JP2012255707A - Fluorescence sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence sensor 30 having high detection sensitivity.SOLUTION: A fluorescence sensor 30 comprises: a PD element 12 for converting fluorescence into electric signals; a sensor frame 17 constructing sides of an indicator space 16 that houses in dry condition an indicator 19 made of hydrogel generating fluorescence by an analyte and excitation light; a filter 13 for transmitting fluorescence and for blocking excitation light; a luminous element 14 for emitting the excitation light; a transparent intermediate layer 15 for constructing an undersurface of the indicator space 16; and a light-shielding layer 18 for constructing an upper surface of the indicator space 16, blocking external light and the excitation light, allowing body fluid including analytes to pass through, and being composed of a hydrophilic part and a hydrophobic part.

Description

  The present invention relates to a fluorescence sensor for measuring the concentration of an analyte in an aqueous solution and a method for producing the fluorescence sensor, and more particularly, to a fluorescence sensor comprising an indicator composed of an analyte and a hydrogel that generates fluorescence by excitation light, and the fluorescence. The present invention relates to a method for manufacturing a sensor.

  A fluorescent sensor for measuring the concentration of an analyte in a liquid, that is, a substance to be measured has been developed. The fluorescence sensor has an indicator that generates fluorescence with a light amount corresponding to the amount of analyte, and a photoelectric conversion element that detects fluorescence from the indicator.

  For example, the fluorescent sensor 110 disclosed in US Pat. No. 5,039,490 can be manufactured using the MEMS technology and can be miniaturized. As shown in FIGS. 1 and 2, the fluorescence sensor 110 includes a transparent substrate 111 that can transmit the excitation light E, a photoelectric conversion element 112 that converts the fluorescence F into an electrical signal, and a condensing light that collects the excitation light E. It is composed of a transparent intermediate layer 115 having a functional part 115A, an indicator 119 that emits a fluorescence F having a light amount corresponding to the amount of analyte by the action of the analyte 2 and the excitation light E, and a light shielding layer 118.

  In the fluorescence sensor 110, only the excitation light E2 that has passed through the gap 112B between the photoelectric conversion element 112 and the photoelectric conversion element substrate 112A of the excitation light E incident from the lower surface of the transparent substrate 111 is incident on the indicator 119.

  On the other hand, US Pat. No. 7,181,096 discloses a fluorescent sensor using a hydrogel as an indicator. Since the hydrogel is easy for the analyte 2 to enter, the fluorescent sensor using the hydrogel as the indicator has good sensitivity.

  However, the characteristics of a fluorescent sensor using hydrogel as an indicator may change with the passage of time from manufacture to use. For this reason, a known fluorescent sensor using hydrogel as an indicator may not be able to easily measure the analyte concentration accurately.

US Pat. No. 5,039,490 U.S. Pat. No. 7,181,096

  An object of the present invention is to provide a fluorescent sensor capable of accurate measurement.

  A fluorescent sensor according to one embodiment of the present invention includes a photoelectric conversion element that converts fluorescence into an electrical signal, and an indicator space in which an indicator composed of an analyte and a hydrogel that generates fluorescence by excitation light is accommodated in a dry state. A sensor frame that is configured, a filter that is disposed so as to cover the photoelectric conversion element and transmits the fluorescence and blocks the excitation light, and a light emitting element that is disposed in the sensor frame and generates the excitation light. A transparent intermediate layer disposed on the light emitting element, which constitutes a lower surface of the indicator space, and an upper surface of the indicator space. A body layer containing the analyte can be passed through the excitation light, and further includes a light shielding layer composed of a hydrophilic part and a hydrophobic part.

  According to the present invention, a fluorescent sensor capable of accurate measurement can be provided.

It is explanatory drawing which showed the cross-section of the conventional fluorescence sensor. It is the exploded view which showed the structure of the conventional fluorescence sensor. It is the exploded view which showed the structure of the fluorescence sensor of 1st Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 1st Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 1st Embodiment. It is a flowchart for demonstrating the manufacturing method of the fluorescence sensor of 1st Embodiment. It is explanatory drawing which showed the cross-section of the light shielding layer of the fluorescence sensor of 2nd Embodiment. It is explanatory drawing which showed the cross-section of the light shielding layer of the fluorescence sensor of 2nd Embodiment. It is explanatory drawing which showed the cross-section of the light shielding layer of the fluorescence sensor of 3rd Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 3rd Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 4th Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 5th Embodiment. It is explanatory drawing which showed the cross-section of the fluorescence sensor of 6th Embodiment.

<First Embodiment>
The fluorescence sensor 30 according to the first embodiment of the present invention detects glucose in the body fluid of the subject. As shown in FIGS. 3 and 4, the fluorescence sensor 30 has a structure in which a substrate 11, a filter 13, a light emitting element 14, a transparent intermediate layer 15, an indicator 19, and a light shielding layer 18 are laminated in order. is there. In the indicator space 16 in which the indicator 19 is accommodated, the lower surface is the transparent intermediate layer 15, the upper surface is the light shielding layer 18, and the side surface is the sensor frame 17. The shape of the indicator space 16 is a rectangular parallelepiped (square column shape), but may be a columnar shape, a polygonal column shape, or the like.

  The substrate 11 includes a photodiode element (hereinafter referred to as “PD element”) 12 which is a photoelectric conversion element that converts the fluorescence F into an electrical signal. The filter 13 disposed so as to cover the PD element 12 transmits the fluorescence F and blocks the excitation light E. The light emitting element 14 disposed on the filter 13 generates excitation light E. The indicator 19 is made of a hydrogel having a fluorescent dye that generates fluorescence F by the excitation light E and the analyte 2 that has entered after passing through the light shielding layer 18. In the fluorescence sensor 30, glucose is the analyte 2.

  In the fluorescence sensor 30, the excitation light E generated by the light emitting element 14 is efficiently applied to the indicator 19. Further, in the fluorescence sensor 30, a part of the fluorescence F generated by the indicator 19 passes through the PD element 12 and the filter 13 and enters the PD element 12. For this reason, the fluorescence sensor 30 is more sensitive than the conventional fluorescence sensor 110 already described.

  And the inventor discovered that the time-dependent change of the characteristic of the fluorescence sensor using hydrogel before use did not generate | occur | produce in a dry state hydrogel (indicator). That is, if the indicator is in a dry state before use and is in a water-containing state at the start of use, the characteristics of the fluorescent sensor at the time of use are stable even after long-term storage.

  For this reason, in the fluorescence sensor 30, the indicator 19 is in a dry state before use. That is, before use, the indicator space 16 is occupied by a dry indicator 19 and a gas such as air. Then, as shown in FIG. 5, when inserted into the body at the start of use, the indicator 19 swells by absorbing body fluid such as blood, that is, water through the light shielding layer 18.

  The indicator 19 may be swollen in advance by immersing the fluorescent sensor 30 in physiological saline or the like before insertion into the body. However, it is preferable that the indicator 19 is swollen with a body fluid containing an analyte because a stable measurement state can be obtained earlier.

  After the fluorescent sensor 30 is inserted into the body, the analyte concentration can be continuously measured for a predetermined period, for example, one week. However, the collected bodily fluid or the bodily fluid circulating through the body via the flow path outside the body may be brought into contact with the fluorescence sensor 30 outside the body without inserting the fluorescence sensor 30 into the body.

  Next, components of the fluorescent sensor 30 will be described in detail.

  The substrate 11 has a PD element 12. As the substrate, a semiconductor substrate such as silicon is suitable when the PD element 12 is formed on the substrate by a semiconductor manufacturing technique. Further, a photoconductor, a phototransistor, or the like may be used as the photoelectric conversion element.

  The filter 13 is disposed so as to cover the PD element 12 that is a light receiving unit. The filter 13 blocks, for example, the excitation light E having a wavelength of 375 nm generated by the light emitting element 14 disposed on the filter 13, but transmits the fluorescence F having a wavelength of 460 nm generated by the indicator 19.

  The filter 13 may be a multiple interference filter, but is preferably a light absorption filter, for example, a single layer made of silicon, silicon carbide, silicon oxide, silicon nitride, or an organic material, or the single layer It is a multilayer layer formed by laminating.

  The filter 13 may be disposed on the PD element 12 via a transparent protective layer made of, for example, silicon oxide or silicon nitride. However, the filter 13 is preferably disposed as close as possible to the PD element 12 in order to prevent light from entering from the side surface of the protective layer. Further, if there is a space between the PD element 12 and the filter 13, an optical loss occurs and the transmittance decreases. For this reason, it is particularly preferable that the filter 13 is disposed in close contact with the PD element 12.

  As the light emitting element 14, an element that transmits fluorescence F is selected from light emitting elements that emit desired excitation light E such as an LED element, an organic EL element, an inorganic EL element, or a laser diode element.

  The light emitting element 14 is an LED element from the viewpoints of fluorescence transmittance, light generation efficiency, wide wavelength selectivity of the excitation light E, and generation of only light other than the wavelength having the excitation action. preferable. Further, among LED elements, an ultraviolet LED element made of a gallium nitride-based compound semiconductor formed on a sapphire substrate having high fluorescence F transmittance is particularly preferable.

  The transparent intermediate layer 15 disposed on the light emitting element 14 is required to have good electrical insulation properties, moisture barrier properties, light transmittance for the excitation light E and fluorescence F, and the like. Further, as a characteristic of the transparent intermediate layer 15, it is important that the generation of the fluorescence F is small even when the excitation light E is irradiated, that is, it is difficult to emit autofluorescence.

  For the transparent intermediate layer 15, quartz, glass, silicone resin, or transparent amorphous fluororesin is preferably used, and among them, silicone resin or transparent amorphous fluororesin is particularly preferable.

  The indicator 19 is made of a hydrogel having a fluorescent dye that generates fluorescence F having a longer wavelength than the excitation light E by the analyte 2 and the excitation light E. In other words, the indicator 19 is composed of a hydrogel that contains the fluorescent dye that generates the fluorescence F with a light amount corresponding to the analyte concentration in the sample and that allows the excitation light E and the fluorescence F to pass therethrough satisfactorily. The indicator 19 may be the analyte 2 itself in which the fluorescent dye that does not contain the fluorescent dye and generates the fluorescent F exists in the solution.

  Hydrogel is water such as acrylic hydrogel produced by polymerizing monomers such as polysaccharides such as methylcellulose or dextran, acrylamide, methylolacrylamide, hydroxyethyl acrylate, or urethane hydrogel produced from polyethylene glycol and diisocyanate. It is formed by encapsulating a fluorescent dye in a material that is easy to contain.

  It is preferable that the hydrogel has a size that does not leave the sensor through the light shielding layer 18. For this reason, the hydrogel has a molecular weight of 1 million or more, or when the light shielding layer 18 has a porous structure, it is in the form of particles having a diameter larger than the pore diameter, for example, 50 nm or larger, or crosslinked. A form that does not flow is preferred.

  On the other hand, as a fluorescent dye, a phenylboronic acid derivative having a fluorescent residue is suitable for measuring saccharides such as glucose. The fluorescent dye is prevented from detaching from the sensor by using a high molecular weight material or chemically fixing to a hydrogel.

  The indicator is produced by allowing a phosphate buffer solution containing a fluorescent dye, a gel skeleton-forming material, and a polymerization initiator to stand for 1 hour in a nitrogen atmosphere and polymerize. For example, as the fluorescent dye, 9,10-bis [N- [2- (5,5-dimethylborinan-2-yl) benzyl] -N- [6 ′-[(acryloylpolyethyleneglycol-3400) carbonylamino ] -N-hexylamino] methyl] -2-acetylanthracene (F-PEG-AAm), acrylamide as the gel skeleton-forming material, sodium peroxodisulfate and N, N, N ′ as the polymerization initiator N'-tetramethylethylenediamine is used.

  In addition, since the indicator 19 which superposition | polymerization was completed is a water-containing state, after drying until it will be in a predetermined | prescribed dry state, the fluorescence sensor 30 will be a completed product.

  Since the indicator 19 in the dry state has little change with time, the characteristics such as sensitivity at the time of use of the fluorescent sensor 30 do not change even when stored for a long period of time.

  The light shielding layer 18 forms an upper surface of the indicator space 16 in which the indicator 19 is accommodated, and prevents the excitation light E and the fluorescence F from leaking to the outside of the fluorescence sensor, and at the same time, external light enters the inside of the fluorescence sensor. To prevent that. Further, the light shielding layer 18 has biocompatibility, and the basic structure portion is hydrophilic so as not to prevent passage of a body fluid containing the analyte 2.

  For the light shielding layer 18, for example, a composite material is used in which a hydrogel used for the indicator 19 is mixed with fine particles that do not transmit light such as carbon black or carbon nanotubes.

  Further, the light shielding layer 18 includes a hydrophilic portion 18A and a hydrophobic portion 18B. As shown in FIG. 3, in the fluorescence sensor 30, the hydrophilic portion 18 </ b> A of the basic structure portion is the central portion of the light shielding layer 18 including the portion directly above the PD element 12, and the hydrophobic portion 18 </ b> B is on the peripheral portion of the PD element 12. This is an edge portion of the light shielding layer 18. The arrangement positions of the hydrophilic portion 28A and the hydrophobic portion 28B of the light shielding layer 28 are not limited to the above arrangement as long as the gas remaining in the indicator space 16 does not greatly affect the measurement. .

  In the indicator space 16, the indicator 19 that absorbs water and expands easily in the vicinity of the hydrophilic portion 18 </ b> A, whereas the indicator 19 spreads in the vicinity of the hydrophobic portion 18 </ b> B because gas tends to stay. Hateful.

  The sensor frame 17 has a function of protecting the sensor main body and a light shielding function, that is, a function of preventing entry of outside light and preventing leakage of light from the inside of the sensor to the outside of the sensor. The sensor frame 17 is made of a highly rigid material in order to protect the sensor body.

  The sensor frame 17 is made of a resin material such as silicon, glass or metal having a Young's modulus of several tens to several hundreds of GPa, or polypropylene or polystyrene having a Young's modulus of about 1 GPa to 5 GPa. In order to improve the light shielding function, black is used when glass or a resin material is used. As will be described later, the sensor frame 17 may be manufactured from a part of the substrate by processing the substrate 11.

  As described above, in the fluorescent sensor 30, the indicator 19 in the dry state is accommodated in the indicator space 16. The capacity of the indicator space 16 is substantially the same as the capacity of the swollen indicator 19, for example, 100% to 110% of the capacity of the swollen indicator 19. That is, as shown in FIG. 8, the indicator space 16 is filled with the swollen indicator 19. That is, the indicator 19 swells in the shape of the indicator space 16.

  The size of the indicator space 16 is, for example, about 0.20 × 1.00 mm and a depth of about 0.05 mm when a commercially available small LED (size: 0.12 × 0.06 mm) is used as the light emitting element 14. Such an indicator space 16 can be easily manufactured using a semiconductor manufacturing technique, as will be described later.

  Next, a change at the start of use of the fluorescence sensor 30 will be described. As already described, in the fluorescent sensor 30, the indicator 19 is housed in the indicator space 16 in a dry state before use. For this reason, the fluorescence sensor 30 can be stored for a long time.

  When the hydrogel, that is, the fluorescent sensor 30 in which the indicator 19 is in a dry state is inserted into the specimen for use, the indicator 19 contacts the body fluid and the like, and the indicator 19 absorbs the body fluid and expands.

  That is, as shown in FIG. 5, in the fluorescence sensor 30, when the light shielding layer 18 is in contact with the body fluid, the body fluid together with the analyte 2 passes through the hydrophilic portion 18 </ b> A of the light shielding layer 18. Is absorbed by the indicator 19 (hydrogel).

  As the indicator 19 expands, the gas in the indicator space 16 is gradually absorbed into the body fluid. As shown in FIG. 5, the gas that has not been absorbed by the body fluid moves to the hydrophobic portion 18 </ b> B side and stays at the edge portion of the indicator space 16. The staying gas is gradually absorbed into the body fluid.

  As described above, since the residual gas is accommodated in the edge portion of the indicator space 16 in the fluorescence sensor 30, the PD element 12 below the central portion of the indicator space 16 has a fluorescence intensity, that is, an analyte concentration. It can be detected with high accuracy and high sensitivity.

  Further, in the fluorescent sensor 30, the indicator 19 is in a dry state until just before the start of use, and therefore does not deteriorate with time.

  Therefore, the fluorescence sensor 30 can accurately measure the analyte concentration.

Next, a method for manufacturing the fluorescence sensor 30 will be briefly described with reference to the flowchart of FIG.
<Step S10> Substrate Fabrication Process PD element 12 that converts fluorescence into an electrical signal is fabricated on substrate 11 by semiconductor manufacturing technology.

<Step S11> Filter Arrangement Step A light absorption filter 13 that transmits fluorescence and blocks excitation light is disposed so as to cover the PD element 12. A transparent protective layer made of silicon oxide or the like is disposed on the filter 13 as necessary.

<Step S12> Sensor Frame Arrangement Step The sensor frame 17 is arranged on the substrate 11 so that the PD element 12 is arranged inside.

<Step S <b>13> Light-Emitting Element Arrangement Step The light-emitting element 14 that generates excitation light is arranged in the sensor frame 17. The sensor frame 17 may be disposed after the light emitting element 14 is disposed.

<Step S14> Transparent Intermediate Layer Arrangement Step A transparent intermediate layer 15 made of a transparent amorphous fluororesin is disposed inside the sensor frame 17, that is, on the light emitting element 14.

<Step S15> Indicator Arrangement Step The sensor frame 17 is filled with a phosphate buffer containing fluorescent molecules, acrylamide, and a polymerization initiator.

<Step S16> Light Shielding Layer Arrangement Step First, the light shielding layer 18 is subjected to a hydrophobic treatment or a hydrophilic treatment. That is, when the basic structure part (base material) of the light shielding layer is hydrophobic, a hydrophilic part is produced, and when it is hydrophilic, a hydrophobic part is produced.
When the base material of the light shielding layer 18 is hydrophobic, the region not masked is oxidized by electron beam irradiation or UV irradiation through the mask to produce the hydrophilic portion 18A.

  In order to accelerate the hydrophilic treatment, the surface may be pretreated. In the pretreatment, a pretreatment solution made of a hydrophilic monomer such as acrylamide, vinyl pyrrolidone, or NN dimethylacrylamide, or a polymer solution thereof is spray-coated or impregnated. When the pretreatment material is solid, it is liquefied by dissolving it in an appropriate solvent, for example, an aqueous solution containing a surfactant, or dissolving it in alcohol. Moreover, you may improve the light-shielding property of the light shielding layer 18 by adding the pigment currently used by the inkjet printer etc. in the pretreatment solution. When the base material of the light shielding layer 18 is hydrophilic, the surface is hydrophobized with, for example, a silane coupling agent.

  In the fluorescent sensor 30, the hydrophilic portion 18A and the hydrophobic portion 18B may be formed only on the upper surface of the indicator space 16. Further, a hydrophilic portion or a hydrophobic portion may be formed on the surface constituting the indicator space 16 of at least one of the sensor frame 17 and the transparent intermediate layer 15.

  The indicator space 16 is sealed by joining the light shielding layer 18 to the sensor frame 17. And by leaving it for 1 hour in nitrogen atmosphere, the hydrogel in the indicator space 16 superposes | polymerizes and the indicator 19 is produced.

<Step S17> Drying Step Since the produced indicator 19 is in a water-containing state, the fluorescent sensor 30 is dried after washing until the indicator 19 becomes a desired water content or less. The indicator 19 shrinks due to drying, and the volume becomes, for example, 50% or less of the indicator space 16.

  A plurality of PD elements 12 are formed on a silicon wafer, and a filter 13, a sensor frame 17, a light emitting element 14, a transparent intermediate layer 15, an indicator 19, and a light shielding layer 18 are disposed on each PD element 12 and dried. After the processing, a plurality of fluorescent sensors 30 may be manufactured in a lump by cutting them into pieces.

  According to the method for manufacturing a fluorescent sensor of the present embodiment, the fluorescent sensor 30 capable of accurately measuring the analyte concentration can be manufactured.

Second Embodiment
Next, the fluorescence sensor 30A of the second embodiment will be described. Since the fluorescence sensor 30 of the present embodiment is similar to the fluorescence sensor 30, the same components are denoted by the same reference numerals and description thereof is omitted.

  The light shielding layer 28 of the fluorescence sensor 30A shields external light and excitation light as well as the light shielding layer 18 of the fluorescence sensor 30, allows body fluids including analytes to pass through, and discharges the gas in the indicator space 16 to the outside. Is possible.

  For example, the light shielding layer 28 is made of a layer having a through hole or a porous material. Further, the light shielding layer 28 includes a hydrophilic portion 28A through which a body fluid containing an analyte passes and a hydrophobic portion 28B through which a gas passes.

  In the production of the hydrophobic portion 28B, for example, after a through-hole through which an analyte can pass is formed in a silicon substrate, a silane coupling agent is applied to the entire surface to make it hydrophobic. Subsequently, when the region to be the hydrophilic portion 28A is irradiated with vacuum ultraviolet light, the silane coupling agent is decomposed to become hydrophilic.

  As shown in FIG. 8, when the body fluid enters the indicator space 16 from the hydrophilic portion 28A of the light shielding layer 28 and the indicator 19 expands, the gas in the indicator space 16 is discharged from the hydrophobic portion 28B.

  That is, in the fluorescence sensor 30A, when the light shielding layer 28 is inserted into a living body and the body fluid comes into contact with the body fluid, the body fluid containing the analyte 2 is absorbed by the indicator 19 (hydrogel) in the indicator space 16 through the hydrophilic portion 28A. The On the other hand, even if the hydrophobic part 28B comes into contact with the body fluid, the body fluid does not enter and is secured as a gas discharge path.

  As shown in FIG. 8, in the fluorescence sensor 30A, gas such as air is completely discharged from the indicator space 16, and the indicator space 16 is filled with the indicator 19 swollen by body fluid. The indicator space 16 is in a uniform state, there is no local change in surface reflectance, light scattering, or transmittance, and the residual gas is incident on the detection region (PD element 12) of the fluorescence F generated by the indicator 19. There will be no disturbance. Further, the residual gas does not adversely affect the intensity of the fluorescence F generated by the indicator 19. Therefore, the PD element 12 below the indicator space 16 can detect the fluorescence intensity, that is, the analyte concentration with high accuracy and high sensitivity.

  The fluorescence sensor 30A has the effect of the fluorescence sensor 30 and can measure the analyte concentration more accurately. Note that gas may remain in the indicator space 16 as long as the volume and position do not hinder measurement.

<Third Embodiment>
Next, the fluorescence sensor 30B of the third embodiment will be described. Since the fluorescence sensor 30B is similar to the fluorescence sensor 30, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 9, the indicator 19 of the fluorescence sensor 30 </ b> B includes a binding region 18 </ b> C of the hydrophilic portion 18 </ b> A of the light shielding layer 18 that forms the upper surface of the indicator space 16 and a part of the sensor frame 17 that forms the side surface of the indicator space 16. It is fixed to the coupling region 17C. For this reason, the position of the dry indicator 19 in the indicator space 16 is always the same.

  For the joining of the light shielding layer 18 and the sensor frame 17 and the indicator 19, an anchor effect due to the entry of the indicator 19 into a hole or the like may be used, or an adhesive may be used. However, the reliability and the manufacturing process are simplified. From the viewpoint of making it easier, bonding via a covalent bond is preferable. A covalent bond is a chemical bond formed by sharing an electron pair between two atoms, and has high bonding strength. A covalent bond can be easily formed during the polymerization reaction of the indicator 19.

  And since the coupling | bond area | region 18C of the light shielding layer 18 to which the indicator 19 is fixed is the hydrophilic part 18A, a bodily fluid tends to contact the indicator 19. FIG. On the other hand, in the coupling region 17C of the sensor frame 17 to which the indicator 19 is fixed, the indicator 19 that gradually swells is set at a position that does not hinder the movement of gas to the hydrophobic portion 18B.

That is, the coupling region 18C of the light shielding layer 18 is the hydrophilic portion 18A, and the coupling region 17C of the sensor frame 17 is at the position farthest from the hydrophobic portion 18B. The arrangement positions of the hydrophilic portion 18A and the hydrophobic portion 18B of the light shielding layer 18 are not limited to the above arrangement as long as the gas in the indicator space 16 can move quickly to the edge portion.

  When the body fluid containing the analyte enters the indicator space 16 via the light shielding layer 18, the absorbed indicator 19 always expands as shown in FIG. That is, the indicator 19 fixed to the coupling region 18C of the light shielding layer 18 and the coupling region 17C of the sensor frame 17 in the dry state always swells in the same manner. For this reason, the gas in the indicator space 16 moves to the edge portion of the indicator space 16 on the peripheral portion of the PD element 12 and does not remain in the central portion of the indicator space 16 on the PD element 12. Therefore, the PD element 12 can detect the fluorescence intensity, that is, the analyte concentration with high accuracy and high sensitivity.

  In the fluorescence sensor 30B, the position of the indicator 19 in the indicator space 16 is fixed, and non-uniform swelling due to local water absorption causes gas to enter the indicator space 16 above the PD element 12 serving as the fluorescence detection region. There is no fear of remaining.

  For this reason, the fluorescence sensor 30B has the effect which the fluorescence sensor 30 has, and a more exact measurement is possible.

<Fourth embodiment>
Next, the fluorescence sensor 30C of the fourth embodiment will be described. Since the fluorescence sensor 30C is similar to the fluorescence sensor 30, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 10, the fluorescence sensor 30 </ b> C has a gas accommodating part 22 in the hydrophobic part 18 </ b> B of the indicator space 16. The gas accommodating portion 22 is disposed at the edge portion of the indicator space 16 that is not easily affected by light scattering and the like, and accommodates the gas pushed out by the expansion of the indicator 19.

  The gas container 22 is, for example, a porous block made of silica or silicon, or a block obtained by making activated carbon or the like hydrophobic with a silane coupling agent.

  In the fluorescence sensor 30 </ b> C, since gas is accommodated in the gas accommodating portion 22, no gas remains in the central portion of the indicator space 16 above the PD element 12. Further, the fluorescence generated by the indicator 19 is reflected by the wall surface of the gas storage unit 22 and enters the PD element 12. That is, when the surface of the gas storage unit 22 is covered with, for example, a metal film having a through-hole so as to reflect fluorescence, more fluorescence is incident on the PD element 12, and thus the detection of the fluorescence sensor 30C is performed. High sensitivity.

  The arrangement position and the number of the gas storage units 22 can be selected as appropriate.

  The fluorescence sensor 30C has the effect that the fluorescence sensor 30 has, and can measure the analyte concentration more accurately.

<Fifth Embodiment>
Next, the fluorescence sensor 30D of the fifth embodiment will be described. Since the fluorescence sensor 30D is similar to the fluorescence sensors 30A and 30B, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 11, the light shielding layer 28 of the fluorescence sensor 30D includes a hydrophilic portion 28A and a hydrophobic portion 28B, and allows gas to pass therethrough. The indicator 19 is fixed to the coupling region 28C of the hydrophilic portion 28A and the coupling region 17C of the sensor frame 17.

  In the fluorescence sensor 30D, when the light shielding layer 28 is inserted into the living body and comes into contact with the body fluid, the body fluid including the analyte 2 is absorbed by the indicator 19 (hydrogel) in the indicator space 16 through the hydrophilic portion 28A. When water is absorbed, since the indicator 19 is fixed to the coupling region 28C and the coupling region 17C, it always expands in the same manner.

  On the other hand, even if the hydrophobic part 28B comes into contact with the body fluid, the body fluid does not enter and is secured as a gas discharge path.

  The fluorescence sensor 30D has the effects that the fluorescence sensors 30A and 30B have.

<Sixth Embodiment>
Next, the fluorescence sensor 30E of the sixth embodiment will be described. Since the fluorescence sensor 30E is similar to the fluorescence sensor 30 and the like, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 12, in the fluorescence sensor 30E, the PD element 12E is formed on the four side surfaces of the recess formed in the substrate 11E made of a semiconductor such as silicon, and the light emitting element 14 is disposed on the bottom surface of the recess. The opening surface of the recess is wider than the bottom surface, and the side surface is not perpendicular to the bottom surface but is inclined at a predetermined angle θ. In addition, the board | substrate 11E which has a recessed part may be produced by joining the frame-shaped sensor frame board | substrate used as a recessed part, and a plane board | substrate.

  In addition, a dried indicator 19 is disposed at the center of a recess made of a transparent intermediate layer 15E that covers the PD element 12E and the filter 13E. A light shielding layer 28 having a hydrophobic portion 28B in the central portion and a hydrophilic portion 28A in the peripheral portion forms the upper surface of the indicator space 16E. Further, on the upper surface of the central portion of the indicator space 16E, a gas accommodating portion 22E is disposed in contact with the hydrophobic portion 28B.

  As shown in FIG. 13, the dried indicator 19 is fixed by covalent bonding in a bottom surface of a recess made of a transparent intermediate layer 15E and a bonding region 15C made of four side surfaces. The dried indicator 19 is also fixed to the bonding region 28C other than the central portion of the light shielding layer 28 by covalent bonding. That is, the dried indicator has a concave portion at the center, and the gas accommodating portion 22E is disposed inside the concave portion. In addition, the outer surface of the gas accommodating portion 22E is covered with a reflective layer made of a metal having a through hole.

  When the fluorescent sensor 30E is inserted into the body, the body fluid containing the analyte is absorbed by the indicator 19 through the hydrophilic portion 28A. The expanded indicator 19 accommodates the gas in the indicator space 16E in the gas accommodating part 22E at the upper center part and is discharged outside from the hydrophobic part 28B via the gas accommodating part 22E.

  In addition, the fluorescence emitted to the gas accommodating portion 22E side is reflected by the reflective layer on the surface and enters the PD element 12E.

  Next, a method for manufacturing the fluorescence sensor 30E will be briefly described. In addition, although it may manufacture for every one fluorescence sensor 30E, it is preferable to manufacture many sensors collectively as a wafer process.

  That is, first, a mask layer having a plurality of mask portions on the first main surface of a silicon wafer having an area where a plurality of elements can be manufactured is manufactured. Then, a plurality of recesses having a bottom surface parallel to the first main surface is formed by an etching method.

  As an etching method, a wet etching method using a tetramethylammonium hydroxide (TMAH) aqueous solution, a potassium hydroxide (KOH) aqueous solution, or the like is preferable, but dry etching such as reactive ion etching (RIE) or chemical dry etching (CDE) is used. Can also be used

  For example, when a silicon (100) surface is used as a silicon wafer, the etching speed of the (111) surface is slower than that of the (100) surface, so that the side surface of the recess becomes the (111) surface. The angle with the (100) plane (bottom surface) is 54.7 degrees.

  Next, PD elements 12E are formed on the four side surfaces of the respective recesses by a known semiconductor process. The concave portion whose side surface is inclined has not only a large area where the PD element 12 can be formed, but also the formation of the PD element 12E on the side surface is easier than the concave portion whose vertical side surface is vertical. Hard to remain. In addition, the said effect is remarkable if the inclination-angle of a side surface is 30-70 degree | times.

  Next, the filter 13E is disposed on the side PD element 12E. Next, the light emitting elements 14 are respectively disposed on the bottom surfaces of the plurality of recesses. Further, after forming the transparent intermediate layer 15E and the covalent bond forming monomer layer, a buffer solution serving as the indicator 19 is filled in the recess. Further, the light shielding layer 28 that is hydrophobic and does not have the covalent bond forming monomer layer is bonded to the central portion where the gas accommodating portion 22E is bonded so as to close the opening of the recess. Then, the silicon wafer on which a plurality of sensors are formed is separated into pieces, and the fluorescence sensor 30E is completed. The drying process may be performed in a wafer state or after being separated into individual pieces.

  The fluorescent sensor 30E has the same effect as the fluorescent sensor 30 and the like, and the substrate 11E also serves as a frame portion, and the side surface of the concave portion that is the PD element forming surface is inclined, so that the manufacturing is easy.

  In addition, although the shape of the whole fluorescence sensor demonstrated in the said several embodiment was a right-angled column shape, it is a trapezoid shape, the shape where the side surface curved, or the needle-type fluorescence sensor etc. which extended one direction of the sensor side surface etc. There may be.

  In addition, a sensor that detects saccharides such as glucose has been described as an example. However, a fluorescent sensor can be used for various applications such as an enzyme sensor, a pH sensor, an immunosensor, or a microorganism sensor by selecting a fluorescent dye. .

  That is, the present invention is not limited to the above-described embodiments and modifications, and various changes and modifications can be made without departing from the scope of the present invention.

2 ... analyte, 11 ... substrate, 12 ... PD element, 13 ... filter, 14 ... light emitting element, 15 ... transparent intermediate layer, 16 ... indicator space, 17 ... sensor frame, 18 ... light shielding layer, 18A ... hydrophilic part, 18B ... hydrophobic part, 19 ... indicator, 22 ... gas storage part, 28 ... light shielding layer, 28A ... hydrophilic part, 28B ... hydrophobic part, 30, 30A-30E ... fluorescence sensor, 110 ... fluorescence sensor, 111 ... transparent Substrate, 112 ... photoelectric conversion element, 115 ... transparent intermediate layer, 118 ... light shielding layer, 119 ... indicator

Claims (9)

A photoelectric conversion element that converts fluorescence into an electrical signal;
A sensor frame constituting a side surface of an indicator space in which an indicator made of a hydrogel that generates fluorescence by an analyte and excitation light is accommodated in a dry state;
A filter disposed so as to cover the photoelectric conversion element and transmitting the fluorescence and blocking the excitation light;
A light emitting element that generates the excitation light, disposed in the sensor frame;
A transparent intermediate layer disposed on the light emitting element and constituting a lower surface of the indicator space, disposed in the sensor frame;
A light shielding layer that constitutes an upper surface of the indicator space, blocks external light and the excitation light, allows the body fluid containing the analyte to pass therethrough, and further includes a hydrophilic portion and a hydrophobic portion; A fluorescent sensor characterized by that.   The fluorescence sensor according to claim 1, wherein the light shielding layer on the photoelectric conversion element includes the hydrophilic portion.   The fluorescence sensor according to claim 1, wherein the light shielding layer is capable of passing a gas.   The fluorescent sensor according to claim 3, wherein the light shielding layer has a through hole.   The fluorescent sensor according to claim 3, wherein the light shielding layer is made of a porous material.   The fluorescent sensor according to any one of claims 1 to 5, wherein the indicator is fixed to at least a part of at least one of surfaces constituting the indicator space.   The fluorescent sensor according to any one of claims 1 to 6, further comprising a gas accommodating portion that accommodates a gas in a region including the hydrophobic portion of the indicator space.   The fluorescence sensor according to any one of claims 1 to 7, wherein when the indicator absorbs the body fluid and swells, the gas in the indicator space moves to the hydrophobic part.   9. The analyte concentration of the bodily fluid is continuously measured based on the intensity of the fluorescence generated by the indicator that is placed in a living body and contains water. The fluorescent sensor according to item.

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