A photoelectric co-detection specific binding device

Abstract

The embodiments of the present invention relate to the field of specific detection, and disclose a photoelectric co-detection specific binding device, including: interdigitated electrodes, an electrical detection unit, a light detection unit, and an output unit, wherein the interdigitated electrodes are made of a porous silicon bottom plate; the output unit will output detection information when the absolute value of the difference between the first impedance value and the second impedance value before and after the addition of the sample to be tested is greater than a first preset threshold value, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum before and after the addition of the sample to be tested is greater than a second preset threshold value, to characterize the presence of a specific substance in the sample to be tested that specifically binds to a specific aptamer. The present application replaces a biological quantity with low detection accuracy by detecting two more accurate photoelectric quantities, and can also detect the two quantities together, thereby significantly improving the sensitivity of the photoelectric co-detection specific binding device, and the detection process is simple, the cost of the photoelectric co-detection specific binding device is low, and it is easy to promote.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of specific detection, and in particular to a photoelectric co-detection specific binding device. Background Art

[0002] Rapid, accurate, and easy-to-promote virus detection technology is of great significance for early detection, early isolation, early diagnosis, and early treatment of virus-infected people. Currently, there are mainly two types of virus detection technologies.

[0003] The first method uses polymerase chain reaction (PCR) to detect viruses. Specifically, it detects whether there is a certain virus in the sample to be tested by detecting whether there is the virus's genetic material (DNA or RNA) in the sample to be tested. This detection technology has stricter detection requirements to maximize the sensitivity of detecting viruses. However, this virus detection technology requires obtaining the nucleic acid sequence of the virus to be detected in advance, and the entire detection process is relatively cumbersome, often requiring multiple sampling operations, which will still limit the sensitivity of detecting viruses to a certain extent. In addition, this detection technology has slow detection speed, high cost, and cannot be detected simultaneously.

[0004] The second method uses the specific binding reaction between antigens and antibodies to detect viruses. This detection technology can only detect whether there are antigens or antibodies in the sample to be tested. It also needs to be coordinated with other detection technologies to specifically determine the type of virus and the reason for the production of antibodies. The detection process is also relatively cumbersome, the sensitivity of virus detection is low, the detection speed is slow, the cost is high, it is not conducive to promotion, and it cannot be detected simultaneously. Summary of the invention

[0005] The purpose of an embodiment of the present invention is to provide a photoelectric co-detection specific binding device. The photoelectric co-detection specific binding device detects more accurate light / electrical quantities to replace biological quantities with low detection accuracy, thereby significantly improving the sensitivity of the photoelectric co-detection specific binding device. The detection process is simple and the cost of the photoelectric co-detection specific binding device is low, which is easy to promote.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a photoelectric co-detection specific binding device, comprising: a forked electrode, an electrical detection unit, a light detection unit and an output unit, wherein the forked electrode is connected to the electrical detection unit, and the electrical detection unit and the light detection unit are respectively connected to the output unit; wherein the forked electrode is made of a porous silicon substrate; the forked electrode is used to react with a thiolated specific aptamer for a first preset time; the electrical detection unit is used to detect the impedance value of the forked electrode after the reaction as the first impedance value, and after adding a sample to be tested to the forked electrode after the reaction, in the same solution (a solution of 1 mM / L potassium ferrocyanide and 1 mM / L potassium ferrocyanide) is used to detect the impedance value of the interdigital electrode as the second impedance value; the light detection unit is used to detect the scattering spectrum of the surface of the interdigital electrode after the reaction as the first scattering spectrum, and after adding the sample to be tested on the interdigital electrode after the reaction, N2 is blown dry to detect the scattering spectrum of the surface of the interdigital electrode as the second scattering spectrum; the output unit is used to output detection information when the absolute value of the difference between the first impedance value and the second impedance value is greater than a first preset threshold value, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than a second preset threshold value, so as to characterize the presence of a specific substance that specifically binds to the specific aptamer in the sample to be tested.

[0007] In an embodiment of the present invention, an interdigitated electrode made of a porous silicon bottom plate is provided in a photoelectric co-detection specific binding device. The interdigitated electrode will first react with the thiolated specific aptamer. After a first preset time, it can be considered that the interdigitated electrode and the specific aptamer have fully reacted. Then, the electrical detection unit detects the first impedance value of the interdigitated electrode after the reaction. At this time, the optical detection unit will also detect the scattering spectrum of the surface of the interdigitated electrode after the reaction as the first scattering spectrum. After that, after the sample to be tested is added to the interdigitated electrode after the reaction, the electrical detection unit detects the second impedance value of the interdigitated electrode in the same solution (1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide), and the optical detection unit detects the scattering spectrum of the surface of the interdigitated electrode after N2 drying as the second scattering spectrum. Then, when the output unit determines that the absolute value of the difference between the first impedance value and the second impedance value is greater than the first preset threshold value, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than the second preset threshold value, the output unit outputs the detection information indicating that there is a specific substance in the sample to be tested that can specifically bind to the specific aptamer. The present application does not require the advance acquisition of the nucleic acid sequence of the virus to be detected as required by the PCR technology, nor does it require the coordination with other detection technologies as required by the specific binding reaction between antigens and antibodies to detect specific substances. The present application determines whether specific binding occurs between the sample to be tested and the specific aptamer by judging whether the change in the capacitance of the interdigitated electrodes before and after the addition of the sample to be tested is too large, and then judges whether specific substances such as viruses exist in the sample to be tested, thereby simplifying the detection process. Moreover, the detection device replaces the biological quantities with low detection accuracy by detecting more accurate electricity and light, thereby significantly improving the sensitivity of the detection device. In addition, the main functional component in the detection device, the interdigitated electrodes, can be mass-produced with low production costs, and are suitable for large-scale detection and analysis, and are easy to promote.

[0008] In addition, the porous silicon bottom plate is obtained by wet etching the surface of single crystal silicon with 15% hydrofluoric acid alcohol solution for a preset number of times and then oxidizing for a second preset time after wet etching. In this embodiment, a specific form of the porous silicon bottom plate is provided.

[0009] In addition, a metal layer is arranged on the surface of the porous silicon bottom plate. The material of the metal layer is a metal with plasma resonance phenomenon. The thickness of the metal layer is 2nm-2μm.

[0010] In addition, the light detection unit is specifically used to detect the dark field scattering spectrum of the surface of the reacted interdigitated electrode within a preset wavelength range as the first scattering spectrum; the light detection unit is also specifically used to add the sample to be tested to the reacted interdigitated electrode, blow dry with N2, and detect the dark field scattering spectrum of the interdigitated electrode within a preset wavelength range as the second scattering spectrum.

[0011] In addition, the photoelectric co-detection specific binding device also includes a voltage unit connected to the interdigital electrode; the voltage unit is used to output a voltage within a preset frequency range to the interdigital electrode; the electrical detection unit is specifically used to detect the impedance of the interdigital electrode under the voltage within the preset frequency range after the reaction, and obtain a first impedance value; the electrical detection unit is also specifically used to detect the impedance of the interdigital electrode under the voltage within the preset frequency range after adding the sample to be tested to the interdigital electrode after the reaction, and obtain a second impedance value. A specific implementation method for obtaining the capacitance value of the interdigital electrode is provided.

[0012] In addition, the connection wires between the interdigital electrodes and the voltage unit, and the connection wires between the interdigital electrodes and the detection unit are all micron metal wires. Since the interdigital electrodes are often small in size, using micron metal wires for connection is more stable than other methods.

[0013] In addition, the electrical detection unit is specifically used to detect and obtain a first impedance value after adding bovine serum albumin to the interdigital electrodes after the reaction, and to detect and obtain a second impedance value in the same solution (1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide) after adding the sample to be tested to the interdigital electrodes to which bovine serum albumin has been added. After the interdigital electrodes react with the specific aptamer for a first preset time, bovine serum albumin is added to the interdigital electrodes after the reaction to seal the area on the interdigital electrodes that has not reacted with the specific aptamer, so as to avoid the presence of substances in the sample to be tested that can react with the interdigital electrodes and thus cause the capacitance of the interdigital electrodes to change, and the phenomenon that the specific aptamer reacts with the interdigital electrodes in the area where the specific aptamer has not reacted with the specific aptamer can effectively improve the accuracy of the photoelectric co-detection specific binding device.

[0014] In addition, the interdigital electrode includes 3 to 60 conductive interdigital fingers arranged in parallel with equal spacing, the spacing of the conductive interdigital fingers is 1 to 50 μm, the width of the conductive interdigital fingers is 2 to 50 μm, the length of the conductive interdigital fingers is 8 mm, the volume of the sample to be tested is 2 μL to 50 μL, and the preset threshold is 1 nF. Compared with the interdigital electrodes in the related art, the interdigital electrodes of the present application are smaller in size, which can effectively improve the sensitivity of the entire photoelectric co-detection specific binding device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0016] Figure 1 is a schematic block diagram of an optoelectronic co-detection specific binding device in one embodiment;

[0017] Figure 2is a schematic diagram of a light path for a light detection unit to detect interdigital electrodes in one embodiment;

[0018] Figure 3 is a schematic diagram of a first scattering spectrum and a second scattering spectrum in one embodiment;

[0019] Figure 4 is a schematic diagram of a process for obtaining a porous silicon substrate in one embodiment;

[0020] Figure 5 is an equivalent circuit model diagram of a photoelectric co-detection specific binding device in one embodiment;

[0021] Figure 6 is a graph of impedance changes of interdigitated electrodes before and after adding a sample to be tested in one embodiment;

[0022] Figure 7 is a schematic diagram of a first impedance spectrum and a second impedance spectrum detected in one embodiment;

[0023] Figure 8 is a graph of the error of the phase angle of impedance at different frequencies in one embodiment;

[0024] Fig. 9 is an error diagram of the phase magnitude of impedance at different frequencies in one embodiment;

[0025] Fig.10 FIG. 1 is a diagram illustrating parameters of interdigital electrodes of a photoelectric co-detection specific binding device according to an embodiment. DETAILED DESCRIPTION

[0026] To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0027] One embodiment of the present invention relates to a photoelectric co-detection specific binding device for rapidly detecting whether a specific substance exists in a sample to be tested, such as a virus, a pseudovirus, and a neurotransmitter. Figure 1The photoelectric co-detection specific binding device includes: a forked electrode 1, an electrical detection unit 2, a light detection unit 3 and an output unit 4, the forked electrode 1 is connected to the electrical detection unit 2, and the electrical detection unit 2 and the light detection unit 3 are respectively connected to the output unit 4; wherein the forked electrode is made of a porous silicon substrate.

[0028] The interdigitated electrode 1 will react with the thiol-specific aptamer for a first preset time period; the electrical detection unit 2 will detect the impedance value of the interdigitated electrode 1 after the reaction as the first impedance value, and after adding the sample to be tested on the interdigitated electrode 1 after the reaction, detect the impedance value of the interdigitated electrode 1 in the same solution (1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide) as the second impedance value; the light detection unit 3 will detect the scattering spectrum of the surface of the interdigitated electrode 1 after the reaction as the first scattering spectrum, and after adding the sample to be tested on the interdigitated electrode 1 after the reaction, N2 blow-dry, and detect the scattering spectrum of the surface of the interdigitated electrode 1 as the second scattering spectrum; the output unit 4 will output detection information when the absolute value of the difference between the first impedance value and the second impedance value is greater than the first preset threshold value, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than the second preset threshold value, to characterize the presence of a specific substance in the sample to be tested that specifically binds to the specific aptamer.

[0029] In this embodiment, the photoelectric co-detection specific binding device is provided with an interdigitated electrode made of a porous silicon base plate. The interdigitated electrode will first react with the thiolated specific aptamer. After a first preset time, it can be considered that the interdigitated electrode and the specific aptamer have fully reacted. The electrical detection unit then detects the first impedance value of the reacted interdigitated electrode. At this time, the optical detection unit will also detect the scattering spectrum of the surface of the reacted interdigitated electrode as the first scattering spectrum. After that, after adding the sample to be tested to the reacted interdigitated electrode, the electrical detection unit detects the second impedance value of the interdigitated electrode, and the optical detection unit detects the scattering spectrum of the surface of the interdigitated electrode as the second scattering spectrum. Then, when the output unit determines that the absolute value of the difference between the first impedance value and the second impedance value is greater than the first preset threshold value, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than the second preset threshold value, it outputs detection information indicating the presence of a specific substance in the sample to be tested that can specifically bind to the specific aptamer. The present application does not require the advance acquisition of the nucleic acid sequence of the virus to be detected as required by the PCR technology, nor does it require the coordination with other detection technologies as required by the specific binding reaction between antigens and antibodies to detect specific substances. The present application determines whether specific binding occurs between the sample to be tested and the specific aptamer by judging whether the change in the capacitance of the interdigitated electrodes before and after the addition of the sample to be tested is too large, and then judges whether specific substances such as viruses exist in the sample to be tested, thereby simplifying the detection process. Moreover, the detection device replaces the biological quantities with low detection accuracy by detecting more accurate electricity and light, thereby significantly improving the sensitivity of the detection device. In addition, the main functional component in the detection device, the interdigitated electrodes, can be mass-produced with low production costs, and are suitable for large-scale detection and analysis, and are easy to promote.

[0030] The implementation details of the photoelectric co-detection specific binding device of this embodiment are specifically described below. The following content is only the implementation details provided for easy understanding and is not necessary for implementing this solution.

[0031] Specifically, the photoelectric co-detection specific binding device is provided with both an electrical detection unit 2 and a light detection unit 3, that is, it can detect whether there is a specific substance that can specifically bind to the specific aptamer in the sample to be tested by both electrical and optical quantities.

[0032] First, the detection of whether specific binding occurs by electrical quantity is explained. First, the specific aptamer is thiolated so that the specific aptamer can react with the interdigital electrode 1. The specific aptamer after thiolation is mostly dissolved in phosphate buffer saline (PBS). The interdigital electrode 1 can be immersed in a PBS solution containing the thiolated specific aptamer to react with the specific aptamer. During the reaction, the interdigital electrode 1 with the added specific aptamer can be shaken so that the specific aptamer and the interdigital electrode 1 can fully react. After a first preset time, it can be considered that the interdigital electrode 1 and the specific aptamer have fully reacted. After the reaction, a layer of specific aptamer will be attached to the surface of the interdigital electrode 1. At this time, the electrical detection unit 2 detects the impedance of the interdigital electrode 1 in the same solution (1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide) before and after adding the sample to be tested, and obtains a first impedance value and a second impedance value. If there is no specific aptamer in the sample to be tested, the impedance of the interdigital electrode 1 can be determined. If there is a specific substance that specifically binds to the specific aptamer, the surface of the interdigitated electrode 1 will still be the specific aptamer that has reacted before, and the impedance value of the interdigitated electrode 1 will hardly change; if there is a specific substance that can specifically bind to the specific aptamer in the sample to be tested, the specific substance will bind to the specific aptamer attached to the surface of the interdigitated electrode 1, which will change the impedance of the interdigitated electrode 1 and cause it to change significantly. At this time, the absolute value of the difference between the first impedance value and the second impedance value will be greater than the first preset threshold value. Therefore, when the output unit 4 determines that the absolute value of the difference between the first impedance value and the second impedance value is greater than the preset threshold value, it will output detection information to indicate that there is a specific substance that can specifically bind to the specific aptamer in the sample to be tested.

[0033] Next, we will explain how to detect specific binding using optical measurements. Figure 2, the light detection unit 3 will specifically emit light as incident to the surface of the first reacted interdigital electrode 1, the light is the white light of the microscope, and then receive the light reflected from the surface of the interdigital electrode 1, and obtain the scattering spectrum of the surface of the interdigital electrode 1 as the first scattering spectrum, and after adding the sample to be tested to the reacted interdigital electrode 1, N2 is blown dry, and the scattering spectrum of the surface of the interdigital electrode 1 is detected as the second scattering spectrum. The specific process of obtaining the second scattering spectrum is roughly the same as the specific process of obtaining the first scattering spectrum. If there is a specific substance that can specifically bind to the specific aptamer in the sample to be tested, the specific substance will bind to the specific aptamer attached to the surface of the interdigital electrode 1, which will cause a relatively large change in the scattering of the interdigital electrode 1, specifically, the dark field scattering will change greatly. At this time, the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum will be greater than the second preset threshold value, so the output unit 4 will output the detection information when it is determined that the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than the second preset threshold value, so as to indicate that there is a specific substance that can specifically bind to the specific aptamer in the sample to be tested. The second preset threshold may be the same as or different from the first preset threshold, which is not limited here.

[0034] The diagram is used as an example to illustrate that when there is a specific substance in the sample to be tested, the light detection unit 3 receives the first scattering spectrum and the second scattering spectrum of the surface of the interdigital electrode 1 before and after the sample to be tested is added. Please refer to Figure 3 , curve 1 is the first scattering spectrum, and curve 2 is the second scattering spectrum.

[0035] In one embodiment, the output unit 4 can also be set to output detection information only when the absolute value of the difference between the first impedance value and the second impedance value is greater than a first preset threshold, and the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than a second preset threshold. That is, when the electrical detection unit 2 and the optical detection unit 3 both determine that there is a specific substance in the sample to be tested that can specifically bind to the specific aptamer, the detection information is output. Double detection can effectively improve the accuracy of detection.

[0036] In one embodiment, the porous silicon substrate is obtained by wet etching the surface of single crystal silicon with a 15% hydrofluoric acid alcohol solution for a preset number of times, and then oxidizing for a second preset time after wet etching. The single crystal silicon can be N-type single crystal silicon or P-type single crystal silicon. For details, please refer to Figure 4The single crystal silicon can be placed in a Teflon container for wet etching, and a 15% hydrofluoric acid alcohol solution can be used to form holes by wet etching on the single crystal silicon surface of 1 ohm per square centimeter. Specifically, a current of 0.13A can be applied to the single crystal silicon for wet etching for 20 seconds. After 12 cycles of etching, a current of 1.186A can be applied for wet etching for 6 seconds. After 12 cycles of etching, the etched single crystal silicon is cleaned with ethanol and water. After cleaning, the etched single crystal silicon is continuously oxidized for more than 30 minutes in a muffle furnace at a high temperature of 800°C. After cooling, a porous silicon base plate can be obtained.

[0037] In one embodiment, a metal layer is disposed on the surface of the porous silicon bottom plate. The material of the metal layer is a metal having a plasma resonance phenomenon, such as gold, silver, copper and the like. The thickness of the metal layer is 2 nm-2 μm.

[0038] In one embodiment, the photoelectric co-detection specific binding device further includes a voltage unit 5 connected to the interdigitated electrode 1, please refer to Figure 1 The voltage unit 5 can output a voltage of a preset frequency range to the interdigital electrode 1, and the preset frequency range is, for example, 100 Hz-1 MHz. The electrical detection unit 2 detects the impedance of the interdigital electrode 1 after the reaction at a voltage of 100 Hz-1 MHz to obtain a first impedance spectrum, and then obtains a first impedance value of the interdigital electrode 1 according to the first impedance spectrum; after adding the sample to be tested, the electrical detection unit 2 measures the impedance of the interdigital electrode 1 at a voltage of 100 Hz-1 MHz in the same solution (1 mM / L potassium ferrocyanide solution and 1 mM / L potassium ferrocyanide) to obtain a second impedance spectrum, and then obtains a second impedance value of the interdigital electrode 1 according to the second impedance spectrum.

[0039] In one embodiment, the electrical detection unit 2 can specifically utilize Figure 5 The equivalent circuit model and related fitting software are used to debug the equivalent circuit model according to the first impedance spectrum and the second impedance spectrum. Figure 5 Where R1 is the internal resistance of the voltage unit 5, R2 is the equivalent resistance of the solution in which the interdigital electrode 1 is immersed, and Q2 is the equivalent capacitance of the interdigital electrode 1. The equivalent model can be used after debugging until R1 and R2 are fixed. The first impedance value can be obtained according to the first impedance spectrum and the equivalent model, and the second impedance value can be obtained according to the second impedance spectrum and the equivalent model.

[0040] The diagram is used as an example to illustrate that when there is a specific substance in the sample to be tested, the first impedance spectrum and the second impedance spectrum of the interdigital electrode 1 detected by the electrical detection unit 2 before and after the sample to be tested is added, please refer to Figure 6In the figure, a and b are the impedance change diagrams of the interdigital electrode 1 measured twice before adding the sample to be tested, and c and d are the impedance change diagrams of the interdigital electrode 1 measured twice after adding the sample to be tested. Then, the first impedance spectrum and the second impedance spectrum are obtained respectively according to the impedance change diagrams. Please refer to Figure 7 , a and b are the first impedance spectra obtained twice, c and d are the second impedance spectra obtained twice. Please refer to Figure 8 , which is the error diagram of the phase angle of impedance at different frequencies. Please refer to Fig. 9 , which is the error diagram of the phase size of impedance at different frequencies.

[0041] In one embodiment, the connection wires between the interdigital electrodes 1 and the voltage unit 5, and the connection wires between the interdigital electrodes 1 and the electrical detection unit 2 are both set as micron metal wires. In this embodiment, since the volume of the interdigital electrodes is often relatively small, the micron metal wires connected by wire bonder can be added with PDMS mixed liquid for curing. Compared with other connection wires, the micron metal wires cured by PDMS are very stable and reliable.

[0042] In one embodiment, when the electrical detection unit 2 detects the impedance spectrum, specifically after adding bovine serum albumin to the reacted interdigital electrode 1, the first impedance value of the interdigital electrode 1 is detected, and then after adding the sample to be tested to the interdigital electrode 1 added with bovine serum albumin, the second impedance value of the interdigital electrode 1 is detected.

[0043] In one embodiment, when the light detection unit 3 detects the dark field scattering spectrum, specifically after bovine serum albumin is added to the reacted interdigitated electrode 1, the dark field scattering spectrum on the surface of the interdigitated electrode 1 is detected as the first scattering spectrum, and then after the sample to be tested is added to the interdigitated electrode 1 to which bovine serum albumin is added, the dark field scattering spectrum on the surface of the interdigitated electrode 1 is detected as the second scattering spectrum.

[0044] In the present embodiment, the electrical detection unit reacts the interdigitated electrodes with the specific aptamer for a first preset time period, and after adding bovine serum albumin to the interdigitated electrodes after the reaction, detects the first impedance value. Adding bovine serum albumin to the interdigitated electrodes after the reaction can block the areas on the interdigitated electrodes that have not reacted with the specific aptamer, so as to avoid the presence of substances in the sample to be tested that can react with the interdigitated electrodes and thereby cause the capacitance of the interdigitated electrodes to change, and the phenomenon that the specific aptamer reacts with the interdigitated electrodes in the area where the specific aptamer has not reacted with the specific aptamer, thereby effectively improving the accuracy of the photoelectric co-detection specific binding device.

[0045] Another embodiment of the present invention relates to a photoelectric co-detection specific binding device, which provides Figure 1 The specific size of the middle interdigital electrode 1 in the corresponding embodiment.

[0046] Please refer to Fig.10 The interdigital electrode 1 includes 3 to 60 conductive interdigital fingers 11 arranged in parallel with equal spacing, the spacing S of the conductive interdigital fingers 11 is 1 to 50 μm, the width W of the conductive interdigital fingers 11 is 1 to 50 μm, the length of the conductive interdigital fingers 11 is 1-8 mm, the volume of the sample to be tested is 1 μL to 50 μL, the preset threshold of the electrical output is 1 nF, and the red shift of the scattering spectrum is 0.2 nanometers.

[0047] In this embodiment, compared with the interdigitated electrodes in the related art, the interdigitated electrodes of the present application are smaller in size, which can effectively improve the sensitivity of the entire photoelectric co-detection specific binding device. At the same time, the light detection can be used on the substrate at the same time, and the signal can be detected together.

[0048] In one embodiment, when preparing the interdigitated electrode 1, a 15% hydrofluoric acid alcohol solution is first used to wet etch 12 times at currents of 0.13A, 20S and 1.186A, 6S, respectively. After washing with ethanol and water, the electrode is oxidized at 800 degrees in a muffle furnace for 30 minutes and cooled to room temperature to form a porous silicon base plate material.

[0049] A mask for photolithography is designed according to the specific size of the interdigitated electrode 1 in the above embodiment, and then a porous silicon base plate with silicon dioxide as the main component is used as a substrate. The substrate is washed, coated and heated, and the substrate is subjected to photolithography and development according to the designed mask to obtain a photolithographic substrate. A magnetron sputtering device is then used to evaporate the photolithographic substrate, and it is necessary to evaporate 5nm of Pt and 15nm of gold. Acetone is used to remove excess photoresist on the interdigitated electrode 1 obtained after the evaporation, and the interdigitated electrode 1 is then blown dry to complete the preparation of the interdigitated electrode 1.

[0050] In one embodiment, when preparing a microporous cover sheet, Dow Corning PDMS and AB liquid silicone are fully mixed in a ratio of 10:1 and then evacuated. The treated mixed liquid is poured on the surface of a polished silicon wafer, and the silicon wafer covered with the mixed liquid is heated at 100°C for 30 minutes. A hole puncher is used to punch holes in the heated cover sheet to obtain a microporous cover sheet. The specific number of holes and the diameter of each hole can be adjusted as needed to meet the flow rate requirement of the added liquid. Preferably, the diameter of the hole can be set, that is, the preset diameter is set to 2-8 mm.

[0051] In one embodiment, before the interdigital electrode 1 is used, it is necessary to soak and clean the interdigital electrode 1 with DI water (Deionized water) for removing impurity ions, and then blow dry the soaked interdigital electrode 1 with nitrogen. After blowing dry the interdigital electrode 1, the interdigital electrode 1 can be immersed in a PBS solution containing a thiolated specific aptamer to allow the interdigital electrode 1 to react with the specific aptamer. The PBS solution containing the thiolated specific aptamer and the interdigital electrode 1 is shaken at room temperature for 120 minutes. After shaking, bovine serum albumin is added to the solution. Bovine serum albumin can bind to the area of ​​the interdigital electrode 1 that is not bound to the specific aptamer, so that other impurities in the subsequent sample to be tested cannot react with the interdigital electrode 1, and will not affect the capacitance of the interdigital electrode 1, thereby improving the detection accuracy of the photoelectric co-detection specific binding device. After 15 minutes of adding bovine serum albumin, it is believed that the bovine serum albumin has bound to all the areas of the interdigital electrode 1 that are not bound to the specific aptamer. At this time, remove the excess bovine serum albumin and add another In one embodiment, after removing excess bovine serum albumin, a 1 mM / L potassium ferrocyanide solution and a 1 mM / L potassium ferrocyanide solution are added to the solution to remove the specific aptamer in the solution that has not reacted with the interdigitated electrode 1, so that after the sample to be tested is subsequently added, the specific substances in the sample to be tested can all be specifically bound to the specific aptamer that reacts with the interdigitated electrode 1, which can effectively improve the detection sensitivity of the photoelectric co-detection specific binding device, that is, the photoelectric co-detection specific binding device can detect whether the specific substance exists in the sample to be tested when the concentration of the specific substance in the sample to be tested is low. Specifically, the photoelectric co-detection specific binding device of the present application can detect whether the specific substance exists in the sample to be tested when the concentration of the specific substance in the sample to be tested is fg / ml.

[0052] After adding 1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide solution to the solution, the electrical detection unit 2 detects the impedance of the interdigital electrode 1 at a voltage of 100Hz-1MHz frequency to obtain a first impedance spectrum. After adding the sample to be tested to the solution, the electrical detection unit 2 detects the impedance of the interdigital electrode 1 at a voltage of 100Hz-1MHz frequency in the same solution (1mM / L potassium ferrocyanide solution and 1mM / L potassium ferrocyanide) to obtain a second impedance spectrum. The impedance spectrum is, for example, Figure 7 The electrical detection unit 2 is then used as Figure 5 The equivalent circuit model and related fitting software are used to debug the equivalent model according to the first impedance spectrum and the second impedance spectrum. The equivalent model is debugged until R1 and R2 are fixed and the equivalent model can be used. The first impedance can be obtained according to the first impedance spectrum and the equivalent model, and the second impedance can be obtained according to the second impedance spectrum and the equivalent model.

[0053] Specifically, the capacitance C of the interdigital electrode 1 is cell It is calculated by the following formulas (1) to (4):

[0054]

[0055]

[0056]

[0057]

[0058] Where ε0 is the absolute dielectric constant of the interdigital electrode 1, ε r-sol is the relative dielectric constant of the interdigital electrode 1, N is the number of the conductive interdigital electrodes 11 of the interdigital electrode 1, S is the spacing between the conductive interdigital electrodes 11 of the interdigital electrode 1, W is the width of the conductive interdigital electrodes 11 of the interdigital electrode 1, and L is the effective length of the conductive interdigital electrodes 11 overlapping to form a capacitor. Please refer to Fig.10 .

[0059] The electrical output unit 2 can output detection information when it is detected that the absolute value capacitance Q2 of the difference between the first impedance and the second impedance is greater than 1 nF, so as to indicate that there is a specific substance in the sample to be tested that specifically binds to the specific aptamer.

[0060] In one embodiment, when the electrical detection unit 2 detects the dark field scattering spectrum, the wavelength of the dark field spectrum scattering can be 400nm to 900nm, wherein the position of the in-situ plasma resonance peak corresponds to the thickness of the metal sputtering layer. In this example, 5nm of Pt and 15nm of gold are used as the metal sputtering layer, and the range of the in-situ plasma resonance peak is specifically between 480nm and 780nm.

[0061] Specifically, when the light output unit 4 detects that the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum exceeds 0.2 nm, it can output detection information to indicate that there is a specific substance that specifically binds to the specific aptamer in the sample to be tested.

[0062] In the present embodiment, there is no need to obtain the nucleic acid sequence of the virus to be detected in advance as required by the PCR technology, nor is there a need to cooperate with other detection technologies as required by the specific binding reaction between antigens and antibodies to detect specific substances. The present application determines whether specific binding occurs between the sample to be tested and the specific aptamer by judging whether the change in the capacitance of the interdigitated electrodes before and after the addition of the sample to be tested is too large, and then judges whether specific substances such as viruses exist in the sample to be tested, thereby simplifying the detection process. Moreover, the detection device replaces biological quantities with low detection accuracy by detecting more accurate electrical quantities, thereby significantly improving the sensitivity of the detection device. In addition, the main functional component in the detection device, the interdigitated electrodes, can be mass-produced with low production costs, and are suitable for large-scale detection and analysis, and are easy to promote.

[0063] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A photoelectric co-detection specific binding device, characterized in that: include: An interdigital electrode, an electrical detection unit, a light detection unit and an output unit, wherein the interdigital electrode is connected to the electrical detection unit, and the electrical detection unit and the light detection unit are respectively connected to the output unit; wherein the interdigital electrode is made of a porous silicon substrate; The interdigitated electrode is used to react with the thiol-specific aptamer for a first preset time period; The electrical detection unit is used to detect the impedance value of the interdigital electrodes after the reaction as a first impedance value, and after adding the sample to be tested on the interdigital electrodes after the reaction, detect the impedance value of the interdigital electrodes in the same solution as a second impedance value; The light detection unit is used to detect the scattering spectrum of the surface of the interdigital electrode after the reaction as a first scattering spectrum, and after adding the sample to be tested on the interdigital electrode after the reaction, detect the scattering spectrum of the surface of the interdigital electrode as a second scattering spectrum; The output unit is used to output detection information when the absolute value of the difference between the first impedance value and the second impedance value is greater than a first preset threshold, or when the absolute value of the red shift of the first scattering spectrum and the second scattering spectrum is greater than a second preset threshold, so as to characterize the presence of a specific substance that specifically binds to the specific aptamer in the sample to be tested.

2. The photoelectric co-detection specific binding device according to claim 1, characterized in that: The porous silicon bottom plate is obtained by wet-etching single crystal silicon with a 15% hydrofluoric acid alcohol solution for a preset number of times on the surface of the single crystal silicon, and then oxidizing for a second preset time after the wet etching.

3. The photoelectric co-detection specific binding device according to claim 1, characterized in that: A metal layer is arranged on the surface of the porous silicon bottom plate. The material of the metal layer is a metal having a plasma resonance phenomenon. The thickness of the metal layer is 2nm-2μm.

4. The photoelectric co-detection specific binding device according to claim 1, characterized in that: The light detection unit is specifically used to detect the dark field scattering spectrum of the surface of the interdigital electrode after the reaction in a preset wavelength range as the first scattering spectrum; The light detection unit is further specifically configured to detect the dark field scattering spectrum of the interdigital electrode within the preset wavelength range as the second scattering spectrum after the sample to be tested is added to the reacted interdigital electrode.

5. The photoelectric co-detection specific binding device according to any one of claims 1 to 4, characterized in that: Also included is a voltage unit connected to the interdigital electrodes; The voltage unit is used to output a voltage within a preset frequency range to the interdigital electrodes; The electrical detection unit is specifically used to detect the impedance of the interdigital electrode after the reaction under the voltage in the preset frequency range to obtain the first impedance value; The electrical detection unit is further specifically configured to detect the impedance of the interdigital electrodes under the voltage within the preset frequency range after adding the sample to be tested onto the reacted interdigital electrodes, so as to obtain the second impedance value.

6. The photoelectric co-detection specific binding device according to claim 5, characterized in that: The connection lines between the interdigital electrodes and the voltage unit, and the connection lines between the interdigital electrodes and the electrical detection unit are all micron metal wires.

7. The photoelectric co-detection specific binding device according to claim 1, characterized in that: The electrical detection unit is specifically used for detecting and obtaining the first impedance value after adding bovine serum albumin to the reacted interdigital electrodes, and detecting and obtaining the second impedance value in the same solution after adding the sample to be tested to the interdigital electrodes to which the bovine serum albumin is added.

8. The photoelectric co-detection specific binding device according to claim 1, characterized in that: The interdigital electrode comprises 3 to 60 conductive interdigital fingers arranged in parallel with equal spacing, the spacing between the conductive interdigital fingers is 1 to 50 μm, the width of the conductive interdigital fingers is 2 to 50 μm, the length of the conductive interdigital fingers is 8 mm, the volume of the sample to be tested is 2 μL to 50 μL, and the preset threshold is 1 nF.

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