JP2012078183A - Sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for uniformly agitating antibody label particles and a specimen in the same mechanism and then transferring liquid onto a chip and performing detection.SOLUTION: A sensor system includes a specimen liquid mixing device and an optical waveguide sensor. The specimen liquid mixing device includes: a device body; a specimen liquid storage chamber formed in the body; a mixing chamber formed in the body, connected to the specimen liquid storage chamber through a first flow channel, and containing antibody label particles to which a second substance specifically reacting to a substance to be measured in the specimen is fixed; a minute pump inserted into the body at an lower end thereof so as to communicate with the mixing chamber and capable of performing suction and discharge; and a mixed liquid transfer space formed above the mixing chamber in the body, connected to the mixing chamber at one end thereof through a second flow channel having a cross section larger than that of the first flow channel, and having an opening to the outside at the other end thereof. The optical waveguide sensor includes a sensing unit placed in the mixed liquid transfer space and having a first substance specifically reacting to the substance to be measured fixed on a surface thereof.

Description

  Embodiments described herein relate generally to a sensor system, and more particularly to a sensor system that quantifies enzyme activity in a sample liquid such as blood or serum.

  Components in biological fluids such as blood provide useful information regarding medical diagnosis. The analysis method is generally a method (wet method) in which a reagent necessary for the reaction of the substance to be measured is mixed with a sample liquid such as blood or serum in a solution, and the change is measured by measuring changes in absorbance, etc. It is. On the other hand, there is a method that is easy to operate, that is, a method (dry method) that can be detected by simply placing the necessary reagents in a dry state in the reaction part on the sheet or in the cell in advance and introducing the sample liquid. It has been actively developed in recent years.

  Measurement system capable of quantitatively measuring the measurement target substance in a shorter amount of sample to be measured in a shorter amount of time using a microparticle labeled with an antibody and an optical waveguide sensor, and measurement of the substance Methods and substance measurement kits have been proposed. (For example, see Patent Document 1)

JP 2009-133842 A

  However, in the measurement system that combines the conventional antibody-labeled fine particles and the optical waveguide sensor as described above, the sample is introduced in a state where the antibody-labeled fine particles are arranged on the sensor, and the antibody-labeled fine particles and the sample are mixed by natural stirring, It was in the form of being detected simultaneously with mixing. However, mixing of antibody-labeled microparticles and a sample by natural agitation is insufficient, and there is concern about sensitivity variations.

  Accordingly, the present invention has been made based on the above circumstances, and an object of the present invention is to provide a system for feeding and detecting the antibody-labeled fine particles and the sample on the chip after they are uniformly stirred in the same mechanism. It is something to try.

  The sensor system according to the embodiment includes a sample liquid mixing device and a planar optical waveguide sensor attached to the mixing device. The sample mixing device includes a device main body and a sample liquid storage formed in the main body. And antibody labeled microparticles formed in the chamber and connected to the sample fluid storage chamber through the first flow path and to which the second substance that specifically reacts with the substance to be measured in the sample is immobilized. A housed mixing chamber, a micro pump capable of suction / discharge operation inserted into the main body so that a lower end thereof communicates with the mixing chamber, and formed above the mixing chamber in the main body; One end of which is connected to the mixing chamber through a second flow path having a larger cross-sectional area than the first flow path, and the other end has a liquid mixture circulation space having an opening to the outside, and the optical waveguide sensor includes: Located in the mixed liquid circulation space Characterized in that it comprises a sensing portion in which the first substance which specifically reacts with the target substance is immobilized on the surface.

The top view which shows the sensor system which concerns on embodiment of this invention. Sectional drawing which follows the II-II line | wire of FIG. Sectional drawing which shows the planar optical waveguide sensor integrated in the sensor system of FIG.

  Hereinafter, a sensor system according to Example 1 will be described with reference to the drawings.

  FIG. 1 is a plan view showing a sensor system according to a first embodiment, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a schematic cross-sectional view showing a planar optical waveguide sensor incorporated in FIG. .

  The sensor system includes a sample liquid mixing apparatus 1 and a planar optical waveguide sensor 21 attached to the sample liquid mixing apparatus 1.

  The sample liquid mixing apparatus 1 includes a rectangular block 2 that is an apparatus main body made of, for example, black acrylic resin. The rectangular block 2 has a structure in which a rectangular lower block piece 2a and a rectangular upper block piece 2b are fixed via a thin film spacer 3 therebetween. For example, the cylindrical mixing chamber 4 is formed inside the center of the block 2. That is, the mixing chamber 4 is formed by penetrating the spacer 3 and drilling the lower block piece 2a into a columnar shape. In the mixing chamber 4, antibody-labeled fine particles 5 on which a second substance that specifically reacts with the measurement target substance contained in the sample liquid is immobilized are disposed in advance in a dry state. As the antibody-labeled fine particles 5, for example, resin beads such as polystyrene latex beads (trade name), metal colloids such as gold colloid, or inorganic oxide particles such as titanium oxide particles can be used. As the fine particles, proteins such as albumin, polysaccharides such as agarose, non-metallic particles such as silica particles and carbon particles can also be used. Latex beads and metal colloids are particularly preferable. Of the latex beads, when the light propagating through the optical waveguide described later is a red laser, blue latex beads are preferable. The antibody-labeled fine particles 5 preferably have a diameter of 50 nm to 10 μm. As the second substance, for example, when the substance to be measured of the sample to be measured is an antigen, an antibody can be used. The block 2 (the upper block piece 2a) above the mixing chamber 4 has a liquid mixture in the liquid mixture circulation space when the liquid mixture in the mixing chamber 4 is swung by repeated suction and discharge of a micro pump described later. A buffer space 6 is formed to prevent the portion from flowing out.

  The sample liquid storage chamber 7 having a cylindrical hole is formed in, for example, the left block 2 portion. That is, the sample liquid storage chamber 7 is fluidly connected to the mixing chamber 4 through the first flow path 8 extending in the horizontal direction. The first flow path 8 is formed by partially and linearly notching the spacer 3 positioned between the mixing chamber 4 and the sample liquid storage chamber 7. Examples of the measurement target substance contained in the sample liquid include proteins, peptides, genes and the like contained in blood, serum, plasma, biological samples, foods and the like. Specifically, insulin, gazein, β-lactoglobulin, ovalbumin, calcitonin, C-peptide, leptin, β-2-microglobulin, retinol binding protein, α-1-microglobulin, α-fetoprotein, carcinoembryonicity Antigen, troponin-I, curcagon-like peptide, insulin-like peptide, tumor growth factor, fibroblast growth factor, platelet growth factor, epidermal growth factor, cortisol, triiodothyronine, hapten hormones such as thyroxine, digoxin, theophylline, etc. Examples include, but are not limited to, infectious substances such as drugs, bacteria, viruses, hepatitis antibodies, IgE, major protein complexes of buckwheat, and soluble proteins including peanut Arah2.

  For example, the columnar through hole 9 having an opening at the top is drilled so that the lower end communicates with the buffer space 6 at the center of the block 2 and the upper end opens on the upper surface of the block 2. A micro pump 10 having a central inverted trapezoidal shape capable of suction and discharge is inserted into the through hole 9 in close contact with the inner peripheral surface of the through hole 9.

  A first rectangular hole 11 having the same shape as the planar optical waveguide sensor 21 is formed in the right side portion of the block 2. The right end of the first rectangular hole 11 is formed with a slight distance from the right side surface of the block 2. The second rectangular hole 12 having an area smaller than the first rectangular hole 11 is formed on the bottom surface of the first rectangular hole 11 substantially similar to the first rectangular hole 11. By forming the second rectangular hole 12, the bottom surface of the first rectangular hole 11 becomes a rectangular frame surface 13 on which the planar optical waveguide sensor is placed. The second rectangular hole 12 functions as a mixed liquid circulation space by forming a second flow path 14 and a third flow path 15 described later. The bottom surface of the second rectangular hole 12 is preferably positioned on the block 2 on the top surface of the mixing chamber 4. The first and second rectangular holes 11 and 12 are formed by performing a process of drilling the upper block piece 2b of the block 2.

  The second flow path 14 is formed in the block 2 so as to be inclined downward from the left end portion of the bottom surface of the second rectangular hole 12 toward the right end of the upper surface of the mixing chamber 4. The second rectangular hole 12 is fluidly connected to the mixing chamber 4 through the second flow path 14. The second flow path 14 has an area whose smallest cross-sectional portion is, for example, twice or more that of the cross section of the first flow path 8. The relationship between the first flow path 8 and the second flow path 14 is, for example, when the cross section of the first flow path 8 is 1 mm (width) × 0.1 mm (height), the cross section of the second flow path 14 is 2 mm ( By setting the width to 1 mm (height), a sufficient conductance difference can be generated between the first flow path 8 and the second flow path 14. For this reason, it is possible to prevent the liquid from flowing back into the sample liquid storage chamber 7 when the liquid in the mixing chamber 4 is mixed and stirred by the suction / discharge of the micro pump 10.

  The third flow path 15 is formed in the block 2 so as to incline downward from the right end portion of the bottom surface of the second rectangular hole 12 toward the right side surface of the block 2. That is, the other end of the third flow path 15 is opened on the right side surface of the block 2 to form the opening 16. The third flow path 15 serves not only for depressurization when the mixed liquid is transferred from the mixing chamber 4 to the mixed liquid circulation space, but also for discharging the mixed liquid that has circulated through the second rectangular hole 12 as necessary. Eggplant. The check valve 17 is attached to the right side surface of the block 2 so as to open and close the opening 16 of the third flow path 15. The check valve 17 functions to open the opening 16 of the third flow path 15 when pressure is applied from the inside to the outside, and to close the opening 16 of the third flow path 15 when suction pressure is applied to the inside. . However, the sample liquid introduced into the sample liquid storage chamber 7 is sufficiently high to quickly move into the mixing chamber 4 due to capillarity and the absorption effect by the fine particles 5 or the like previously placed in the mixing chamber 4 in a dry state. When the viscosity is low, the reverse support valve 17 is not always necessary as will be described later.

  The planar optical waveguide sensor 21 is placed on the rectangular frame surface 13 around the second rectangular hole 12 so that the sensing film faces the direction of the second rectangular hole 12. The planar optical waveguide sensor 21 is in close contact with the block 2 with a light-shielding double-sided tape (not shown), and is sealed so as not to leak liquid from the second rectangular hole 12 that functions as a mixed liquid circulation space.

  The planar optical waveguide sensor 21 includes a glass substrate 22 as shown in FIG. Near both end portions of the main surface of the glass substrate 22, an incident side grating 23a and an output side grating 23b, which are a pair of gratings as optical elements, are formed. These gratings 23 a and 23 b are made of, for example, titanium oxide having a higher refractive index than the glass substrate 22. An optical waveguide layer 24 having a thickness of 3 to 300 μm is formed on the main surface of the glass substrate 22. The optical waveguide layer 24 can be formed of, for example, a thermosetting resin such as a phenol resin or an epoxy resin, or alkali-free glass. Specifically, the material used here is a material having a higher refractive index than the glass substrate 22 and a predetermined light transmittance, and is particularly preferably an epoxy resin or the like having a main structure of polystyrene. In this optical waveguide sensor, a sensing unit 25 in which a first substance that specifically reacts with a measurement target substance of a sample to be measured is fixed on an optical waveguide layer 24 located between the gratings 23a and 23b. Yes. For example, the first substance is immobilized on the surface hydrophobized by a silane coupling agent or the like by the hydrophobic interaction of the substance. As the first substance, for example, when the substance to be measured of the specimen to be measured is an antigen, an antibody can be used.

  On the rear surface side of the glass substrate 22, a light source 26 (for example, a laser diode) that makes laser light incident through a polarization filter (not shown), and a light receiving element 27 that receives light emitted from the glass substrate 22 through the optical waveguide layer 24. For example, photodiodes are arranged.

  Next, the operation of the sensor system shown in FIGS. 1 to 3 will be described.

  (A) The sample liquid is stored in the sample liquid storage chamber 7.

  (B) The micro pump 10 is driven to suck the sample liquid from the lower end thereof into the through hole 9, the buffer space 6 communicating with the through hole 9, and the mixing chamber 4. At this time, the mixing chamber 4, the second flow path 14, the mixed liquid circulation space which is the second rectangular hole 12, and the opening 16 communicating through the third flow path 15 are blocked by the reverse support valve 17. For this reason, the inside of the mixing chamber 4, the second flow path 14, the mixed liquid circulation space 12, and the third flow path 15 becomes negative pressure, and a part of the sample liquid in the sample liquid storage chamber 7 is the first flow path. 8 is introduced into the mixing chamber 4.

Alternatively, since the viscosity of the sample liquid is sufficiently low, the micropump is used when the sample liquid moves quickly into the mixing chamber 4 due to capillarity and the absorption effect by the fine particles 5 or the like previously placed in the mixing chamber 4 in a dry state. The suction operation by 10 is not always necessary, and in this case, the reverse valve 17 is not necessary.

  (C) The suction / discharge operation by the micro pump 10 is repeated, and a constant amount of the sample liquid in the sample liquid storage chamber 7 is introduced into the mixing chamber 4 for each suction / discharge operation cycle. By introducing such sample liquid into the mixing chamber 4, the dried antibody-labeled fine particles 5 delivered in advance into the mixing chamber 4 and the sample liquid are mixed and stirred. The second flow path 14 has an area whose smallest cross-sectional portion is, for example, twice or more that of the cross section of the first flow path 8. For this reason, a sufficient conductance difference can be generated between the first flow path 8 and the second flow path 14. As a result, it is possible to prevent the liquid in the mixing chamber 4 from flowing back into the sample liquid storage chamber 7 during discharge by the micro pump 10.

  (D) After mixing and stirring, the discharge operation of the micro pump 10 is performed. At this time, the liquid mixture is transferred from the mixing chamber 4 to the liquid mixture circulation space 12 through the second flow path 14 by increasing the discharge force of the micro pump 10.

  (E) After the mixed solution is transferred to the mixed solution circulation space 12, the concentration is measured. In the concentration measurement, the laser light from the light source 26 is incident on the optical waveguide layer 24 through the incident side grating 23a, propagates through the optical waveguide layer 24, and then the laser light emitted from the emission side grating 23b is received by the light receiving element. This is performed by receiving light at 27 and detecting a change in the intensity of the laser beam.

  Here, if the transferred liquid does not contain an antigen that specifically reacts with the first substance immobilized on the sensing unit 25 and the second substance immobilized on the antibody-labeled microparticles, the second substance is the first substance. Disperse in the mixture without binding to one substance. In this state, laser light is propagated through the optical waveguide layer 24 to generate evanescent light near the surface. At this time, since the antibody-labeled fine particles 5 in the mixed solution are dispersed on the sensing unit 25, the antibody-labeled fine particles 5 are hardly present in the evanescent light region. Therefore, the antibody-labeled fine particles 5 hardly participate in the absorption and scattering of the evanescent light, and the intensity of the evanescent light is hardly attenuated. As a result, when the laser beam emitted from the emission side grating 23b is received by the light receiving element 27, the intensity of the laser beam hardly changes.

  On the other hand, if there is an antigen that specifically reacts with the first substance immobilized on the sensing unit 25 and the second substance immobilized on the antibody-labeled microparticle 5 in the mixed liquid transferred to the mixed liquid circulation space 12, The antigen causes an antigen-antibody reaction and binds to the first substance of the sensing unit 25 and further binds to the second substance of the antibody-labeled microparticle 5 by causing an antigen-antibody reaction. That is, since an antigen-antibody reaction occurs between the first substance and the second substance via the antigen, the antibody-labeled fine particles 5 are immobilized on the surface of the sensing unit 25. In this state, laser light is propagated through the optical waveguide layer 24 to generate evanescent light near the surface. At this time, since the antibody-labeled fine particles 5 are fixed to the sensing unit 25, the antibody-labeled fine particles 5 are present in the evanescent light region. That is, since the antibody-labeled fine particles 5 are involved in the absorption and scattering of the evanescent light, the intensity of the evanescent light is attenuated. As a result, when the laser beam emitted from the emission side grating 23b is received by the light receiving element 27, the intensity of the laser beam decreases with the passage of time due to the influence of the immobilized antibody-labeled fine particles 5.

  The rate of decrease in the intensity of the laser beam received by the light receiving element 27 is proportional to the amount of antibody-labeled fine particles 5 immobilized on the sensing unit 25, that is, the antigen concentration in the specimen involved in the antigen-antibody reaction. Therefore, a laser light intensity decrease curve with the passage of time is created in a sample solution whose antigen concentration is known, and the rate of decrease of the laser light intensity over a predetermined time of this curve is obtained. A calibration curve showing the relationship with the decrease rate is prepared in advance. By determining the laser light intensity decrease rate at a predetermined time from the time measured by the above method and the laser light intensity decrease curve, and comparing the laser light intensity decrease rate with the calibration curve, the antigen concentration in the specimen Can be measured.

  (F) After the concentration measurement, the discharge operation of the micro pump 10 is performed as necessary. By the discharge operation of the micro pump 10, the liquid mixture is discharged from the opening 16 to the outside via the third flow path 15.

  According to such an embodiment, the sample liquid and the antibody-labeled fine particles 5 are mixed and mixed in the mixing chamber 4 by introducing the sample liquid in the sample liquid storage chamber 7 into the mixing chamber 4 by suction / discharge of the micro pump 10. Agitation is performed and mixing of them can proceed rapidly.

In addition, mixing of antibody-labeled microparticles and a sample by natural agitation is insufficient, and there is concern about variations in sensitivity. According to this embodiment, mixing can be sufficiently advanced and sensitivity variations can be reduced. can do.

  Furthermore, by using the planar optical waveguide sensor 21, a very small amount of measurement object in the sample liquid can be detected with high sensitivity.

  As mentioned above, although embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of 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 1 ... Sample liquid mixing apparatus, 2 ... Block, 4 ... Mixing chamber, 5 ... Antibody labeled fine particle, 7 ... Sample liquid storage chamber, 8 ... 1st flow path, 10 ... Micro pump, 12 ... 2nd rectangular hole (reaction liquid (Circulation space), 14 ... second flow path, 15 ... third flow path, 17 ... check valve, 21 ... planar optical waveguide sensor, 24 ... optical waveguide layer, 25 ... sensing section

Claims (4)

A sample liquid mixing device, and a planar optical waveguide sensor attached to the mixing device,
The sample mixing apparatus includes an apparatus main body, a sample liquid storage chamber formed in the main body, and formed in the main body, connected to the sample liquid storage chamber through the first flow path, and an object to be measured in the sample A mixing chamber containing antibody-labeled microparticles in which a second substance that specifically reacts with the substance is immobilized, and a suction / discharge operation inserted into the main body so that the lower end communicates with the mixing chamber are possible. The micro pump is formed in the main body above the mixing chamber, and one end is connected to the mixing chamber through a second channel having a larger cross-sectional area than the first channel, and the other end is connected to the outside. A mixed liquid circulation space having an opening,
The optical waveguide sensor includes a sensing unit that is located in the mixed solution circulation space and has a first substance that specifically reacts with a substance to be measured fixed on a surface thereof.   The sensor system according to claim 1, wherein the sample mixing device further includes a reverse support valve attached to the main body for opening and closing the opening.   The sensor system according to claim 1 or 2, wherein the antibody-labeled fine particles are disposed in the mixing chamber in a dry state.   The sensor system according to any one of claims 1 to 3, wherein the measurement target substance is an antigen, and the first substance and the second substance that specifically react with the measurement target substance are each an antibody.

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