Electrochemical transistor sensor and preparation method and application thereof

Abstract

The invention relates to the technical field of biosensors, and discloses an electrochemical transistor sensor and a preparation method and application thereof. The electrochemical transistor sensor comprises a flexible substrate, an electrode layer deposited on the surface of the flexible substrate, and a flexible printed circuit board connected with the electrode layer, the electrode layer comprises a source electrode, a drain electrode and a grid electrode; a channel is arranged between the source electrode and the drain electrode; and the surface of the grid electrode is modified with a dual-network hydrogel layer containing biological recognition enzyme. According to the electrochemical transistor sensor provided by the invention, the dual-network hydrogel layer containing the biological recognition enzyme is formed, so that the detection of biomolecules such as glucose is realized; the organic electrochemical transistor is utilized to amplify a detection signal, and when the sensor is applied to glucose detection, the detection limit can be as low as 5 [mu] mol / L; the transistor is combined with the molecule detection module and the signal acquisition and processing module, so that real-time monitoring of biomolecules is realized, and the sensor has the characteristics of high sensitivity, high stability and portability.

Description

Technical Field

[0001] The present invention relates to the technical field of biosensors, and in particular to an electrochemical transistor sensor and a preparation method and application thereof. Background Art

[0002] If examination and treatment are not carried out until obvious symptoms of disease appear in the body, it is easy to miss the opportunity for early prevention and treatment of the disease, which will have an adverse effect on the patient's subsequent physical recovery and quality of life. This passive and lagging medical system cannot issue timely health warnings in the early stages of the disease. Therefore, it is urgent to develop a biological detection system that can quickly, accurately, conveniently and in real time monitor human health information, realize preventive medical treatment, enable patients to receive treatment as soon as possible, and avoid deterioration of the disease due to time delays.

[0003] There are many types of existing biochemical sensors, including electrochemical sensors, bio-optical sensors, potentiometric sensors, etc. Among them, electrochemical transistors are a type of sensor that combines transistor characteristics with biosensing functions. They can directly amplify biological signals at the bio-electronic interface and detect biochemical substances. Because they have both detection and signal amplification functions and are highly integrated, they show great potential in the field of biological detection systems.

[0004] In recent years, researchers have achieved the detection of a variety of biochemical information by fixing biorecognition markers (enzymes, antibodies, peptides, etc.) on the gate or channel of transistors. However, due to the concentration gradient and molecular diffusion effect, low-concentration detection is prone to deviation, limiting the detection limit and resolution of the sensor; in addition, the semiconductor layer of the transistor is sensitive to the environment and is easily corroded and degraded during long-term detection, which reduces the performance of the device or even makes it unable to work. Summary of the invention

[0005] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide an electrochemical transistor sensor; the second purpose of the present invention is to provide a method for preparing such an electrochemical transistor sensor; the third purpose of the present invention is to provide an application of such an electrochemical transistor sensor; the fourth purpose of the present invention is to provide a product; the fifth purpose of the present invention is to provide a health monitoring system.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides an electrochemical transistor sensor, which includes a flexible substrate, an electrode layer deposited on the surface of the flexible substrate, and a flexible printed circuit board connected to the electrode layer; the electrode layer includes a source electrode, a drain electrode and a gate electrode; a channel is provided between the source electrode and the drain electrode; the surface of the gate electrode is modified with a double network hydrogel layer containing a biorecognition enzyme.

[0008] In some embodiments of the present invention, the flexible substrate is made of at least one material selected from polyethylene naphthalate, polyparaxylene, polyimide, and polydimethylsiloxane.

[0009] In some specific embodiments of the present invention, the flexible substrate is made of polyethylene naphthalate (PEN).

[0010] In some embodiments of the present invention, the electrode layer includes a chromium bottom electrode and a gold top electrode; the thickness of the chromium bottom electrode is 3-10 nm; the thickness of the gold top electrode is 50-200 nm.

[0011] In the present invention, the chromium bottom electrode can be used as an adhesion layer between the gold top electrode and the flexible substrate.

[0012] In some embodiments of the present invention, the length of the channel between the source and the drain is 50-500 μm, and the width is 500-5000 μm.

[0013] In some embodiments of the present invention, an organic semiconductor layer is provided in the channel between the source electrode and the drain electrode; the preparation material of the organic semiconductor layer is selected from at least one of a p-type polymer PEDOT:PSS and an n-type polymer BBL.

[0014] In some specific embodiments of the present invention, the organic semiconductor layer is made of a p-type polymer PEDOT:PSS.

[0015] In some embodiments of the present invention, the double network hydrogel layer containing biorecognition enzymes is formed by solidifying a double network hydrogel prepolymer containing biorecognition enzymes; the double network hydrogel prepolymer containing biorecognition enzymes includes the following preparation raw materials: biorecognition enzymes, acrylamide, gelatin, N,N-methylenebisacrylamide, a photoinitiator and water.

[0016] In some embodiments of the present invention, the biorecognition enzyme is selected from one of glucose oxidase, catalase, uricase, lactase, antibiotic enzyme, aminopeptidase, and protein kinase.

[0017] In some specific embodiments of the present invention, the biorecognition enzyme is glucose oxidase.

[0018] In some embodiments of the present invention, the content of the biorecognition enzyme in the double network hydrogel prepolymer solution containing the biorecognition enzyme is 5-20 mg / L.

[0019] In some specific embodiments of the present invention, the content of the biorecognition enzyme in the double network hydrogel prepolymer solution containing the biorecognition enzyme is 5-10 mg / L.

[0020] In some embodiments of the present invention, in the double network hydrogel prepolymer solution containing the biorecognition enzyme, the ratio of acrylamide, gelatin, N,N-methylenebisacrylamide, photoinitiator and water is (3-7) g: (0.8-1.5) g: (0.3-0.8) g: (0.03-0.08) g: (20-30) mL.

[0021] In some specific embodiments of the present invention, in the double-network hydrogel prepolymer solution containing the biorecognition enzyme, the ratio of acrylamide, gelatin, N,N-methylenebisacrylamide, photoinitiator and water is (4-6) g: (0.8-1.2) g: (0.3-0.6) g: (0.04-0.06) g: (20-25) mL.

[0022] The second aspect of the present invention provides a method for preparing the electrochemical transistor sensor according to the first aspect of the present invention, comprising the following steps:

[0023] S1, cleaning the flexible substrate and depositing an electrode layer on the surface;

[0024] S2, after connecting the electrode layer to the flexible printed circuit board, subjecting the obtained device to ozone treatment;

[0025] S3, dropping an organic semiconductor material into the channel between the source and drain of the device, and curing the material to form an organic semiconductor layer;

[0026] S4, dripping a double network hydrogel prepolymer solution containing a biorecognition enzyme onto the gate surface of the device, solidifying it to form a double network hydrogel layer containing a biorecognition enzyme, and obtaining the electrochemical transistor sensor.

[0027] In some embodiments of the present invention, the method of cleaning the flexible substrate includes plasma cleaning.

[0028] In the present invention, the flexible substrate is cleaned so as to enhance the adhesion performance of the surface electrode layer.

[0029] In some embodiments of the present invention, the electrode layer is deposited by thermal evaporation.

[0030] In some embodiments of the present invention, the deposition rate of the electrode layer is

[0031] In some specific embodiments of the present invention, the deposition rate of the chromium bottom electrode is

[0032] In some specific embodiments of the present invention, the deposition rate of the gold top electrode is

[0033] In some embodiments of the present invention, the electrode layer is connected to the flexible printed circuit board by using anisotropic conductive film (ACF) and high voltage heating.

[0034] In the present invention, by adopting anisotropic conductive film (ACF) and high-voltage heating, the electrode layer and the flexible printed circuit board can be firmly combined, thereby improving the conductive performance.

[0035] In some embodiments of the present invention, the ozone treatment time is 5-10 minutes.

[0036] In the present invention, the hydrophilicity of the device after being connected to the flexible printed circuit board can be improved by performing ozone treatment, so as to facilitate the uniform application of the subsequent gate surface modification mixed solution.

[0037] In some embodiments of the present invention, the curing method of the organic semiconductor material layer is air drying.

[0038] In some embodiments of the present invention, after the organic semiconductor material layer is cured, the method further includes using a multimeter's conduction position to detect channel conduction and simultaneously checking conduction between electrodes and wires to confirm that there is no open circuit or short circuit.

[0039] In some embodiments of the present invention, the curing method of the double network hydrogel prepolymer solution containing the biorecognition enzyme is ultraviolet light curing.

[0040] In the present invention, a photoinitiator is added to a double network hydrogel prepolymer solution containing a biorecognition enzyme, and the mixed solution is cured by ultraviolet light curing, thereby forming a double network hydrogel sensitive layer on the surface of the gate, and fixing the biorecognition enzyme therein.

[0041] The third aspect of the present invention provides the use of the electrochemical transistor sensor described in the first aspect of the present invention in combination to construct an electrochemical transistor sensor array for synchronous detection of different target substances.

[0042] In some embodiments of the present invention, the target substance includes glucose.

[0043] In the present invention, the working principle of the electrochemical transistor sensor for detecting glucose is as follows: Glucose molecules undergo electrochemical reactions under the action of enzymes, resulting in an increase in the transistor gate current, that is, an increase in the effective gate voltage of the sensor. Under the action of the gate voltage, cations in the solution are injected into the channel film and complexed with PSS- in PEDOT:PSS, and the conductive PEDOT+ is reduced to a non-conductive state, so that the channel current decreases. This change can reflect the change in glucose concentration by measuring the change in the channel current, thereby realizing the detection of glucose.

[0044] A fourth aspect of the present invention provides a product, which comprises the electrochemical transistor sensor according to the first aspect of the present invention.

[0045] In some embodiments of the present invention, the product includes a skin patch, an ear-worn device, glasses, or a wristband.

[0046] The fifth aspect of the present invention provides a health monitoring system, which includes the electrochemical transistor sensor described in the first aspect of the present invention, and a customized circuit system; the customized circuit system includes a communication module, a microprocessor, a voltage management module and a current detection module.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1) The electrochemical transistor sensor provided by the present invention realizes the detection of biological molecules such as glucose by forming a double network hydrogel layer containing a biological recognition enzyme; the detection signal is amplified by an organic electrochemical transistor, and when applied to glucose detection, the detection limit can be as low as 5 μmol / L; by combining the transistor with a molecular detection module and a signal acquisition and processing module, real-time monitoring of biological molecules is realized, and it has the characteristics of high sensitivity, high stability and portability;

[0049] 2) The electrochemical transistor sensor provided by the present invention improves the electrochemical performance of the sensor by providing an organic semiconductor layer between the source electrode and the drain electrode;

[0050] 3) The preparation method of the electrochemical transistor sensor provided by the present invention has simple steps and uses technologies such as substrate pretreatment and device ozone treatment to enable the electrochemical transistor sensor to have better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of the electrochemical transistor sensor of the present invention, wherein 1 is a chromium bottom electrode and a gold top electrode, 2 is an enzyme-containing electrolyte, 3 is an organic semiconductor layer, D is a drain electrode, S is a source electrode, and G is a gate electrode;

[0052] Figure 2Schematic diagram of the structure of a double network hydrogel composed of cross-linked polyacrylamide and gelatin in the embodiment;

[0053] Figure 3 is a graph showing the relationship between glucose concentration and gate-source current when the electrochemical transistor sensor is used for glucose detection in the embodiment;

[0054] Figure 4 Graph showing the relationship between glucose concentration and source-drain current when the electrochemical transistor sensor is used for glucose detection in the embodiment. Specific embodiments

[0055] The present invention is further described in detail below by specific examples. The raw materials, reagents or devices used in the examples can be obtained from conventional commercial sources or by prior art methods unless otherwise specified. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0056] Example

[0057] This embodiment prepares an electrochemical transistor sensor, and the steps are as follows:

[0058] S11, preparing a polyethylene naphthalate flexible substrate with a size of 2 cm×10 cm, removing protective films covering the upper and lower surfaces thereof, and placing the polyethylene naphthalate flexible substrate into a plasma cleaning device for cleaning to increase the adhesion of the metal electrode;

[0059] S12, the cleaned polyethylene naphthalate flexible substrate is used to prepare electrodes by thermal evaporation, and a metal mask is used to The chromium bottom electrode with a thickness of 5 nm was deposited at a rate of A 100nm thick gold top electrode was deposited at a rate of 100nm; the electrode pattern was designed as an OECT array, and the design parameters of each OECT were: channel width of 1000μm and channel length of 500μm;

[0060] S21. Take out the sample with the prepared electrode, prepare the connected flexible printed circuit board, stick a thin double-sided tape on the connection, press lightly with tweezers first and then peel off the isolation paper, place it on a 72°C heater for slight heating, and align the flexible printed circuit board with the electrode interface for connection. Use tweezers to press the connection again to better fix it. After gluing, heat the device at 150°C high temperature and high pressure for 1 minute to make the connection between the flexible printed circuit board and the electrode tighter and the conductive performance better.

[0061] S22, placing the device in S21 in an ozone generator and treating with ozone for 5 minutes to increase the hydrophilicity of the device surface;

[0062] S31, use a microsyringe to take 0.3 μL of PEDOT:PSS solution and drop it on the channel connection between the source and drain electrodes, place it at room temperature and wait for it to dry naturally;

[0063] S32, then use the conduction position of the multimeter to detect the conduction of the channel, and at the same time check the conduction between each electrode and the wire to confirm that there is no open circuit or short circuit;

[0064] S41. Use a microsyringe to drop 3 μL of double-network hydrogel prepolymer solution containing glucose oxidase (containing 5 g acrylamide, 1 g gelatin, 0.05 g photoinitiator, 0.5 g N,N-methylenebisacrylamide, 25 mL water, and the content of glucose oxidase is 5 mg / mL) on the gate of the device, and form a gel sensitive layer through ultraviolet exposure to fix the glucose oxidase to obtain an electrochemical transistor sensor.

[0065] Figure 1 is a schematic diagram of the structure of the electrochemical transistor sensor of the present invention, comprising Figure 1 It can be seen that the electrochemical transistor sensor provided by the present invention has an electrode layer composed of a chromium bottom electrode and a gold top electrode, the electrode layer has an OECT array structure, a channel is provided between the source and drain of the electrode layer, and the channel is provided with an organic semiconductor layer.

[0066] Figure 2 is a schematic diagram of the structure of a double network hydrogel composed of cross-linked polyacrylamide and gelatin in the embodiment, Figure 2 It can be seen that the double network hydrogel in the embodiment is composed of cross-linked polyacrylamide (PAAm) and gelatin. Compared with the single network hydrogel, the double network hydrogel has better mechanical properties and a faster gelation speed.

[0067] Figure 3 is a graph showing the relationship between the glucose concentration and the gate-source current when the electrochemical transistor sensor is used for glucose detection in the embodiment, Figure 4 is a graph showing the relationship between glucose concentration and source-drain current when the electrochemical transistor sensor is used for glucose detection in the embodiment, Figure 3 and Figure 4 It can be seen that by utilizing the electrochemical doping effect of the transistor, the current change of the sensing electrode is amplified from the microampere level to the milliampere level. The sensor sensitivity is increased from 2.3μA / mmol / L to 137μA / mmol / L, which is about 60 times higher. By introducing the highly conductive material PEDOT:PSS, the electrochemical transistor sensor has good electrochemical properties, and the glucose detection limit can be as low as 5μmol / L.

Claims

1. An electrochemical transistor sensor, characterized in that: The electrochemical transistor sensor includes a flexible substrate, an electrode layer deposited on the surface of the flexible substrate, and a flexible printed circuit board connected to the electrode layer; the electrode layer includes a source electrode, a drain electrode and a gate electrode; a channel is provided between the source electrode and the drain electrode; the surface of the gate electrode is modified with a double network hydrogel layer containing a biorecognition enzyme.

2. The electrochemical transistor sensor according to claim 1, characterized in that: The flexible substrate is made of at least one material selected from polyethylene naphthalate, polyparaxylene, polyimide and polydimethylsiloxane.

3. The electrochemical transistor sensor according to claim 1, characterized in that: The electrode layer comprises a chromium bottom electrode and a gold top electrode; the thickness of the chromium bottom electrode is 3-10nm; the thickness of the gold top electrode is 50-200nm.

4. The electrochemical transistor sensor according to claim 1, characterized in that: The length of the channel between the source and the drain is 50-500 μm, and the width is 500-5000 μm; And / or, an organic semiconductor layer is provided in the channel between the source electrode and the drain electrode; and a material for preparing the organic semiconductor layer is selected from at least one of a p-type polymer PEDOT:PSS and an n-type polymer BBL.

5. The electrochemical transistor sensor according to claim 1, characterized in that: The double network hydrogel layer containing the biorecognition enzyme is formed by solidifying the double network hydrogel prepolymer solution containing the biorecognition enzyme; the double network hydrogel prepolymer solution containing the biorecognition enzyme comprises the following preparation raw materials: biorecognition enzyme, acrylamide, gelatin, N,N-methylenebisacrylamide, photoinitiator and water; Preferably, the biorecognition enzyme is selected from one of glucose oxidase, catalase, uricase, lactase, antibiotic enzyme, aminopeptidase and protein kinase.

6. The electrochemical transistor sensor according to claim 6, characterized in that: In the double network hydrogel prepolymer solution containing the biorecognition enzyme, the content of the biorecognition enzyme is 5-20 mg / L; And / or, the ratio of acrylamide, gelatin, N,N-methylenebisacrylamide, photoinitiator and water is (3-7) g: (0.8-1.5)g: (0.3-0.8)g: (0.03-0.08)g: (20-30)mL.

7. The method for preparing the electrochemical transistor sensor according to claim 5 or 6, characterized in that: The following steps are involved: S1, cleaning the flexible substrate and depositing an electrode layer on the surface; S2, after connecting the electrode layer to the flexible printed circuit board, subjecting the obtained device to ozone treatment; S3, dropping an organic semiconductor material into the channel between the source and drain of the device, and curing the material to form an organic semiconductor layer; S4, dripping a double network hydrogel prepolymer solution containing a biorecognition enzyme onto the gate surface of the device, solidifying it to form a double network hydrogel layer containing a biorecognition enzyme, and obtaining the electrochemical transistor sensor.

8. Use of the electrochemical transistor sensor according to any one of claims 1 to 6 in combining and constructing an electrochemical transistor sensor array for synchronous detection of different target substances.

9. A product, characterized in that The product comprises the electrochemical transistor sensor according to any one of claims 1 to 6; Preferably, the product comprises a skin patch, an ear-worn device, glasses, or a wristband.

10. A health monitoring system, characterized in that: The health monitoring system comprises the electrochemical transistor sensor according to any one of claims 1 to 6, and a customized circuit system; the customized circuit system comprises a communication module, a microprocessor, a voltage management module and a current detection module.

Images