MOSFET (Metal Oxide Semiconductor Field Effect Transistor) biosensor based on extended gate, detection workstation and detection method

Abstract

The invention relates to the technical field of medical examination, biosensing and semiconductors, in particular to an MOSFET biosensor based on an extended gate, a detection workstation and a detection method.The sensor comprises an extended gate electrode module, an FET transduction module and an amplification circuit board, and the extended gate electrode module is detachably connected with the FET transduction module; the expanded gate electrode module comprises an electrode plate and a reference electrode, the reference electrode is arranged on the electrode plate, and a detection probe is fixed on the electrode plate; the FET transduction module comprises an MOSFET detection plugboard and an MOSFET, the electrode slice is inserted into the MOSFET detection plugboard, and a grid electrode of the MOSFET is connected with the expansion gate electrode module through the MOSFET detection plugboard; the amplification circuit board is electrically connected with the MOSFET detection plugboard; the MOSFET biosensor based on the extended gate has the advantages of being low in cost, high in benefit, simple in packaging, insensitive to temperature and light and excellent in long-term stability.

Description

Technical Field

[0001] The present invention relates to the fields of medical testing, biosensing and semiconductor technology, and in particular to an extended-gate-based MOSFET biosensor, a detection workstation and a detection method.

[0002] Extended-gate MOSFET biosensor and detection method Background Art

[0003] Biosensors are devices that can convert biological signals into visual signals. As tiny detection tools, they are playing an important role in the fields of biomedicine, food testing, environmental testing, etc. According to the different types of signal transduction elements, biosensors can be divided into electrochemical biosensors, optical biosensors, and field effect (Field Effect Transistor, FET) biosensors. Among them, FET biosensors are the most widely used and fastest growing biosensors due to their high selectivity, high sensitivity, real-time response and label-free detection.

[0004] There are two main types of FET, including Junction FET (JFET) and Metal-Oxide Semiconductor FET (MOSFET). MOSFET has become an important device in the current scientific research field due to its low power consumption, low noise and fast switching speed.

[0005] Since 1970, the first FET-based sensor originated from the ion-sensitive field effect transistor (ISFET) introduced by Bergweld, and ISFET has been developed in a large number of applications, including pH sensing, early disease detection, drug screening, etc. Typical FET-based devices share the same basic architecture as metal oxide semiconductor field effect transistors (MOSFETs) with embedded source, drain and gate metallized contact terminals, but ISFET transducers and the later introduced BioFETs remove the metal gate and replace it with a structure including an ion-sensitive or bioreceptor layer, an analyte solution, and an immersed reference electrode.

[0006] However, the ion-sensitive membrane of the traditional ISFET is in direct contact with the solution to be tested. When the sensing area is exposed to the electrolyte for a long time, the corrosive ions will damage the surface of the sensing area, seriously affecting the service life of the device. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides a MOSFET biosensor based on an extended gate, a detection workstation and a detection method to solve the problem that the ion-sensitive membrane of a traditional ISFET is in direct contact with the solution to be tested. When the sensing area is exposed to the electrolyte for a long time, corrosive ions will damage the surface of the sensing area, seriously affecting the service life of the device.

[0008] One solution of the present invention provides a MOSFET biosensor based on an extended gate and a detection method, comprising an extended gate electrode module, a FET transducer module and an amplifying circuit board, wherein the extended gate electrode module is detachably connected to the FET transducer module;

[0009] The extended gate electrode module includes an electrode sheet and a reference electrode, wherein the reference electrode is arranged on the electrode sheet, and a detection probe is fixed on the electrode sheet for contacting with the solution to be tested and transferring the potential change to the FET transducer module;

[0010] The FET transducer module comprises: a MOSFET detection plug-in board and a MOSFET, the electrode sheet is plugged into the MOSFET detection plug-in board, and the gate of the MOSFET is connected to the extended gate electrode module through the MOSFET detection plug-in board, so as to convert the potential change into the change of the current signal;

[0011] The amplifying circuit board is electrically connected to the MOSFET detection plug board and is used to amplify the current signal of the MOSFET and output it as detection data.

[0012] In one of the schemes of the present invention, the MOSFET detection plug-in board includes a PCB board, an electrode holder and a terminal; the electrode holder is arranged at one end of the PCB board, and the electrode sheet is inserted and connected to the electrode holder; the MOSFET is electrically connected to the PCB board.

[0013] In one of the solutions of the present invention, the reference electrode is electrically connected to the power supply terminal of the amplifying circuit board through the wiring terminal and the first cable, so as to supply power to the extended gate electrode module;

[0014] The voltage of the power supply end is a battery or an external power supply, and the power supply end has a transformer for DC stable power supply.

[0015] In one embodiment of the present invention, the MOSFET includes a main component and a source electrode, a drain electrode and the gate electrode disposed on the main component; the gate electrode and the source electrode are disposed on one side of the main component, and the drain electrode is disposed on the other side of the main component;

[0016] The main component is configured to switch from an off state to an on state when a gate voltage reaches a threshold voltage.

[0017] In one embodiment of the present invention, in the off state, when there is no voltage between the gate and the source, the MOSFET is in the off state and is non-conductive; in this state, the oxide between the gate and the source acts as an insulating layer to prevent the flow of current; when the gate voltage is 0, there is no conductive channel between the source and the drain, so no current flows;

[0018] In the on state, when a positive voltage is applied to the gate, an electric field is formed, and the direction of the electric field affects the movement of charge carriers; in an N-channel enhancement MOSFET, the positive voltage causes electrons in the gate region to flow to the channel region, forming a conductive channel; when the voltage between the source and the gate is high enough, the MOSFET will become on, allowing current to flow from the source to the drain.

[0019] In one embodiment of the present invention, the main component is an insulating gate oxide, and the insulating gate oxide is SiO 2 、Si 3 N 4 、Al 2 O 3 、HFO 2 or 2 O 5 .

[0020] In one of the solutions of the present invention, the source and the drain are electrically connected to the amplifying circuit board through the connection terminal and the second cable respectively.

[0021] In one embodiment of the present invention, the electrode sheet includes a working electrode, an auxiliary electrode and a reference electrode, the working electrode, the auxiliary electrode and the reference electrode are respectively connected to the wiring terminals, and the MOSFET is electrically connected to the working electrode through the wiring terminals;

[0022] The working electrode and the auxiliary electrode are made of gold, platinum or silver, and the reference electrode is made of silver chloride.

[0023] In one solution of the present invention, the MOSFET is disposed on the amplifying circuit board, and the MOSFET and the amplifying circuit board are integrally formed to form an integrated detector;

[0024] Alternatively, the MOSFET is welded onto the MOSFET detection plug-in board.

[0025] In one of the schemes of the present invention, a detection workstation is also pointed out, comprising a container box and a MOSFET biosensor based on an extended gate as described in any one of the above-mentioned schemes, wherein the MOSFET biosensor based on an extended gate is encapsulated inside the container box, and the container box is provided with a plug-in opening corresponding to the extended gate electrode module and at least one data interface, wherein the plug-in opening is used to realize the plug-in and pull-out of the extended gate electrode module and the FET transducer module, and the data interface is used to establish a data connection between the amplification circuit board and the data processing end;

[0026] The container box is also provided with a display component, which is electrically connected to the amplifying circuit board and is used for visually displaying the detection data.

[0027] In one of the schemes of the present invention, a detection method of a MOSFET biosensor based on an extended gate is also pointed out, comprising:

[0028] S10. Select appropriate electrode sheet and probe fixing method according to the properties of the object to be tested;

[0029] S20, dropping 50 to 100 uL of the solution to be tested on the electrode sheet fixed with the probe, the electrode sheet forms a potential change and is transferred to the FET transducer module;

[0030] S30, converting the potential change into a detection signal of current change by the FET transducer module, and amplifying the detection signal by an amplifying circuit board;

[0031] S40, recording the amplified detection signal and displaying the current change through a visualization device, and outputting the detection result by analyzing the detection signal.

[0032] The MOSFET biosensor based on extended gate, detection workstation and detection method provided by the present invention can achieve the following technical effects:

[0033] 1. Reasonable separation of the FET transducer module and the extended gate electrode module can effectively extend the service life of the MOSFET biosensor, that is, the extended gate electrode module is used to contact the solution to be tested and transfer the potential change to the gate of the MOSFET, and the FET transducer module converts the potential change into a change in the current signal. In the present invention, the gate sensing area is formed by the spatially separated FET transducer module and the extended gate electrode module. The sensor using this structure has the advantages of low cost, high efficiency, simple packaging, insensitivity to temperature and light, and excellent long-term stability.

[0034] 2. The used FET transducer module can be recycled, and the extended gate electrode module can be used as a disposable component due to its detachable connection mode, which significantly reduces the operation and maintenance costs of the MOSFET biosensor and makes the measurement more economical. Positioning the extended gate electrode module away from the gate surface of the FET transducer module can eliminate interference signals caused by chemical reactions between the solution to be tested and the semiconductor channel material or by the influence of light intensity, temperature and humidity.

[0035] 3. The separate extended gate electrode module also provides more functional structural possibilities for the sensor element in terms of conductive film selection, functionalization process, electrode geometry and ultimately easy integration into the sensor array, which can meet the detection needs of various situations and has greater detection flexibility.

[0036] 4. The testing workstation has good portability. By setting a display component on the container box or the magnifying circuit board, the test data can be displayed for the user to make qualitative judgments, and further connected to a data processing terminal such as a computer or mobile phone, detailed data can be obtained. The testing workstation can be displayed directly on the magnifying circuit board, or it can be connected to a computer or mobile phone to realize the miniaturization of the testing workstation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0038] Figure 1 A schematic diagram showing the structure of the MOSFET biosensor of the present invention;

[0039] Figure 2 A schematic diagram showing the structure of the separation of the extended gate electrode module and the FET transducer module of the present invention;

[0040] Figure 3 A schematic diagram showing the three-dimensional structure of a MOSFET of the present invention;

[0041] Figure 4 A schematic diagram showing the circuit structure of a MOSFET of the present invention;

[0042] Figure 5 A schematic diagram showing the structure of a MOSFET of the present invention;

[0043] Figure 6 A diagram showing the working principle of the device using antigen-antibody binding as an example;

[0044] Figure 7 A comparison table showing some English abbreviations, English full names, and Chinese full names in the instructions;

[0045] Figure 8 A schematic diagram showing the structure of a detection workstation of the present invention;

[0046] Fig. 9 A schematic diagram showing a flow chart of the detection method of the present invention.

[0047] The following are the descriptions of the reference numerals:

[0048] 1-extended gate electrode module; 11-electrode sheet; RE-reference electrode; WE-working electrode; CE-auxiliary electrode; 2-FET transducer module; 3-amplifier circuit board; 4-MOSFET detection plug-in board; 41-PCB board; 42-electrode holder; 43-terminal; 44-first cable; 45-second cable; 5-MOSFET; G-gate; S-source; D-drain. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Please refer to Figure 1-Figure 5 One embodiment of the present invention provides a MOSFET biosensor based on an extended gate, comprising an extended gate electrode module 1, a FET transducer module 2 and an amplifying circuit board 3, wherein the extended gate electrode module 1 is detachably connected to the FET transducer module 2;

[0051] The extended gate electrode module 1 includes an electrode sheet 11 and a reference electrode RE, wherein the reference electrode RE is disposed on the electrode sheet 11, and a detection probe is fixed on the electrode sheet 11 for contacting with the solution to be tested and transferring the potential change to the FET transducer module 2;

[0052] The FET transducer module 2 comprises: a MOSFET detection plug-in board 4 and a MOSFET 5, the electrode sheet 11 is plugged into the MOSFET detection plug-in board 4, and the gate G of the MOSFET 5 is connected to the extended gate electrode module 1 through the MOSFET detection plug-in board 4, so as to convert the potential change into the change of the current signal;

[0053] The amplifying circuit board 3 is electrically connected to the MOSFET detection plug board 4 and is used to amplify the current signal of the MOSFET 5 and output it as detection data.

[0054] It can be understood that the principle of the present invention is as follows: the sensing gate G is spatially separated from the FET transducer module 2 by a detachably connected extended gate electrode module 1, the gate G is extended and externally connected, the welding of the FET transducer module 2 and the amplifier circuit is relatively fixed, the detection electrode (i.e., the working electrode, the biologically modified gold electrode) and the FET transducer module 2 and the Gate pole are plug-in connected for easy replacement; the reference electrode RE (power supply electrode) in the extended gate electrode module 1 is directly connected to the power supply of the amplifier circuit board 3. The sensing gate G electrode and the gate G terminal of the FET transducer module 2 are connected through a detection plug-in board, and the FET transducer module 2 is fixed on the MOSFET detection plug-in board 4. By modifying and fixing the biological receptor on the plug-in extended gate electrode module 1, when the target object is contained in the liquid to be tested, the probe modified on the surface of the working electrode will bind to the target analyte, thereby causing a change in the carrier density inside the channel, causing the current of the drain D / source S to change, and finally collecting the signal through the detection system.

[0055] This embodiment can achieve the following technical effects:

[0056] 1. Reasonably separating the FET transducer module 2 and the extended gate electrode module 1 can effectively extend the service life of the MOSFET biosensor, that is, the extended gate electrode module 1 is used to contact the solution to be tested and transfer the potential change to the gate G of the MOSFET5, and the FET transducer module 2 converts the potential change into a change in the current signal. In the present invention, the gate sensing area is formed by the spatially separated FET transducer module and the extended gate electrode module. The sensor using this structure has the advantages of low cost, high efficiency, simple packaging, insensitivity to temperature and light, and excellent long-term stability.

[0057] 2. The used FET transducer module 2 can be recycled, and the extended gate electrode module 1 can be used as a disposable component due to its detachable connection mode, thereby significantly reducing the operation and maintenance costs of the MOSFET biosensor and making the measurement more economical. Positioning the extended gate electrode module 1 on the surface of the gate G away from the FET transducer module 2 can eliminate interference signals caused by chemical reactions between the solution to be tested and the semiconductor channel material or by the influence of light intensity, temperature and humidity.

[0058] 3. The separate extended gate electrode module 1 also provides the sensing element with more functional structural possibilities in terms of conductive film selection, functionalization process, electrode geometry, and ultimately easy integration into the sensing array, which can meet the detection needs of various situations and has greater detection flexibility.

[0059] Please refer to Figure 2In one embodiment of the present invention, the MOSFET detection plug-in board 4 includes a PCB board 41, an electrode holder 42 and a terminal 43; the electrode holder 42 is arranged at one end of the PCB board 41, and the electrode sheet 11 is inserted and connected to the electrode holder 42; the MOSFET5 is electrically connected to the PCB board 41.

[0060] It can be understood that in this embodiment, the combination of the PCB board 41 and the electrode holder 42 provides a compact and reliable connection method. This design makes the circuit connection between the electrode sheet 11 and the MOSFET detection plug-in board 4 more stable and reduces the risk of poor connection.

[0061] At the same time, since the electrode sheet 11 can be inserted and connected to the electrode holder 42, this design facilitates integration and maintenance. When a new or different electrode sheet 11 needs to be replaced, the electrode sheet 11 can be easily removed and reinstalled through the electrode holder 42, thereby improving the convenience of maintenance.

[0062] In addition, the electrical connection setting between MOSFET5 and PCB board 41 ensures the stability and reliability of signal transmission, reduces the risk of poor contact and signal loss through direct electrical connection, makes MOSFET5 detect the voltage and current changes of the electrode sheet 11 more accurately, and is also conducive to achieving high integration and low power consumption design.

[0063] Please refer to Figure 2 In one embodiment of the present invention, the reference electrode RE is electrically connected to the power supply end of the amplifying circuit board 3 through the wiring terminal 43 and the first cable 44, so as to supply power to the extended gate electrode module 1;

[0064] The power supply end is a battery or an external power supply, and the power supply end has a transformer for DC stable power supply. In one application scenario, the voltage of the power supply end can be selected to be 2-5V.

[0065] It can be understood that connecting the reference electrode RE to the power supply end of the amplifying circuit board 3 through the terminal 43 and the first cable 44 can ensure that the extended gate electrode module 1 obtains a stable power supply, helps maintain signal integrity, and reduces noise and interference caused by power supply fluctuations, thereby improving the detection accuracy of the sensor, which is crucial to maintaining stable operation of the sensor and improving measurement accuracy.

[0066] It can be understood that a circuit connecting the wiring terminal 43 and the electrode holder 42 is pre-embedded on the PCB board 41. The design of connecting the wiring terminal 43 set on the PCB board 41 and the first cable 44 makes the power connection of the extended gate electrode module 1 simple and direct, which facilitates the integration of the sensor into a more complex system, while simplifying the circuit design and wiring.

[0067] In addition, the voltage range of the power supply end is set to 2-5V. This design allows the sensor to adapt to a variety of power supply environments and increases its application flexibility. This design allows the sensor to operate in a wider voltage range, improving its versatility. It can avoid excessive voltage from damaging the sensor or the circuit connected to it, ensuring the safety of the system, and the lower supply voltage helps to reduce the power consumption of the entire system.

[0068] Please refer to Figure 3 In one embodiment of the present invention, the MOSFET 5 includes a main component and a source S, a drain D and the gate G arranged on the main component; the gate G and the source S are arranged on one side of the main component, and the drain D is arranged on the other side of the main component;

[0069] The main components are configured to switch from an off state to an on state when the gate G voltage reaches a threshold voltage.

[0070] Understandably, from an electrochemical point of view, a MOSFET-based biosensor is a three-electrode system, including a source S, a drain D and a gate G; the source S and the drain D serve to connect the semiconductor channel, while the gate G is responsible for modulating the conductance of the channel; the nanomaterial connected between the source S and the drain D in the semiconductor channel serves as the sensing element of the device; generally, the bioreceptor is modified and fixed on the surface of the semiconductor channel to identify the target analyte through its high specificity and strong binding force in a buffer environment; the target-receptor interaction changes the surface potential of the semiconductor channel and regulates the channel conductance, and finally the signal is collected through the detection system.

[0071] The MOSFET5 used in the present invention is an N-channel enhancement type MOSFET, and its structure is as follows: Figure 1 As shown in Figure 1, the working principle of N-channel enhancement MOSFET is based on the electric field in the semiconductor to control the current. It has three main electrodes: source S (Source), drain D (Drain) and gate G (Gate); the main components in MOSFET isolate the gate G from the semiconductor material. When the gate G voltage (V GS ) reaches a certain value, a conductive channel is formed between the source S and the drain D, allowing current to flow.

[0072] It can be understood that the threshold voltage refers to the gate G-source S voltage required to make the MOSFET change from the off state to the on state. For N-channel enhancement MOSFET, when the gate G voltage reaches the threshold voltage (V T ), a conductive channel is formed between the source S and the drain D, and the magnitude of the turn-on voltage depends on the specific design and material properties of the MOSFET.

[0073] For example, the threshold voltage (V T ) factors mainly include:

[0074] Channel doping concentration. In N-type MOSFET, the channel region is P-type doped. If the doping concentration increases, it means that more gate G voltage is needed to attract electrons to form a conductive channel, so the threshold voltage will increase accordingly.

[0075] The gate oxide thickness is another factor that affects the threshold voltage of the MOSFET. The thicker the gate oxide, the weaker the ability of the channel current to be controlled by the gate voltage, so the threshold voltage is also higher. By using high-quality gate oxide materials and processes, the thickness can be reduced and the leakage current can be reduced while maintaining a stable threshold voltage.

[0076] Insulating layer materials and properties. Different semiconductor materials (such as silicon, gallium arsenide, etc.) have different energy band structures and electron mobility. These properties directly affect the threshold voltage. The charge Qss in the silicon dioxide (gate oxide layer) as a medium and the nature of the charge will affect the threshold voltage. This charge is usually generated by a variety of reasons, some of which are positively charged and some are negatively charged. The net charge will affect the threshold voltage.

[0077] Environmental factors: As the temperature rises, the bandgap width of the semiconductor material decreases, the carrier concentration increases, and the mobility changes. These factors work together to affect the threshold voltage; at the same time, the number of impurity ionizations and impurity concentrations increase, resulting in a decrease in the threshold voltage.

[0078] Structural design, including channel length and trench width. When the channel length is reduced, the channel surface area is reduced, which affects the flow and control of current. Therefore, the shorter the channel, the lower the threshold voltage.

[0079] Please refer to Figure 6 , Figure 6 This is a device working principle diagram taking antigen-antibody binding as an example. In one of the embodiments of the present invention, in the off state, when there is no voltage between the gate G and the source S, the MOSFET is in the off state and is non-conductive; in this state, the oxide between the gate G and the source S acts as an insulating layer to prevent the flow of current; when the gate G voltage is 0, there is no conductive channel between the source S and the drain D, so no current flows;

[0080] In the on state, when a positive voltage is applied to the gate G, an electric field is formed, and the direction of the electric field affects the movement of charge carriers; in an N-channel enhancement MOSFET, the positive voltage causes electrons in the gate G region to flow to the channel region, forming a conductive channel; when the voltage between the source S and the gate G is high enough, the MOSFET will become on, allowing current to flow from the source S to the drain D.

[0081] In one embodiment of the present invention, the main component is an insulating gate oxide, and the insulating gate oxide is SiO 2 、Si 3 N 4 、Al 2 O 3 、HFO 2 or 2 O 5 .

[0082] It can be understood that among the various materials that can be used for insulating gate oxide, SiO 2 (Silicon dioxide) is the traditional gate dielectric material, SiO 2 The thermal and electrical stability is good, the interface quality with silicon is very good, the electrical isolation performance is excellent, and the R&D and production costs are low due to its mature process;

[0083] Si 3 N 4 (Silicon nitride) has a high dielectric constant, low gate leakage and high breakdown field voltage, which helps to reduce the gate dielectric thickness, thereby reducing gate leakage and making the detection more accurate;

[0084] Al 2 O 3 (Aluminum oxide) has a larger band gap, a relatively high dielectric constant, and a higher breakdown electric field, and can be a preferred material for the gate G dielectric;

[0085] HFO 2 As a high dielectric constant material, hafnium oxide has obvious advantages in insulation properties, which can reduce the interaction between the gate dielectric and the carriers, enhance the insulation performance of the gate G, and improve the switching characteristics of the transistor. It also has a high dielectric constant and good contact with the substrate.

[0086] Ta 2 O 5 Tantalum oxide has a larger dielectric constant and is compatible with traditional semiconductor manufacturing processes. 2 Thin films help improve the electrical performance of thin-film transistors.

[0087] In one embodiment of the present invention, the source electrode S and the drain electrode D are electrically connected to the amplifying circuit board 3 through the wiring terminal 43 and the second cable 45 respectively.

[0088] In this embodiment, the wiring terminal 43 connected to the source S and the drain D is also connected to the working electrode of the electrode sheet 11. It can be understood that the use of the wiring terminal 43 and the cable can provide electrical isolation and reduce the parasitic inductance and parasitic capacitance that may be introduced by direct welding, which is very important for maintaining signal integrity and reducing noise; at the same time, the use of the wiring terminal 43 and the second cable 45 can make the wiring of the PCB board 41 and the amplifier circuit board 3 more flexible, and the designer can adjust the length and position of the second cable 45 as needed to adapt to different installation environments and space restrictions. At the same time, the source S and the drain D are respectively connected to the amplifier circuit board 3, and the current change signal detected by the source S and the drain D can be amplified by the amplifier circuit board 3, which is helpful for recording the detection signal.

[0089] In one embodiment of the present invention, the size of the electrode sheet 11 is 6x36x0.25mm;

[0090] The electrode sheet 11 includes a working electrode, an auxiliary electrode and the reference electrode RE, the working electrode, the auxiliary electrode and the reference electrode RE are respectively connected to the wiring terminal 43, and the MOSFET5 is electrically connected to the working electrode through the wiring terminal 43;

[0091] The working electrode and the auxiliary electrode are made of gold, platinum or silver, and the reference electrode RE is made of silver chloride.

[0092] Understandably, platinum electrodes are very commonly used in three-electrode systems due to their high stability and low polarization characteristics; platinum electrodes are usually used as auxiliary electrodes (counter electrodes) because they have lower resistivity and their area should be larger than that of the working electrode to reduce polarization effects and improve the sensitivity and accuracy of the measurement;

[0093] Gold electrodes have excellent electrical conductivity, which is crucial for efficient electron transfer in electrochemical processes. Using gold electrodes as working electrodes can take advantage of this property of gold to ensure minimum resistance and accurate measurement. In addition, gold exhibits good chemical stability in most environments and is not easily corroded, thus ensuring the long-term use of gold electrodes. At the same time, gold has good plasticity and ductility, and is easy to process into gold electrodes of various shapes and sizes. The surface of the gold electrode can be modified so that it has different chemical properties and electrochemical properties in different environments. Therefore, using gold electrodes as working electrodes not only has the above effects, but also because the electrochemical reaction rate is extremely fast, the occurrence of the original electrochemical reaction can be quickly detected.

[0094] Silver electrodes are mainly used in applications where their reactivity does not need to be a concern, such as reference electrodes RE such as silver / silver chloride.

[0095] In one embodiment of the present invention, the MOSFET 5 is disposed on the amplifying circuit board 3 , and the MOSFET 5 and the amplifying circuit board 3 are integrally formed to form an integrated detector;

[0096] Alternatively, the MOSFET 5 is welded onto the MOSFET detection plug-in board 4 .

[0097] In one application scenario of the present embodiment, the MOSFET 5 and the amplifier circuit board 3 are integrally formed, which can improve the integration and reduce external connections, thereby reducing space occupation and complexity; and because the external connection points are reduced, the detector formed by the integral molding can improve the reliability and durability of the entire sensor device, and the integral molding design simplifies the production and assembly process, because there is no need to separately install the MOSFET 5 and connect the amplifier circuit board 3, thereby reducing the manufacturing cost;

[0098] In the first application scenario of the present embodiment, MOSFET5 is welded and arranged on the MOSFET detection plug board 4, which provides higher flexibility and allows the same MOSFET5 to be used in different applications by simply replacing the detection plug board; if there is a problem with the MOSFET5 or the detection plug board, the connection method in this application scenario can quickly replace or upgrade the MOSFET5; and, different MOSFET detection plug boards 4 can be customized according to different detection requirements, while MOSFET5 can remain unchanged, which can reduce inventory and the types of spare parts.

[0099] Please refer to Figure 8 , Figure 8 The invention is a schematic diagram of the architecture of a detection workstation, comprising a container box and a MOSFET biosensor based on an extended gate as described in any one of the above-mentioned embodiments, wherein the MOSFET biosensor based on an extended gate is encapsulated inside the container box, and the container box is provided with a plug-in opening corresponding to an extended gate electrode module and at least one data interface, wherein the plug-in opening is used to realize the plug-in and pull-out of the extended gate electrode module and the FET transducer module, and the data interface is used to establish a data connection between an amplifying circuit board and a data processing end;

[0100] The container box is also provided with a display component, which is electrically connected to the amplifying circuit board and is used for visually displaying the detection data.

[0101] It can be understood that the detection workstation has good portability. By setting a display component on the container box or the magnifying circuit board, the detection data can be displayed for the user to make a qualitative judgment, and by further connecting to a data processing terminal such as a computer or mobile phone, detailed data can be further obtained; the detection workstation can be displayed directly on the magnifying circuit board, or it can be connected to a computer or mobile phone to realize the miniaturization of the detection workstation.

[0102] Please refer to Fig. 9 In one embodiment of the present invention, a detection method of a MOSFET biosensor based on an extended gate is also pointed out, comprising:

[0103] S10. Select appropriate electrode sheet and probe fixing method according to the properties of the object to be tested;

[0104] S20, dropping 50 to 100 uL of the solution to be tested on the electrode sheet fixed with the probe, the electrode sheet forms a potential change and is transferred to the FET transducer module;

[0105] S30, converting the potential change into a detection signal of current change by the FET transducer module, and amplifying the detection signal by an amplifying circuit board;

[0106] S40, recording the amplified detection signal and displaying the current change through a visualization device, and outputting the detection result by analyzing the detection signal.

[0107] It can be understood that the principle of the method of this embodiment is as follows:

[0108] In step S10, commonly used materials for the electrode sheet 11 include gold, silver, platinum, and carbon-based materials such as graphite and conductive polymers, which not only have good electrochemical properties but also provide stability and corrosion resistance;

[0109] The choice of probe fixation method directly affects the sensitivity and stability of the sensor. Common probe fixation methods include adsorption method, self-assembly method, biotin-avidin fixation method, covalent bonding method and cross-linking method.

[0110] In the field of biosensing or medical testing, depending on the properties of the object to be tested, the following probes can be considered: nucleic acid probes, protein probes or enzyme probes. For nucleic acid probes, the stability and hybridization efficiency of the probes need to be considered. Covalent fixation methods and self-assembly methods can provide strong fixation strength and maintain the biological activity of the probes. For protein probes or enzyme probes, it is necessary to consider maintaining their activity and selectivity. The biotin-avidin system and covalent bonding method are commonly used fixation methods, which can provide stable binding and good biological activity retention.

[0111] In step S20, the test substance is diluted to an appropriate concentration according to the experimental requirements, and the uniformity of the solution is ensured. At the same time, a precise micropipette is used to drop the test solution onto the electrode sheet 11 to avoid overflow or uneven distribution of the solution.

[0112] After the solution to be tested interacts with the probe, a potential change is formed on the electrode sheet 11 , and the potential change is transferred to the FET transducer module through the MOSFET detection plug-in board 4 .

[0113] In step S30, the FET transducer module detects the potential change on the electrode sheet 11 through its gate G; wherein, the principle of signal conversion is as follows: the voltage change of the gate G of the MOSFET will cause the current change between the source S and the drain D, thereby realizing the conversion of potential to current; the weak current change signal detected by the FET transducer module is amplified by the amplifying circuit board 3 to improve the signal strength and readability.

[0114] In step S40, the amplified detection signal is recorded using a data acquisition system, and the data will be used for subsequent analysis and result output; the real-time data or historical data of the current change is displayed through a visualization device, such as a computer screen or a chart; the recorded detection signal is analyzed to output the final detection result. The data is processed using statistical and analysis software to identify the change trend and pattern of the signal, and the nature and concentration of the test object are interpreted based on the analysis results to draw a detection conclusion.

[0115] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A MOSFET biosensor based on extended gate, characterized in that: It comprises an extended gate electrode module, a FET transducer module and an amplifying circuit board, wherein the extended gate electrode module is detachably connected to the FET transducer module; The extended gate electrode module includes an electrode sheet and a reference electrode, wherein the reference electrode is arranged on the electrode sheet, and a detection probe is fixed on the electrode sheet for contacting with the solution to be tested and transferring the potential change to the FET transducer module; The FET transducer module comprises: a MOSFET detection plug-in board and a MOSFET, the electrode sheet is plugged into the MOSFET detection plug-in board, and the gate of the MOSFET is connected to the extended gate electrode module through the MOSFET detection plug-in board, so as to convert the potential change into the change of the current signal; The amplifying circuit board is electrically connected to the MOSFET detection plug board and is used to amplify the current signal of the MOSFET and output it as detection data.

2. The extended gate MOSFET biosensor according to claim 1, characterized in that: The MOSFET detection plug-in board includes a PCB board, an electrode holder and a wiring terminal; the electrode holder is arranged at one end of the PCB board, and the electrode sheet is inserted and connected to the electrode holder; the MOSFET is electrically connected to the PCB board.

3. The extended gate MOSFET biosensor according to claim 2, characterized in that: The reference electrode is electrically connected to the power supply end of the amplifying circuit board through the wiring terminal and the first cable, and is used to supply power to the extended gate electrode module; The power supply end is a battery or an external power supply, and the power supply end has a transformer for DC stable power supply.

4. The extended gate MOSFET biosensor according to any one of claims 2 to 3, characterized in that: The MOSFET includes a main component and a source, a drain and the gate arranged on the main component; the gate and the source are arranged on one side of the main component, and the drain is arranged on the other side of the main component; The main component is configured to switch from an off state to an on state when a gate voltage reaches a threshold voltage.

5. The extended gate MOSFET biosensor according to claim 4, characterized in that: In the off state, when there is no voltage between the gate and the source, the MOSFET is in the off state and does not conduct electricity; the oxide between the gate and the source acts as an insulating layer to prevent the flow of current; When the gate voltage is 0, no current flows between the source and the drain; In the on state, when a positive voltage is applied to the gate, an electric field is formed, the direction of which affects the movement of charge carriers; in an N-channel enhancement MOSFET, the positive voltage causes electrons in the gate region to flow to the channel region, forming a conductive channel; When the voltage between the source and the gate is high enough, the MOSFET will turn on, allowing current to flow from the source to the drain.

6. The extended gate MOSFET biosensor according to claim 4, characterized in that: The main component is an insulating gate oxide, and the insulating gate oxide is SiO2, Si3N4, Al2O3, HFO2 or Ta2O5; The source electrode and the drain electrode are electrically connected to the amplifying circuit board through the connection terminal and the second cable, respectively.

7. The extended gate MOSFET biosensor according to claim 2, characterized in that: The electrode sheet comprises a working electrode, an auxiliary electrode and a reference electrode, the working electrode, the auxiliary electrode and the reference electrode are respectively connected to the wiring terminals, and the MOSFET is electrically connected to the working electrode through the wiring terminals; The working electrode and the auxiliary electrode are made of gold, platinum or silver, and the reference electrode is made of silver chloride.

8. The extended gate MOSFET biosensor according to claim 1, characterized in that: The MOSFET is arranged on the amplifying circuit board, and the MOSFET and the amplifying circuit board are integrally formed to form an integrated detector; Alternatively, the MOSFET is welded onto the MOSFET detection plug-in board.

9. A detection workstation, characterized in that: A container box and a MOSFET biosensor based on an extended gate as claimed in any one of claims 1 to 8, wherein the MOSFET biosensor based on an extended gate is encapsulated inside the container box, and the container box is provided with a plug-in opening corresponding to the extended gate electrode module and at least one data interface, wherein the plug-in opening is used to realize the plug-in and pull-out of the extended gate electrode module and the FET transducer module, and the data interface is used to establish a data connection between the amplification circuit board and the data processing end; The container box is also provided with a display component, which is electrically connected to the amplifying circuit board and is used for visually displaying the detection data.

10. A detection method, which can be used for the extended gate MOSFET biosensor according to any one of claims 1 to 8, characterized in that: include: S10. Select appropriate electrode sheet and probe fixing method according to the properties of the object to be tested; S20, dropping 50 to 100 uL of the solution to be tested on the electrode sheet fixed with the probe, the electrode sheet forms a potential change and is transferred to the FET transducer module; S30, converting the potential change into a detection signal of current change by the FET transducer module, and amplifying the detection signal by an amplifying circuit board; S40, recording the amplified detection signal and displaying the current change through a visualization device, and outputting the detection result by analyzing the detection signal.

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