Biosensing element, biosensor and biological detection chip

Abstract

The embodiment of the utility model provides a biological sensing element, a biological sensor and a biological detection chip, relates to the technical field of display, and is used for improving the detection stability and accuracy of the biological sensing element. The biosensing element comprises a substrate, a thin film transistor and a reaction cavity, the thin film transistor and the reaction cavity are located on one side of the substrate, the thin film transistor comprises a grid electrode, a grid insulating layer, an active layer, a source electrode and a drain electrode which are stacked, the thin film transistor is located in the reaction cavity, and an antibody is arranged in the reaction cavity; the thin film transistor further includes a protective layer including at least one of a first protective layer and a second protective layer; wherein the first protection layer is located between the gate insulation layer and the active layer; the second protection layer comprises a first part which is positioned on one side, far away from the substrate, of the part, exposed by the source electrode and the drain electrode, of the active layer; wherein a heterojunction is arranged between the protective layer and the active layer. The biosensing element is used for detecting the Alzheimer disease.

Description

Technical Field

[0001] This disclosure relates to the field of chip technology, and in particular to a biosensing element, a biosensor, and a biodetection chip. Background Technology

[0002] Thin-film transistor (TFT) biosensor technology, as a rapid, accurate, and label-free detection technique, has already been used in medical and environmental analysis. In the field of clinical diagnostics, the demand for rapid point-of-care testing and analysis in various settings near the test subject is foreseeably increasing.

[0003] Electrical detection methods can achieve label-free detection; they utilize DNA hybridization reactions or antigens. Detection is achieved by changes in electrical signals such as potential, electrical charge, or electrical conductance on the surface of biomolecular carrier materials caused by antibody biorecognition reactions. The detection process is simple and rapid, with high sensitivity, and requires no complex detection equipment, truly achieving the goals of low cost, miniaturization, and portability. Utility Model Content

[0004] The purpose of this disclosure is to provide a biosensing element, a biosensor, and a biodetection chip to improve the stability and accuracy of the detection performance of the biosensing element.

[0005] To achieve the above objectives, the embodiments of this disclosure provide the following technical solutions:

[0006] On one hand, a biosensing element is provided, comprising: a substrate, a thin-film transistor located on one side of the substrate, and a reaction chamber. The thin-film transistor includes: a gate, a gate insulating layer, an active layer, a source, and a drain, all stacked together. The thin-film transistor is located within the reaction chamber, and an antibody is disposed within the reaction chamber. The thin-film transistor further includes: a protective layer, comprising at least one of a first protective layer and a second protective layer. The first protective layer is located between the gate insulating layer and the active layer. The second protective layer includes: a first portion located on the side of the active layer exposed by the source and the drain, away from the substrate. The water contact angle of the material of the protective layer is greater than the water contact angle of the material of the gate insulating layer.

[0007] In the aforementioned biosensor element, the protective layer, due to its larger water contact angle than the gate insulating layer, exhibits stronger hydrophobicity. The first part of the second protective layer enhances the active layer's resistance to water and oxygen corrosion. The first protective layer avoids oxygen vacancy defects caused by lattice mismatch between the active layer and the gate insulating layer, or it can fill these vacancies. Therefore, the first protective layer effectively prevents charge traps from forming on the gate insulating layer surface under bias voltage, thus mitigating the thin-film transistor characteristic transfer curve drift and improving the stability of the thin-film transistor. This, in turn, enhances the stability and accuracy of the biosensor element's detection performance.

[0008] In some embodiments, the material of the protective layer includes any one of organic semiconductor materials, inorganic semiconductor materials, and hydrophobic materials.

[0009] In some embodiments, the material of the protective layer includes at least one of the following groups.

[0010] , , , , -F and -CN.

[0011] Wherein, R1 is selected from , , or n1 is selected from 1, 2 or 3.

[0012] In some embodiments, the material of the protective layer includes at least one of the following structural formulas.

[0013] , , , , , , , , , , , , , , , , , , and .

[0014] R2 includes: R3 includes: R4 includes: R5 includes: 2-EtHex, -C 16 H 33 or -(CH2)2CH(C 10 H 21 )2; n2 is selected from positive integers greater than or equal to 50 and less than or equal to 10000.

[0015] In some embodiments, the thickness of the protective layer ranges from 5 nm to 100 nm.

[0016] In some embodiments, the material of the protective layer includes at least one of perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate, and fluorinated graphene.

[0017] In some embodiments, the thickness of the protective layer ranges from 3 nm to 10 nm.

[0018] In some embodiments, the material of the protective layer is an inorganic semiconductor material, and the density of the material of the protective layer is greater than the density of the material of the gate insulating layer.

[0019] In some embodiments, the material of the protective layer includes at least one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, indium tin oxide, molybdenum disulfide, silicon carbide, and gallium nitride.

[0020] In some embodiments, the thickness of the protective layer ranges from 1 nm to 5 nm.

[0021] In some embodiments, the material of the protective layer includes at least one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, and indium tin oxide; the antibody is attached to the surface of the first part.

[0022] In some embodiments, the biosensing element further includes: an interlayer dielectric layer; the interlayer dielectric layer is located on the side of the first portion away from the active layer; the biosensing element further includes: a detection electrode and a sensing electrode located within the reaction chamber, the detection electrode being located on the side of the interlayer dielectric layer away from the substrate, the detection electrode being electrically connected to the sensing electrode; wherein the antibody is attached to the surface of the sensing electrode.

[0023] In some embodiments, the material of the protective layer includes a semiconductor material, and the second protective layer further includes a second portion connected to the first portion; the second portion is located between the active layer and the source electrode, and between the active layer and the drain electrode.

[0024] In some embodiments, the active layer is made of indium gallium zinc oxide.

[0025] On the other hand, a biosensor is provided, comprising an array of multiple biosensing elements, wherein at least one of the multiple biosensing elements is a biosensing element as described in any of the above embodiments; the gate of each biosensing element is connected to a gate signal line; the source of each biosensing element in the same column is connected to the same source connection line; and the drain of each biosensing element in the same row is connected to the same drain connection line.

[0026] In another aspect, a biosensing chip is provided, comprising a biosensor as described in any of the above embodiments, a detector connected to the biosensor, and a controller; wherein the controller is configured to analyze antigen samples injected into the reaction chambers of each biosensing element of the biosensor based on the electrical signal of the biosensor detected by the detector and output detection results.

[0027] On the other hand, an application of the biodetection chip as described in any of the above embodiments in the detection of Alzheimer's disease is provided.

[0028] The aforementioned biosensors, biodetection chips, and their applications in Alzheimer's disease detection have the same structure and beneficial technical effects as the biosensing elements provided in some of the above embodiments, and will not be described again here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual process of the method, etc. involved in the embodiments of this disclosure.

[0030] Figure 1 Here are structural diagrams of biosensors according to some embodiments of this disclosure;

[0031] Figure 2 for Figure 1 A cross-sectional view of the biosensor along section line AA;

[0032] Figure 3 This is a structural diagram of a biosensing element according to some embodiments of the present disclosure;

[0033] Figure 4 This is another structural diagram of a biosensing element according to some embodiments of the present disclosure;

[0034] Figure 5 This is yet another structural diagram of a biosensing element according to some embodiments of the present disclosure;

[0035] Figure 6 Here is a structural diagram of a biological detection chip according to some embodiments of this disclosure;

[0036] Figure 7 This is a characteristic transfer curve of the antibody on the biosensor element provided in Embodiment 1 of this disclosure after binding with antigens of different concentrations;

[0037] Figure 8 These are characteristic transfer curves of the biosensing elements provided in Embodiments 1 to 5 and Comparative Example 1 of this disclosure. Detailed Implementation

[0038] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0039] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0040] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0041] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. The term "coupled" indicates, for example, that two or more components have direct physical or electrical contact. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0042] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0043] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0044] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0045] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable deviation range for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable deviation range for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable deviation range for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0046] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on another layer or substrate, or that there is an intermediate layer between the layer or element and another layer or substrate.

[0047] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0048] Alzheimer's disease (AD) is a progressive neurodegenerative disease that primarily affects older adults and is the most common cause of dementia.

[0049] Early stages of Alzheimer's disease (AD) often present with no obvious symptoms; however, this stage may be the most effective for treatment. With the approval of anti-AD drugs, early screening and treatment are expected to become effective interventions to inhibit AD progression. Currently, patients in my country are scattered, and the penetration rate of AD testing at the grassroots level is low. Conventional scales and imaging methods are not suitable for detection in primary healthcare settings and are only used for mid-to-late-stage diagnosis, not for early screening.

[0050] Field-effect transistor (FET) biosensors are fast and highly sensitive, and have been widely used in research on early screening of Alzheimer's disease (AD) in recent years. However, the stability and reliability issues of biosensors limit their potential for large-scale application.

[0051] For example, indium gallium zinc oxide thin-film transistors (IGZO-TFTs) are widely used in organic light-emitting diodes (OLEDs) due to their high on / off ratio and high output current.

[0052] However, when a voltage is applied to an IGZO-TFT device, oxygen atoms or ions may migrate within the IGZO thin film, causing changes in the chemical composition and electronic structure of the IGZO film. These changes affect the conductivity and mobility of the IGZO film, leading to characteristic drift in the IGZO-TFT device. Characteristic drift in IGZO-TFT devices refers to the changes in the electrical properties of the TFT during prolonged operation or under specific environmental conditions, causing a shift in the TFT's threshold voltage within a certain range. This threshold voltage shift ultimately manifests as a change in the TFT characteristic transfer curve.

[0053] Furthermore, IGZO films are sensitive to humidity and oxygen in the environment. When a voltage is applied, water molecules and oxygen in the environment may react with the IGZO film, causing changes in its properties, which can also lead to characteristic drift in IGZO-TFT devices.

[0054] Therefore, in order to apply mass-producible IGZO devices to AD early screening detection devices, it is necessary to solve the problem of characteristic transfer curve drift.

[0055] Based on this, such as Figures 1-3 As shown, embodiments of this disclosure provide a biosensing element 10. Figure 1 This is a structural diagram of the biosensor 100. Figure 2 for Figure 1 The biosensor 100 is shown in a cross-sectional view along section line AA. The biosensor 100 includes a biosensing element 10. For a description of the biosensor 100, please refer to the following content. It will not be described in detail here.

[0056] The biosensing element 10 includes: a substrate 101, a thin-film transistor 102 located on one side of the substrate 101, and a reaction chamber 103. The thin-film transistor 102 includes: a gate 12, a gate insulating layer 15, an active layer 14, a source 16, and a drain 17 stacked together. The thin-film transistor 102 is located in the reaction chamber 103, and an antibody 24 is disposed in the reaction chamber 103.

[0057] For example, substrate 101 includes a glass substrate, gate insulating layer 15 is made of silicon oxide, and active layer 14 is made of indium gallium zinc oxide.

[0058] In some examples, such as Figure 2 and Figure 3 As shown, the biosensing element 10 further includes an interlayer dielectric layer 21, which is located on the side of the active layer 14 away from the substrate 101. The biosensing element 10 also includes a detection electrode 22 and a sensing electrode 23 located within the reaction chamber 103. The detection electrode 22 is located on the side of the interlayer dielectric layer 21 away from the substrate 101, and the detection electrode 22 is electrically connected to the sensing electrode 23. An antibody 24 is attached to the surface of the sensing electrode 23.

[0059] For example, the interlayer dielectric layer 21 is made of silicon nitride, and the sensing electrode 23 is made of gold. For instance, in a projected image onto the substrate 101, the sensing electrode 23 is square, and its area is 0.64 cm². 2 .

[0060] The connection between antibody 24 and sensing electrode 23 will be described later and will not be elaborated here.

[0061] The biosensor 10 can be used to detect Alzheimer's disease, wherein the reaction chamber 103 is a space for accommodating the sample solution input during the detection process and the antibody pre-set on the sensing electrode 23 to perform a detection reaction.

[0062] For example, a barrier 25 is formed using photoresist, which encloses a plurality of reaction chambers 103. For instance, the height of the barrier 25 is 0.5 cm; in a projected image onto the substrate 101, the reaction chambers 103 are square, and their area is 1.44 cm². 2 .

[0063] The detection principle of the biosensor 10 is as follows: a detection electrode 22 and a sensing electrode 23 are disposed outside the thin-film transistor 102. An antibody 24 is adsorbed on the sensing electrode 23 and reacts with the antigen in the sample solution injected into the reaction chamber 103, for example, biological protein binding. When the protein binds on the sensing electrode 23, the protein has a double layer charge in the non-isoelectric point region. After the antigen and antibody bind, the double layer charge of the solution on the surface of the sensing electrode 23 changes, causing a change in the surface potential of the sensing electrode 23. The electron migration of the detection electrode 22 connected to the sensing electrode 23 changes, which further causes a change in the voltage signal of the thin-film transistor 102, thereby detecting and analyzing the sample solution.

[0064] In some examples, such as Figure 2 and Figure 3 As shown, to improve the stability and accuracy of the biosensing element 10, the thin-film transistor 102 further includes a protective layer 13, which includes at least one of a first protective layer 131 and a second protective layer 132. The first protective layer 131 is located between the gate insulating layer 15 and the active layer 14. The second protective layer 132 includes a first portion 1321 located on the side of the active layer 14 exposed by the source electrode 16 and the drain electrode 17, away from the substrate 101. The water contact angle of the material of the protective layer 13 is greater than that of the material of the gate insulating layer 15.

[0065] The water contact angle refers to the angle θ between the tangent line drawn at the solid-liquid interface at the liquid-solid junction and the solid-liquid interface line on the liquid side. The water contact angle is an important parameter for measuring the wettability of a liquid on a material surface. If θ < 90°, the solid surface is hydrophilic, meaning the liquid easily wets the solid; the smaller the angle, the better the wettability. If θ > 90°, the solid surface is hydrophobic, meaning the liquid does not easily wet the solid and easily moves on the surface.

[0066] In other words, the water contact angle can be used to determine the strength of a material's hydrophobic properties; the larger the water contact angle, the stronger the hydrophobic properties of the material.

[0067] For example, it can be done through XRD (X X-ray diffraction (XRD) or X-ray photoelectric energy dispersive spectroscopy is used to test the hydrogen bond content on the surface of a material. The lower the hydrogen bond content, the stronger the hydrophobicity of the material.

[0068] The portion of the active layer 14 exposed by the source 16 and drain 17 refers to the portion of the active layer 14 not covered by the source 16 and drain 17 after the source 16 and drain 17 are formed. It can also be understood as the portion of the active layer 14 not covered by the source 16 and drain 17 in the orthogonal projection onto the substrate 101.

[0069] For example, thin-film transistor 102 includes a first protective layer 131. In other examples, thin-film transistor 102 includes a second protective layer 132.

[0070] For example, such as Figure 3 As shown, the thin-film transistor 102 includes a first protective layer 131 and a second protective layer 132.

[0071] As can be seen from the above analysis of the impact of changes in the IGZO thin film on the performance of the IGZO-TFT device, the IGZO thin film is the active layer 14. Oxygen atoms or oxygen ions may migrate in the active layer 14, causing changes in the chemical composition and electronic structure of the active layer 14. In addition, the active layer 14 is sensitive to humidity and oxygen in the environment. When a voltage is applied to the gate 12, water molecules and oxygen in the environment may react with the active layer 14, causing changes in the characteristics of the active layer 14. This leads to a drift in the characteristic transfer curve of the thin film transistor 102, resulting in poor stability and accuracy of the biosensor 10.

[0072] The embodiments of this disclosure, through the provision of protective layer 13, have a stronger hydrophobicity due to the larger water contact angle of the material of protective layer 13 compared to the material of gate insulating layer 15. The provision of the first part 1321 of the second protective layer 132 can improve the resistance of the active layer 14 to water and oxygen corrosion. The provision of the first protective layer 131 can avoid the problem of oxygen vacancy defects caused by lattice mismatch between the active layer 14 and the gate insulating layer 15, or the first protective layer 131 can fill oxygen vacancy. Therefore, the first protective layer 131 can effectively prevent the problem of charge traps formed on the surface of the gate insulating layer 15 under bias voltage due to charge carrier transitions between the active layer 14 and the gate insulating layer 15, thereby alleviating the problem of characteristic transfer curve drift of the thin-film transistor 102 and improving the stability of the thin-film transistor 102, thus improving the stability and accuracy of the detection performance of the biosensing element 10.

[0073] In some embodiments, such as Figure 3As shown, the material of the protective layer 13 includes any one of organic semiconductor materials, inorganic semiconductor materials, and hydrophobic materials. A heterojunction exists between the protective layer 13 and the active layer 14.

[0074] A heterojunction is an interface region formed by the contact of two different semiconductor phases.

[0075] For example, the material of the protective layer 13 includes at least one of the following groups.

[0076] , , , , -F and -CN.

[0077] Wherein, R1 is selected from , , or ;n1 is selected from 1, 2, or 3. In the above structural formula, is used... This indicates that the bond is used to connect with other groups.

[0078] The above-mentioned groups are highly electronegative groups. The stronger the electron-acquiring ability of the organic material containing the above-mentioned groups, the deeper its energy level structure. The protective layer 13 formed by the organic material can prevent the active layer 14 from contacting the gate insulating layer 15 to form a charge trap, alleviate the problem of characteristic transfer curve drift of the thin film transistor 102, and improve the stability of the thin film transistor 102, so as to improve the stability and accuracy of the detection performance of the biosensing element 10.

[0079] In some embodiments, such as Figure 3 As shown, the material of the protective layer 13 includes at least one of the following structural formulas.

[0080] , , , , , , , , , , , , , , , , , , and .

[0081] R2 includes: R3 includes: R4 includes: R5 includes: 2-EtHex, -C 16 H 33 or -(CH2)2CH(C 10 H 21 )2; n2 is selected from positive integers greater than or equal to 50 and less than or equal to 10000. Among them, EtHex is an abbreviation for ethoxyacetylene.

[0082] P(NDI2OD-T2) is poly{[N,N′-bis(2-octyldodecyl)benzo[LMN][3,8]o-diazaphenanthroline-1,3,6,8(2H,7H)-tetraone-4,9-diyl)([2,2′]dithienyl-5,5′-diyl)}, also known as N2200.

[0083] Among them, P(NDI2OD-T2), P(NDI2OD-BiTz), PTzNDI-2FT, PNBT, P(NDI-BBTV-F), BDPPV and F4BDOPV-2T are n-type organic polymers containing highly electronegative groups. They are electron transport materials and belong to organic semiconductor materials.

[0084] Different values ​​of n2 result in n-type organic polymers with different molecular weights. The protective layer 13 formed using the above-mentioned n-type organic polymers is less prone to generating oxygen vacancies, alleviating the problem of characteristic transfer curve drift of thin-film transistor 102, improving the stability of thin-film transistor 102, and thus improving the stability and accuracy of the detection performance of biosensor 10.

[0085] Structural formulas I-1, I-2, I-3, I-4, I-5, I-6, I-7, I-8, I-9, I-10, I-11, I-12, and I-13 are n-type organic small molecule materials containing highly electronegative groups. They are electron transport materials and belong to organic semiconductor materials. The protective layer 13 formed using the above-mentioned n-type organic small molecule materials is less prone to generating oxygen vacancies, thus alleviating the problem of characteristic transfer curve drift in thin-film transistor 102.

[0086] In some embodiments, such as Figure 3 As shown, when the material of the protective layer 13 is an organic semiconductor material, the thickness d1 of the protective layer 13 ranges from 5 nm to 100 nm.

[0087] For example, the thickness d1 of the protective layer 13 can be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm or 100nm, etc., and there is no limitation here.

[0088] For example, the thickness d11 of the first protective layer 131 and the thickness d12 of the second protective layer 132 can be the same or different, and there is no limitation here.

[0089] When the material of the protective layer 13 is an organic semiconductor material, by setting the thickness d1 of the protective layer 13 to be in the range of 5nm~100nm, it is possible to improve the water and oxygen corrosion resistance of the active layer 14 and effectively avoid the problem of charge traps formed on the surface of the gate insulating layer 15 when the active layer 14 and the gate insulating layer 15 are subjected to bias voltage. This can alleviate the problem of characteristic transfer curve drift of the thin film transistor 102, improve the stability of the thin film transistor 102, and thus improve the stability and accuracy of the detection performance of the biosensing element 10.

[0090] In some embodiments, such as Figure 3 As shown, the material of the protective layer 13 includes at least one of perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate, and fluorinated graphene.

[0091] Among them, the chemical formula of perfluoroalkyltriethoxysilane is C6F. 15 O3Si, the chemical formula of perfluoroalkyl methacrylate is C4F3HO2. Fluorinated graphene is a two-dimensional planar structure, which is a product of partial or complete fluorination of graphene, in which carbon atoms and fluorine atoms are bonded in the form of covalent bonds.

[0092] Perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate and fluorinated graphene are hydrophobic semiconductor materials that can be vapor-deposited into films, and a protective layer can be formed through the vapor deposition process 13.

[0093] In some embodiments, such as Figure 3 As shown, when the material of the protective layer 13 includes at least one of perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate and fluorinated graphene, the thickness d1 of the protective layer 13 ranges from 3 nm to 10 nm.

[0094] For example, the thickness d1 of the protective layer 13 is 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, etc., and there is no limitation here.

[0095] When the material of the protective layer 13 includes at least one of perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate and fluorinated graphene, by setting the thickness d1 of the protective layer 13 to be in the range of 3nm~10nm, it is possible to improve the water and oxygen corrosion resistance of the active layer 14 and effectively avoid the problem of charge traps formed on the surface of the gate insulating layer 15 when the active layer 14 and the gate insulating layer 15 are subjected to bias voltage. This alleviates the problem of characteristic transfer curve drift of the thin film transistor 102, improves the stability of the thin film transistor 102, and thus improves the stability and accuracy of the detection performance of the biosensing element 10.

[0096] In some embodiments, such as Figure 3 As shown, the material of the protective layer 13 is an inorganic semiconductor material, and the density of the material of the protective layer 13 is greater than the density of the material of the gate insulating layer 15.

[0097] In semiconductor materials, packing density refers to the percentage of volume occupied by atoms within a unit cell, that is, the ratio of the volume of atoms contained in the unit cell to the volume of the unit cell. It is also known as packing ratio or maximum space utilization.

[0098] The density of inorganic semiconductor materials is greater than that of the gate insulating layer 15. The protective layer 13 formed by using such inorganic semiconductor materials can effectively prevent water and oxygen from entering the active layer 14, thereby improving the water and oxygen corrosion resistance of the active layer 14. Moreover, no charge traps are generated between the interface between the protective layer 13 and the active layer 14, which alleviates the problem of characteristic transfer curve drift of the thin film transistor 102 and improves the stability of the thin film transistor 102, thereby improving the stability and accuracy of the detection performance of the biosensing element 10.

[0099] In some embodiments, such as Figure 3 As shown, the material of the protective layer 13 includes at least one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, indium tin oxide, molybdenum disulfide, silicon carbide, and gallium nitride.

[0100] For example, iridium oxide is iridium trioxide, with the chemical formula Ir₂O₃ and a molecular weight of 432.432.

[0101] Zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, indium tin oxide, molybdenum disulfide, silicon carbide, and gallium nitride are all inorganic semiconductor materials with high density. The protective layer 13 formed by these materials can fill oxygen vacancies, thereby improving the stability of the thin film transistor 102 and thus improving the stability and accuracy of the detection performance of the biosensing element 10.

[0102] In some embodiments, such as Figure 3 As shown, when the material of the protective layer 13 is an inorganic semiconductor material, the thickness d1 of the protective layer 13 ranges from 1 nm to 5 nm.

[0103] For example, the thickness d1 of the protective layer 13 is 1nm, 2nm, 3nm, 4nm or 5nm, etc., and there is no limitation here.

[0104] For example, an inorganic semiconductor material is formed into a protective layer 13 by a sputtering process.

[0105] When the material of the protective layer 13 is an inorganic semiconductor material, by setting the thickness d1 of the protective layer 13 to be in the range of 1nm~5nm, it is possible to improve the water and oxygen corrosion resistance of the active layer 14 and effectively avoid the problem of charge traps formed on the surface of the gate insulating layer 15 when the active layer 14 and the gate insulating layer 15 are subjected to bias voltage. This can alleviate the problem of characteristic transfer curve drift of the thin film transistor 102, improve the stability of the thin film transistor 102, and thus improve the stability and accuracy of the detection performance of the biosensing element 10.

[0106] In some embodiments, such as Figure 3 As shown, the materials of the first protective layer 131 and the second protective layer 132 can be the same or different, and there is no limitation here.

[0107] In some embodiments, such as Figure 4 As shown, when the material of the protective layer 13 includes at least one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide and indium tin oxide, the antibody 24 is attached to the surface of the first part 1321.

[0108] Because the protective layer 13, formed by zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, and indium tin oxide, has hydroxyl groups on its surface, the presence of these hydroxyl groups allows antibody 24 to be attached to the surface of the first part 1321. A description of antibody 24 attachment to the surface of the first part 1321 will follow later and will not be elaborated here.

[0109] By attaching antibody 24 to the surface of the first part 1321, the formation of detection electrode 22 and sensing electrode 23 is unnecessary, simplifying the fabrication steps of biosensor 10. Furthermore, this biosensor 10 can more directly detect changes in interfacial charge caused by antibody-antigen binding, without requiring a dual-gate structure formed by detection electrode 22 and gate 12 to control conduction detection, thus facilitating more sensitive detection performance of the biosensor 10.

[0110] In some embodiments, such as Figure 4 and Figure 5 As shown, the material of the protective layer 13 includes a semiconductor material, and the second protective layer 132 further includes a second part 1322 connected to the first part 1321; the second part 1322 is located between the active layer 14 and the source electrode 16, and between the active layer 14 and the drain electrode 17.

[0111] In other words, the second protective layer 132 covers the surface of the active layer 14 away from the substrate 101 and the side surface of the active layer 14. Thus, after the second protective layer 132 is formed by sputtering, the portions of the second protective layer 132 located between the active layer 14 and the source electrode 16 and between the active layer 14 and the drain electrode 17 do not need to be removed, so as to form the second portion 1322.

[0112] Moreover, when the second protective layer 132 includes the first part 1321 and the second part 1322, the second protective layer 132 has a larger coverage area on the active layer 14, which allows the second protective layer 132 to better protect the active layer 14 from water and oxygen erosion.

[0113] Furthermore, since the protective layer 13 is made of a semiconductor material, the arrangement of the second part 1322 does not affect the electron transport between the active layer 14 and the source 16, or between the active layer 14 and the drain 17. For example, when the protective layer 13 is made of an organic semiconductor material, the polymer material itself has deeper least occupied molecular orbitals, which is beneficial for electron transport from the active layer 14 to the source 16 and the drain 17. When the protective layer 13 is made of an inorganic semiconductor material, the thickness d1 of the protective layer 13 ranges from 1 nm to 5 nm, and this thickness d1 does not affect the electron transport from the active layer 14 to the source 16 and the drain 17.

[0114] like Figures 1-3 As shown, embodiments of this disclosure also provide a biosensor 100, which includes a plurality of biosensing elements 10 arranged in an array, wherein at least one of the plurality of biosensing elements 10 is a biosensing element 10 as described in any of the above embodiments.

[0115] For example, multiple biosensor elements 10 are arranged in an array along the row direction X and the column direction Y.

[0116] For example, the biosensor 100 has a barrier 25 that encloses to form a plurality of reaction chambers 103. The outer boundary of the barrier 25 has a dimension d2 of approximately 6 cm in the row direction X and a dimension d3 of approximately 5 cm in the column direction Y.

[0117] For example, the biosensor 100 has a dimension d4 of approximately 8 cm in the row direction X and a dimension d5 of approximately 6 cm in the column direction Y.

[0118] Each biosensor 10 has its gate 12 connected to a gate signal line G. The sources 16 of biosensors 10 in the same column are connected to the same source connection line S, and the drains 17 of biosensors 10 in the same row are connected to the same drain connection line D. The gates 12 of the thin-film transistors 102 of each biosensor 10 are controlled by different gate signal lines G, thereby achieving individual control of each biosensor 10.

[0119] The biosensor 100 includes at least one biosensing element 10 as described in any of the above embodiments. Therefore, the biosensor 100 has the same beneficial effects as the biosensing element 10 described above, which will not be repeated here.

[0120] Based on the aforementioned biosensor 100, such as Figure 3 and Figure 6 As shown, embodiments of this disclosure also provide a biodetection chip 1000, which includes the aforementioned biosensor 100, a detector 200 connected to the biosensor 10, and a controller 300. The controller 300 is configured to analyze antigen samples injected into the reaction chambers 103 of each biosensing element 10 of the biosensor 100 based on the electrical signals of the biosensor 100 detected by the detector 200 and output detection results.

[0121] In this embodiment, the biodetection chip 1000 controls the biosensor 100 via the controller 300 to detect the sample solution injected into the reaction chamber 103. Based on the electrical signal output by the biosensor 100 detected by the detector 200—that is, the voltage signal formed during the detection process due to the reaction between the adsorbed antibody 24 on the sensing electrode 23 of the biosensor element 10 and the antigen in the sample solution—the controller 300 analyzes the voltage signal to obtain the detection result of the sample solution. Because the biosensor element 10 is provided with a protective layer 13, the detection accuracy and stability of the biodetection chip 1000 are improved, thereby enhancing the detection precision and stability of the biosensor element 10.

[0122] Embodiments of this disclosure also provide an application of the biodetection chip 1000 as described in any of the foregoing embodiments in the detection of Alzheimer's disease.

[0123] Because the biosensor 10 is provided with a protective layer 13, the biosensor 10 has high detection accuracy and detection stability, and the biosensor chip 1000 can be mass-produced for AD early screening detection.

[0124] Based on the content of the biosensing element 10, biosensor 100 and biodetection chip 1000 disclosed herein, the following specific embodiments are provided.

[0125] Example 1

[0126] The structure of the biosensing element 10 is as follows Figure 3 As shown.

[0127] (1) Preparation of protective layer 13

[0128] The material of protective layer 13 was dissolved in a 5 mg / mL chlorobenzene solution. For example, the material of protective layer 13 was N2200. The structure of N2200 is described above and will not be repeated here. The electron mobility of N2200 is 0.06 cm⁻¹. 2 V -1 S -1 .

[0129] In a nitrogen atmosphere, a patterned protective layer 13 was prepared by spin-coating a film on the surface of the sacrificial layer. The coating process was: 1500 rpm (Revolutions Per Minute), spin-coating time was 60 seconds, film thickness was 10 nm, and after removing the sacrificial layer, a film was prepared.

[0130] By spin-coating a second protective layer 132 onto the surface of the active layer 14, water and oxygen in the air can be effectively prevented from penetrating into the active layer 14, thereby improving the stability of the biosensor 10. Furthermore, the presence of the first protective layer 131 prevents the migration of charge carriers from inside the active layer 14 to the interface between the active layer 14 and the first protective layer 131 due to the applied bias from reacting to generate new oxygen vacancies or hydroxyl groups, thus improving the repeatability and stability of the biosensor 10.

[0131] (2) Preparation of sensing electrode 23

[0132] By aligning and bonding a customized hard mask with the biosensor element 10 to be fabricated as the sensing electrode 23, gold material is directly sputtered in the sputtering equipment cavity. After sputtering, the hard mask is peeled off from the biosensor element 10, and the patterned sensing electrode 23 can be obtained directly.

[0133] (3) Antibody modification

[0134] Prior to antibody 24 modification of sensing electrode 23, the process includes: surface modification of sensing electrode 23.

[0135] The steps for surface modification of sensing electrode 23 include: injecting a 10 μg / mL ethanol solution of mercaptohexanoic acid into the surface of sensing electrode 23 and reacting it at room temperature for 4 hours to give sensing electrode 23 a carboxyl functional group, and further activating the carboxyl group by EDC / NHC for use in the next step of antibody modification reaction.

[0136] EDC is short for 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, a crosslinking agent used for the coupling of carboxyl groups with primary amines. EDC is mainly used to activate carboxyl groups, promoting the formation of amides and esters.

[0137] NHC stands for N-heterocyclic carbene. NHC is a class of heterocyclic organic molecules with two-electron coordination ability. Due to its unique coordination properties and stability, it has become an important ligand in the fields of organic synthesis and organometallic chemistry.

[0138] The steps for modifying the antibody 24 of the sensing electrode 23 include: injecting a PBS solution containing 1 mg / mL biotin-labeled P-tau181 antibody into the reaction chamber 103, incubating at room temperature for 3 hours, removing the liquid, washing three times with PBS buffer containing Tris-HCl, aspirating the liquid, and then blocking with 50 μM BSA PBS buffer for 30 minutes. After blocking, removing the liquid, washing three times with PBS buffer containing Tris-HCl, aspirating the liquid, and using it for the next step of testing.

[0139] The pH of the PBS buffer for the P-tau181 antibody is 7.2. PBS buffer is one of the most widely used buffers in biochemical research, and its main components include Na2HPO4, KH2PO4, NaCl, and KCl. It is generally used as a solvent to dissolve and protect reagents. The P-tau181 antibody is a human phosphorylated Tau-P181 protein.

[0140] In the Tris-HCl PBS buffer, the volume ratio of Tris-HCl to PBS is 10%.

[0141] BSA stands for bovine serum albumin, which is a type of albumin found in bovine serum.

[0142] (4) Antigen capture

[0143] PBS buffers containing different gradient concentrations of P-tau181 antigen were introduced into different reaction chambers 103 and incubated at 37°C for 10 minutes. The PBS buffers containing Tris-HCl were aspirated and washed three times, and the liquid was aspirated for the next step of the test.

[0144] The concentration range of P-tau181 antigen is 10 pg / mL to 1 ng / mL, the pH of the PBS buffer is 7.2, and the volume ratio of Tris-HCl to PBS in the Tris-HCl PBS buffer is 10%.

[0145] (5) Detection of biological targets

[0146] The electrical performance of the thin-film transistor 102 is tested, and the specific test steps include the following 5.1 to 5.6.

[0147] 5.1 Apply a control signal to the gate 12 of the blank biosensor element 10 and measure the initial Ids of the thin-film transistor 102 of the blank biosensor element 10. Vg (characteristic transfer) curve.

[0148] 5.2. Immerse the biosensing element 10 in the antibody 24 solution so that the antibody 24 is adsorbed on the sensing electrode 23, that is, modify the sensing electrode 23 with antibody 24.

[0149] 5.3 Apply an electrical signal to the drain 17 of the thin-film transistor 102 of the biosensor 10, apply a control signal to the gate 12 of the thin-film transistor 102 of each biosensor 10, and measure the Ids of the antibody-modified biosensor 10. The Vg curve can measure the shift in the property transfer curve after antibody 24 modification.

[0150] 5.4. A sample solution is injected into the reaction chamber 103 of the biosensor element 10. The target antigen in the sample solution specifically binds to the antibody 24, causing a change in the induced charge on the detection electrode 22 of the thin-film transistor 102. 2= Detecting electrode 22 senses electrical charge 2. Changes in electrical charge caused by the reaction between antigen and antibody 24 equal.

[0151] 5.5. Measure the Ids of the thin-film transistor 102 again. The Vg curve shows a shift in the characteristic transfer curve; V FG =V G1 +Q SENS / C, where V is the equivalent gate voltage of active layer 14. G1 The voltage across gate 12 is given by C, where C is the double-layer capacitance of water, and the equivalent gate voltage is given by C. Affects IDs.

[0152] 5.6 Compare with initial IDs Vg curve, Ids before antibody-antigen binding (Vg curve), Vg curve, Ids after antibody-antigen binding to antigen 24 The Vg curve was obtained, and the change was used for quantitative analysis of the concentration of P-tau181 antigen.

[0153] Figure 7 This is a characteristic transfer curve of antibody 24 on the biosensor element 10 provided in Embodiment 1 of this disclosure after binding with antigens of different concentrations. The horizontal axis represents the gate voltage Vg, in V; the vertical axis represents the source-drain current Ids, in A. Curve 1 represents the Ids of the biosensor element 10 before antibody 24 antigen binding. Vg curve, curve 2 represents the Ids of biosensor element 10 when the antigen concentration is 100 fg / mL. Vg curve, curve 3 represents the Ids of biosensor element 10 when the antigen concentration is 1 pg / mL. Vg curve, curve 4 represents the Ids of biosensor element 10 when the antigen concentration is 100 pg / mL. Vg curve.

[0154] from Figure 7 It can be seen that the Ids of biosensor element 10 before binding to antibody 24 antigen Compared to the Vg curve, the characteristic transfer curve of biosensor element 10 remained essentially unchanged at an antigen concentration of 100 fg / mL; however, at antigen concentrations of 1 pg / mL and 100 pg / mL, the characteristic transfer curve of biosensor element 10 shifted significantly to the right. Therefore, the Ids of sample solutions containing different concentrations of antigen... The drift of the Vg curve is positively correlated with the antigen concentration in the sample solution.

[0155] Example 2

[0156] The structure of the biosensing element 10 is as follows Figure 3 As shown.

[0157] The protective layer 13 in this embodiment is made of F4BDOPV-2T. The structure of F4BDOPV-2T is described above and will not be repeated here.

[0158] The polymer F4BDOPV-2T was dissolved in a chlorobenzene / NMP (N-Methylpyrrolidone) mixed solvent, wherein the concentration of F4BDOPV-2T was 2 mg / mL and the volume ratio of chlorobenzene to NMP was 9:1. During the preparation of the protective layer 13, the spin-coating speed was 1000 rpm and the spin-coating time was 60 seconds.

[0159] The modification and testing conditions for antibody 24 are as described in Example 1.

[0160] In Example 1, the electron mobility of the material N2200 in the protective layer 13 is 0.06 cm⁻¹. 2 V -1 S -1 In Example 2, the electron mobility of F4BDOPV-2T was 14.9 cm⁻¹. 2 V -1 S -1 The F4BDOPV-2T has a higher electron mobility, which is more conducive to electron transport and can improve the detection sensitivity of the biosensor element 10.

[0161] Example 3

[0162] The structure of the biosensing element 10 is as follows Figure 3 As shown.

[0163] In this embodiment, the protective layer 13 is made of an n-type organic small molecule material. For example, the protective layer 13 is formed by vapor deposition. The process of forming the protective layer 13 using an n-type organic small molecule material is more suitable for mass production. In addition, compared with n-type organic polymer materials, the n-type organic small molecule material can obtain a protective layer 13 with higher purity through vapor deposition, avoiding charge trapping problems caused by impurities in the material, thereby further improving the working life of the biosensor element 10.

[0164] Example 4

[0165] The structure of the biosensing element 10 is as follows Figure 3 As shown.

[0166] In this embodiment, the protective layer 13 is made of zinc oxide. For example, a film with a thickness d1 of 5 nm is formed on the side of the active layer 14 away from the substrate 101 by sputtering, and a dense protective layer 13 is formed by further annealing. Compared with organic materials, the inorganic zinc oxide film has lower photoelectric reactivity, which is beneficial to improving the working life of the biosensor element 10.

[0167] Example 5

[0168] The structure of the biosensing element 10 is as follows Figure 4 As shown, the protective layer 13 in this embodiment is made of zinc oxide.

[0169] Compared to Figure 3The biosensor element 10 shown in this embodiment has a simpler fabrication process, avoiding the use of expensive precious metal material gold to form the sensing electrode 23. Furthermore, the antibody 24 directly binds to the surface of the first part 1321 of the protective layer 13, which can more directly detect the change in interfacial charge caused by antibody 24-antigen binding. It does not require detection through dual-gate control, which is conducive to achieving more sensitive detection performance. At the same time, the setting of the protective layer 13 can effectively prevent the surface of the active layer 14 from directly contacting water, thereby improving the stability of the biosensor element 10.

[0170] For example, zinc oxide has hydroxyl groups on its surface. These hydroxyl groups react with 3-aminopropyltrimethoxysilane to form an amino-modified zinc oxide layer. After further activation with EDC / NHC, antibody 24 can be directly linked to form a biosensor 100. The antibody 24 modification process can be referred to the relevant content in Example 1. The antigen concentration can be directly quantitatively analyzed by detecting the drift of the characteristic transfer curve of the thin-film transistor 102 under different antigen concentration conditions.

[0171] Comparative Example 1

[0172] Compared with Example 5, the thin film transistor 102 in this example does not have a protective layer 13, and the antibody 24 is directly connected to the surface of the active layer 14.

[0173] Figure 8 The graphs show the characteristic transfer curves of the biosensing element 10 provided in Embodiments 1 to 5 and Comparative Example 1 of this disclosure. The horizontal axis represents the gate voltage Vg, in V; the vertical axis represents the source-drain current Ids, in A.

[0174] Taking the characteristic transfer curve of Example 1 as an example, the closer the inflection point Q of the curve is to 0V, the smaller the threshold voltage offset of the biosensor 10, and the better the characteristics of the biosensor 10.

[0175] from Figure 8 It can be seen that the threshold voltage deviation of the biosensor 10 provided in Examples 1 to 4 is smaller; compared with the dual-gate biosensor 10 provided in Examples 1 to 4, the threshold voltage deviation of the single-gate biosensor 10 provided in Example 5 is slightly larger. That is to say, the characteristics of the dual-gate biosensor 10 provided in Examples 1 to 4 are better than those of the single-gate biosensor 10 provided in Example 5; compared with the biosensor 10 provided in Examples 1 to 5 with a protective layer 13, the characteristics of the biosensor 10 without a protective layer 13 provided in Comparative Example 1 are worse.

[0176] Therefore, the embodiments of this disclosure improve the resistance of the active layer 14 to water and oxygen corrosion by setting the protective layer 13, and / or effectively avoid the problem of charge traps forming on the surface of the gate insulating layer 15 when the active layer 14 and the gate insulating layer 15 are subjected to bias voltage, thereby alleviating the problem of characteristic transfer curve drift of the thin film transistor 102, improving the stability of the thin film transistor 102, and thus improving the stability and accuracy of the detection performance of the biosensing element 10.

[0177] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A biosensing element, characterized in that, include: A substrate, a thin-film transistor located on one side of the substrate, and a reaction chamber. The thin-film transistor includes a gate, a gate insulating layer, an active layer, a source, and a drain, all stacked together. The thin-film transistor is located within the reaction chamber, and an antibody is disposed within the reaction chamber. The thin-film transistor further includes: a protective layer, the protective layer comprising: at least one of a first protective layer and a second protective layer; wherein the first protective layer is located between the gate insulating layer and the active layer; the second protective layer comprises: a first portion located on the side of the active layer exposed by the source and the drain that is away from the substrate; The protective layer and the active layer are in a heterojunction.

2. The biosensing element according to claim 1, characterized in that, The material of the protective layer includes any one of organic semiconductor materials, inorganic semiconductor materials, and hydrophobic materials.

3. The biosensing element according to claim 1, characterized in that, The thickness of the protective layer ranges from 5 nm to 100 nm.

4. The biosensing element according to claim 1 or 2, characterized in that, The protective layer is made of any one of perfluoroalkyltriethoxysilane, perfluoroalkyl methacrylate, and fluorinated graphene.

5. The biosensing element according to claim 4, characterized in that, The thickness of the protective layer ranges from 3 nm to 10 nm.

6. The biosensing element according to claim 1, characterized in that, The material of the protective layer includes any one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, indium tin oxide, molybdenum disulfide, silicon carbide, and gallium nitride.

7. The biosensing element according to claim 6, characterized in that, The thickness of the protective layer ranges from 1 nm to 5 nm.

8. The biosensing element according to claim 6, characterized in that, The material of the protective layer includes any one of zinc oxide, zirconium oxide, iridium oxide, titanium dioxide, and indium tin oxide; The antibody is attached to the surface of the first part.

9. The biosensing element according to claim 1, characterized in that, The biosensing element further includes: an interlayer dielectric layer; the interlayer dielectric layer is located on the side of the first part away from the active layer; The biosensing element further includes: a detection electrode and a sensing electrode located within the reaction chamber, wherein the detection electrode is located on the side of the interlayer dielectric layer away from the substrate, and the detection electrode is electrically connected to the sensing electrode; The antibody is attached to the surface of the sensing electrode.

10. The biosensing element according to claim 1, characterized in that, The second protective layer further includes: a second part connected to the first part; the second part is located between the active layer and the source electrode, and between the active layer and the drain electrode.

11. The biosensing element according to claim 1, characterized in that, The active layer is made of indium gallium zinc oxide.

12. A biosensor, characterized in that, It includes a plurality of biosensing elements arranged in an array, wherein at least one of the plurality of biosensing elements is a biosensing element as described in any one of claims 1 to 11; Each of the aforementioned biosensing elements has its gate connected to a gate signal line; The sources of all biosensing elements in the same column are connected to the same source connection line; The drains of all biosensors in the same row are connected to the same drain connection line.

13. A bio-detection chip, characterized in that, Includes the biosensor as described in claim 12, a detector connected to the biosensor, and a controller; The controller is configured to analyze the antigen sample injected into the reaction chamber of each biosensing element of the biosensor based on the electrical signal of the biosensor detected by the detector and output the detection result.

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