A biochemical molecule detection method based on the quantum capacitance effect of conductive composite materials

Abstract

The present invention discloses a method for detecting biochemical molecules based on the quantum capacitance effect of conductive composite materials, which belongs to the field of molecular sensor technology. A three-electrode system consisting of a working electrode, a reference electrode, and a counter electrode is used for testing. A solution is dripped into a liquid tank so that both the working electrode and the reference electrode are in contact with the solution to form a circuit. A phase-locked amplifier or an impedance analyzer is used for quantum capacitance testing. Based on the test results, the liquid environment in which the sensor is located is evaluated to detect the concentration of biochemical molecules in the liquid. The present invention is easy to prepare, has a controllable structure, high stability, and good biocompatibility. It can realize Internet-style instant sensing and information communication and has extremely high detection sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sensors, and in particular to a biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material. Background Art

[0002] Biochemical molecular sensing technology plays an important role in biomedicine, environmental monitoring, clinical treatment, chemical industry, and other fields. Two-dimensional conductive materials, due to their excellent electrical properties, unique two-dimensional structure, and good chemical inertness, have excellent sensing sensitivity and great potential in the field of molecular sensing technology.

[0003] Quantum capacitance detection, as a highly sensitive detection mechanism, offers unique advantages for detecting target molecules in medical and environmental applications. Its sensing principle is based on detecting the charge of the target biochemical molecule. The quantum capacitance change signal reflects the significant change in the energy density of states (EDS) caused by the field effect when the charged biochemical molecule adsorbs on the graphene surface. Since the adsorption of biochemical molecules on the graphene surface is rapid, and the electrical signal detection itself is real-time, detection time is short, enabling rapid online detection. Among solid-state materials, two-dimensional materials like graphene are unique in that all their atoms are located on the surface. This makes the surface and its EDS extremely sensitive to environmental changes, resulting in high detection sensitivity and enabling trace detection. Since graphene quantum capacitance detection was first demonstrated using ionic liquids in 2009, graphene-based quantum capacitance has been used for gas detection, pH in solutions, and glucose detection. However, due to the current immaturity of large-area 2D material preparation and transfer technologies, highly stable and uniform 2D substrates remain difficult to obtain. Currently, biochemical sensors based on conductive 2D materials are mostly limited to laboratory testing. One way to solve the above problems is to combine conductive two-dimensional materials with other materials to obtain cheap, stable multi-layer composite materials with macroscopic dimensions (micrometer thickness) that can exist independently.

[0004] Generally, sensing occurs only at the nanoscale layer or so on the surface of the material, and the composite material itself has a micrometer-level thickness, making it difficult to detect the resistance change caused by the adsorption of biochemical molecules. In fact, the maximum thickness of the materials used in the gas and ion sensors reported so far is only 15nm. Therefore, it is very necessary to explore a method for detecting biochemical molecules using a conductive composite material with a micrometer-level thickness and macroscopic dimensions. This type of conductive composite material is expected to be used for biochemical sensing on the surface of ceramic teeth, bones, or other ceramic or polymer materials, promoting the intelligent application of such products. Summary of the Invention

[0005] The present invention aims to provide a biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material, which is characterized by comprising the following steps:

[0006] The test is carried out using a three-electrode system consisting of a working electrode, a reference electrode, and a counter electrode. A solution is dripped into a liquid tank so that both the working electrode and the reference electrode are in contact with the solution to form a circuit.

[0007] A lock-in amplifier or impedance analyzer is used to perform quantum capacitance testing. Based on the test results, the liquid environment in which the sensor device is located is evaluated and the concentration of biochemical molecules in the liquid is detected.

[0008] The working electrode is a conductive composite material, the reference electrode is calomel or silver chloride, and the counter electrode is a graphite or platinum electrode.

[0009] The biochemical molecules include hydrogen ions, hydroxide ions, potassium ions, chloride ions, DNA, RNA, and glucose.

[0010] The specific procedures for quantum capacitance testing using a lock-in amplifier or impedance analyzer are as follows:

[0011] While the applied DC potential remains constant, the frequency of the applied AC potential is continuously changed, the current passing through the system is measured, and a current-frequency curve of the sensor device is obtained; based on the relationship between current, capacitive reactance, and frequency, the linear portion of the obtained current-frequency curve is extended, and the capacitance of the system is obtained through the intercept, where the capacitance of the system is the series capacitance of the intrinsic capacitance of the conductive composite material and the interface capacitance;

[0012] While the external AC potential remains unchanged, the magnitude of the applied DC potential is continuously changed, the current passing through the system is measured, and the current-gate voltage relationship curve of the sensor device is obtained; based on the relationship between current and capacitive reactance, and capacitive reactance and capacitance, the current-gate voltage relationship curve is converted into a capacitance-gate voltage relationship curve.

[0013] The liquid environment in which the sensor device is located is evaluated based on the test results, including:

[0014] The capacitance-voltage relationship curves measured under different liquid environments are plotted on the same coordinate system, and the liquid environment is determined based on the regular changes in the curves as the molecular concentration in the solution changes.

[0015] Obtain the intrinsic capacitance of the system under the same external DC potential in different liquid environments, and judge the liquid environment based on the regular changes in intrinsic capacitance as the molecular concentration in the solution changes;

[0016] The minimum value, inflection point, and bias value of the turning point of the capacitance-gate voltage relationship curve under different liquid environments are obtained, and the liquid environment is judged based on the regular changes of this bias value with the molecular concentration in the solution.

[0017] The conductive composite material is composed of a conductive two-dimensional material and a stable matrix material, wherein the weight percentage of the conductive two-dimensional material is 0 to 99.9%;

[0018] The conductive two-dimensional materials include graphene and its derivatives, single-layer or multi-layer transition metal sulfides, two-dimensional nanostructured perovskites, graphyne, and metal nanosheets;

[0019] The stable matrix materials include oxide ceramics of silicon dioxide, aluminum dioxide, titanium dioxide, zirconium dioxide, and hafnium dioxide, nitride ceramics of silicon nitride and boron nitride, carbide ceramics of silicon carbide, metal ceramics, functional ceramics and ceramic composites thereof, polyaniline, epoxy resin, phenolic resin, PBS, PVC organic matter and composites thereof.

[0020] The preparation method of the conductive composite material is as follows:

[0021] The conductive two-dimensional material is uniformly dispersed in a stable base material at the atomic scale by intercalation, ultrasonic dispersion or powder mixing, and the pressure sintering and atmosphere pressure sintering methods are used to further promote and induce the two-dimensional material sheets to achieve directional arrangement in the ceramic base; the edge is obtained by cutting or dissociating in a direction perpendicular to the directional arrangement of the two-dimensional material.

[0022] After obtaining the edge of the two-dimensional material by cutting or dissociating it in a direction perpendicular to the directional arrangement of the two-dimensional material, grinding, chemical etching, and physical etching are added to further optimize the edge of the two-dimensional material.

[0023] After obtaining its edge by cutting or dissociating in a direction perpendicular to the directional arrangement of the two-dimensional material, surface chemical modification is performed to modify the receptor that specifically binds to a specific target substance.

[0024] The preparation method of the sensor device is as follows:

[0025] An adhesive is applied to a stable substrate to fix the conductive composite material and expose its cut surface for sensing as the upper surface; a conductive glue is applied to one side of the conductive composite material to serve as an electrode lead; and the non-sensing part is encapsulated with an insulating material to create a liquid tank that only exposes the sensing surface and prevents liquid from contacting the electrode.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention is cheap, easy to prepare, has controllable structure, high stability, good biocompatibility, and is reusable;

[0028] 2. The composite material of the present invention can be reused for molecular detection, which greatly increases the service life of the sensor, reduces costs, and is simple to operate;

[0029] 3. The optical and mechanical properties of graphene can be used to realize photoelectric coupling and flexible sensor design. By forming an LC oscillation circuit with a graphene quantum capacitor and a suitable inductor, wireless readout can be adopted to achieve Internet-style instant sensing and information communication.

[0030] 4. The present invention utilizes the local field enhancement effect of exposed graphene edges and has extremely high detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 (a)(b)(c)(d) are the sensor device preparation processes respectively;

[0032] Figure 2 is the SEM image of the cross section of the graphene composite material;

[0033] Figure 3 This is the field simulation diagram of the conductive composite material;

[0034] Figure 4 (a) (b) The actual circuit and equivalent circuit diagram of the test system respectively;

[0035] Figure 5 The current-frequency relationship curve for intrinsic capacitance measurement;

[0036] Figure 6 It is the capacitance-voltage curve measurement diagram;

[0037] Figure 7 is the capacitance-gate voltage relationship curve;

[0038] Figure 8 The capacitance-time dependence curves for different pH values. DETAILED DESCRIPTION

[0039] The present invention provides a biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material. The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] Sensor device structure:

[0041] The main structure of the sensor device includes a conductive composite material as a sensing element, an electrode led out, and a liquid tank obtained by packaging.

[0042] The conductive composite material can be obtained by combining a two-dimensional conductive material with a quantum capacitance effect with a stable matrix material. There are no specific requirements for its size. For ease of operation, a size of 1 to 50 mm is preferred.

[0043] Two-dimensional conductive materials have a finite energy density of states, resulting in extremely low intrinsic capacitance. Suitable two-dimensional conductive materials include, but are not limited to, graphene and its derivatives, single-layer or multi-layer transition metal sulfides, two-dimensional nanostructured perovskites, graphyne, and metal nanosheets.

[0044] Generally, matrix materials are inexpensive, stable, and easy to prepare. Matrix materials include, but are not limited to, oxide ceramics such as silicon dioxide, aluminum dioxide, titanium dioxide, zirconium dioxide, and hafnium dioxide; nitride ceramics such as silicon nitride and boron nitride; carbide ceramics such as silicon carbide; various metal ceramics; functional ceramics and ceramic composites thereof; and organic materials such as polyaniline, epoxy resin, phenolic resin, PBS, and PVC and composites thereof.

[0045] The surface of the conductive composite material can be obtained by cutting or dissociation. Cutting or dissociation in a direction perpendicular to the directional arrangement of the two-dimensional material can obtain its edge, and grinding, chemical etching, physical etching and other treatments can be added or not to further optimize the edge of the two-dimensional material. Surface chemical modification can be performed or not to modify receptors that specifically bind to specific target substances.

[0046] The extraction electrode includes, but is not limited to, conductive materials such as gold, silver, and copper. In a preferred embodiment, the extraction electrode is silver.

[0047] The material for encapsulating the liquid tank includes but is not limited to non-toxic epoxy resin, silicone and other insulators. In a preferred embodiment, the material for encapsulating the liquid tank is a biocompatible silicone.

[0048] Detection method:

[0049] Quantum capacitance testing methods include but are not limited to current-frequency curve measurement and CV curve measurement of sensor devices.

[0050] When measuring the current-frequency curve, the frequency of the applied alternating current potential can range from 1 mHz to 10 MHz. The amplitude of the applied alternating current potential is typically a sinusoidal wave, ranging from 1 mV to 100 mV, preferably 7.07 mV. The DC potential can be set between -10 V and 10 V, and in a preferred embodiment, is 0 V.

[0051] When measuring a CV curve, the frequency range of the applied constant AC potential can be determined by determining the linear portion of the current-frequency curve, and its amplitude can be 1 mV to 100 mV, preferably 7.07 mV. The applied DC potential can vary from -10 V to 10 V, preferably from -1 V to 1 V. Based on the relationship between current and capacitance, i.e., C = I / 2πfV, the current-gate voltage curve is converted to a capacitance-gate voltage curve.

[0052] Detection of biochemical molecules:

[0053] In one embodiment, the method is used to sense a biochemical molecule. In this embodiment, a working electrode is in contact with a carrier medium that may include the molecule, and the quantum capacitance properties of the conductive composite material in response to an applied potential are sensitive to the presence of the molecule. If the carrier medium does contain the molecule, a specific quantum capacitance property will be achieved. Similarly, as the concentration of the molecule in the carrier medium changes, the quantum capacitance properties will also change accordingly.

[0054] Although the carrier medium may also be a gaseous medium, it is preferably in liquid form. The carrier liquid (or carrier gas) can be any liquid (or gas) that can suspend or dissolve (or disperse) the substance. In one embodiment, the carrier comprises a pH buffer solution.

[0055] The sensor device includes a receptor portion capable of binding the substance, and the quantum capacitive response of the sensor device to an applied potential is sensitive to the binding of the substance to the receptor portion. Preferably, the receptor portion is capable of specifically binding to the substance. "Capable of specifically binding to the substance" generally means that the binding constant for the substance is at least 50 times greater, preferably at least 100 times greater, and more preferably at least 200 times greater than the binding constant for any other substance present in the carrier medium.

[0056] Examples of receptor moieties include antibodies, antibody fragments, nucleic acids, nucleic acid aptamers, oligosaccharides, peptides and proteins. Preferably, the receptor moiety is selected from antibodies, nucleic acids and peptides. The most preferred receptor moiety is an antibody.

[0057] The antibody or antibody fragment can be selected from one or more of IgA, IgD, IgE, IgG, and IgM. The antibody selectively binds to the target substance. The antibody or antibody fragment can be derived from mammals, including but not limited to humans, mice, rats, rabbits, goats, sheep, and horses. The nucleic acid aptamer can be selected from peptide aptamers, DNA aptamers, and RNA aptamers.

[0058] Obviously, the choice of receptor moiety for a given electrode depends on the identity of the substance of interest (i.e., the intended "target"). For example, the target can be alpha-synuclein (α-sync), in which case the receptor moiety typically includes or consists of anti-α-synuclein. The target species that the user wishes to detect / sens may be present or absent in the carrier medium, optionally with one or more other non-target species. Most commonly, the method is a method for determining the concentration of the target species in the carrier medium.

[0059] Examples of target species include those selected from the group consisting of CRP protein, insulin, and one or more markers of neurodegeneration, cancer, myocardial infarction, diabetes, and general trauma.

[0060] More generally, suitable target species for detection according to the methods of the present invention include proteins, polypeptides, antibodies, nanoparticles, drugs, toxins, noxious gases, hazardous chemicals, explosives, viral particles, cells, multicellular organisms, cytokines and chemokines, gametocytes, organelles, lipids, nucleic acid sequences, oligosaccharides, chemical intermediates of metabolic pathways, and macromolecules. In preferred embodiments, the target species includes, consists essentially of, or is entirely composed of a biochemical molecule, more preferably a biomacromolecule, and most preferably a polypeptide. A biomarker is an example of a particular purpose biochemical molecule.

[0061] Environmental parameter sensing:

[0062] This method can be used to sense changes in environmental parameters of the environment in which the electrode is located. Examples of these environmental parameters include the temperature of the environment, the intensity of light in the environment (e.g., the intensity of visible light, or alternatively or additionally, the intensity of ultraviolet light), and the humidity of the environment. In such methods, the interaction of light, temperature, or ambient / surface water affects the measured quantum capacitance properties of the sensor device.

[0063] Figure 1 (a)(b)(c)(d) are the sensor device preparation processes respectively. The sensor device is prepared according to the following steps:

[0064] (a) A biocompatible silicone is coated on a stable substrate as an adhesive;

[0065] (b) fixing a conductive composite material on the binder: a reduced graphene oxide / silicon dioxide ceramic composite material, wherein the reduced graphene oxide content is 5%;

[0066] (c) Silver paste is applied to one side of the composite material to serve as an electrode lead;

[0067] (d) The non-sensing part is encapsulated with silicone to create a liquid tank to prevent the liquid from contacting the electrodes.

[0068] Figure 2 The SEM image of the cross section of the graphene composite material; the conductive composite material used was characterized by scanning electron microscopy: reduced graphene oxide (5%) / silicon dioxide ceramic composite material, and the characterization results are as follows Figure 2 The conductive graphene edges are clearly visible, and the graphene is dispersed in layers on the fuzzy non-conductive ceramic matrix, confirming that the intercalation method has been successfully used to uniformly disperse the reduced graphene oxide in the ceramic matrix at the atomic scale.

[0069] Figure 3 The field simulation diagram of the conductive composite material is shown in Figure 2. Comsol is used to simulate the edge of reduced graphene oxide. The results are shown in Figure 2. Figure 3A sharp voltage drop is observed near the graphene edge, leading to a prominent local electric field enhancement at the graphene edge, which is an order of magnitude stronger near the graphene edge than just 1 nm away from the edge.

[0070] Example 1 Quantum Capacitance Test

[0071] Reagents: 0.1 mol / L standard hydrochloric acid solution, sodium hydroxide

[0072] Apparatus: MFLI lock-in amplifier, probe station, saturated calomel electrode

[0073] Experimental methods and steps:

[0074] a) Preparation of a series of hydrochloric acid and sodium hydroxide solutions (pH = 3-11)

[0075] Use a pipette to take 9.9 mL of deionized water. Then, pipette 100 μL of 0.1 mol / L standard hydrochloric acid solution and add it dropwise to the deionized water to obtain a 1 mM hydrochloric acid solution (pH = 3). Dilute this hydrochloric acid solution tenfold with deionized water to obtain a hydrochloric acid solution with a pH of 4. Subsequently, use the same tenfold dilution method to obtain hydrochloric acid solutions with pH = 5 and 6.

[0076] Weigh 0.4g of sodium hydroxide using an electronic balance and dissolve it in 10mL of deionized water to obtain a 1mol / L sodium hydroxide solution. Use a pipette to take 9.09mL of deionized water, and then use a pipette to take 10μL of 1mol / L standard hydrochloric acid solution and drop it into the deionized water to obtain a 1mM sodium hydroxide solution (pH=11). Dilute this solution tenfold with deionized water to obtain a sodium hydroxide solution with a pH of 10. Then, use the same tenfold dilution method to obtain sodium hydroxide solutions with pH=5 and 6.

[0077] b) Test system circuit construction

[0078] Figure 4 (a) and (b) show the actual circuit and equivalent circuit diagrams of the test system, respectively. Testing was performed using a three-electrode system. The graphene / ceramic composite served as the working electrode, the reference electrode was a calomel electrode, and the counter electrode was an inert graphite electrode. Solution was dripped into a liquid tank, ensuring contact between the working and reference electrodes, completing the circuit.

[0079] c) Intrinsic capacitance measurement

[0080] exist Figure 4 In the circuit shown, after dripping the solution into the device solution tank, the frequency of the AC voltage output by the power supply is changed and the current in the circuit is measured. During the test, the AC voltage is set to 7.07mV (i.e. V pk=10mV), the DC voltage is set to 0V, the frequency range is 1-100kHz, and a scan is performed back and forth; the frequency sampling points are selected in log mode, and 101 sampling points are taken in one test to obtain the current-frequency relationship curve as shown below Figure 5 As shown. Based on the RC equivalent circuit, the intercept (i.e. 2πfC, where the total series capacitance C = C Q C DL / (C Q +C DL )), and then calculate the quantum capacitance C of the graphene / ceramic composite material Q (C DL Generally a known constant value). Figure 5 The intercept is obtained after a function fitting is performed on the linear part. After calculation, the intrinsic capacitance of the material at this time is C = 1μF / cm 2 .

[0081] d) Capacitance-gate voltage relationship curve measurement

[0082] exist Figure 4 In the circuit shown, after the prepared solution is dripped into the device solution tank, the DC voltage output by the power supply (i.e. the solution gate voltage V ref ) size, measure the current in the circuit, and then calculate the capacitance-gate voltage relationship curve according to C=I / 2πVf. During the test, the AC voltage is set to 7.07mV (i.e. V pk =10mV), 77.77Hz, the DC voltage is set to change from -1V to 1V, and scan back and forth once, sampling every 0.02V, and the capacitance-voltage relationship curve is obtained as shown in Figure 6 As shown. Figure 6 As shown, the capacitance-voltage curve is V-shaped, indicating good field effect performance. In actual testing, it is not ruled out that capacitance-voltage curves with inverted V shapes or other shapes may be obtained.

[0083] Example Sensor Response Test of Potassium Chloride Concentration

[0084] Reagent: 1 mol / L potassium chloride solution

[0085] Apparatus: MFLI lock-in amplifier, probe station, silver / silver chloride electrodes

[0086] Experimental methods and steps:

[0087] a) Preparation of potassium chloride solution with a series of concentrations

[0088] Use a pipette to take 9 mL of deionized water. Then, use a pipette to add 1 mL of 1 mol / L potassium chloride solution to the deionized water to make a 100 mM potassium chloride solution. Repeat this ten-fold dilution process to obtain potassium chloride solutions with concentrations of 10 mM and 1 mM, respectively.

[0089] b) Test system circuit construction

[0090] The test was conducted using a three-electrode system. The graphene / titanium dioxide material served as the working electrode, the silver / silver chloride electrode was used as the reference electrode, and the inert graphite electrode was used as the counter electrode. A solution was dripped into a liquid tank, ensuring that both the working and reference electrodes were in contact with the solution, thus completing the circuit.

[0091] c) Capacitance curve measurement at different potassium chloride concentrations

[0092] After adding prepared potassium chloride solutions of different concentrations into the device solution tank, the DC voltage output by the power supply (i.e., the solution gate voltage V ref ) size, measure the current in the circuit, and then calculate the capacitance-gate voltage relationship curve according to C=I / 2πVf. During the test, the AC voltage is set to 0.707mV (i.e. V pk =1mV), 121Hz, the DC voltage setting range is -0.5V to 0.5V, and sampling is performed every 0.01V to obtain the capacitance-voltage relationship curve as shown below Figure 7 shown.

[0093] like Figure 7 As shown, the capacitance-voltage curve exhibits a Λ-shape, distinct from conventional graphene capacitance curves. Furthermore, increasing the potassium chloride concentration results in a positive shift of the "Λ" point (<5 mV dec-1). This order of magnitude smaller inductive response, compared to the Nernst limit of 59.2 mV dec-1 at room temperature, suggests that the graphene edge exhibits relatively weak adsorption of negatively charged Cl- ions. In other words, both K+ and Cl- ions are chemically inert and have a low tendency to adsorb specifically at the graphene edge. Therefore, there is no significant ionic charge doping effect.

[0094] Example 3 pH sensor response test

[0095] Reagent: pH=3-12 buffer solution

[0096] Apparatus: MFLI lock-in amplifier, probe station, silver / silver chloride electrodes

[0097] Experimental methods and steps:

[0098] a) Test system circuit construction

[0099] The test was conducted using a three-electrode system. A graphene / silicon nitride material served as the working electrode, a silver / silver chloride electrode was used as the reference electrode, and an inert graphite electrode was used as the counter electrode. A solution was dripped into a liquid tank, ensuring that both the working and reference electrodes were in contact with the solution, completing the circuit.

[0100] b) Capacitance-time dependence curves at different pH values

[0101] Add the prepared buffer solution to the device solution tank, replace the buffer solution every ten minutes, change the pH value from low to high, and measure the capacitance in the circuit. During the test, the AC voltage is set to 7.07mV (V pk =10mV), the DC voltage is set to 0V, the frequency is 216Hz, and the time dependence curve of the capacitance change is calculated based on the size of the initial capacitance. The capacitance time dependence curves of different pH values ​​are as follows Figure 8 As shown in the figure, the capacitance changes significantly with the change of hydrogen ion concentration, showing good sensing performance.

[0102] In summary, the present invention utilizes graphene composite materials to perform biochemical molecule detection based on the quantum capacitance effect. Through intrinsic capacitance measurement and capacitance-voltage relationship curve measurement, the graphene composite material exhibits a field effect in which the capacitance can be regulated by the gate voltage. The intrinsic capacitance is small and easy to detect, and the detection sensitivity is high.

Claims

1. A biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material, characterized in that: The following steps are involved: The test is performed using a three-electrode system consisting of a working electrode, a reference electrode, and a counter electrode. A solution is dripped into a liquid tank so that both the working electrode and the reference electrode are in contact with the solution to form a circuit. The working electrode is a conductive composite material, the reference electrode is calomel or silver chloride, and the counter electrode is a graphite or platinum electrode. Use a lock-in amplifier or impedance analyzer to perform quantum capacitance testing, evaluate the liquid environment in which the sensor device is located based on the test results, and detect the concentration of biochemical molecules in the liquid; The preparation method of the conductive composite material is as follows: The conductive two-dimensional material is uniformly dispersed in a stable base material at the atomic scale by intercalation, ultrasonic dispersion or powder mixing, and the pressure sintering and atmosphere pressure sintering methods are used to further promote and induce the two-dimensional material sheets to achieve directional arrangement in the ceramic base; the edge is obtained by cutting or dissociating in a direction perpendicular to the directional arrangement of the two-dimensional material.

2. The biochemical molecule detection method based on the quantum capacitance effect of the conductive composite material according to claim 1, characterized in that: The biochemical molecules include hydrogen ions, hydroxide ions, potassium ions, chloride ions, DNA, RNA, and glucose.

3. The biochemical molecule detection method based on the quantum capacitance effect of the conductive composite material according to claim 1, characterized in that: The specific procedures for quantum capacitance testing using a lock-in amplifier or impedance analyzer are as follows: While the applied DC potential remains constant, the frequency of the applied AC potential is continuously changed, the current passing through the system is measured, and a current-frequency curve of the sensor device is obtained; based on the relationship between current, capacitive reactance, and frequency, the linear portion of the obtained current-frequency curve is extended, and the capacitance of the system is obtained through the intercept, where the capacitance of the system is the series capacitance of the intrinsic capacitance of the conductive composite material and the interface capacitance; While the external AC potential remains unchanged, the magnitude of the applied DC potential is continuously changed, the current passing through the system is measured, and the current-gate voltage relationship curve of the sensor device is obtained; based on the relationship between current and capacitive reactance, and capacitive reactance and capacitance, the current-gate voltage relationship curve is converted into a capacitance-gate voltage relationship curve.

4. The biochemical molecule detection method based on the quantum capacitance effect of the conductive composite material according to claim 1, characterized in that: The liquid environment in which the sensor device is located is evaluated based on the test results, including: The capacitance-voltage relationship curves measured under different liquid environments are plotted on the same coordinate system, and the liquid environment is determined based on the regular changes in the curves as the molecular concentration in the solution changes. Obtain the intrinsic capacitance of the system under the same external DC potential in different liquid environments, and judge the liquid environment based on the regular changes in intrinsic capacitance as the molecular concentration in the solution changes; The minimum value, inflection point, and bias value of the turning point of the capacitance-gate voltage relationship curve under different liquid environments are obtained, and the liquid environment is judged based on the regular changes of this bias value with the molecular concentration in the solution.

5. The biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material according to any one of claims 1 to 4, characterized in that: The conductive composite material is composed of a conductive two-dimensional material and a stable matrix material, wherein the weight percentage of the conductive two-dimensional material is 0 to 99.9%; The conductive two-dimensional materials include graphene and its derivatives, single-layer or multi-layer transition metal sulfides, two-dimensional nanostructured perovskites, graphyne, and metal nanosheets; The stable matrix materials include oxide ceramics of silicon dioxide, aluminum dioxide, titanium dioxide, zirconium dioxide, and hafnium dioxide, nitride ceramics of silicon nitride and boron nitride, carbide ceramics of silicon carbide, metal ceramics, functional ceramics and ceramic composites thereof, polyaniline, epoxy resin, phenolic resin, PBS, PVC organic matter and composites thereof.

6. The biochemical molecule detection method based on the quantum capacitance effect of the conductive composite material according to claim 1, characterized in that: After obtaining the edge of the two-dimensional material by cutting or dissociating it in a direction perpendicular to the directional arrangement of the two-dimensional material, grinding, chemical etching, and physical etching are added to further optimize the edge of the two-dimensional material.

7. The biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material according to claim 1 or 6, characterized in that: After obtaining its edge by cutting or dissociating in a direction perpendicular to the directional arrangement of the two-dimensional material, surface chemical modification is performed to modify the receptor that specifically binds to a specific target substance.

8. The biochemical molecule detection method based on the quantum capacitance effect of a conductive composite material according to claim 1 or 3, characterized in that: The preparation method of the sensor device is as follows: An adhesive is applied to a stable substrate to fix the conductive composite material and expose its cut surface for sensing as the upper surface; a conductive glue is applied to one side of the conductive composite material to serve as an electrode lead; and the non-sensing part is encapsulated with an insulating material to create a liquid tank that only exposes the sensing surface and prevents liquid from contacting the electrode.

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