JP2007248323A - Molecular detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of providing a small-sized and highly-sensitive sensor at low cost. <P>SOLUTION: This sensor 10 has a pump 20, an adsorbing unit 30, a gas chromatography unit 40, and a sensor unit 50 all of which are provided on a substrate 80. The pump 20 sucks in and condenses surrounding gas, and the adsorbing unit 30 adsorbs molecules contained in the gas. The gas chromatography unit 40 separates a particular type of molecules from those adsorbed to the adsorbing unit 30. An absorption film in the sensor unit 50 then adsorbs the separated particular type of molecules. The sensor unit 50 detects adsorption of the molecules to the adsorption film. On the basis of the detection level of the adsorption, a measurement processing unit 60 determines the presence of the particular type of molecules or measures the amount of the molecules. The sensor thus detects the presence of a particular type of molecules or measures the amount of the molecules. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molecular detection sensor suitable for use in detecting odors, gases, and the like.

Conventionally, there have been sensors for detecting the presence of explosive hazards and harmful gases, or their quantitative concentrations. This sensor adsorbs a specific type of molecule contained in a gas and detects the presence or concentration of the gas or the like by detecting the presence or absence or the amount of adsorption. Such a sensor is installed in a facility, equipment, device or the like that handles gas or the like, and is used to control gas leakage or gas amount.
In recent years, fuel cells have been actively developed. Since the fuel cell uses hydrogen, it is preferable to monitor the hydrogen station and vehicles, devices, equipment, etc. that use the fuel cell for hydrogen leakage. The sensor can be applied to such applications.
In addition to the above applications, sensors that detect the presence or amount of adsorption by adsorbing specific types of molecules, such as food freshness and component analysis, environmental control to provide and maintain a comfortable space, May be used for detecting the state of a living body such as a human body.

Conventionally, there are two types of sensors as described above.
One is a molecular adsorption film (sensitive film) that adsorbs specific types of molecules on the cantilever, and detects the adsorption of molecules from the change in the state of the cantilever when the molecules are adsorbed on the molecular adsorption film. is there. When molecules are adsorbed on the molecular adsorption film, the mass of the molecular adsorption film increases. Thereby, since the amount of deflection of the cantilever changes, the adsorption of a specific type of molecule can be detected from the amount of change. Further, when the mass of the molecular adsorption film increases due to the adsorption of molecules, the resonance frequency of the system composed of the cantilever and the molecular adsorption film changes, so that the adsorption of a specific type of molecule can be detected from the change (for example, (Refer nonpatent literature 1.).
In another method, a molecular adsorption film is provided on the crystal resonator, and the adsorption of a specific type of molecule is detected from the change in the resonance frequency of the crystal resonator when the molecule is adsorbed on the molecule adsorption film.

It has already been reported that by adopting such a method, hydrogen gas detection using platinum or palladium as a hydrogen molecule adsorption film, alcohol component detection using PMMA polymer, food odor detection, etc. can be realized. Yes. In particular, in the method of detecting the change in the resonance frequency of the cantilever or the crystal resonator, when a specific molecule is adsorbed on the adsorption film and a minute mass change occurs, the resonance frequency of the crystal resonator or cantilever having a high vibration Q value is obtained. Is sensitive to the change in mass and produces a change, enabling highly sensitive detection.
In such a conventional method of detecting gas using the change in resonance frequency of a quartz crystal resonator or cantilever, the sensor itself is a solid element of quartz or a cantilever having a size of several tens to several hundreds μm manufactured by a fine processing technology. Constitute. Therefore, the sensor can be downsized and the vibration Q value can be increased as described above. Therefore, it can be said that the configuration is excellent in terms of downsizing and high sensitivity.

Suman Cherian, Thomas Thundat, “Determination of adsorption-induced variation in the spring constant of a microcantilever”, Applied Physics Letter, 2002, Vol. 80, No. 12, pp. 2219-2221

  As described above, there is a problem that when the sensor itself is downsized, the sampling amount of the gas to be detected becomes small, and the sensitivity is not improved as expected. In order to make this a practical sensitivity, it is necessary to improve the sensitivity of the sensor to about 10,000 times as compared with the current situation.

  Conventionally, since such a sensor is a highly specialized device, the price is very high and expensive, and the detection work itself requires specialized knowledge. There was a problem of hanging.

In recent years, interest in health and the like has greatly increased. As an index indicating the degree of health, it is conceivable to detect an odor such as body odor.
In order for the general public who has no specialized knowledge to be able to easily detect odors, it is necessary to perform detection quickly and easily with a low-cost sensor, but such a sensor has been provided in the past. There is no current situation.

  In addition, when a sensor is used for such an application, since the odor is generated by combining various molecules, a plurality (a large number) of molecules must be detected by the sensor. In order to make the sensor have such a configuration, it is simply necessary to unitize a plurality of sensors, but in practice, this leads to an increase in the size of the sensor. Further, since the structure becomes complicated, the manufacturing cost of the sensor increases.

  An object of the present invention is to provide a technique capable of providing a small and highly sensitive sensor at a low cost.

For this purpose, the molecular detection sensor of the present invention sucks in fluid such as atmospheric gas from the outside and concentrates the fluid, and an adsorption unit that adsorbs molecules contained in the fluid concentrated by the concentration pump, The molecule is detected by detecting the change of vibration in the molecule recognition unit and the molecule recognition unit that recognizes the molecule by vibration characteristics changing due to the adhesion or adsorption of a specific type of molecule adsorbed in the adsorption unit. And a detection unit, and at least a concentration pump, an adsorption unit, and a molecule recognition unit are integrally formed on the substrate.
In such a molecular detection sensor, at least the concentration pump, the adsorption unit, and the molecular recognition unit are integrally formed on the substrate, so that the molecular detection sensor can be made into one chip, which can be downsized, and MEMS. By applying (Micro Electro Mechanical Systems) technology and semiconductor manufacturing technology, it is possible to reduce costs by miniaturization and mass production.
And it becomes possible to improve the detection sensitivity of a molecular detection sensor by concentrating a fluid with a concentration pump. At this time, the concentration pump has a pump body in which a flow path for feeding fluid from the outside to the adsorption section is formed, a volume change generation section that causes a volume change in the fluid in the flow path, and a fluid change by the volume change generation section. When a volume change occurs in the flow path, a configuration including a backflow prevention unit that prevents the fluid from moving in a direction away from the detection unit in the flow path can be configured as a mechanism-less configuration without a movable unit. In addition, mounting on a substrate is possible and high reliability can be obtained.

The molecule recognition unit recognizes the molecule by changing the vibration characteristics due to the adhesion or adsorption of the molecule. As such a molecular recognition part, a molecular adsorption film (sensitive film) that adsorbs a specific type of molecule is provided on a cantilever-shaped or disk-shaped vibrator, and molecules are adsorbed on the molecular adsorption film. Some of them detect the adsorption of molecules from the change in state of the vibrator. When molecules are adsorbed on the molecular adsorption film, the mass of the molecular adsorption film increases. Thereby, in the case of a cantilever-like vibrator, the amount of deflection and the resonance frequency change, and from this change, the adsorption of molecules can be detected. In addition, when the mass of the molecular adsorption film increases due to molecular adsorption, the resonance frequency of the system consisting of the vibrator and molecular adsorption film changes. It can also be detected.
Another method is to provide a molecular adsorption film on the crystal unit and detect the adsorption of a specific type of molecule from the change in the resonance frequency of the crystal unit when molecules are adsorbed on the molecular adsorption layer. .
In addition to this, it is of course possible to employ other types of molecular recognition units as appropriate.

The molecular detection sensor of the present invention may further include a molecular weight analysis unit that analyzes the molecular weight of the molecules adsorbed by the adsorption unit. As this molecular weight analysis unit, gas chromatography is suitable. This is because mounting is possible by forming a column or capillary on the substrate. When such a molecular weight analyzing unit is provided, the molecular recognizing unit recognizes the molecule by a change in vibration characteristics due to adhesion or adsorption of the molecule whose molecular weight is analyzed by the molecular weight analyzing unit. In the case of gas chromatography, the time required for molecular desorption depends on the molecular weight, and thus the type of molecule can be identified. This makes it possible to extract only a specific type of molecule and to recognize its presence and quantity in the molecule recognition unit.
This molecular weight analysis unit is not an essential component.

  A plurality of molecular recognition units having different sensitivities can be provided. In this case, when the molecule cannot be recognized by the low-sensitivity molecular recognition unit, the detection unit recognizes the molecule using another sensitive molecular recognition unit. As a result, the dynamic range of the molecular detection sensor can be expanded, and its practicality can be enhanced. At this time, the molecular recognition units having different sensitivities may set the sensitivity to two or more levels. In order to vary the sensitivity of the molecular recognition unit, the surface area may be varied, or the volume ratio (weight ratio) between the molecular adsorption film and the vibrator may be varied.

  Moreover, the molecular recognition part can also provide multiple types from which the kind of molecule | numerator which adheres or adsorb | sucks mutually differs. This not only enables recognition of multiple types of molecules, but the detection unit identifies the combination of molecules contained in the fluid based on the type of the molecular recognition unit that recognized the molecule among the multiple molecular recognition units. Since it is possible, it becomes possible to specify the substance contained in the fluid.

Such molecular detection sensors target gases, biological molecules, living space floating molecules, volatile molecules, etc. as specific types of molecules, for example, explosive and harmful gases, etc. It can be used as a gas detection sensor for detecting the presence or the quantitative concentration thereof. Such a molecular detection sensor is installed in a facility, facility, apparatus or the like that handles gas or the like, and is used for controlling gas leakage or gas amount. In addition, the molecular detection sensor is also used for monitoring hydrogen leaks in hydrogen stations for fuel cells, vehicles, devices and equipment that use fuel cells, which have been actively developed in recent years. it can.
In addition to this, molecular detection sensors that detect the presence or amount of adsorption by adsorbing specific types of molecules, or multiple types of molecules with specific characteristics or characteristics, can be used, for example, for food freshness and component analysis. It can be considered to be used for environmental control for providing / maintaining a comfortable space, and for detecting the state of a living body such as a human body. In addition, by detecting various substances from the human body, exhaled breath and metabolic components of intestinal flora, etc. with high sensitivity, monitoring of health status, simple screening of diseases, diagnosis of lifestyle-related diseases, monitoring of infectious diseases, etc. It will be possible to do such things.
It is also possible to detect a group of molecules having specific characteristics or a group of molecules having the same side chain, which is called global recognition. Furthermore, the same function can be exhibited in the molecular detection sensor of the present invention not only for gas but also for liquid.
In addition, the molecular detection sensor of the present invention is not limited to a conventional business sensor, and is a small, stable, highly sensitive home and personal sensor, and a disposable sensor excellent in portability. Or the like.

  According to the present invention, it is possible to achieve high sensitivity while miniaturizing the molecular detection sensor by making it one chip, and it is possible to reduce the manufacturing cost and provide an inexpensive molecular detection sensor.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram for explaining the overall configuration of the sensor 10 according to the present embodiment.
The sensor 10 shown in FIG. 1 detects the presence (occurrence) or the concentration of a gas itself or a specific substance or odor contained in the gas by adsorbing a specific type of molecule to be detected. Is. The sensor 10 includes a pump (concentration pump, pump body) 20 that sucks in ambient gas (hereinafter simply referred to as a fluid), an adsorption unit 30 that adsorbs the gas sucked by the pump 20, and an adsorption unit 30. Gas chromatography unit (molecular weight analysis unit) 40 for separating a specific type of gas component from the adsorbed gas, and a sensor unit for adsorbing a specific type of molecule contained in the separated gas component and detecting the adsorption of the molecule (Molecule recognition unit) 50, a measurement processing unit (detection unit) 60 that measures the presence or amount of a specific type of molecule based on the detection level in the sensor unit 50, and a control unit 70 that controls each unit of the sensor 10. It is equipped with.

As shown in FIG. 2, among these, the pump 20, the adsorption unit 30, the gas chromatography unit 40, and the sensor unit 50 perform predetermined pattern formation on a substrate 80 made of Si or SiO ₂ , and further, the substrate 81. It is mounted by laminating.

  As shown in FIG. 3, the pump 20 includes a chamber portion 22 having a predetermined volume, an inlet side channel 23 for introducing gas from the outside into the chamber portion 22, an outlet side channel 24 for sending gas from the chamber portion 22, a chamber An inlet side diffuser part (backflow prevention part) 25 provided between the part 22 and the inlet side channel 23 and an outlet side diffuser part (backflow prevention part) 26 provided between the chamber part 22 and the outlet side channel 24 are formed. In addition, the chamber 22 has a configuration in which a heater (volume change generation unit) 29 is provided.

  As shown in FIG. 2, the pump 20 is formed between a substrate 80 and a substrate 81 provided so as to face the substrate 80. By forming a concave portion having a predetermined shape on one or both mating surfaces of the substrates 80 and 81, the chamber part 22, the inlet side channel 23, the outlet side channel 24, the inlet side diffuser part 25, and the outlet side diffuser part 26 are formed. Is formed.

  As shown in FIG. 3, the chamber part 22 has, for example, a circular cross section. An inlet side diffuser portion 25 is formed on one side of the chamber portion 22, and an outlet side diffuser portion 26 is formed on the other side.

  The inlet-side diffuser portion 25 is formed so as to communicate the inlet-side channel 23 and the chamber portion 22, and has a tapered nozzle shape whose sectional area (inner diameter) gradually decreases from the inlet-side channel 23 side toward the chamber portion 22 side. It is said that.

  The outlet side channel 24 is formed so as to be continuous with an adsorption portion 30 described later in detail, and the other end is formed so as to communicate with the outlet side diffuser portion 26. The outlet-side diffuser portion 26 communicates with the chamber portion 22 and the outlet-side channel 24 and is formed to open to the chamber portion 22 at a position different from the inlet-side diffuser portion 25, and the outlet-side channel 24 extends from the chamber portion 22 side. A taper nozzle shape whose cross-sectional area gradually decreases toward the side.

  Thus, in the pump 20, a gas flow path is formed in which the inlet side channel 23, the inlet side diffuser portion 25, the chamber portion 22, the outlet side diffuser portion 26, and the outlet side channel 24 communicate with each other.

The heater 29 provided in the chamber portion 22 is disposed on the upper surface side or the lower surface side of the chamber portion 22. For example, a noble metal such as Au, Pt, Cu, Pd, Ir, Cr, Mo, Ti, or a high melting point is provided. The heating wire is made of metal, a metal oxide film such as ITO, SnO, or Poly-Si, or a semiconductor, and is electrically connected to a power source (not shown) disposed outside the substrate 80. The application of voltage to the heater 29 in a power source (not shown) is controlled by the control unit 70.
When a voltage is applied from the power source under the control of the control unit 70, the heater 29 generates heat. As a result, the temperature in the chamber unit 22 rises to expand the gas, and when the application of the voltage to the heater 29 is stopped, Heat generation is stopped, the temperature in the chamber portion 22 is lowered, and the gas contracts. In the pump 20, the heater 29 and the control unit 70 function as a temperature change unit and a volume change generation unit, and perform gas supply by utilizing gas expansion / contraction. This will be described in detail below.

In the pump 20, external gas is introduced from the inlet side channel 23 and the inlet side diffuser portion 25 into the chamber portion 22 and discharged from the outlet side diffuser portion 26. When the heater 29 generates heat while the gas is introduced into the chamber portion 22, the temperature in the chamber portion 22 rises and the gas expands. Then, the expanded gas tends to flow out of the chamber portion 22 from the inlet side diffuser portion 25 and the outlet side diffuser portion 26.
At this time, the inlet-side diffuser portion 25 has a cross-sectional area from the inlet-side channel 23 side toward the chamber portion 22 side, and the outlet-side diffuser portion 26 has a cross-sectional area from the chamber portion 22 side toward the outlet-side channel 24 side. The taper nozzle shape gradually decreases. For this reason, in the inlet side diffuser part 25 and the outlet side diffuser part 26, when the gas flows in a direction in which the cross-sectional area gradually decreases (hereinafter, this direction is referred to as the forward direction), the reverse direction, that is, the cross-sectional area is The pressure loss differs when the gas flows in a gradually increasing direction (a direction from the outlet channel 24 side to the inlet channel 23 side: this direction is hereinafter referred to as a reverse direction). That is, in the inlet side diffuser portion 25 and the outlet side diffuser portion 26, the pressure loss when the gas flows in the reverse direction is larger than the pressure loss when the gas flows in the forward direction. This is because the turbulent vortex is generated due to the viscosity of the gas at the edges 25a and 26a of the inlet side diffuser portion 25 and the outlet side diffuser portion 26, and thereby the kinetic energy of the fluid is lost. As a result, the inlet side diffuser portion 25 This is because the gas flow in the outlet side diffuser portion 26 is smoother in the forward direction than in the reverse direction.
Thereby, when the gas in the chamber part 22 expands and tries to flow out of the pump 20, the gas flows out of the chamber part 22 from the outlet side diffuser part 26 having a smaller resistance (pressure loss).

Thereafter, when the application of voltage to the heater 29 is stopped, the heat generation of the heater 29 is stopped, the temperature in the chamber portion 22 is lowered, and the gas is contracted. Then, as the gas contracts, the gas is introduced from the inlet side diffuser portion 25 and the outlet side diffuser portion 26 into the chamber portion 22.
At this time, in the tapered nozzle-like inlet-side diffuser portion 25 and outlet-side diffuser portion 26, the pressure loss varies depending on the gas flow direction as described above. Then, the gas is introduced from the inlet side diffuser portion 25 having a smaller resistance (pressure loss) into the chamber portion 22.

Thus, when the heater 29 is heated, the gas in the chamber part 22 expands and flows out from the outlet side diffuser part 26 to the outlet side channel 24, and when the heater 29 is stopped, the gas in the chamber part 22 contracts and enters the inlet side. Gas is introduced into the chamber portion 22 from the side channel 23 via the inlet side diffuser portion 25.
Therefore, in the pump 20, by repeating heating and stopping of the heater 29, the gas can be sucked from the inlet side channel 23 and discharged from the outlet side channel 24, and functions as a pump.
For this reason, in the control part 70, ON / OFF of the heater 29 is switched alternately by a predetermined cycle. For example, the controller 70 can be controlled to repeat ON / OFF of the heater 29 in a cycle of 100 microseconds to 1 millisecond. Further, it is preferable that the control unit 70 performs control so that a temperature change occurs within a range of room temperature to 1000 ° C., preferably room temperature to 500 ° C., when the heater 29 is turned on / off.

  At this time, if the power of the heater 29 is increased, the temperature difference during ON / OFF increases, and the flow rate in the pump 20 increases. Further, if the ON / OFF switching frequency is increased, the flow rate is increased. What is necessary is just to set suitably the temperature difference and switching frequency at the time of these ON / OFF according to the application object of a pump 20, a use, etc. For example, when it is used for an application where gas is decomposed at a high temperature, it is necessary to lower the temperature.

  As described above, the pump 20 reliably changes the volume by utilizing the thermal expansion of the gas, and can reliably transport the gas even at a very small flow rate. Moreover, in order to transport the gas, it is only necessary to provide a flow path including the chamber part 22, the inlet side channel 23, the outlet side channel 24, the inlet side diffuser part 25, the outlet side diffuser part 26, and the heater 29. Since a movable part is unnecessary, high reliability can be obtained, and it is also possible to avoid problems such as operating noise and heat generation due to operation as in the case where a movable part is provided.

The gas discharged from the outlet side channel 24 of the pump 20 is sent to the adsorption unit 30 and concentrated.
The adsorption unit 30 that adsorbs the gas sent from the pump 20 is formed of, for example, an adsorption film formed of an organic material or an adsorption film 31 formed of an inorganic material. Adsorbed by physical adsorption with low selectivity.
The adsorption film 31 formed of an organic material adsorbs molecules by a chemical reaction with the molecules, and thus has excellent adsorption performance. However, once the molecules are adsorbed, the molecules are not easily detached, and can be used stably over a long period of time. It is difficult.
On the other hand, the inorganic material can easily desorb the adsorbed molecules by applying heat or the like. Since the sensor 10 of the present invention sequentially sends molecules contained in the gas from the pump 20 side to the downstream side, the molecular detachability is important. For this reason, it is preferable to use an inorganic material as the adsorption part 30. However, inorganic materials are inferior to organic materials in terms of adsorption performance. Therefore, it is preferable to secure the amount of molecules adsorbed by securing the surface area of the adsorption film 31. Also, the amount of adsorption can be increased by ensuring a long gas contact time with the adsorption film 31. A typical example of such an inorganic material is titanium dioxide (TiO ₂ ), and it is preferable to form titanium dioxide in a porous form in order to increase adsorption efficiency.

A heater 32 is provided on the lower or upper surface of the adsorption film 31. The heater 32 is formed of the same material as that of the heater 29 and is electrically connected to a power source (not shown) disposed outside the substrate 80. The application of voltage to the heater 32 by a power source (not shown) is controlled by the control unit 70.
When gas is fed from the pump 20 side and comes into contact with the adsorption film 31, molecules (mainly volatile organic compounds) contained in the gas are adsorbed on the adsorption film 31. When the heater 32 generates heat when a voltage is applied from the power source under the control of the control unit 70, the molecules adsorbed on the adsorption film 31 are volatilized and detached from the adsorption film 31.
In such an adsorbing unit 30, the pump 20 is operated for a predetermined time, and the molecules in the gas fed during the operation are adsorbed by the adsorbing film 31. The sampling amount of the gas can be determined by the operation time of the pump 20, that is, the length of the adsorption time in the adsorption unit 30.

The gas chromatography unit 40 provided on the downstream side of the adsorption unit 30 uses the groove 41 formed in the substrate 80 as a column or capillary. Thus, a column or capillary material of the substrate 80, i.e. Si, or is formed by SiO _2, which is referred to as the stationary phase. In order to form such a groove 41, after a predetermined photoresist process is performed on the substrate 80, the groove 41 having a depth of 50 to 100 μm and a width of 5 to 20 μm is formed by a technique such as RIE (Reactive Ion Etching). Form. Here, since Si reacts with other metals even at a relatively low temperature, the inside is oxidized and an oxide film is formed on the surface. Further, a barrier film such as SiN ₄ can be formed as necessary.

A gas adsorbing material 42 is filled in the groove 41 constituting the column or capillary. Examples of the gas adsorbing material 42 include finely divided carbon, oxides such as silicon and metal (aluminum, zinc, tin, titanium), similarly finely divided polymer, and nanoparticles coated with metal on the surface. It is done. In such a gas adsorbing material 42, there are a case where all gases are uniformly adsorbed depending on a method and a case where a specific gas species is selectively adsorbed to some extent. In the case of uniform adsorption, finely divided carbon is suitable, and in order to provide selectivity, it is preferable to use polymer powder. In order to increase the adsorption efficiency in such a gas adsorbing material 42, it is preferable to increase the surface area, and for this purpose, it is necessary to reduce the size of particles and ceramic pores.
Considering the integration process, the gas adsorbing material 42 is formed by a spin-on method using silicon or a metal oxide, dissolved in a solvent such as xylene using an organic metal or a sol-gel method, and then subjected to sintering. Although it is preferable to form, other manufacturing methods and materials may be appropriately used depending on the relationship with other devices formed on the substrate 80.

  The gas chromatography unit 40 is provided with a heater 43 made of the same material as the heater 29. The heater 43 heats the groove 41 constituting the column or capillary to a predetermined temperature, and volatilizes (desorbs) the molecules adsorbed on the gas adsorbing material 42 to perform molecular weight analysis. That is, since a molecule having a small molecular weight escapes from the column or capillary of the groove 41 quickly, and a molecule having a large molecular weight takes time to escape from the groove 41, the molecular weight is analyzed based on (difference) in the escape time of this molecule. It can be done.

The sensor unit 50 includes an adsorption film 51 that adsorbs molecules contained in the gas separated by the gas chromatography unit 40, and a vibrator 52 that detects adsorption of molecules onto the adsorption film 51.
The adsorption film 51 can be formed of an organic material or an inorganic material, like the adsorption portion 30. Also in this case, since the inorganic material can easily desorb the adsorbed molecules by applying heat by the heater 53, the inorganic material is used as the adsorption film 51 in the sensor 10 of the present invention. preferable. In addition, it is preferable to secure the amount of molecules adsorbed by securing the surface area of the adsorption film 51. Also, the amount of adsorption can be increased by ensuring a long gas contact time with the adsorption film 51.
As such an organic material, a film made of any polymer such as polyacrylic acid, polystyrene, polyacrylamine, polydimethylsiloxane, polyvinyl chloride, and polymethyl methacrylate is a candidate. The selectivity for molecules is considered to be determined by various factors such as the functional group forming the polymer and the state of crosslinking.

Such an adsorption film 51 includes a global recognition material and a selection recognition material from a functional viewpoint.
A global recognition material is a polymer that adsorbs a specific molecular group, such as alcohol or ether, although the selectivity is not strong. It is also effective to increase the surface area by making these polymers into nanofibers or making them porous. The term “polymer nanofiber” as used herein means that the polymer has a size of several nanometers to several hundreds of micrometers (length, thickness) in order to dramatically improve the adsorption ability of polymers with different adsorption characteristics for various molecules. ).
Examples of highly selective recognition materials include biological materials that cause antigen-antibody reactions, acceptor-receptor combinations, probes with specific base sequences that hybridize with genes, DNA, and RNA. is there. A lipid bilayer membrane may also be used.

Such an adsorption film 51 is preferably formed on the surface of the vibrator 52.
The vibrator 52 can be a cantilever type in which a base end portion is fixed and cantilevered, or a disk shape having a circular shape, a rectangular shape, or another shape as appropriate.
The vibrator 52 includes a drive source (not shown) for driving it. As such a drive source, there are an electrostatic capacity method, a piezo drive method, and the like, both of which vibrate the vibrator 52 at a predetermined frequency, and the measurement processing unit 60 uses a drive circuit ( (Not shown).
The vibration frequency of the vibrator 52 changes when a detection object such as a molecule having a mass adheres to the adsorption film 51 in a state where the vibrator 52 is vibrated at a predetermined frequency.
The sensor unit 50 is provided with a heater 53 made of the same material as that of the heater 29 so that molecules adsorbed by the adsorption film 51 can be detached.

The sensor unit 50 detects the change in the vibration frequency of the vibrator 52 described above.
The sensor unit 50 can detect a change in the vibration frequency of the vibrator 52 as an electric signal by a capacitance method or the like. Here, reading by capacitance is taken as an example, but the reading method may use the electrostriction of a piezoelectric element or the piezoelectric effect of silicon or a piezoelectric element.

  The measurement processing unit 60 receives the electrical signal output from the sensor unit 50 and detects the change in the electrical signal, thereby measuring the presence / absence or the amount of adsorption of a specific type of molecule on the adsorption film 51. In the sensor 10, it is preferable that the measurement result in the measurement processing unit 60 can be output by ON / OFF of a lamp, a buzzer, etc., a measurement value, a display of a measurement level, and the like.

  The control unit 70 controls each part of the sensor 10. For example, it is possible to control the operation of the heaters 29, 32, 43, 53, and the vibrator 52 for volatilizing molecules and components adsorbed in each part.

  In such a sensor 10, ambient gas is sucked and concentrated by the pump 20 under the control of the control unit 70, and molecules contained in the gas are adsorbed by the adsorption unit 30. Then, from the molecules adsorbed by the adsorption unit 30, a specific type of molecule is separated by the gas chromatography unit 40, and the separated specific type of molecule is adsorbed by the adsorption film 51 of the sensor unit 50. Adsorption of molecules on the adsorption film 51 is detected by the sensor unit 50, and based on the detection level, the presence or amount of a specific type of molecule is measured by the measurement processing unit 60. In this way, it is possible to detect the presence or absence of a specific type of molecule, or to measure the amount thereof. As a result, it is possible to detect the presence of a specific gas, odor or specific substance, or to detect the amount or concentration thereof.

In addition, the control unit 70 can perform control for detecting a plurality of types of molecules in the sensor 10 and expanding the detection dynamic range.
When detecting a plurality of types of molecules, a plurality of sets of sensor units 50 are provided as shown in FIG. In the plurality of sets of sensor units 50, the types of molecules adsorbed by the adsorption film 51 are different from each other.
If it does in this way, according to the component contained in gas, the vibrator | oscillator 52 which a molecule | numerator adsorb | sucks by the adsorption | suction film | membrane 51 and a vibration frequency changes will differ. As a result, the control unit 70 identifies the type of the sensor unit 50 that has detected the adsorption of the molecules by the adsorption film 51, the amount of the detected molecules, etc., among the plurality of sets of sensor units 50, and Based on the combination, the detected substance can be identified.

Further, the detection dynamic range of the sensor 10 can be expanded as follows. That is, as shown in FIG. 5, a plurality of sets of sensor units 50 are provided. At this time, the sensitivity is varied among the plural sets of vibrators 52 by changing the weight, size, material, area ratio or volume ratio of the vibrators 52 with the adsorption film 51.
And in the control part 70, for example, it detects from the sensor part 50 with low sensitivity, and when the variation | change_quantity of the vibration frequency by the adsorbed molecule is not constant, it switches to the sensor part 50 with a sharp sensitivity one by one, Expands the dynamic range and enables sensitive molecular detection.

  In this manner, the sensor 10 can detect the presence or absence of a specific type of molecule or measure the amount thereof. Thereby, it is possible to detect the presence of a specific gas, a specific substance or the like, or to detect the amount and concentration thereof. At this time, the pump 20 compresses and feeds the gas, so that even a minute gas amount can be detected with high sensitivity, and the sensor 10 has an unprecedented high sensitivity detection performance while being ultra-compact with one chip. It can be.

In addition, by making it possible to detect a plurality of types of molecules in the sensor unit 50, it is possible to specify a substance composed of a plurality of types of molecules, measure the concentration thereof, and the like. Moreover, the detection dynamic range in the sensor 10 can be expanded by providing a plurality of vibrators 52 having different sensitivities.
In this way, the sensor 10 can be provided with functions and performance equal to or higher than those of the conventional sensor while being very small. Since such a sensor 10 is also excellent in portability, the sensor 10 can be used regardless of the place of use and the environment, and measurement in a place, environment, and situation where conventional measurement could not be performed is possible.

  Such a sensor 10 can be manufactured by a microfabrication technique such as a MEMS technique, thereby enabling cost reduction by mass production.

Note that the measurement processing unit 60 and the control unit 70 as described above may be provided separately from the substrate 80 without being provided.
Further, the gas chromatography unit 40 is not an essential configuration, and may be a simple configuration in which this is omitted.
The substrates 80 and 81 are also made of silicon or silicon oxide that can be easily processed, but may be formed of glass, ceramics, or other semiconductors.
In addition to this, the configuration of the pump 20, the adsorption unit 30, the gas chromatography unit 40, the sensor unit 50, the measurement processing unit 60, the control unit 70, and the like is the same as that of the above embodiment unless departing from the gist of the present invention. The listed configurations can be selected or changed to other configurations as appropriate.

It is a figure which shows the structure of the sensor in this Embodiment. It is sectional drawing of a sensor. It is a figure which shows the structure of a pump. It is a figure which shows the other example of a sensor. It is a figure which shows the further another example of a sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Sensor, 20 ... Pump (concentration pump, pump main body), 22 ... Chamber part, 25 ... Inlet side diffuser part (backflow prevention part), 26 ... Outlet side diffuser part (backflow prevention part), 29 ... Heater (volume change) Generating part), 30 ... adsorption part, 31 ... adsorption film, 32 ... heater, 40 ... gas chromatography part (molecular weight analysis part), 41 ... groove, 42 ... gas adsorption material, 43 ... heater, 50 ... sensor part (molecular recognition) Part), 51 ... adsorption film, 52 ... vibrator, 53 ... heater, 60 ... measurement processing part (detection part), 70 ... control part, 80 ... substrate, 81 ... substrate

Claims (5)

A concentration pump for sucking fluid from the outside and concentrating the fluid;
An adsorbing part that adsorbs molecules contained in the fluid concentrated by the concentration pump;
A molecular recognition unit for recognizing the molecule by changing vibration characteristics due to adhesion or adsorption of the specific type of the molecule adsorbed by the adsorption unit;
A detection unit for detecting the molecule by detecting a change in vibration in the molecule recognition unit, and
At least the concentration pump, the adsorption unit, and the molecule recognition unit are integrally formed on a substrate. The concentration pump is
A pump body in which a flow path for sending the fluid from the outside to the adsorption unit is formed;
A volume change generating section for generating a volume change in the fluid in the flow path;
A backflow prevention unit that prevents the fluid from moving in a direction away from the detection unit in the flow path when a volume change occurs in the fluid by the volume change generation unit;
The molecular detection sensor according to claim 1, comprising: A molecular weight analyzer for analyzing the molecular weight of the molecules adsorbed by the adsorption unit;
The molecular detection sensor according to claim 1, wherein the molecular recognition unit recognizes the molecule by a change in vibration characteristics due to adhesion or adsorption of the molecule whose molecular weight is analyzed by the molecular weight analysis unit. . The molecular recognition unit is provided with a plurality of different sensitivities,
4. The detection unit according to claim 1, wherein when the molecule cannot be recognized by the molecule recognition unit having low sensitivity, the molecule is recognized by another molecule recognition unit having high sensitivity. The molecular detection sensor according to 1. The molecular recognition unit is provided with a plurality of different types of molecules to be attached or adsorbed,
The said detection part specifies the substance contained in the said fluid based on the kind of the said molecule recognition part which recognized the said molecule | numerator among several said molecule recognition parts. The molecular detection sensor according to 1.

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