Sensor

Abstract

To provide a technique for releasing a target substance captured by a molecularly imprinted polymer.SOLUTION: A sensor for detecting a target substance is provided, the sensor comprising a detection unit including a membrane having a space for the target substance to enter and containing a molecularly imprinted polymer for capturing the target substance entering the space, and a release mechanism for releasing the target substance captured by the molecularly imprinted polymer from the molecularly imprinted polymer, where the release mechanism is a mechanism for changing electric potential of the membrane and is configured to release the target substance captured in the molecularly imprinted polymer using electrostatic repulsion of surface potentials of the target substance captured in the molecularly imprinted polymer and the molecularly imprinted polymer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to sensors. [Background technology]

[0002] Several proposals have been made to detect target substances using molecularly imprinted polymers. For example, Patent Document 1 discloses a field-effect transistor having a detection electrode on the surface of which a film of a molecularly imprinted polymer is formed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-061890 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to repeatedly use a sensor that uses a molecularly imprinted polymer, it is necessary to desorb the target substance captured by the molecularly imprinted polymer. In Patent Document 1, in the process of preparing a template for the target substance during the production of the molecularly imprinted polymer, a cyclic voltammetry technique is used to scan the potential applied between the working electrode and the counter electrode relative to the potential of the reference electrode, and the target substance is removed by reaching a potential at which the chemical bond is broken. However, if such a method is used as a desorption method for repeated use of the sensor, there is a risk that the molecularly imprinted polymer will deteriorate due to electron exchange. Therefore, there is a need for another technique that can desorb the target substance captured by the molecularly imprinted polymer. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a sensor for detecting a target substance, the sensor comprising: a detection unit having a membrane containing a space for the target substance to enter and a molecular imprinted polymer that captures the target substance that has entered the space; and a desorption mechanism for desorbing the target substance captured by the molecular imprinted polymer from the molecular imprinted polymer, the desorption mechanism being a mechanism for changing the potential of the membrane and causing the target substance captured by the molecular imprinted polymer to desorb by electrostatic repulsion between the surface potentials of the target substance captured by the molecular imprinted polymer and the molecular imprinted polymer. According to this aspect of the sensor, the desorption mechanism includes a mechanism for changing the potential of the membrane, and thus the target substance captured by the molecular imprinted polymer can be desorbed by electrostatic repulsion between the surface potentials of the target substance captured by the molecular imprinted polymer and the molecular imprinted polymer.

[0007] (2) In the sensor described in (1) above, the target substance may be charged. In this sensor, since the target substance is charged, adjusting the potential of the membrane to a potential opposite to that of the target substance can enhance the electrostatic repulsion of the surface potential, thereby reducing the interaction between the captured target substance and the molecularly imprinted polymer. As a result, the target substance can be easily released from the molecularly imprinted polymer.

[0008] (3) In the sensor described in (1) or (2), the target substance may be at least one selected from the group consisting of ions, bacteria, viruses, pollen, PM2.5, yellow sand, and aerosols. In this sensor, the target substance is electrically charged. Therefore, by adjusting the potential of the membrane to a potential opposite to that of the target substance, the electrostatic repulsion of the surface potential can be increased, thereby further reducing the interaction between the captured target substance and the molecularly imprinted polymer. As a result, the target substance can be more easily released from the molecularly imprinted polymer.

[0009] (4) In the sensor according to any one of (1) to (3), the target substance may be at least one selected from the group consisting of bacteria and viruses. In this sensor, the target substance is electrically nonconductive and electrically charged. Therefore, by adjusting the potential of the membrane to a potential opposite to that of the target substance, the electrostatic repulsion of the surface potential can be increased, thereby further reducing the interaction between the captured target substance and the molecularly imprinted polymer. As a result, the target substance can be more easily released from the molecularly imprinted polymer.

[0010] (5) The sensor according to any one of (1) to (4) above may be a field-effect transistor type sensor or a mass detection type sensor. Since the sensor of this form is a field-effect transistor type sensor or a mass detection type sensor, a desorption mechanism that changes the potential of the membrane can be easily applied.

[0011] The present disclosure can be realized in various forms, for example, a method for manufacturing a sensor, a method for monitoring a target substance using a sensor, and the like. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is an explanatory diagram illustrating a schematic configuration of a sensor. [Figure 2] FIG. 1 is an explanatory diagram showing how a target substance is desorbed from a molecularly imprinted polymer. [Figure 3] FIG. 10 is a cross-sectional view schematically showing the general configuration of a sensor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] A. First embodiment FIG. 1 is an explanatory diagram illustrating a schematic configuration of a sensor 100 according to an embodiment of the present disclosure. For convenience of illustration, FIG. 1 illustrates only the configuration of the main components of the sensor 100. The sensor 100 detects a target substance contained in a sample. The sample is not particularly limited, but examples thereof include gases such as air and exhaled breath, and liquids such as water. The sensor 100 of this embodiment is a mass detection sensor, and more specifically, is formed by a QCM (Quartz Crystal Microbalance) sensor. The sensor 100 includes a detection unit 10 and a desorption mechanism 20.

[0014] The detection unit 10 has a membrane 12 containing a molecularly imprinted polymer (MIP). A space 14 into which a target substance enters is formed in this molecularly imprinted polymer. This space 14 is formed according to the size and surface structure of the target substance by a method described below. The molecularly imprinted polymer chemically interacts with the target substance in this space 14, thereby capturing the target substance that has entered the space 14. The chemical interaction is not particularly limited, but examples thereof include hydrogen bonding.

[0015] The molecularly imprinted polymer is not particularly limited, but preferably has a non-covalent functional group in the main chain or branched chain. Examples of the non-covalent functional group include, but are not particularly limited to, an OH group. Examples of the molecularly imprinted polymer include, but are not particularly limited to, polypyrrole, polyaniline, acrylic polymers, photocurable polymers, and photosolubilizable polymers. The monomer for forming the molecularly imprinted polymer is not particularly limited, but preferably has a double bond for polymerization. The double bond may be present in the molecular chain or may be a double bond of an aromatic ring. Furthermore, from the viewpoint of the polymerization reaction, a monomer having an amino group is preferred. Therefore, the monomer for forming the molecularly imprinted polymer is preferably a compound having a double bond, an OH group, and an amino group.

[0016] Although one type of monomer may be used as the monomer for forming the molecularly imprinted polymer, it is preferable to use two or more types of monomers. When two or more types of monomers are used, a monomer without a non-covalent functional group may be included. The monomer for forming the molecularly imprinted polymer may be either water-soluble or water-insoluble, but a water-soluble monomer is preferable from the viewpoint of ease of handling. Specific examples of the monomer for forming the molecularly imprinted polymer include pyrrole, aniline, ortho-phenylenediamine, acrylamide, N,N'-methylenebisacrylamide, aminophenylboronic acid, aminophenol, aminobenzoic acid, and dopamine.

[0017] The target substance is not particularly limited, and examples thereof include substances with three-dimensional structures, chemical substances, fine particles, etc. The substances with three-dimensional structures are not particularly limited, and examples thereof include viruses, fungi, microorganisms, proteins, etc. The fungi are not particularly limited, and examples thereof include bacteria, fungi, archaea, etc. The viruses and fungi may be pathogenic to animals such as humans. The microorganisms are not particularly limited, and examples thereof include yeasts and algae. The proteins are not particularly limited, and examples thereof include disease-related proteins, antibodies, antigens, etc. The antigens may contain polysaccharides, peptides, nucleic acids, etc., or may be protein-free substances such as lipopolysaccharides. The chemical substances are not particularly limited, and examples thereof include drugs and hormones. The fine particles are not particularly limited, and examples thereof include pollen, PM2.5, yellow sand, aerosols, etc.

[0018] From the viewpoint of efficient desorption by the desorption mechanism 20, the target substance is preferably charged, and more preferably charged and non-conductive. If the target substance is charged, the electrostatic repulsion of the surface potential can be enhanced by adjusting the potential of the membrane 12 to a potential opposite to that of the target substance. The charged substance is preferably at least one selected from the group consisting of ions, bacteria, viruses, pollen, PM2.5, yellow sand, and aerosols, and at least one selected from the group consisting of bacteria and viruses is more preferred because it has non-conductive properties. Whether the target substance is charged or not is determined by measuring the zeta potential of the target substance. The zeta potential is measured under pure water conditions. If the absolute value of the zeta potential exceeds 5 mV, the substance is determined to be charged. On the other hand, if the zeta potential value is 5 mV or less, the substance is determined to be uncharged.

[0019] The target substance may be one or more types, but is preferably one type from the viewpoint of preventing a decrease in detection accuracy. In an embodiment in which two or more types of target substances are detected, two or more types of spaces 14 are formed in the molecular imprinted polymer according to the target substances.

[0020] The detection unit 10 of this embodiment further includes a quartz crystal plate 51, an upper electrode 52, a lower electrode 53, and a substrate 54. The quartz crystal plate 51 has a substantially disc-shaped exterior. The upper electrode 52 and the lower electrode 53 are each formed of a thin-film electrode and are disposed on either side of the quartz crystal plate 51. The lower electrode 53 is disposed on the substrate 54. The upper electrode 52 and the lower electrode 53 are configured to be electrically connectable to an AC power supply 58. A switch 59 switches between a connected state and a disconnected state between the upper electrode 52, the lower electrode 53, and the AC power supply 58. The upper electrode 52 and the lower electrode 53 may be formed of any conductive material, including, but not limited to, a metal. Examples of metals include, but are not limited to, gold, silver, copper, aluminum, and indium tin oxide (ITO). In this embodiment, the film 12 is disposed on the surface of the upper electrode 52 opposite the surface on which the quartz crystal plate 51 is disposed. The sensor 100 may be provided with a reference electrode (not shown), and a film containing a non-imprinted polymer (NIP) may be provided on the surface of the reference electrode. The non-imprinted polymer is made of the same material as the molecularly imprinted polymer, and is not subjected to template formation.

[0021] To detect a target substance, an AC voltage is applied to the upper electrode 52 and the lower electrode 53 of the sensor 100. This causes the quartz crystal plate 51 to vibrate at a certain frequency. When a target substance is captured in the space 14 formed in the molecularly imprinted polymer, an impedance change occurs according to the mass of the target substance, and the target substance can be detected based on this value.

[0022] The desorption mechanism 20 desorbs the target substance captured by the molecularly imprinted polymer from the molecularly imprinted polymer. The desorption mechanism 20 in the present disclosure is a mechanism that changes the potential of the membrane 12. The desorption mechanism 20 desorbs the target substance captured by the molecularly imprinted polymer by electrostatic repulsion between the target substance captured by the molecularly imprinted polymer and the molecularly imprinted polymer. In this embodiment, the desorption mechanism 20 is configured by a mechanism that can apply a constant voltage to the membrane 12. More specifically, the desorption mechanism 20 is configured to include a constant voltage application device 28 that can be electrically connected to the upper electrode 52 and the lower electrode 53 of the detection unit 10. The upper electrode 52, the lower electrode 53, and the constant voltage application device 28 are switched between a connected state and a disconnected state by a switch 29.

[0023] When the sensor 100 desorbs a target substance captured by the molecularly imprinted polymer, it disconnects the upper electrode 52 and the lower electrode 53 from the AC power supply 58 and electrically connects the upper electrode 52 and the lower electrode 53 to the constant-voltage application device 28. This allows a constant voltage to be applied to the membrane 12, thereby adjusting the potential of the membrane 12 to the same potential as the surface charge of the target substance. The timing at which the desorption mechanism 20 changes the potential of the membrane 12 is not particularly limited. The potential of the membrane 12 may be changed at regular intervals, but it is preferable to change the potential of the membrane 12 after the target substance is captured in the detection unit 10. Examples of methods for changing the potential of the membrane 12 after the target substance is captured include switching the switches 29 and 59 when impedance changes due to the capture of the target substance in the detection unit 10. The magnitude of the voltage applied to the membrane 12 is not particularly limited, but is preferably 5 V to 15 V, and more preferably 8 V to 12 V. The length of time for which a voltage is applied to the film 12 is not particularly limited, but is preferably 10 seconds or more and 3 minutes or less, and more preferably 20 seconds or more and 1 minute or less.

[0024] FIG. 2 is an explanatory diagram showing how a target substance 90 is captured by a membrane 12 containing a molecularly imprinted polymer and how the target substance 90 is desorbed from the membrane 12 containing a molecularly imprinted polymer. In FIG. 2, the left side of the page shows how the target substance 90 is captured in a space 14 formed in the molecularly imprinted polymer, and the right side of the page shows how the target substance 90 is desorbed by a change in the potential of the membrane 12. For ease of explanation, FIG. 2 also schematically illustrates a functional group 13 in the molecularly imprinted polymer as an example of a group that interacts with the target substance 90. In addition, FIG. 2 shows a negatively charged target substance 90 such as a virus or a bacterium as the target substance 90.

[0025] When the potential of the membrane 12 containing the molecularly imprinted polymer is adjusted to be positive, the negatively charged target substance 90 is attracted to the membrane 12 by electrostatic action and becomes more likely to be captured in the space 14. Therefore, by adjusting the potential of the membrane 12 containing the molecularly imprinted polymer to be opposite to the surface potential of the target substance 90, the target substance 90 can be easily captured.

[0026] On the other hand, when the target substance 90 is desorbed, if the potential of the film 12 is adjusted to be negative by the constant voltage application device 28 of the desorption mechanism 20, the negatively charged target substance 90 is desorbed due to electrostatic repulsion with the surface potential of the molecularly imprinted polymer. Note that even in an embodiment in which the film 12 containing the molecularly imprinted polymer is formed from a conductive material, no current will flow even if a voltage is applied to the film 12 unless a circuit including the film 12 is formed.

[0027] The desorption mechanism 20 of the present disclosure is a mechanism for changing the potential of the membrane 12, thereby desorbing the target substance 90 by electrostatic repulsion between the surface potential of the molecularly imprinted polymer and the target substance 90 captured by the molecularly imprinted polymer, thereby suppressing deterioration of the molecularly imprinted polymer. Therefore, compared to an embodiment in which the target substance 90 is removed by, for example, using a cyclic voltammetry technique different from the present application, scanning the potential applied between the working electrode and the counter electrode relative to the potential of the reference electrode until the potential reaches a potential at which the chemical bond is broken, deterioration of the molecularly imprinted polymer due to electron exchange can be suppressed. As a result, a decrease in the detection accuracy of the sensor 100 can be suppressed. This allows the sensor 100 to be used repeatedly, and a shortened lifespan of the sensor 100 can be suppressed.

[0028] Furthermore, according to this embodiment, the target substance 90 is desorbed by changing the potential of the film 12, without causing an oxidation-reduction reaction. Therefore, the voltage required for desorption can be reduced, and even target substances that require a large amount of energy for an oxidation-reduction reaction can be desorbed from the molecularly imprinted polymer.

[0029] Furthermore, unlike the embodiment of the present invention in which the target substance 90 is removed using an organic solvent such as acetonitrile or a base such as sodium hydroxide, the use of an organic solvent or a base can be omitted, thereby suppressing deterioration of the molecularly imprinted polymer. Furthermore, compared to the embodiment in which the target substance 90 is removed using an organic solvent, the impact on the environment can be reduced. Furthermore, compared to the embodiment in which the target substance 90 is removed using an organic solvent, the use of the sensor 100 is not limited to places where an organic solvent can be used, thereby expanding the range of use of the sensor 100.

[0030] Furthermore, in the sensor 100 of this embodiment, when detecting the target substance 90, the potential of the film 12 containing the molecular imprinted polymer is adjusted to have a sign different from that of the surface potential of the target substance, and when desorbing the captured target substance 90 from the molecular imprinted polymer, the potential of the film 12 containing the molecular imprinted polymer is adjusted to have the same sign as that of the surface potential of the target substance. Therefore, the target substance 90 can be easily captured and desorbed.

[0031] The uses of the sensor 100 of this embodiment are not particularly limited, but may be applied to, for example, virus and bacteria monitoring, air quality monitoring, water quality management, food hygiene management, health management of humans, animals and plants, high sensitivity sensors, etc.

[0032] The method for manufacturing the detection unit 10 having the membrane 12 containing the molecularly imprinted polymer of this embodiment is not particularly limited, but it can be manufactured, for example, by the following method. An example of the method for manufacturing the detection unit 10 having the membrane 12 containing the molecularly imprinted polymer in the case where the target substance 90 is penicillin V potassium will be described below.

[0033] First, 8 mg (0.028 mmol) of methacrylic acid (MAA) and penicillin V potassium (PenV-K) were dissolved in 800 μL of DMSO and sonicated for approximately 15 minutes. Next, 4 mg (0.024 mmol) of AIBN was added as an initiator, and ethylene glycol dimethacrylate (EGDMA) was added as a crosslinker. The solution was then kept in an ice bath and argon was passed through for approximately 20 minutes to remove oxygen. The mixture was then thermally polymerized at 60 °C for approximately 30 minutes while stirring to obtain an oligomer solution. A similar method can be used to prepare an oligomer solution for forming a non-imprinted polymer (NIP) without PenV-K.

[0034] A commercially available AT-cut quartz plate (e.g., approximately 168 μm thick and 13.8 mm long) is sputtered with gold. The desired gold electrode pattern can then be obtained by sequentially applying photoresist and etching. Next, 5 μL of the PenV-K-containing oligomer solution is dispensed onto the upper electrode of the dual-electrode QCM using a piston pipette at a rotation speed of, for example, 2000 rpm, and the rotation is maintained for 15 seconds. 5 μL of the PenV-K-free oligomer solution is dispensed onto the lower electrode of the dual-electrode QCM using a piston pipette at a rotation speed of, for example, 2000 rpm, and the rotation is maintained for 15 seconds. This coats one of the upper and lower electrodes, then the polymer is cured, and then the other electrode is coated. The polymer is cured by incubating overnight at approximately 80°C to evaporate the DMSO. This forms a working electrode coated with a MIP. If a reference electrode is to be fabricated, this reference electrode may also be coated with a NIP. The PenV-K used for template formation is then removed from the molecularly imprinted polymer by washing with distilled water overnight at room temperature in a stirring beaker, thereby producing a detection unit 10 having a membrane 12 containing a molecularly imprinted polymer.

[0035] B. Second embodiment FIG. 3 is an explanatory diagram showing a schematic configuration of a sensor 100a according to the second embodiment. The sensor 100a according to the second embodiment differs from the sensor 100 according to the first embodiment in that it is a FET sensor including a field effect transistor (FET sensor). Since the other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof will be omitted. Note that the sensor 100a according to the second embodiment is a so-called extended gate FET sensor, but is not limited to this and may be any FET sensor such as a bottom contact type or a top contact type.

[0036] The sensor 100a includes a substrate 61, a gate electrode 62, a gate insulating film 63, a source electrode 64, a drain electrode 65, a bank 66, a semiconductor thin film 67, a sealing film 68, a detection unit 10a, and a desorption mechanism 20a.

[0037] The substrate 61 is not particularly limited and may be formed from an inorganic or organic material. Examples of inorganic materials include, but are not limited to, glass, ceramics, and metals. Examples of organic materials include, but are not limited to, resins and paper. The gate electrode 62 is not particularly limited and may be formed from, but is not limited to, aluminum, silver, gold, copper, titanium, ITO, poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, conductive carbon nanotubes, graphene, conductive organic-inorganic composite materials, and the like. The gate insulating film 63 is not particularly limited and may be formed from, but is not particularly limited to, silica (silicon oxide), alumina (aluminum oxide), self-assembled monolayers, polystyrene, polyvinylphenol, polyvinyl alcohol, polymethyl methacrylate, polydimethylsiloxane, polysilsesquioxane, ionic liquids, polytetrafluoroethylene, and the like. The substrate 61 and the gate electrode 62 may be integrally formed, and for example, a metal substrate or a Si substrate may be used. The Si substrate is preferably doped to improve conductivity, and when the semiconductor thin film is p-type, it is preferable to use an n-type doped substrate, and when the semiconductor thin film is n-type, it is preferable to use a p-type doped substrate. SiO2 formed by oxidizing the surface of the Si substrate may also be used as the gate insulating film 63.

[0038] The source electrode 64 and the drain electrode 65 may be formed of, but are not limited to, a metal, a conductive polymer, conductive carbon, a conductive organic-inorganic composite material, or the like. Examples of metals include, but are not limited to, gold, silver, copper, platinum, and aluminum. Examples of conductive polymers include, but are not limited to, PEDOT and PSS. Examples of conductive carbon include, but are not limited to, conductive carbon nanotubes and graphene. The substrate 61, the gate electrode 62, the gate insulating film 63, the source electrode 64, and the drain electrode 65 may be subjected to a surface treatment, and for example, a self-assembled monolayer may be formed on the surface to adjust the liquid repellency.

[0039] The bank 66 may be formed of, for example, polytetrafluoroethylene, and the sealing film 68 may be formed of, for example, polytetrafluoroethylene, polyparaxylylene, etc. The semiconductor thin film 67 is not particularly limited, but if it is an organic semiconductor of P type, it may be formed of pentacene, dinaphthothienothiophene, benzothienobenzothiophene (Cn-BTBT), TIPS pentacene, TES-ADT, rubrene, P3HT, PBTTT, etc., and if it is an organic semiconductor of N type, it may be formed of fullerene, etc.

[0040] The detection unit 10a has a substrate 70, an extended gate electrode 71, and a counter electrode 72. The detection unit 10a is placed in an aqueous solution 73 containing a target substance.

[0041] The extended gate electrode 71 is electrically connected to the gate electrode 62 via a conductive wire 69. A film 12 containing a molecularly imprinted polymer is provided on the surface of the extended gate electrode 71. The extended gate electrode 71 may be formed, for example, from the same material as the gate electrode 62 described above. A metal thin film, a conductive inorganic material thin film, or a conductive organic material thin film having a thickness of, for example, 10 nm to 1000 μm may be formed on the surface of the extended gate electrode 71. Examples of metals include, but are not limited to, gold. Examples of conductive inorganic materials include, but are not limited to, carbon nanotubes and graphene. Furthermore, a metal oxide film having a thickness of 1 nm to 1000 nm, preferably 1 nm to 50 nm, may be formed on the surface of the extended gate electrode 71. Examples of metal oxides include, but are not limited to, SiO2. In the present disclosure, the term "surface of the extended gate electrode 71" includes both an embodiment in which the material of the extended gate electrode 71 itself is the surface and an embodiment in which a metal thin film or a metal oxide film is formed on the surface.

[0042] The substrate 70 is provided on the surface of the extended gate electrode 71 opposite to the surface on which the film 12 is provided. The substrate 70 is not particularly limited, but may be formed from, for example, glass, ceramics, resin, etc. The resin is not particularly limited, but examples thereof include PET, PEN, polyether ether ketone, and PC.

[0043] The counter electrode 72 is not particularly limited as long as it is conductive, and may be formed of, for example, a metal electrode or a carbon electrode. The counter electrode 72 may be formed by forming a conductive film on a substrate made of the same material as the substrate 70. The counter electrode 72 may also be formed by forming a film made of the same material as the molecularly imprinted polymer-containing film 12 or a different material. The counter electrode 72 may also be a reference electrode made of Ag / AgCl or the like.

[0044] In this embodiment, the desorption mechanism 20a is configured by a mechanism capable of applying a constant voltage to the membrane 12. More specifically, in the sensor 100a, the desorption mechanism 20a is configured to include a mechanism for applying a voltage to the counter electrode 72.

[0045] Measurement using the sensor 100a is performed, for example, with the detection unit 10a immersed in an aqueous solution 73 containing a target substance. When a target substance is captured in the space 14 formed in the molecularly imprinted polymer, the value of the threshold voltage changes depending on the concentration of the target substance. Therefore, for example, a relationship curve between the concentration of the target substance and the threshold voltage is created in advance, and then the threshold voltage of the aqueous solution containing the target substance to be measured is measured, thereby allowing the concentration of the target substance to be calculated based on the relationship curve. Alternatively, measurement may be performed using a current value instead of the threshold voltage.

[0046] When the sensor 100a desorbs a target substance captured by the molecular imprinted polymer, it applies a voltage opposite to that applied when detecting the target substance to the counter electrode 72. As a result, the target substance captured by the molecular imprinted polymer is desorbed due to electrostatic repulsion between the target substance captured by the molecular imprinted polymer and the surface potential of the molecular imprinted polymer.

[0047] The method for manufacturing the detection unit 10a having the membrane 12 containing the molecularly imprinted polymer of the second embodiment is not particularly limited, but it can be manufactured, for example, by the following method. An example of the method for manufacturing the detection unit 10a having the membrane 12 containing the molecularly imprinted polymer in the case where the target substance 90 is Escherichia coli will be described below.

[0048] First, for example, a metal mask is used on a PEN (polyethylene naphthalate) substrate to form a thin gold film of approximately 100 nm by vacuum deposition to obtain an electrode for the extended gate electrode 71. After washing this electrode with ethanol and ultrapure water, the potential is scanned five times from -0.7 V to +0.7 V in a solution containing 0.1 M LiClO4 and 50 mM pyrrole to perform electropolymerization of pyrrole. Then, 1 × 104 After adding CFU / mL of E. coli to the electropolymerization cell, molecularly imprinted polymers were synthesized by scanning the potential at a scan rate of 100 mV / s for five more cycles. This was followed by ultrasonic cleaning in water for 5 minutes or by 1 × 10 -3 The E. coli used for template formation is removed from the molecularly imprinted polymer by incubating it in a surfactant solution containing M. The sensor 100a can be manufactured by connecting the electrode (extended gate electrode 71) on which the membrane 12 containing the molecularly imprinted polymer is formed to the gate electrode 62 of the field effect transistor.

[0049] C. Variations The configuration of the sensors 100 and 100a in the above-described embodiments is merely an example and can be modified in various ways. For example, the sensors 100 and 100a are not limited to QCM sensors or FET sensors, but may be any type of sensor, such as a resistance sensor or an impedance sensor. Furthermore, the location of the desorption mechanism 20 is not limited, as long as the potential of the film 12 can be changed. Furthermore, for example, the desorption mechanism 20 may be used in combination with a desorption mechanism having another mechanism for desorbing the target substance captured by the molecularly imprinted polymer. Examples of desorption mechanisms having another mechanism include, but are not limited to, mechanisms that desorb by releasing a stimulant, mechanisms that desorb by light irradiation, mechanisms that desorb by heating or cooling, and mechanisms that desorb by vibration. Desorption mechanisms having another mechanism are preferably mechanisms that desorb by heating or cooling, or mechanisms that desorb by vibration. Examples of stimulants include at least one selected from the group consisting of ozone, hydroxyl radicals, and superoxide.

[0050] The present invention is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present invention. For example, the technical features in the embodiments and examples corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0051] 10, 10a...detection unit, 12...membrane, 13...functional group, 14...space, 20, 20a...desorption mechanism, 28...constant voltage application device, 29...switch, 51...quartz crystal plate, 52...upper electrode, 53...lower electrode, 54...substrate, 58...AC power supply, 59...switch, 61...substrate, 62...gate electrode, 63...gate insulating film, 64...source electrode, 65...drain electrode, 66...bank, 67...semiconductor thin film, 68...sealing film, 69...conductor, 70...substrate, 71...extension gate electrode, 72...counter electrode, 73...aqueous solution, 90...target substance, 100, 100a...sensor

Claims

1. A sensor for detecting a target substance, a detection unit having a space into which the target substance enters and a membrane containing a molecular imprinted polymer that captures the target substance that has entered the space; a desorption mechanism for desorbing the target substance captured by the molecular imprinted polymer from the molecular imprinted polymer; Equipped with the desorption mechanism is a mechanism that changes the potential of the membrane, and desorbs the target substance captured by the molecular imprinted polymer by electrostatic repulsion of the surface potential between the target substance captured by the molecular imprinted polymer and the molecular imprinted polymer; A sensor characterized by:

2. 2. The sensor of claim 1, The target substance is charged. A sensor characterized by:

3. 3. The sensor according to claim 1, The target substance is at least one selected from the group consisting of ions, bacteria, viruses, pollen, PM2.5, yellow sand, and aerosols. A sensor characterized by:

4. 3. The sensor according to claim 1, The target substance is at least one selected from the group consisting of bacteria and viruses. A sensor characterized by:

5. 3. The sensor according to claim 1, A field effect transistor type sensor or a mass detection type sensor. A sensor characterized by:

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