the fourth core is exposed to the outside through an opening provided in the clad.

  Preferably, the detector detects an intensity change of the plurality of reflected lights by an optical time domain reflectometry.

  Preferably, the detector measures a detection time delay from when the light pulse is emitted from the light pulse light source to when the light pulse after interference in the optical waveguide biosensor reflected by the fiber Bragg grating reaches the detection unit. By doing so, the optical waveguide biosensor in which the antigen-antibody reaction has occurred is specified, and the light intensity is detected for each optical waveguide biosensor.

  Preferably, the optical waveguide of the optical waveguide biosensor is a single mode optical waveguide, and the optical fiber is a single mode optical fiber.

  In the optical waveguide biosensor according to the present invention, the incident light is branched into light propagating through the third core and light propagating through the fourth core, and the light propagating through the third core and the fourth The antigen is detected by changing the interference condition when the light propagated through the core interferes with the presence or absence of the antigen. The interference condition is changed by a change in the refractive index of the fourth core due to the antigen adhering to the antibody.

  Therefore, the antigen can be detected with higher sensitivity than the conventional biosensor.

  Further, according to the present invention, it is possible to simultaneously measure the light intensity that changes due to the antigen-antibody reaction using the sensing object as an antigen at many observation points, and to identify the optical waveguide biosensor that detects the sensing object. it can.

  Furthermore, a single-mode optical fiber with a transmission loss smaller than that of the multimode is used, and the optical waveguide of the Mach-Zehnder optical waveguide biosensor is used as a single-mode optical waveguide. The optical fiber and the Mach-Zehnder optical waveguide type are used. Since a sensor network is constructed by connecting biosensors with low coupling loss, highly sensitive detection is possible even at long distances.

1 is a perspective view of a biosensor according to an embodiment of the present invention. It is the top view of the core seen from the A direction shown in FIG. FIG. 3 is a cross-sectional view of the biosensor along line III-III shown in FIG. 1. FIG. 3 is a first process diagram for explaining a manufacturing method of the optical waveguide biosensor shown in FIG. 1. FIG. 6 is a second process diagram for explaining the manufacturing method of the optical waveguide biosensor shown in FIG. 1. FIG. 6 is a third process diagram for explaining the manufacturing method of the optical waveguide biosensor shown in FIG. 1. FIG. 6 is a fourth process diagram for explaining the manufacturing method of the optical waveguide biosensor shown in FIG. 1. It is a schematic diagram for demonstrating the detection of the antigen in an optical waveguide type | mold biosensor. It is a perspective view of another optical waveguide type biosensor according to an embodiment of the present invention. FIG. 10 is a cross-sectional view of the optical waveguide biosensor between line XX shown in FIG. 9. It is a block diagram of the biosensor system provided with the optical waveguide type biosensor shown in FIG. It is a conceptual diagram of the detected pulsed light.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a perspective view of a biosensor according to an embodiment of the present invention. With reference to FIG. 1, an optical waveguide biosensor 10 according to an embodiment of the present invention includes a substrate 1, a clad 2, a core 3, and an opening 4. The optical waveguide biosensor 10 is a Mach-Zehnder biosensor.

The optical waveguide biosensor 10 has a substantially rectangular planar shape. The substrate 1 includes a silicon substrate 11 and a silicon oxide (SiO ₂ ) film 12. The SiO ₂ film 12 has a thickness of 6 μm and is formed on one main surface of the silicon substrate 11.

The clad 2 is made of, for example, sol-gel glass containing 3- (trimethoxysilyl) propyl methacrylate (MAPTMS) as a main component, and is formed on the SiO ₂ film 12 of the substrate 1. The clad 2 has a refractive index of 1.487 with respect to a wavelength of 1550 nm.

  The core 3 is made of, for example, sol-gel glass containing MAPTMS as a main component, and is disposed in the clad 2 along the length direction DR1 of the optical waveguide biosensor 10. The core 3 has a width of 6 to 8 μm, a thickness of 3 to 4 μm, and a length of 5 mm. The core 3 has a refractive index of 1.5. Furthermore, the end surface 3A of the core 3 coincides with the end surface 2A of the clad 2, and the end surface 3B of the core 3 coincides with the end surface 2B of the clad 2. The core 3 is a single mode optical waveguide.

  The opening 4 is provided in the clad 2 so as to contact a part of the core 3. Thereby, a part of the core 3 is exposed to the outside.

  FIG. 2 is a plan view of the core 3 as viewed from the direction A shown in FIG. With reference to FIG. 2, the core 3 includes cores 31 to 34. Each of the cores 31 and 34 has a linear shape.

  The core 32 has one end connected to the core 31 and the other end connected to the core 34. A partial region 321 of the core 32 is doped with an antibody. This partial region 321 has the same refractive index as the other regions of the core 32 when the antigen that is the detection target is not attached to the antibody, and the refractive index changes when the antigen is attached to the antibody.

  In addition, the antibody doped in the partial area | region 321 of the core 32 is determined according to the kind of antigen which is a detection target.

  The core 33 has a shape symmetrical to the core 32 with respect to the axis AX of the cores 31 and 34. The core 33 has one end connected to the core 31 and the other end connected to the core 34. The core 33 has the same length as the core 32.

  Thus, the core 3 is a Mach-Zehnder type core having two Y-type branches.

  FIG. 3 is a cross-sectional view of the optical waveguide biosensor 10 taken along line III-III shown in FIG. Referring to FIG. 3, core 3 has a substantially square cross-sectional shape. The core 3 is surrounded by the cladding 2 except for a part of the region 321, and the part of the region 321 of the core 3 is in contact with the opening 4 and exposed to the outside through the opening 4. .

  4 to 7 are first to fourth process diagrams for explaining a method of manufacturing the optical waveguide biosensor 10 shown in FIG.

Referring to FIG. 4, when the production of the optical waveguide biosensor 10 is started, the silicon substrate 11 is oxidized at a temperature of 1000 ° C. using oxygen (O ₂ ) gas to form one main surface of the silicon substrate 11. A SiO ₂ film 12 is formed. As a result, the substrate 1 is manufactured (see step (a)).

  Thereafter, a sol-gel silica solution in which the molar ratio MAPTMS / ZrPO between MAPTMS and ZrPO (zirconium (IV) -n-propoxide) is set to 95% / 5% is prepared, and the prepared sol-gel silica solution is spin-coated on the substrate 1. Apply on top.

In this case, the thickness of the applied sol-gel silica solution is a thickness corresponding to the distance from the surface of the SiO ₂ film 12 to the upper surface of the core 3 in FIG.

  Then, the sol-gel silica solution is baked at a temperature of 150 ° C. for 1 hour to form the sol-gel silica 21 on the substrate 1 (see step (b)). The sol-gel silica 21 is a part of the clad 2.

  Subsequently, wet etching of the sol-gel silica 21 is performed by irradiating with UV light and immersing the sample in isopropyl alcohol for 30 seconds to 1 minute. In order to leave only the portion irradiated with UV light consisting of i-line (wavelength = 365 nm) of a mercury lamp without dissolving in isopropyl alcohol, the sol-gel silica solution for performing wet etching has a hydrolysis initiator (for example, manufactured by CIBA). IRGCURE 184). Thereby, compared with the sol-gel silica part which interrupted | blocked UV irradiation with the photomask, the hydrolysis rate of the part irradiated with UV increases, and only a UV irradiation part remains.

Therefore, after the step (b), the sol-gel silica 21 is irradiated through the mask 22 with UV light composed of i rays (wavelength = 365 nm) of a mercury lamp. In this case, the irradiation intensity of UV light is 11 mW / cm ² and the irradiation time is 10 minutes. The mask 22 is made of glass 221 and a metal film 222. The metal film 222 is formed on one main surface 221 </ b> A of the glass 221. The metal film 222 blocks UV light composed of i-line (wavelength = 365 nm). Thereby, UV light is irradiated to areas other than the part 211 of the sol-gel silica 21 (see step (c)). Note that a portion 21A of the sol-gel silica 21 contains a hydrolysis initiator.

  Referring to FIG. 5, after step (c), a portion 211 of sol-gel silica 21 is removed by wet etching to form hole 23 in the region where core 3 is formed (see step (d)). In this case, as described above, wet etching is performed by immersing the sample in isopropyl alcohol for 30 seconds to 1 minute.

  Thereafter, a sol-gel silica solution in which the molar ratio MAPTMS / ZrPO of MAPTMS / ZrPO mixed with a hydrolysis initiator is set to 85% / 15% is prepared, and the prepared sol-gel silica solution is put into the hole 23 by spin coating. Apply.

  The applied sol-gel silica solution is baked at a temperature of 80 ° C. for 10 minutes. Thereby, the sol-gel silica 24 is formed in the clad 2 (see step (e)).

Subsequently, the sol-gel silica 24 is irradiated with UV light composed of i rays (wavelength = 365 nm) of a mercury lamp through the mask 25. In this case, the irradiation intensity of UV light is 11 mW / cm ² and the irradiation time is 10 minutes. Thereby, UV light is irradiated to parts other than the part 241 in the sol-gel silica 24 (see step (f)). The mask 25 is made of glass 251 and metal films 252 and 253. The metal films 252 and 253 are formed on one main surface 251A of the glass 251.

  Referring to FIG. 6, after step (f), part 241 of sol-gel silica 24 is removed by wet etching to form hole 26 (see step (g)). In this case, wet etching is performed by immersing the sample in isopropyl alcohol for 30 seconds to 1 minute.

  Thereafter, a sol-gel silica solution in which the molar ratio MAPTMS / ZrPO between MAPTMS and ZrPO mixed with a hydrolysis initiator is set to 95% / 5% is prepared, and the prepared sol-gel silica solution is applied to the entire surface of the sample by spin coating. To do. Thereby, a partial region 321 of the cladding 3 is filled with the sol-gel silica solution.

  In this case, the thickness of the applied sol-gel silica solution is a thickness corresponding to the distance from the upper surface of the core 3 to the upper surface of the clad 2 in FIG.

  Then, the sol-gel silica solution is baked at a temperature of 80 ° C. for 10 minutes to form the sol-gel silica 27 on the substrate 1 (see step (h)). This sol-gel silica 27 is a part of the clad 2.

After the step (h), the sol-gel silica 27 is irradiated with UV light composed of i rays (wavelength = 365 nm) of a mercury lamp through the mask 28. In this case, the irradiation intensity of UV light is 11 mW / cm ² and the irradiation time is 3 minutes. The mask 28 is made of glass 281 and a metal film 282. The metal film 282 is formed on one main surface 281A of the glass 281 and blocks UV light composed of i-line (wavelength = 365 nm). Thereby, UV light is irradiated to the area | regions other than the part 271 among the sol-gel silica 27 (refer process (i)).

  Referring to FIG. 7, after step (i), part 271 of sol-gel silica 27 is removed by wet etching to form opening 4 (see step (j)), and then at 150 ° C. for 1 hour. Heat. In this case, wet etching is performed by immersing the sample in isopropyl alcohol for 30 seconds to 1 minute. Further, a part of the region 321 of the clad 3 is also etched by this wet etching. Note that the sol-gel silicas 21 and 27 constitute the clad 2.

  Thereafter, a sol-gel silica solution in which the molar ratio MAPMS / ZrPO between MAPTMS and ZrPO was set to 85% / 15% was prepared, and the prepared sol-gel silica solution was doped with an antibody (for example, GFP), and the antibody was doped. A sol-gel silica solution is applied to the opening 4 by spin coating. Thus, the sol-gel silica solution doped with the antibody is also applied to a partial region 321 of the clad 3. Thereafter, the applied sol-gel silica solution (including the antibody) is irradiated with UV light for 9 minutes.

  As a result, the clad 3 containing the antibody in the partial region 321 is formed in the part 21 of the clad 2 (see step (k)). Then, the optical waveguide biosensor 10 is completed.

  FIG. 8 is a schematic diagram for explaining detection of an antigen in the optical waveguide biosensor 10. Referring to FIG. 8, when the antigen as the detection target is not attached to a part of the region 321 of the core 3, the light incident from the end surface 3 </ b> A of the core 3 travels straight through the core 31, and then the core Branches into 32 and 33. Then, the light travels through the cores 32 and 33 and is strengthened and synthesized at the connecting portion between the cores 32 and 33 and the core 34. Thereafter, the synthesized light travels through the core 34 and is emitted to the outside of the optical waveguide biosensor 10 (see FIG. 8A).

  On the other hand, when the antigen 20 as the detection target is attached to the antibody contained in the partial region 321 of the core 3, the refractive index of the partial region 321 of the core 32 increases and the inside of the core 32 passes through. A phase difference is generated between the light that has traveled and the light that has traveled in the core 33, and as a result, the two light beams that have traveled in the cores 32 and 33 are connected at the connection portion between the cores 32 and 33 and the core 34. Synthesized with weakness. The synthesized light travels through the core 34 and is emitted to the outside of the optical waveguide biosensor 10 (see FIG. 8B).

  Therefore, the antigen 20 can be detected by detecting the intensity of light emitted from the optical waveguide biosensor 10.

  Thus, in the optical waveguide biosensor 10, the Mach-Zehnder type core 3 is used to split incident light into light propagating through the core 32 and light propagating through the core 33. By detecting a change in the intensity of the interference light when the propagating light and the light propagating through the core 33 interfere, the presence or absence of an antigen-antibody reaction in the region 321, that is, the presence or absence of an antigen can be detected with high sensitivity.

  FIG. 9 is a perspective view of another biosensor according to an embodiment of the present invention. The biosensor according to the embodiment of the present invention may be an optical waveguide biosensor 10A shown in FIG.

  Referring to FIG. 9, an optical waveguide biosensor 10 </ b> A is obtained by adding a flow path 5 to the optical waveguide biosensor 10 shown in FIG. 1, and is otherwise the same as the optical waveguide biosensor 10.

  The flow path 5 includes flow paths 51 and 52. The flow path 51 communicates with the opening 4 at one end side of the opening 4 in the length direction DR1 of the optical waveguide biosensor 10A, and the flow path 52 extends from the opening 4 in the length direction DR1. The other end side communicates with the opening 4.

  Further, the end surface 51A of the flow path 51 coincides with the end surface 2C of the clad 2 in the width direction DR2, and the end surface 52A of the flow dew 52 coincides with the end surface 2C of the clad 2 in the width direction DR2.

  This flow path 5 is a flow path for flowing water. By flowing water through the flow path 5, the antigen is washed and the antigen is removed.

  Therefore, the optical waveguide biosensor 10A is not a disposable sensor, but can be used multiple times by washing and removing the antigen.

  FIG. 10 is a cross-sectional view of the optical waveguide biosensor 10A taken along line XX shown in FIG. With reference to FIG. 10, the flow path 5 (51) is disposed in communication with the opening 4. The height of the bottom surface of the channel 5 (51) is substantially the same as the height of the bottom surface of the opening 4.

  The optical waveguide biosensor 10A is manufactured by the following method. After the step (k) shown in FIG. 7, the region other than the region where the flow path 5 (51, 52) is formed is irradiated with UV light from the end face 2C of the cladding 2, and the region where the UV light is not irradiated is described above. Wet etching under conditions. Thus, the optical waveguide biosensor 10A is completed. Finally, the etched channels 51 and 52 are covered with a substrate (for example, a silica glass substrate) and the like, and the portion of the opening 4 is in contact with the outside (see FIG. 10).

  FIG. 11 is a configuration diagram of a biosensor system including the optical waveguide biosensor 10 shown in FIG.

  Referring to FIG. 11, a biosensor system 100 includes an OTDR (Optical Time Domain Reflectometry) 110, a coupler 120, an optical fiber 130, optical waveguide biosensors 131 to 13n (n is an integer of 2 or more), fiber black, and the like. Gratings 141 to 14n.

  The optical waveguide biosensors 131 to 13n are optically connected in series by an optical fiber 130. The optical fiber 130 is a single mode optical fiber. The fiber black gratings 141 to 14n are provided corresponding to the optical waveguide biosensors 131 to 13n, respectively.

  The OTDR 110 includes a light projecting unit 111 and a light receiving unit 112. The light projecting unit 111 has an optical pulse light source (not shown), and the light receiving unit 112 has an optical pulse detection unit (not shown).

  The optical pulse light source emits a plurality of optical pulses having a half-value width on the order of nsec and having mutually different wavelengths. In this case, the wavelengths of the plurality of optical pulses coincide with the reflection frequencies of the fiber black gratings 141 to 14n.

  The light projecting unit 111 and the light receiving unit 112 of the OTDR 110 are connected to the optical fiber 130 by a coupler 120.

  The fiber Bragg gratings 141 to 14n are obtained by giving periodic strength to the refractive index of the core in the optical fiber by, for example, irradiating the optical fiber with ultraviolet laser light. As a result, the fiber Bragg gratings 141 to 14n obtain a periodic refractive index modulation in the longitudinal direction of the optical fiber, reflect only light having a wavelength matching the period, and pass light having other wavelengths. This is because light of other wavelengths does not sense this periodic refractive index fluctuation.

  In the embodiment of the present invention, the fiber Bragg gratings 141 to 14n are set so as to selectively reflect only light of a predetermined wavelength set for each of the optical waveguide biosensors 131 to 13n.

  The optical pulse detector of the OTDR 110 detects the reflected light from the fiber Bragg gratings 141 to 14n installed at the subsequent stage of the plurality of optical waveguide biosensors 131 to 13n. That is, the optical pulse detection unit of the OTDR 110 detects the reflected light from the fiber Bragg gratings 141 to 14n by the optical time domain reflection measurement method. The OTDR 110 is a method for evaluating an optical fiber by utilizing a phenomenon that a part of optical power returns to the incident side from an optical pulse propagating in the optical fiber 130 (refer to JIS C 6823: optical fiber loss test method). For example, a photodiode (PD) is connected through the coupler 120, converted into a digital signal by an A / D converter, and a pulse signal is analyzed by a control device. Specifically, after emitting an optical pulse from an optical pulse light source, fiber Bragg gratings 141-installed corresponding to a plurality of optical waveguide biosensors 141-14 n connected in series by a single mode optical fiber 130. The distance to the optical waveguide biosensors 131 to 13n (that is, the position of the optical waveguide biosensors 131 to 13n) is determined by measuring the delay time until the reflected light from 14n reaches the optical pulse detector. To detect.

  The delay time until the reflected light reaches the optical pulse detector depends on the length of the fiber (dt = n dL / c, n: the refractive index of the optical fiber). For example, the optical waveguide biosensor 131 at a distance of 500 m is used. The time delay for detecting ~ 13n is 5 μs for 1 km round trip. FIG. 12 is a conceptual diagram of detected pulsed light. In FIG. 12, the vertical axis represents signal intensity, and the horizontal axis represents time.

  When an antigen-antibody reaction has not occurred, a signal as shown in (a) is detected. For example, when an antigen-antibody reaction occurs in the second optical waveguide biosensor, a signal as shown in (b) is obtained. .

  The biosensor network of the present invention is a Mach-Zehnder optical waveguide biosensor in which reflected light from the fiber Bragg gratings 141 to 14n installed in the network is detected by the OTDR 110, and an antigen-antibody reaction occurs from the time difference. In this method, the positions of 131 to 13n are specified.

  Therefore, in order to discriminate and detect the position, the Mach-Zehnder optical waveguide biosensors 131 to 13n are considered in consideration of the time resolution Δt of the optical pulse detection unit of the OTDR 110 and the optical transmission speed c in the optical fiber 130. It is necessary to determine the installation interval S.

  When the attenuation in the optical fiber 130 is 0.16 dB / km and the minimum detection sensitivity of the optical pulse detection unit of the OTDR 110 is 40 dB, the total extension distance L of the biosensor network system 100 of the present invention is about 125 km (round trip distance). 250 km).

  As described above, according to the Mach-Zehnder type optical waveguide biosensor of the present invention and the biosensor network system using the same, the occurrence of the antigen-antibody reaction in the sensing objects installed at a plurality of positions Even long distances can be measured quickly, simply and accurately.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  For example, as the light pulse light source of the light projecting unit, a commercially available wavelength tunable laser is used and the wavelength of the laser is varied in accordance with the reflection wavelength of each fiber Bragg grating, or the reflection of each fiber Bragg grating. A method of projecting light by combining pulsed laser light from a plurality of laser light sources corresponding to wavelengths with a coupler is conceivable.

  In the above description, each of the n biosensors 131 to 13n of the biosensor system 100 has been described as including the optical waveguide biosensor 10 illustrated in FIG. 1. However, the present invention is not limited to this. Each of the n biosensors 131 to 13n may include an optical waveguide biosensor 10A illustrated in FIG.

  In this case, since the antigen adhering to the antibody is removed by flowing water through the flow path 5, it is possible to detect the antigen a plurality of times using the n biosensors 131 to 13n in the biosensor system 100.

  In the embodiment of the present invention, the core 31 constitutes a “first core”, the core 34 constitutes a “second core”, and the core 33 constitutes a “third core”. The core 32 constitutes a “fourth core”.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The Mach-Zehnder optical waveguide biosensor according to the present invention, and the network system including the same, apply the principle of the Mach-Zehnder interference system and increase the reflected light intensity change caused by the antigen-antibody reaction. Sensitivity can be detected, and a sensor network is constructed using optical fibers. Optical fibers are smaller in diameter than coaxial cables, and there is no risk of electrical leakage. Easy to lay on. In addition, since the optical fiber has a smaller transmission loss than the coaxial cable, signal transmission over 100 km is possible without optical amplification.

  1 substrate, 2 clad, 3 core, 4 opening, 10 optical waveguide biosensor, 321 Partial region.

Claims (7)

A substrate,
A clad formed on the substrate and made of sol-gel glass;
A core made of sol-gel glass is formed in the clad,
The core is
A first core;
A second core;
A third core connected to the first and second cores;
A fourth core having a shape symmetrical to the third core with respect to the axes of the first and second cores and connected to the first and second cores and including an antibody;
The region containing the antibody in the fourth core is an optical waveguide biosensor exposed to the outside through an opening provided in the clad.   The optical waveguide biosensor according to claim 1, further comprising a flow path provided in the clad in contact with the opening for flowing water.   The optical waveguide biosensor according to claim 1 or 2, wherein the antibody contained in the fourth core is determined according to the type of antigen that is a detection target. A plurality of optical waveguide biosensors each detecting an antigen;
An optical fiber optically connecting the plurality of optical waveguide biosensors in series;
An optical pulse light source that is connected to one end of the optical fiber and emits a plurality of pulse lights having different wavelengths;
A plurality of fiber Bragg gratings provided in the optical fiber corresponding to the plurality of optical waveguide biosensors, each reflecting interference light in the corresponding optical waveguide biosensor;
Detecting a plurality of reflected light reflected by the plurality of fiber Bragg gratings, and detecting the presence or absence of an antigen-antibody reaction in the optical waveguide biosensor based on the detection result,
Each of the plurality of optical waveguide biosensors is
A substrate,
A clad formed on the substrate and made of sol-gel glass;
A core made of sol-gel glass formed in the cladding,
The core is
A first core;
A second core;
A third core connected to the first and second cores;
A fourth core having a shape symmetrical to the third core with respect to the axes of the first and second cores and connected to the first and second cores and including an antibody;
The biosensor system, wherein the antibody-containing region of the fourth core is exposed to the outside through an opening provided in the cladding.   The biosensor system according to claim 4, wherein the detector detects an intensity change of the plurality of reflected lights by an optical time domain reflectometry.   The detector has a detection time delay after the light pulse is emitted from the light pulse light source until the light pulse after interference in the optical waveguide biosensor reflected by the fiber Bragg grating reaches the detection unit. The biosensor system according to claim 4, wherein an optical waveguide biosensor in which an antigen-antibody reaction has occurred is specified by measurement, and the light intensity is detected for each optical waveguide biosensor. The optical waveguide of the optical waveguide biosensor is a single mode optical waveguide,
The biosensor system according to any one of claims 4 to 6, wherein the optical fiber is a single-mode optical fiber.

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