JP4903911B2 - Chemical substance sensing device and chemical substance sensing system including the same - Google Patents

Description

  The present invention relates to a chemical substance sensing apparatus and a chemical substance sensing system including the chemical substance sensing apparatus, and more particularly to a chemical substance sensing apparatus capable of selectively detecting a specific breath marker substance and a chemical substance sensing system including the chemical substance sensing apparatus.

  At present, in Japan, there are concerns about an increase in medical expenses and a collapse of the medical insurance system, and there is an urgent need to realize a preventive medical society that can prevent reliance on medical care. In order to realize a preventive medical society, it is said that each person needs to have a system that can easily and quickly check a health condition.

  Blood, urine, sweat, saliva, exhalation and the like are generally known as biological specimens used for easily and quickly grasping the health condition of an individual. In particular, exhaled breath is known to contain a large amount of biological information related to diseases because the air in the alveoli in the body and the blood in the capillaries are only separated by a very thin membrane.

  Therefore, by measuring the concentration of a volatile substance present in a minute amount in human breath, measurement data of the concentration of the volatile substance is obtained, and based on the measurement data, the health condition (metabolic reaction, biochemical Research is ongoing on how to understand the pathological mechanism. Since exhaled breath can detect living body information non-invasively, it is expected to be widely used as a system that can easily and quickly check a health condition.

For example, ethane, pentane, H ₂ O _{2 and the} like contained in exhaled breath have a high correlation with oxidative stress, and when these concentrations in exhaled breath increase, they tend to have symptoms such as lipid oxidation, asthma and bronchitis. Further, NO, CO, and H ₂ O ₂ contained in exhaled breath have a high correlation with lung diseases, and when these concentrations in exhaled breath increase, they tend to have symptoms such as asthma and chronic obstructive pneumonia. Further, H ₂ and carbon isotopes contained in exhaled breath have a high correlation with gastrointestinal diseases, and symptoms such as indigestion, gastritis, and duodenal ulcer are observed when these concentrations in exhaled breath increase.

  In addition, acetone contained in exhaled breath has a high correlation with metabolic abnormalities, and when the concentration of acetone in the exhaled breath tends to have diabetes symptoms, a decrease in the concentration of acetone contained in exhaled breath tends to cause metabolic syndrome. There is.

  Thus, by detecting the concentration of the gas contained in the exhalation of the subject, the tendency of the symptoms that the subject has can be grasped beforehand. As described above, a specific gas whose concentration in the breath significantly increases or decreases in conjunction with a disease is defined as “expiration marker substance”. In recent years, several breath measuring devices for diagnosing a disease tendency by grasping the concentration of such a breath marker substance have been developed.

For example, Japanese Patent Laid-Open No. 2001-349888 (hereinafter also referred to as “Patent Document 1”) uses an oxide semiconductor sensor widely used in a gas sensor to detect a specific breath marker substance contained in the breath. An apparatus is disclosed. The oxide semiconductor sensor used in the breath measuring device has a surface made of an n-type semiconductor such as SnO ₂ or ZnO. When the n-type semiconductor adsorbs the exhalation marker substance, the exhalation marker substance and oxygen react to change the electrical resistance. By measuring this change in electrical resistance, a specific exhalation marker substance (for example, acetone) among the exhalation marker substances is detected.

  As described above, the oxide semiconductor sensor has a property of specifying the breath marker substance by referring to the amount of oxygen that reacts. Therefore, an exhalation marker substance having a large amount of reacting oxygen, such as an exhalation marker substance having a large number of carbon atoms and an exhalation marker substance having a high degree of unsaturation, can be measured with higher accuracy. By using such an oxide semiconductor sensor, it is possible to provide a breath measuring device that is small and detects a specific breath marker substance.

  Normally, exhaled air contains as much as 80% of moisture, but if exhaled air is introduced into the oxide semiconductor sensor in this state, there is a problem that the oxide semiconductor sensor deteriorates due to moisture. Further, in a state where moisture is still contained in the exhaled breath, there is a problem that the moisture inhibits the detection of the exhaled marker substance, and the oxide semiconductor sensor cannot detect the exhaled marker substance having a low concentration of ppm to ppb level.

  Therefore, in order to accurately measure the moisture-containing gas, the moisture removing means for measuring the gas in the soil as disclosed in Japanese Patent Application Laid-Open No. 11-281605 (hereinafter also referred to as “Patent Document 2”). Is required. By providing the moisture removing means as shown in Patent Document 2, it is possible to avoid a decrease in measurement accuracy due to moisture as described above.

  However, the oxide semiconductor sensor disclosed in Patent Document 1 has the same sensitivity when measuring an exhalation marker substance having the same amount of oxygen necessary for oxidation. For this reason, it is impossible in principle to selectively detect only a specific exhalation marker substance (for example, acetone) from 200 kinds or more of exhalation marker substances.

  Moreover, said oxide semiconductor sensor detects an exhalation marker substance by heating about 300 degreeC and burning an exhalation marker substance. For this reason, the power consumption of the breath measuring device is greatly lost by heating, and as a result, the consumption of the breath measuring device is expedited, and there is a problem that the use time of the breath measuring device becomes extremely short.

  In order to avoid these problems, US Patent Application Publication No. 2007/0048180 (hereinafter also referred to as “Patent Document 3”) discloses a sensor for detecting an exhalation marker substance other than the above-described oxide semiconductor sensor. A nanostructure sensor using a nanostructure represented by a carbon nanotube (hereinafter also simply referred to as “CNT”) is also disclosed.

  Such a nanostructure sensor using CNTs is expected to be a next-generation sensor because it is ultra-compact, has low power consumption, is an ultra-sensitive gas sensor, and can measure exhalation in a non-invasive manner. Has been sent.

JP 2001-349888 A Japanese Patent Laid-Open No. 11-281605 US Patent Application Publication No. 2007/0048180

  By using the nanostructure sensor as described above, a specific exhalation marker substance can be detected from 200 or more exhalation marker substances. However, the accuracy of the detection is still not sufficient, and it is required to detect the expiration marker substance with higher accuracy.

  It is also required to detect a specific exhalation marker substance from other exhalation marker substances contained in exhaled breath by enhancing the selectivity between the exhalation marker substance and the nanostructure sensor.

  The present invention has been made in view of such a current situation, and an object thereof is to provide a chemical substance sensing device capable of detecting a specific exhalation marker substance with higher accuracy, and the same. It is to provide a chemical substance sensing system.

  The present inventors can detect a specific exhalation marker substance with high accuracy by eliminating exhalation marker substances and moisture that are not required to be contained in the exhalation before the exhalation reaches the chemical substance sensing element. I got the idea. Based on this idea, various studies were made on the configuration of the chemical substance sensing device.

  As a result, by providing an introduction molecular sieve membrane and an exhaust molecular sieve membrane in the chamber, it is possible to efficiently eliminate exhalation marker substances and moisture that do not need to be measured, and to detect specific exhalation marker substances with higher accuracy. I found out that I can.

  In addition, by disposing a hollow fiber in the moisture removing section provided in the chemical substance sensing system, moisture contained in exhaled air can be efficiently removed, thereby detecting a low concentration exhaled marker substance contained in exhaled breath. As a result, the present invention has been completed.

  That is, the chemical substance sensing device of the present invention includes a chamber divided into three spaces by an introduced molecular sieve membrane and an exhausted molecular sieve membrane, and a chemical substance sensing element in contact with the chamber in the space sandwiched between the introduced molecular sieve membrane and the exhausted molecular sieve membrane It is characterized by providing.

  The introduced molecular sieve membrane and the discharged molecular sieve membrane are preferably made of zeolite. The average pore diameter of the introduced molecular sieve membrane is preferably larger than the average pore diameter of the discharged molecular sieve membrane.

  Moreover, it is preferable to provide a heating device on the outer surface of the introduced molecular sieve membrane and the outer surface of the discharged molecular sieve membrane.

  The chemical substance sensing element is preferably a nanostructure sensor. The nanostructure sensor is preferably composed of carbon nanotubes whose surface is modified with a metal complex in the sensing part.

  The present invention includes the above-described chemical substance sensing device, a gas introduction path for introducing gas into the chemical substance sensing apparatus, a gas introduced from the gas introduction path and the chemical substance sensing apparatus, and gas from the gas introduction path It is also a chemical substance sensing system comprising a moisture removing unit for adsorbing the moisture and a gas discharge path for discharging gas from the chemical substance sensing device.

  It is preferable that a check valve is installed between the chemical substance sensing device and the moisture removing unit, and a check valve is installed between the chemical substance sensing device and the gas discharge path. It is preferable that the moisture removing unit includes a hollow fiber. The hollow fiber is preferably made of a fluororesin.

  ADVANTAGE OF THE INVENTION According to this invention, the chemical substance sensing apparatus which can detect a specific expiration | expired_air marker substance from multi-component type expiration with high precision, and a chemical substance sensing system provided with the same can be provided.

  According to the chemical substance sensing device of the present invention, it is possible to exclude low molecular and high molecular exhalation marker substances, and to suppress deterioration of the chemical substance sensing element.

  In addition, biological information depending on a disease can be detected, and a chemical substance sensing element that is non-invasive, ultra-compact, low power consumption, ultra-sensitive, and highly selective can be provided. Accordingly, it is possible to provide a chemical substance sensing device with less stress on the user during use, and a chemical substance sensing system including the chemical substance sensing apparatus.

It is a schematic diagram which shows one form of the chemical substance sensing system of this invention. (A) It is a figure which shows an example of the shape of the base material used for the chemical substance sensing apparatus of this invention, (b) is a figure which shows an example of the shape of the base material different from (a). (C) In the chemical substance sensing apparatus of this invention, it is typical sectional drawing when a chamber is cut | disconnected by the surface containing a discharge | emission molecular sieve membrane. It is a schematic diagram which shows an example of the semiconductor sensor which can be used as a chemical substance sensing element. It is a schematic diagram which shows an example of the nanostructure sensor provided with the sensing part comprised from the carbon nanotube surface-modified by the metal complex. (A) It is a graph which shows the result when the gas discharged | emitted from the chemical substance sensing apparatus of Example 1 is measured by GC-MS, (b) The gas discharged | emitted from the chemical substance sensing apparatus of the comparative example 1 is GC. -It is a graph which shows a result when measured by MS. It is a graph which shows resistance change when sample gas is introduce | transduced into the chemical substance sensing apparatus of Example 1 and Comparative Example 1. FIG. It is a graph which shows resistance change when sample gas is introduce | transduced into the chemical substance sensing system of Example 2 and Comparative Example 2. FIG. It is a schematic diagram which shows one form of the connection method of the chemical substance sensing system of this invention and a terminal device. It is a schematic diagram which shows another form of the connection method of the chemical substance sensing system of this invention and a terminal device. (A) And (b) is the figure which expanded the display screen of the terminal device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, dimensions, such as length, a magnitude | size, a width | variety, etc. in drawing are changed suitably for clarification and simplification of drawing, and do not represent an actual dimension.

<Chemical substance sensing system>
FIG. 1 is a schematic diagram showing the structure of the chemical substance sensing system of the present invention. As shown in FIG. 1, the chemical substance sensing system 1 of the present invention includes a chemical substance sensing device 2, a gas introduction path 13 for introducing gas into the chemical substance sensing apparatus 2, a gas introduction path 13, and a chemical substance. A moisture removing unit 12 that is disposed between the sensing device 2 and adsorbs moisture in the gas from the gas introduction path 13 and a gas discharge path 14 that discharges the gas from the chemical substance sensing device 2 are provided. It is characterized by that.

  As described above, in the chemical substance sensing system 1 of the present invention, exhaled air is introduced into the chemical substance sensing device 2 from the gas introduction path 13 through the moisture removing unit 12. And the said exhaled air is discharge | released to external air through the gas exhaust path 14, after detecting the specific exhalation marker substance in the chamber 11 of the chemical substance sensing apparatus 2. FIG. The material used for the gas introduction path 13 and the gas discharge path 14 is not particularly limited as long as it is lightweight and has an appropriate durability. For example, an acrylic one, a polypropylene one or the like can be used. Can be used.

  Here, as a method of supplying exhalation into the chemical substance sensing device, a method of supplying exhalation into the chemical substance sensing device using a mouthpiece is generally used. When supplying exhalation using the mouthpiece in this way, a check valve for making the supply of exhalation into the chemical substance sensing device 2 constant between the water removing unit 12 and the chemical substance sensing device 2. 15 is preferably provided. In addition, it is preferable to provide a check valve 15 between the chemical substance sensing device 2 and the gas discharge path 14 so that exhaled air can be quickly discharged from the chemical substance sensing device 2 to the outside.

  By providing the check valve 15 in this way, exhaled air can be supplied into the chemical substance sensing device 2 at a predetermined flow rate. Thereby, the exhaled breath supplied into the chemical substance sensing device 2 at a constant pressure and flow rate can be analyzed, and the accuracy of measuring a specific exhaled marker substance can be increased. In addition, the method of introducing exhalation into the chemical substance sensing device 2 is not limited to the supply method using the mouthpiece. For example, once collected in a Tedlar back, the Tedlar back to the chemical substance sensing device 2 is collected. Exhalation may be supplied.

  The material used for such a check valve 15 is not particularly limited as long as it has appropriate durability, and for example, Teflon (registered trademark) or the like can be used.

<Moisture removal part>
The chemical substance sensing system 1 of the present invention is characterized in that a moisture removing unit 12 is provided between the chemical substance sensing device 2 and the gas introduction path 13. The moisture removing unit 12 is provided for removing moisture in the exhaled breath introduced from the gas introduction path 13. As described above, by providing the chemical substance sensing system 1 with the water removing unit 12, it is possible to remove the water contained in the exhaled breath. And the exhalation marker substance of the extremely low density | concentration of a ppm-ppb level is detectable by removing the water | moisture content contained in exhalation in this way. In addition, by providing the moisture removing unit 12, it is possible to suppress deterioration of the chemical substance sensing element 10 due to moisture.

  It is preferable that such a water removal part 12 is equipped with what shows water absorption, such as a hollow fiber, a silica gel, and calcium chloride. Among these water-absorbing materials, the hollow fiber is not an adsorption-type moisture removal mechanism, so that moisture in the expired air is removed without losing the pressure of the expired air, thereby reducing the burden on the user supplying the expired air. . Moreover, the hollow fiber is effective because it is small in size and has little fear of attaching or detaching other exhalation marker substances.

  Such a hollow fiber material is preferably a fluororesin from the viewpoint of heat resistance and chemical resistance. The hollow fiber preferably has a helical structure with an interval of 0.1 to 2.0 mm from the viewpoint of efficiently removing moisture in the breath, and among them, a helical structure with an interval of 1.0 mm is preferable. The structure is more preferable.

<Chemical substance sensing device>
As shown in FIG. 1, the chemical substance sensing device 2 of the present invention includes a chamber 11 divided into three spaces by an introduced molecular sieve membrane 16 and an exhausted molecular sieve membrane 17, and an introduced molecular sieve membrane 16 and an exhausted molecular sieve membrane 17. And a chemical substance sensing element 10 disposed in contact with a chamber in the sandwiched space. The introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17 divide the chamber 11 into three spaces.

  Thus, by providing the introduction molecular sieve membrane 16 and the discharge molecular sieve membrane 17 in the chamber 11, only the exhalation marker substance having a specific molecular diameter is concentrated in the space in the chamber 11 including the chemical substance sensing element 10. This means that the chemical substance sensing element 10 can detect a breath marker substance having a specific molecular diameter with high accuracy.

  This is because the exhalation marker substance having a large molecular diameter among the exhalation marker substances contained in the exhalation is prevented from permeating into the chamber 11 by the introduction molecular sieve membrane 16, and the exhalation marker substance having a small molecular diameter is excluded from the exhaust molecular sieve membrane 17. This is because only the exhalation marker substance having a specific molecular diameter remains in the space in the chamber 11 including the chemical substance sensing element 10 through the gas and discharged to the outside from the chamber 11.

Below, each member which comprises a chemical substance sensing apparatus is demonstrated.
(Chamber)
The chamber 11 supports the chemical substance sensing element 10 therein, and the introduction molecular sieve film 16 and the exhaust molecular sieve film 17 so that the space containing the chemical substance sensing element 10 can detect only a specific breath marker substance. It is a hollow member provided with. A gas introduction path 13 is connected to one surface of the surface of the chamber 11 via a moisture removing unit 12, and a gas discharge path 14 is connected to the other surface.

  The shape of the chamber 11 is not limited to a cylindrical shape as shown in FIG. 1, but may be a rectangular shape, a cube, or the like as long as it is a hollow member that can support the chemical substance sensing element 10. A sphere or the like may be used. Moreover, it is preferable that the chamber 11 is comprised with a lightweight and highly durable material, As such a material, resin materials, such as an acrylic resin and a polypropylene resin, can be mentioned, for example.

  The chamber 11 has a structure necessary for transmitting and receiving a sensor signal change from the chemical substance sensing element 10. Here, “necessary structure” means, for example, having a hole or the like through which the signal measuring conductor 19 connected from the chemical substance sensing element 10 is passed. With such a structure, a low voltage power supply device (not shown) for sensor signal measurement, a digital multimeter (not shown), a display device (not shown) such as a display, and a chemical substance sensing element 10 can be connected to each other by a conductive wire, and information obtained by the chemical substance sensing element 10 can be output to the outside.

(Introduced molecular sieve membrane)
The introduced molecular sieve membrane 16 is provided to prevent permeation of an exhalation marker substance having a large molecular diameter in the exhaled breath introduced from the moisture removing unit 12 into the chamber 11. The introduced molecular sieve membrane 16 is preferably a zeolite membrane from the viewpoints of high mechanical strength and excellent pressure resistance and heat resistance. Among the zeolite membranes, an MOR membrane (average pore diameter: 0.56 nm) is preferable. BEA membrane (average pore size: 0.76 nm), FAU membrane (average pore size: 0.72 nm), or MFI membrane (average pore size: 0.56 nm) is more preferable.

  The average pore size of the introduced molecular sieve membrane 16 is preferably larger than the average pore size of the discharged molecular sieve membrane 17, preferably 0.5 nm or more and 0.8 nm or less, and 0.50 nm or more and 0.56 nm or less. It is more preferable that If the average pore diameter of the introduced molecular sieve membrane 16 is less than 0.5 nm, the expiration marker substance cannot be sufficiently supplied to the chemical substance sensing element 10, and if it exceeds 0.8 nm, It will permeate, and the selectivity of the exhalation marker substance will decrease. Moreover, it is preferable to use the introduced molecular sieve membrane 16 having a thickness of about 5 μm.

  Further, it is preferable to provide a gas discharge port 21 in the chamber 11 between the introduced molecular sieve membrane 16 and the water removing unit 12. As a result, an exhalation marker substance having a large molecular diameter that does not pass through the introduced molecular sieve membrane 16 can be prevented from remaining in the chamber 11 between the introduced molecular sieve membrane 16 and the water removing unit 12. A check valve 15 is preferably installed in the connection between the gas outlet 21 and the chamber 11. Thus, exhaled air can be discharged while keeping the pressure in the chamber 11 constant.

(Exhaust molecular sieve membrane)
The exhaust molecular sieve membrane 17 is provided to allow only molecules having a small molecular diameter to pass through the gas exhaust path 14 out of the exhaled gas exhausted from the chamber 11 to the gas exhaust path 14. Such an exhaust molecular sieve membrane 17 is preferably a zeolite membrane from the same viewpoint as the introduced molecular sieve membrane 16 described above, and more preferably a DDR membrane (average pore diameter: about 0.44 nm) among the zeolite membranes. preferable. The average pore diameter of the discharged molecular sieve membrane 17 is more preferably 0.36 nm or more and 0.44 nm or less. Further, it is preferable to use a discharge molecular sieve membrane 17 having a thickness of about 5 μm.

  By defining the average pore size of the introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17 in this way, molecules having a large molecular diameter among the exhalation marker substances do not permeate the introduced molecular sieve membrane 16. Further, molecules having a small molecular diameter that are not used for measurement pass through the discharged molecular sieve membrane 17. In this way, only the exhalation marker substance necessary for detection can be supplied to the chemical substance sensing element 10, and the detection accuracy can be improved.

(Base material)
The base material 20 is provided to support the introduction molecular sieve membrane 16 and the exhaust molecular sieve membrane 17 without hindering the supply and discharge of exhaled air. That is, even if exhaled air is introduced into the chamber 11 at a high pressure, by providing the base material 20 in the chamber 11, it is possible to prevent the introduction molecular sieve membrane 16 and the exhaust molecular sieve membrane 17 from shifting to the gas exhaust path 14 side. Can do.

  As shown in FIG. 1, such a base material 20 is preferably provided with a total of two base materials 20, one on each of the introduction molecular sieve membrane 16 and the discharge molecular sieve membrane 17. And it is preferable to be provided on the gas discharge path 14 side of the introduced molecular sieve membrane 16 in the chamber 11. Moreover, it is preferable to be provided also on the gas discharge path 14 side of the discharge molecular sieve membrane 17. Moreover, the material used for the base material 20 will not be specifically limited if it is lightweight, For example, the product made from acrylic, a product made from a polypropylene, etc. can be used.

  FIGS. 2 (a) and 2 (b) are schematic views of a substrate for supporting the introduced molecular sieve membrane and the exhausted molecular sieve membrane, and FIG. 2 (c) shows the chamber cut along the surface including the exhausted molecular sieve membrane. It is a figure which shows the cross section when it did.

  The base material 20 used in the present invention may be one in which one hole is formed as shown in FIG. 2 (a), or as shown in FIG. 2 (b), Nine holes may be formed inside the mesh. Thus, as long as the base material 20 is provided with the hole used as the path of exhalation, what kind of thing may be sufficient as it. However, from the viewpoint of more stably supporting the introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17, a mesh shape is preferable.

(Heating device)
The heating device 18 is provided for detaching the exhalation marker substance adhering to the introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17 installed in the chemical substance sensing device 2. That is, when the heating device 18 warms the introduction molecular sieve membrane 16 and the exhaust molecular sieve membrane 17, the exhalation marker substance adsorbed on the introduction molecular sieve membrane 16 and the exhaust molecular sieve membrane 17 can be desorbed, and thereby the exhalation marker substance Measurement accuracy can be increased.

  Moreover, even when the chemical substance sensing device 2 is used for a long time and the performance as the molecular sieve of the introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17 is lowered, the performance can be recovered by heating the heating device 18. You can also.

  Such a heating device 18 is preferably disposed on the outer surface of the introduction molecular sieve membrane 16 and the discharge molecular sieve membrane 17, and as shown in FIG. 2C, the introduction molecular sieve membrane 16 and the discharge molecular sieve membrane 17. More preferably, it is arranged so as to surround the outer surface. By disposing the heating device 18 in this way, it is possible to apply a temperature uniformly to the introduced molecular sieve membrane 16 and the discharged molecular sieve membrane 17 and to suppress the exhalation marker substance from being desorbed non-uniformly.

  Further, it is preferable to provide a gas outlet 21 on the side surface of the chamber 11 on the introduction molecular sieve membrane 16 side. By providing the gas discharge port 21 at such a position, exhaled air containing molecules having a large molecular system can be discharged to the outside.

(Chemical substance sensing element)
The chemical substance sensing element 10 is a sensor that can selectively detect a specific exhalation marker substance. The chemical substance sensing element 10 is disposed in contact with a chamber in a space sandwiched between the introduction molecular sieve membrane 16 and the exhaust molecular sieve membrane 17.

  In FIG. 1, one chemical substance sensing element 10 is provided in the chamber 11, but the number of chemical substance sensing elements 10 provided in the chamber 11 is not limited to one. There may be two or more. By providing two or more chemical substance sensing elements 10, a plurality of types of exhalation marker substances can be detected.

  The chemical substance sensing element 10 is not limited to being provided in the chamber 11 but may be provided in the gas discharge path 14. By providing the chemical substance sensing element 10 in the gas discharge path 14, an exhalation marker substance having a smaller molecular diameter than the chemical substance sensing element 10 provided in the chamber 11 can be detected.

  As the chemical substance sensing element 10 as described above, a semiconductor sensor, a nanostructure sensor, or the like can be used. Depending on the type of the breath marker substance, either one or both of the semiconductor sensor and the nanostructure sensor is used. Use it.

  FIG. 3 is a schematic diagram showing an example of a chemical substance sensing element used in the present invention. As shown in FIG. 3, the chemical substance sensing element 10 has a positive electrode 110 and a negative electrode 111, and further includes a sensing unit 104 disposed so as to be in contact with the positive electrode 110 and the negative electrode 111, a positive electrode 110, a negative electrode 111, and An insulator 105 in contact with the sensing unit 104 and a constant resistance 106 are provided.

  Here, as a method of bringing the sensing unit 104 into contact with the exhaled air introduced into the chamber 11, for example, by pressing a button or the like, a window provided between the sensing unit 104 and the chamber 11 is provided for a certain period of time. For example, an open structure may be used. Deterioration of the sensing unit 104 can be suppressed by adopting a structure in which the air in the chamber 11 is in contact with the sensing unit 104 only when measuring in this way.

The sensing unit 104 is provided to detect a specific exhalation marker substance. The sensing unit 104 is mainly made of a metal oxide and has a property of adsorbing oxygen in the air. At this time, the adsorbed oxygen traps free electrons in the sensing unit 104, and the resistance value of the sensing unit 104 is high in this state. When a sample gas containing an exhalation marker substance, for example, air containing CO, is brought into contact with the sensing unit 104, oxygen on the surface of the sensing unit 104 and CO react to become CO ₂ , and adsorbed oxygen is transferred from the sensing unit 104. Leave. That is, oxygen on the surface of the sensing unit 104 is reduced, and the trapped electrons are released, thereby reducing the resistance value of the sensing unit 104. The fluctuation of the resistance value is calculated by measuring the change in the voltage V _RL at the constant resistance 106, and the presence and content of a specific exhalation marker substance can be detected.

Such a semiconductor sensor is preferably used as a sensor element for detecting an exhalation marker substance such as acetone, CO, an organic gas containing carbon atoms (for example, hydrocarbon gas, alcohol, etc.), and a flammable gas such as H _2. Can be used.

  In addition, the nanostructure sensor used in the chemical substance sensing element 10 is the same as the above semiconductor except that the sensing unit 104 is composed of a nanoscale conductive material and that the sensor temperature control means and the insulator are not accompanied. The structure of the sensor can be the same. For example, a structure such as a nanotube, a nanowire, or fullerene can be used.

  And as a nanoscale electroconductive substance, carbon nanofiber etc. are used suitably other than the carbon nanotube mentioned later. By using a nanoscale conductive material such as a carbon nanotube as a material constituting the sensing unit, the chemical substance sensing element 10 that is small, light, and highly sensitive at room temperature can be realized.

In the nanostructure sensor including a sensing unit composed of carbon nanotubes, the sensing unit 104 includes an aggregate 108 of carbon nanotubes subjected to surface modification. When exhalation containing an exhalation marker substance is brought into contact with the sensing unit, the exhalation marker substance is adsorbed on the surface of the sensing unit, thereby changing the resistance value of the entire nanostructure sensor. The fluctuation of the resistance value can be calculated by measuring the change in the voltage V _RL at the constant resistance, and the presence and content of the expiration marker substance in expiration can be clarified.

  As a method for producing a sensing unit composed of carbon nanotubes, film carbon nanotubes are dispersed in a solvent and then filtered through a membrane filter or the like, or a microwave plasma CVD apparatus is used on a substrate. There are methods for directly growing carbon nanotubes.

  It is also effective to use a sensing part of the nanostructure sensor that is composed of carbon nanotubes whose surface is modified with a metal complex. By subjecting the carbon nanotube to surface modification with a metal complex, the adsorption selectivity for a specific breath marker substance can be further improved, and thereby the detection accuracy of the specific breath marker substance can be further improved.

FIG. 4 is a schematic diagram showing an example of a nanostructure sensor provided with a sensing unit composed of carbon nanotubes whose surface is modified with a metal complex. As shown in FIG. 4, the nanostructure sensor in the present invention is a part for detecting an exhalation marker substance, which is arranged so as to be in contact with two electrodes; a positive electrode 110 and a negative electrode 111; A sensing unit 104; and a constant resistance 106. The sensing unit 104 is composed of an aggregate of carbon nanotubes whose surface is modified with a metal complex 109. When a specimen gas containing an exhalation marker substance is brought into contact with the sensing unit 104, a specific exhalation marker substance is selectively adsorbed on a part of the metal complex 109 of the sensing unit 104, thereby the entire nanostructure sensor. The resistance value of changes. The fluctuation of the resistance value is calculated by measuring the change of the voltage V _RL at the constant resistance 106, and the presence and content of the expiration marker substance in the expiration can be clarified.

  The metal complex is preferably one that selectively adsorbs a specific exhalation marker substance. That is, for example, as a metal complex, cobalt (II) phthalocyanine that selectively adsorbs nitric oxide; iron (II) phthalocyanine that selectively adsorbs carbon monoxide; copper (II) phthalocyanine that adsorbs pentane; acetone Mention may be made of manganese (II) phthalocyanine which is selectively adsorbed.

  As a method for producing the sensing unit 104, in addition to a method in which a metal complex is attached and contained in advance in a carbon nanotube, the nanotube is dispersed in a solvent, and then filtered through a membrane filter or the like, or by microwave plasma CVD. There is a method in which carbon nanotubes are directly grown on a substrate using an apparatus or the like, and then a solution containing a metal complex is applied by spraying with an inkjet or the like.

(Exhalation marker substance)
The chemical substance sensing device of the present invention is for detecting a specific exhalation marker substance from about 200 or more exhalation marker substances contained in exhalation. Examples of the breath marker substance showing biological information include nitric oxide, carbon monoxide, methyl mercaptan, ethane, pentane, acetone, ammonia and the like. Among the above breath marker substances, acetone can grasp the state of lipid burning, diabetes and the like.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Chemical substance sensing device>
≪Study 1: Effect of introduced molecular sieve membrane and discharged molecular sieve membrane≫
Example 1
In Example 1, the chemical substance sensing device 2 shown in FIG. 1 was produced. The chemical substance sensing apparatus 2 of Example 1 is provided with a 5 μm thick MFI film (average pore diameter: 0.56 nm) as the introduced molecular sieve film 16 in the chamber 11, and a 5 μm thick DDR film (average fine film) as the discharged molecular sieve film 17. (Pore diameter: 0.44 nm). Moreover, the nanostructure sensor which modified manganese phthalocyanine which adsorb | sucks specifically with acetone was used for the sensing part of the chemical substance sensing element 10 used for this chemical substance sensing apparatus.

First, N ₂ gas containing 40% of moisture was exposed to the chamber 11 of the chemical substance sensing device 2 for 4 minutes. And the window which separated the chemical substance sensing element 10 and the chamber 11 was opened, and the resistance change of the chemical substance sensing element 10 was measured for 1 minute.

  Next, a nitrogen gas containing 15 ppm of acetone, 32 ppm of ethanol, 27 ppm of methanol, and 5 ppm of acetic acid is used as a base gas, and a sample gas containing 40% of moisture is added to the base gas at a flow rate of 250 mL / min for 4 minutes. Was introduced into the chemical substance sensing device 2. And the window which separated the chemical substance sensing element 10 and the chamber 11 was opened, and the resistance change of the chemical substance sensing element 10 was measured for 1 minute.

  In addition, the resistance change of said chemical substance sensing element 10 was measured using the constant voltage power supply device (Product name: Digital multimeter (made by Agilent)). In addition, the gas discharged from the gas discharge path 14 is collected and analyzed using mass spectrometry gas chromatography (GC-MS: Gas Chromatography-Mass Spectroscopy product name: JMS-K9 (manufactured by JEOL)). It was.

(Comparative Example 1)
The chemical substance sensing apparatus of Comparative Example 1 was the same as the chemical substance sensing apparatus of Example 1 except that the chemical substance sensing apparatus of Example 1 was equipped with the introduction molecular sieve film 16 and the exhaust molecular sieve film 17 removed. . And also with respect to the chemical substance sensing apparatus of the comparative example 1, while measuring resistance change by the method similar to Example 1, the gas discharged | emitted from the gas exhaust path 14 was analyzed.

  FIG. 5A is a graph showing a measurement result of mass spectrometry gas chromatography of the gas discharged from the gas discharge path of the chemical substance sensing apparatus of Example 1, and FIG. It is a graph which shows the measurement result of the mass spectrometry gas chromatography of the gas discharged | emitted from the gas discharge path | route of a chemical substance sensing apparatus.

  When comparing the spectra of FIGS. 5 (a) and 5 (b), acetone and acetic acid peaks that were not detected in the spectrum of FIG. 5 (a) were detected in the spectrum of FIG. 5 (b). From this result, since the chemical substance sensing device of Example 1 was provided with the introduction molecular sieve membrane and the exhaust molecular sieve membrane, acetone and acetic acid remained in the chamber, and therefore the peaks of acetone and acetic acid in the spectrum of FIG. It is probable that was not detected.

  In addition, in the spectra of FIGS. 5A and 5B, the peaks of methanol and ethanol were detected more sharply in the spectrum of FIG. 5A. From this, it can be said that the chemical substance sensing apparatus of Example 1 selectively excludes methanol and ethanol more than the chemical substance sensing apparatus of Comparative Example 1.

  FIG. 6 is a graph showing a change in resistance of the chemical substance sensing element provided in the chemical substance sensing devices of Example 1 and Comparative Example 1. Here, the horizontal axis of FIG. 6 indicates time (seconds), and the vertical axis indicates a change in electrical resistance of the chemical substance sensing element. As shown in FIG. 6, the resistance change of the chemical substance sensing elements of Example 1 and Comparative Example 1 showed no difference when nitrogen gas containing 40% of moisture was introduced, whereas 40% of moisture was changed. The chemical substance sensing element of Example 1 when introducing the containing sample gas had a larger resistance change than the chemical substance sensing element of Comparative Example 1.

  This is because the chemical substance sensing device of Example 1 is provided with the introduced molecular sieve membrane and the discharged molecular sieve membrane, so that acetone to be measured is concentrated in the chamber, and the nanostructure sensor of Example 1 However, it is considered that acetone was selectively adsorbed over that of Comparative Example 1.

  Further, from the results of the present example and the comparative example, by changing the type and combination of the zeolite membranes used for the introduced molecular sieve membrane and the discharged molecular sieve membrane, the gas other than acetone is also contained in the chamber in the same manner as the acetone in Example 1. It is thought that it will be possible to stay in.

(Example 2)
<Chemical substance sensing system>
<< Examination 2: Effect of hollow fiber >>
In Example 2, the chemical substance sensing system shown in FIG. 1 was produced. The chemical substance sensing system 1 adsorbs gas moisture from the gas introduction path 13 to the chemical substance sensing apparatus 2 of the first embodiment and a gas introduction path 13 for introducing gas into the chemical substance sensing apparatus 2. The water removal part 12 for performing and the gas discharge path 14 for discharging | emitting gas are provided. The moisture removing unit 12 was provided with a hollow fiber having a helical structure with an interval of 1.0 nm, and the hollow fiber made of a fluororesin was used.

  To such a chemical substance sensing system of Example 2, nitrogen gas containing 85% moisture and nitrogen gas containing no moisture were alternately introduced for 1 minute each, and each was introduced at a flow rate of 250 mL / min. The specimen was brought into contact with the chemical substance sensing element.

  During the introduction of the specimen, the window separating the chemical substance sensing element 10 and the chamber 11 was opened so that the breath marker substance was in contact with the chemical substance sensing element 10. Thus, the resistance change of the chemical substance sensing element 10 was confirmed. The resistance change was measured by the same method using the same apparatus as in Example 1.

(Comparative Example 2)
The chemical substance sensing system of Comparative Example 2 was the same as the chemical substance sensing system of Example 2, except that the moisture removing unit of the chemical substance sensing system of Example 2 was excluded. The sample introduced into the chemical substance sensing system of Comparative Example 2 was the same as the sample used in Example 2, and the resistance change was measured by the same method.

  FIG. 7 is a graph showing a change in electrical resistance in the chemical substance sensing element used in Example 2 and Comparative Example 2. The horizontal axis of this graph indicates the time (seconds) after the introduction of the specimen, and the vertical axis indicates the resistance change of the chemical substance sensing element.

  The chemical substance sensing element used in Example 2 is a chemical substance sensing element between them even if nitrogen gas containing 85% moisture is introduced for 1 minute after introducing nitrogen gas containing no moisture for 1 minute. There was no change in the resistance detected.

  On the other hand, the chemical substance sensing element used in Comparative Example 2 introduced nitrogen gas containing no moisture for 1 minute, and then introduced nitrogen gas containing 85% moisture for 1 minute. A change in resistance was observed.

  This is because the chemical substance sensing system of Comparative Example 1 does not have a moisture removal unit having a hollow fiber, so that the sample is introduced into the chamber without removing moisture, and nitrogen gas does not contain moisture. It is considered that there was a difference in resistance change between the introduction of nitrogen and the introduction of nitrogen gas containing 85% moisture.

  That is, it has been clarified that the chemical substance sensing system of Example 2 can efficiently remove moisture by providing a moisture removal unit having a hollow fiber, and can stably measure an expiration marker substance.

≪Display results≫
FIG. 8 is a schematic diagram showing a connection relationship between the chemical substance sensing system of the present invention and a terminal device. As shown in FIG. 8, the chemical substance sensing system 1 of the present invention is configured such that the chemical substance sensing element constituting the chemical substance sensing system 1 and the terminal device 203 are connected via a communication cable 202. Data detected by the sensing element can be transmitted to the terminal device 203.

  The connection between the chemical substance sensing element and the terminal device 203 is not limited to an electrical connection by a wired means such as the communication cable 202, but is connected by a communication by a wireless means (for example, Bluetooth). Also good. The result of determining the health condition based on the measurement value obtained by such communication means is displayed on the display 201 of the terminal device 203.

  FIG. 9 is a schematic diagram showing a connection relationship between the chemical substance sensing system of the present invention and a terminal device. The terminal device 203 connected to the chemical substance sensing system 1 of the present invention is not limited to a notebook personal computer as shown in FIG. 8, but any electronic device having a display capable of displaying the result. For example, a mobile phone as shown in FIG. 9 may be used.

  10A and 10B are schematic views of a display that displays the result of detection of the expiration marker substance by the chemical substance sensing element 10.

  The concentration of the exhalation marker substance is calculated using a calibration curve for the characteristic value created in advance at a known concentration. That is, the characteristic value is a value representing (peak top conductance−conductance immediately before change in electric resistance) / (conductance immediately before change in electric resistance) as a percentage.

  On the display 201, the calculated acetone concentration is displayed, and when the acetone concentration shows a value larger than the standard, as shown in FIG. 10A, a display for prompting attention such as the possibility of diabetes is performed. On the other hand, when the acetone concentration is smaller than the standard value, as shown in FIG. In this way, the subject can easily know his / her physical condition.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, a chemical substance sensing system that can detect biological information related to a subject's disease and has low stress during use for a non-invasive, ultra-compact, low power consumption, ultra-sensitive, and highly selective user. It has been confirmed that steady progress has been made toward the realization of a medical prevention society.

  DESCRIPTION OF SYMBOLS 1 Chemical substance sensing system, 2 Chemical substance sensing apparatus, 10 Chemical substance sensing element, 11 Chamber, 12 Moisture removal part, 13 Gas introduction path, 14 Gas discharge path, 15 Check valve, 16 Introducing molecular sieve film, 17 Exhausting molecular sieve film , 18 Heating device, 19 Signal measuring conductor, 20 Base material, 21 Gas outlet, 104 Sensing part, 105 Insulator, 106 Constant resistance, 108 Aggregate, 109 Metal complex, 110 Positive electrode, 111 Negative electrode, 201 Display, 202 Communication cable, 203 terminal device.

Claims (10)

A chamber (11) divided into three spaces by an introduced molecular sieve membrane (16) and an exhaust molecular sieve membrane (17);
A chemical substance sensing device (2) comprising a chemical substance sensing element (10) in contact with a chamber (11) in a space sandwiched between the introduced molecular sieve membrane (16) and the discharged molecular sieve membrane (17).   The chemical substance sensing device (2) according to claim 1, wherein the introduction molecular sieve membrane (16) and the exhaust molecular sieve membrane (17) are made of zeolite.   The chemical substance sensing device (2) according to claim 1, wherein an average pore diameter of the introduced molecular sieve membrane (16) is larger than an average pore diameter of the discharged molecular sieve membrane (17).   The chemical substance sensing device (2) according to claim 1, comprising a heating device (18) on an outer surface of the introduced molecular sieve membrane (16) and an outer surface of the discharged molecular sieve membrane (17).   The chemical substance sensing device (2) according to claim 1, wherein the chemical substance sensing element (10) is a nanostructure sensor.   The chemical substance sensing device (2) according to claim 5, wherein the nanostructure sensor is composed of carbon nanotubes whose surface is modified with a metal complex in the sensing part (104). The chemical substance sensing device (2) according to claim 1,
A gas introduction path (13) for introducing gas into the chemical substance sensing device (2);
A water removal unit (12) disposed between the gas introduction path (13) and the chemical substance sensing device (2), and for adsorbing moisture of the gas from the gas introduction path (13);
A chemical substance sensing system (1) comprising a gas discharge path (14) for discharging gas from the chemical substance sensing device (2).   A check valve (15) is installed between the chemical substance sensing device (2) according to claim 1 and the moisture removing unit (12), and the chemical substance sensing device (2), The chemical substance sensing system (1) according to claim 7, wherein a check valve (15) is installed between the gas discharge path (14).   The chemical substance sensing system (1) according to claim 7, wherein the moisture removing unit (12) includes a hollow fiber.   The chemical substance sensing system (1) according to claim 9, wherein the hollow fiber is made of a fluororesin.

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