Uric acid sensitive component, preparation method, uric acid sensor and system

Abstract

The invention discloses a uric acid sensitive assembly, a preparation method, a uric acid sensor and a system, the uric acid sensitive assembly comprises a monocrystalline silicon substrate, a plurality of polycrystalline silicon crystal columns are arranged on the monocrystalline silicon substrate, and a porous silicon structure is arranged between the crystal boundaries of the adjacent polycrystalline silicon crystal columns. The uric acid sensor comprises a uric acid sensitive assembly; a grid electrode of the field effect transistor is connected with the monocrystalline silicon substrate of the uric acid sensitive assembly through a wire, a drain electrode of the field effect transistor is connected with power supply voltage, a source electrode of the field effect transistor is connected with one end of a resistor and a voltage output port, and the other end of the resistor is grounded. The porous silicon structure is prepared through the polycrystalline silicon crystal column and is combined with the field effect transistor, so that the large specific surface area of the porous silicon structure can be used for sensing, the electric signal path of the sensor can be effectively improved, and the sensitivity and the accuracy of uric acid detection are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a uric acid sensitive component and a preparation method thereof, and a uric acid sensor and a uric acid sensing system containing the same. Background Art

[0002] Uric acid sensors are mainly used to quickly detect uric acid levels in blood and other body fluids. Uric acid concentration is an important health indicator and is associated with common diseases such as gout, hyperuricemia, and proteinuria.

[0003] Urinary tract sensors based on field effect transistor technology have good application prospects. The sensitive site of the field effect transistor is its gate structure. Uric acid molecules are decomposed and released under the action of uricase, and the charge applies voltage to the gate of the field effect transistor, thereby changing the conduction state of the field effect transistor channel, and finally converting the concentration value of uric acid into the current / voltage signal of the sensor.

[0004] Uric acid sensors based on field effect transistors have the advantages of easy preparation, simple operation, and low cost. However, they also have the following disadvantages:

[0005] (1) Limited sensing area. The sensitive site of a field effect transistor is its gate structure. However, the gate area of ​​a general field effect transistor is limited, which limits its ability to sense uric acid molecules and leads to insufficient sensitivity. When the gate structure of a field effect transistor is set too large, its gate dielectric layer is prone to breakdown and rapid aging due to individual material defects.

[0006] (2) Susceptible to interference from macromolecular substances. A considerable proportion of patients with high uric acid levels have poor kidney function, and their blood and other body fluids contain a large number of macromolecular substances, which can easily interfere with uric acid testing and reduce the accuracy of the test.

[0007] (3) Sensitive to ambient temperature. Field effect transistors are sensitive to ambient temperature. When the ambient temperature changes, the sensing signal of uric acid will also fluctuate greatly, reducing the detection accuracy. Summary of the invention

[0008] The technical problem to be solved by this application is how to improve the sensitivity and accuracy of uric acid detection.

[0009] In order to solve the above technical problems, in the first aspect, an embodiment of the present application provides a uric acid sensitive component, including a single crystal silicon substrate, on which a plurality of polycrystalline silicon columns are arranged, and a porous silicon structure is arranged between the grain boundaries of adjacent polycrystalline silicon columns.

[0010] When the liquid to be tested enters the porous silicon structure, the sensing signal generated by the porous silicon structure is transmitted to the polycrystalline silicon column and further transmitted to the single crystal silicon substrate, thereby realizing the sensing of biological molecules.

[0011] Preferably, the surface of the porous silicon structure is modified with a uric acid sensitive membrane layer having specific sensitivity to uric acid molecules.

[0012] Preferably, the diameter of the polysilicon column is between 20 and 500 nm.

[0013] In a second aspect, the present application provides a method for preparing a uric acid sensitive component, the preparation method comprising the following steps:

[0014] Selecting a single crystal silicon substrate, and depositing polycrystalline silicon columns on the single crystal silicon substrate;

[0015] Electrochemically etching the single crystal silicon substrate to form a porous silicon structure between the grain boundaries of the polycrystalline silicon columns;

[0016] The formed porous silicon structure is passivated to keep its structure stable.

[0017] Preferably, before electrochemically etching the single crystal silicon substrate, the method further comprises:

[0018] The polysilicon crystal column is subjected to P-type diffusion doping, and the doped impurities are concentrated at the grain boundaries of the polysilicon crystal column, so that the grain boundaries become the preferred sites for electrochemical corrosion.

[0019] Preferably, after oxidative strengthening of the formed porous silicon structure, the method further comprises:

[0020] A sensitive membrane layer is modified on the surface of the porous silicon structure to make it specifically sensitive to uric acid molecules.

[0021] In a third aspect, an embodiment of the present application provides a uric acid sensor, the uric acid sensor comprising:

[0022] The uric acid sensitive component described above;

[0023] A field effect transistor, wherein the gate of the field effect transistor is connected to the single crystal silicon substrate of the uric acid sensitive component through a wire, the drain of the field effect transistor is connected to the power supply voltage, the source of the field effect transistor is connected to one end of the resistor and the voltage output port, and the other end of the resistor is grounded.

[0024] Preferably, the field effect transistor is a dual-gate transistor, the positive gate and the back gate of the dual-gate transistor can both adjust the conductive state of its channel, and the field effect transistor is placed in an optimal sensing state by applying a back gate point voltage to the back gate.

[0025] Preferably, the uric acid sensor further comprises a container disposed outside the uric acid sensitive component, and a macromolecular filtration membrane is disposed on the top of the container to filter macromolecular substances in the liquid to be tested to prevent them from entering the uric acid sensitive component to form an interference signal;

[0026] The container contains a reference electrode for providing a reference voltage to the uric acid sensitive component.

[0027] In a fourth aspect, an embodiment of the present application provides a uric acid sensor system, comprising two sets of the above-mentioned uric acid sensors;

[0028] A container is provided outside the uric acid sensitive components of the two sets of uric acid sensors;

[0029] A macromolecular filtration membrane is arranged on the top of one of the containers, and the uric acid sensor in the container is used to detect uric acid molecules in the liquid to be tested;

[0030] The top of the other container is open, and the uric acid sensor in the container is used to detect uric acid molecules in the contrast solution;

[0031] The difference between the output signals of the voltage output ports of the two sets of uric acid sensors forms the output signal of the uric acid sensor system.

[0032] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0033] 1. In the embodiment of the present application, a plurality of polycrystalline silicon columns are arranged on a single crystal silicon substrate, and a porous silicon structure is prepared using the polycrystalline silicon columns, which can not only utilize its large specific surface area for sensing, but also effectively improve the electrical signal path of the sensor, thereby improving the sensitivity and accuracy of uric acid detection.

[0034] 2. By performing P-type diffusion doping on the polysilicon column, since the doping impurities are easily enriched at the polysilicon grain boundaries, the silicon material adjacent to the grain boundaries is easily doped first, while the doping concentration of the silicon material inside the column is relatively low. This makes the grain boundaries have a higher corrosion rate in the subsequent electrochemical corrosion process, that is, it is easy to form more porous silicon structures at the grain boundaries, which improves the sensitivity and accuracy of uric acid detection.

[0035] 3. By modifying the sensitive film layer on the surface of the porous silicon structure, it becomes specifically sensitive to uric acid molecules, thereby improving the sensitivity of uric acid detection.

[0036] 4. This embodiment combines a uric acid sensitive component with a porous silicon structure with a field effect transistor. The porous silicon structure has a large specific surface area and is very suitable for biomolecule sensing. It greatly increases the effective sensing area of ​​the field effect transistor and can be applied to the detection of key indicator molecules such as uric acid, thereby improving the sensitivity and accuracy of uric acid detection.

[0037] 5. A container is set outside the uric acid sensitive component, and a macromolecular filter membrane is set on the top of the container. The liquid to be tested is first filtered through the macromolecular filter membrane, and then enters the container to contact the uric acid sensitive component. In this way, macromolecular substances in urine, blood or other body fluids cannot reach the surface of the uric acid sensitive component, avoiding the interference of macromolecular substances in urine, blood or other body fluids on uric acid detection and improving the accuracy of uric acid detection.

[0038] 6. Considering that field effect transistors are sensitive to temperature, two sets of uric acid sensors are used, one set is used to sense uric acid molecules, and the other set is added with contrast solution to provide reference sensing signals. The difference in output voltages of the two sets of uric acid sensors is the output voltage caused by the uric acid molecule sensing signal, thereby avoiding the influence of temperature on the detection results and achieving accurate detection of the uric acid molecules being detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0040] Figure 1 This is a schematic diagram of the structure of the uric acid sensitive component provided in Example 1 of the present application;

[0041] Figure 2 This is a flow chart of the preparation method of the uric acid sensitive component provided in Example 1 of the present application;

[0042] Figure 3 This is a partial enlarged view of the porous silicon structure in Example 1 of the present application;

[0043] Figure 4 This is a schematic diagram of the combination of the porous silicon structure and the detected molecule in the solution in Example 1 of the present application;

[0044] Figure 5 This is a cross-sectional view of the porous silicon structure in Example 1 of the present application;

[0045] Figure 6 This is a schematic diagram of the structure of a uric acid sensor provided in Example 2 of the present application;

[0046] Figure 7 This is a schematic diagram of the structure of another uric acid sensor provided in Example 2 of the present application;

[0047] Figure 8 This is a schematic diagram of the structure of the uric acid sensor system provided in Example 2 of the present application;

[0048] Fig. 9 This is a schematic diagram of the structure of the amplifier circuit provided in Example 2 of the present application.

[0049] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0050] In order to better understand the above technical solution, exemplary embodiments will be described in detail here, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are only examples of devices consistent with some aspects of the present application as detailed in the attached claims.

[0051] Embodiment 1

[0052] Figure 1 This is a schematic diagram of the structure of the uric acid sensitive component 100 provided in Example 1 of the present application. The uric acid sensitive component 100 includes a single crystal silicon substrate 101, a plurality of polycrystalline silicon columns 102 are provided on the single crystal silicon substrate 101, and a porous silicon structure 103 is provided between the grain boundaries of adjacent polycrystalline silicon columns 102.

[0053] When the liquid to be tested enters the porous silicon structure 103 , the sensing signal generated by the porous silicon structure 103 is transmitted to the polycrystalline silicon column 102 , and further transmitted to the single crystal silicon substrate 101 , thereby realizing the sensing of biomolecules.

[0054] In a preferred embodiment, the surface of the porous silicon structure 103 is modified with a uric acid sensitive membrane layer that is specifically sensitive to uric acid molecules.

[0055] Furthermore, the diameter of the polysilicon column 102 is between 20 nm and 500 nm.

[0056] Furthermore, both the single crystal silicon substrate 101 and the polycrystalline silicon column 102 have a relatively low resistivity, which is less than or equal to 0.1Ω.cm.

[0057] Figure 2 The flowchart of the preparation method of the uric acid sensitive component is shown, and the preparation method specifically comprises the following steps:

[0058] S1: Select a single crystal silicon substrate material and deposit polycrystalline silicon columns on the single crystal silicon substrate.

[0059] The deposition of polycrystalline silicon columns on a single crystal silicon substrate is usually achieved by low pressure chemical vapor deposition (LPCVD).

[0060] The single crystal silicon substrate and the polycrystalline silicon column both have a relatively low resistivity, which is less than or equal to 0.1Ω.cm.

[0061] S2: Optionally, doping the polysilicon column.

[0062] The doping is mainly P-type doping. Since the doping impurities are easily enriched at the polysilicon grain boundaries, the silicon material adjacent to the grain boundaries is easily doped first, while the doping concentration of the silicon material inside the crystal column is relatively low. This makes the grain boundaries have a higher corrosion rate in the subsequent electrochemical etching process, that is, it is easy to form more porous silicon structures at the grain boundaries.

[0063] The doping element may be boron B or a compound containing B, and the doping method may be diffusion doping, ion implantation doping, etc. After impurity doping, high-temperature annealing greater than 800° C. is required to activate the doped impurities.

[0064] S3: electrochemically etching the single crystal silicon substrate to form a porous silicon structure between the grain boundaries of the polycrystalline silicon columns.

[0065] Specifically, during the etching process, a positive voltage is applied to the single crystal silicon substrate.

[0066] Preferably, the etching solution is a mixed solution of hydrofluoric acid HF and ethanol. The use of ethanol as a solvent helps to reduce the surface tension of hydrofluoric acid, making it easier to penetrate and corrode the polysilicon material deeply.

[0067] Furthermore, during the electrochemical corrosion process, the single crystal silicon substrate may be illuminated to a certain extent so as to generate more photogenerated carriers inside the substrate, thereby making the electrochemical corrosion more complete and faster.

[0068] S4: passivating the formed porous silicon structure so that the Si-H bonds on the surface of the porous silicon material basically disappear, thereby making the porous silicon structure have a relatively stable morphology.

[0069] When passivating the porous structure, a combination of one or more of the following methods is used:

[0070] Performing oxygen annealing on the porous structure to form an oxide layer with a thickness of more than 2 nm on the surface of the porous structure;

[0071] Using atomic layer deposition technology to deposit an insulating dielectric layer with a thickness of >2nm on the surface of the porous structure;

[0072] The porous structure is placed in an electrochemical corrosion tank containing oxidizing molecules or ions, such as H2O2, SO4 2+ 、NO 3-etc., using electrochemical oxidation to oxidize an oxide film layer with uniform thickness on the surface of the porous structure;

[0073] The porous structure is placed in a high-temperature and high-pressure water vapor environment (temperature ≥ 250°C), and the strong oxidizing property of water vapor in the high-temperature and high-pressure environment is utilized to form an oxide film layer with uniform thickness and good quality on the surface of the porous structure.

[0074] S5: Optionally, a sensitive membrane layer is modified on the surface of the porous silicon structure to make it specifically sensitive to uric acid molecules.

[0075] Specifically, the sensitive membrane layer is a uricase membrane layer, and the uricase material has specific sensitivity to uric acid molecules.

[0076] The thickness of the sensitive film layer is greater than or equal to 2 nm, and it has good electrical insulation properties.

[0077] Specifically, when modifying the sensitive membrane layer on the surface of the porous structure, a combination of one or more of the following methods is adopted:

[0078] The porous silicon structure is immersed in a solution rich in hydroxyl groups so that the surface of the porous silicon structure has strong binding activity, and then the porous silicon structure is immersed in a solution rich in uricase so that the uricase is bound to the surface of the porous silicon structure.

[0079] The porous silicon structure is immersed in an electrochemical tank, the solution in the tank contains abundant uricase, and current is applied to the porous silicon structure to enrich the uricase on the surface of the porous silicon structure.

[0080] The porous silicon structure is placed in an oxygen, nitrogen and argon plasma environment, abundant dangling bonds are bombarded on the surface of the porous silicon structure, and then the porous silicon structure is immersed in a solution rich in uricase.

[0081] The uricase is ionized and directly deposited on the surface of the porous structure by plasma enhanced chemical vapor deposition.

[0082] Figure 3 The porous silicon structure 103 is located between the grain boundaries of the polycrystalline silicon column 102 ( Figure 3 Only two crystal pillars and the porous silicon structure in the gap between them are shown in the figure, wherein the silicon material of the porous silicon structure 103 is still connected to the polycrystalline silicon crystal pillar 102 and further extends to the single crystal silicon substrate 101.

[0083] The porous silicon structure 103 has a larger specific surface area, and thus can more fully combine with the detected molecule P in the solution to generate a stronger sensing signal, such as Figure 4 shown.

[0084] Figure 5 The figure shows a cross-sectional view of the prepared porous silicon structure. The cross-section includes polycrystalline silicon columns and corrosion holes between the polycrystalline silicon columns. The corrosion holes contain abundant porous structures. The pore size of the porous structure is between 2 and 50 nm, and it is sponge-like. Therefore, it has a large specific surface area and is particularly suitable for sensing specific molecules in the solution. The single crystal silicon substrate is below the porous silicon structure.

[0085] In the above method, when preparing the porous silicon structure, polycrystalline silicon crystal pillars are used as the starting basis, and the porous silicon structure will be formed along the polycrystalline silicon grain boundary, that is, the porous silicon material is close to the polycrystalline silicon crystal pillars. Porous silicon has strong sensing ability but weak conductivity. When there are conductive crystal pillars next to it, the charge signal sensed by it can be quickly conducted outward by the conductive crystal pillars, thereby realizing the sensing of biological molecules.

[0086] The advantages of using polycrystalline silicon columns to prepare porous silicon structures are:

[0087] If single crystal silicon is used directly to prepare porous silicon structure, because porous silicon is a sponge-like structure with silicon material at the pore wall, when the pore wall is thin and the pore is large, the conductivity of porous silicon is poor, and it is difficult to effectively transmit the sensing signal to the single crystal silicon substrate.

[0088] When using polycrystalline silicon columns to prepare porous silicon structures, after electrochemical corrosion, some silicon columns still remain in the columnar polycrystalline silicon, which have strong conductivity. The sensing signal generated by the porous silicon structure at the side wall of the column can be easily transmitted to the column structure and further transmitted to the single crystal silicon substrate.

[0089] In summary, the present embodiment uses polycrystalline silicon pillars to prepare porous silicon structures, which can not only utilize their larger specific surface area for sensing, but also effectively improve the electrical signal path of the sensor, thereby improving the sensitivity and accuracy of uric acid detection.

[0090] Embodiment 2

[0091] Figure 6 This is a schematic diagram of the structure of the uric acid sensor provided in Example 2 of the present application, wherein the uric acid sensor comprises:

[0092] The uric acid sensitive component 100 is as described in the first embodiment;

[0093] A field effect transistor 200, wherein the gate of the field effect transistor 200 is connected to the single crystal silicon substrate 101 of the uric acid sensitive component 100 through a wire, the drain of the field effect transistor 200 is connected to the power supply voltage, the source of the field effect transistor 200 is connected to one end of the resistor 300 and the voltage output port 400, and the other end of the resistor 300 is grounded.

[0094] In a preferred embodiment, the field effect transistor 200 is a dual-gate transistor, that is, both its positive gate and back gate can adjust the conductive state of its channel, and by applying a certain back gate bias to the back gate, the field effect transistor can be in the best sensing state.

[0095] Furthermore, the field effect transistor 200 may be an NMOS or a PMOS. When the sensing signal changes, the conduction capacity of the transistor channel changes, that is, the current flowing through it changes, thereby changing the voltage signal on the resistor 300, and finally changing the voltage signal output by the voltage output port 400. That is, the sensing signal of the uric acid molecule is converted into an output voltage signal.

[0096] For field effect transistor sensors, an effective way to improve their sensing sensitivity is to increase their effective sensing area. The porous silicon structure has a large specific surface area, which is very suitable for biomolecule sensing. This embodiment combines a uric acid sensitive component with a porous silicon structure with a field effect transistor, which can be applied to the detection of key indicator molecules such as uric acid, greatly improving the sensitivity and accuracy of uric acid detection.

[0097] The method of using the above uric acid sensor is as follows:

[0098] Obtaining samples of blood, urine or other body fluids from the person being tested;

[0099] Optionally, the liquid to be tested is diluted by a certain ratio;

[0100] Optionally, the liquid to be tested is centrifuged to remove most of the macromolecular interferences;

[0101] The treated liquid to be tested is dropped into the uric acid sensitive component of the uric acid sensor. After a period of time (such as 10 seconds), the voltage signal of the voltage output port is read and the voltage signal is converted into the corresponding uric acid concentration, thereby completing the uric acid detection.

[0102] In a preferred embodiment, Figure 7 As shown, the uric acid sensor further includes a container 400 disposed outside the uric acid sensitive component, and a macromolecular filtration membrane 500 is disposed on the top of the container 400. The container 400 contains a reference electrode 600 for providing a reference voltage to the uric acid sensitive component 100.

[0103] When in use, the liquid to be tested is first filtered through the macromolecular filtration membrane 500, and then enters the container 400 to contact the uric acid sensitive component. In this way, macromolecular substances in urine, blood or other body fluids cannot reach the surface of the uric acid sensitive component, avoiding the interference of macromolecular substances in urine, blood or other body fluids on uric acid detection, thereby improving the accuracy of uric acid detection.

[0104] Furthermore, the macromolecular filtration membrane 500 is any one of cellulose diacetate (CA), cellulose triacetate (CTA), mixed cellulose (CA-CN), polysulfone (PS), sulfonated polysulfone (SPS), and polyethersulfone (PES).

[0105] This embodiment also provides a uric acid sensor system, such as Figure 8 As shown, two sets of the uric acid sensors are included, and containers 400 are arranged outside the two uric acid sensitive components. The two containers 400 contain reference electrodes 600 to provide reference voltage to the uric acid sensitive components 100.

[0106] A macromolecular filtration membrane 500 is disposed on the top of one of the containers 400 , and the uric acid sensor in the container is used to detect uric acid molecules in urine, blood or other body fluid samples.

[0107] The top of another container 400 is open, and the uric acid sensor in the container is used to detect uric acid molecules in a contrast solution, and the contrast solution can be pure water, deionized water or distilled water.

[0108] The difference between the output signals of the voltage output ports of the two sets of uric acid sensors forms the output signal of the entire system.

[0109] Considering that field effect transistors are sensitive to temperature, when the external ambient temperature changes, the conduction state of their channels also changes. Figure 7 When using the uric acid sensor in a room, its output signal is easily affected by the ambient temperature. Figure 8 The uric acid sensing system in the device can effectively shield the output signal changes caused by temperature fluctuations. Its main principles are: Figure 8 The two sets of uric acid sensors use the same field-effect transistor, and the temperature makes the signal fluctuations they produce basically consistent. Therefore, the difference in output voltages of the two sets of uric acid sensors is the output voltage caused by the uric acid molecule sensing signal, thereby achieving accurate detection of the uric acid molecules being detected.

[0110] In another preferred embodiment, Fig. 9 As shown, a signal amplifier is connected to the back end of the primary output signal of the uric acid sensor to amplify the power of the weak sensing signal, which is suitable for the subsequent reading circuit to perform a reading operation, and then after specific data processing, the final uric acid molecule sensing intensity is displayed, thereby realizing accurate detection of the uric acid molecules being detected.

[0111] It should be understood that the directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to different positions and different usage conditions. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0112] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0113] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0114] The above is only a preferred embodiment of the present application, and is not any formal or substantial limitation to the present application. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present application, and these improvements and supplements should also be regarded as the protection scope of the present application. Any technician familiar with this profession can make some changes, modifications and evolutions of the technical content disclosed above without departing from the spirit and scope of the present application, which are equivalent embodiments of the present application; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the substantial technology of the present application are still within the scope of the technical solution of the present application.

Claims

1. A uric acid sensitive component, characterized in that: The invention comprises a single crystal silicon substrate, on which a plurality of polycrystalline silicon crystal columns are arranged, and a porous silicon structure is arranged between the grain boundaries of adjacent polycrystalline silicon crystal columns.

2. The uric acid sensitive component according to claim 1, characterized in that: The surface of the porous silicon structure is modified with a uric acid sensitive membrane layer which is specifically sensitive to uric acid molecules.

3. The uric acid sensitive component according to claim 1, characterized in that: The diameter of the polysilicon crystal column is between 20 and 500 nm.

4. A method for preparing a uric acid sensitive component according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: Selecting a single crystal silicon substrate, and depositing polycrystalline silicon columns on the single crystal silicon substrate; Electrochemically etching the single crystal silicon substrate to form a porous silicon structure between the grain boundaries of the polycrystalline silicon columns; The formed porous silicon structure is passivated to keep its structure stable.

5. The method for preparing the uric acid sensitive component according to claim 4, characterized in that: Before electrochemically etching the single crystal silicon substrate, the method further comprises: The polysilicon crystal column is subjected to P-type diffusion doping, and the doped impurities are concentrated at the grain boundaries of the polysilicon crystal column, so that the grain boundaries become the preferred sites for electrochemical corrosion.

6. The method for preparing the uric acid sensitive component according to claim 4, characterized in that: After the formed porous silicon structure is oxidized and strengthened, the following steps are further included: A sensitive membrane layer is modified on the surface of the porous silicon structure to make it specifically sensitive to uric acid molecules.

7. A uric acid sensor, characterized in that: The uric acid sensor comprises: The uric acid sensitive component according to any one of claims 1 to 3; A field effect transistor, wherein the gate of the field effect transistor is connected to the single crystal silicon substrate of the uric acid sensitive component through a wire, the drain of the field effect transistor is connected to the power supply voltage, the source of the field effect transistor is connected to one end of the resistor and the voltage output port, and the other end of the resistor is grounded.

8. The uric acid sensor according to claim 7, characterized in that: The field effect transistor is a dual-gate transistor, and both the positive gate and the back gate of the dual-gate transistor can adjust the conductive state at its channel. By applying a back gate point voltage to the back gate, the field effect transistor is in an optimal sensing state.

9. The uric acid sensor according to claim 7, characterized in that: The uric acid sensor also includes a container arranged outside the uric acid sensitive component, and a macromolecular filtration membrane is arranged on the top of the container to filter macromolecular substances in the liquid to be tested to prevent them from entering the uric acid sensitive component to form an interference signal; The container contains a reference electrode for providing a reference voltage to the uric acid sensitive component.

10. A uric acid sensor system, characterized in that: comprising two sets of uric acid sensors as claimed in claim 7; A container is provided outside the uric acid sensitive components of the two sets of uric acid sensors; A macromolecular filtration membrane is arranged on the top of one of the containers, and the uric acid sensor in the container is used to detect uric acid molecules in the liquid to be tested; The top of the other container is open, and the uric acid sensor in the container is used to detect uric acid molecules in the contrast solution; The difference between the output signals of the voltage output ports of the two sets of uric acid sensors forms the output signal of the uric acid sensor system.

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