Preparation and detection method of a microfluidic chip based on bubble array for electrochemical detection

Abstract

The application belongs to the technical field of electrochemical detection, and particularly relates to a preparation and detection method of an electrochemical detection microfluidic chip based on a bubble array. The preparation method comprises the following steps: designing a three-dimensional structure diagram of a top layer structure, a middle layer structure and a bubble capturing structure mold, wherein the top layer structure and the middle layer structure both comprise a connected solution inlet and a solution outlet, the middle layer structure comprises a detection chamber, and the detection chamber is connected with the solution inlet and the solution outlet through a straight channel; using polymethyl methacrylate as a material to process the top layer structure and the middle layer structure; using polydimethylsiloxane and the bubble capturing structure mold to prepare the bubble capturing structure; and assembling the microchip, wherein the top layer structure and the middle layer structure are sequentially arranged from top to bottom, and the bubble capturing structure is fixed on the top layer structure and covers the detection chamber. The technical scheme can simplify the microchip preparation process and improve the electrochemical detection performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochemical detection, and particularly relates to a preparation and detection method of an electrochemical detection microfluidic chip based on a bubble array. BACKGROUND

[0002] Electrochemical sensors have attracted more and more attention in the field of biochemical sensing detection due to their high sensitivity, simple device and low cost. In particular, the method of combining them with transition metal and its composite nanomaterials can greatly improve the sensing and detection performance of electrochemical electrodes by utilizing the large specific surface area and large number of metal active sites of transition metal nanomaterials, and has a wide application prospect in the field of biochemical detection. Further integrating electrochemical electrodes with microfluidic platforms to build small-sized electrochemical detection devices shows great application potential in the field of point-of-care testing (POCT). However, the flow of fluid at a microscale is laminar, which is not conducive to the mass transfer of substances to the surface of the electrochemical electrode, hindering the performance improvement of such sensing platforms.

[0003] In order to improve the electrochemical detection performance in the chip, those skilled in the art introduce microstructures capable of generating turbulent flow into the chip structure design to enhance the contact between the measured substances in the solution and the electrode surface. Such structures often involve complex processing techniques and require continuous fluid sampling to generate turbulent flow by regulating the flow rate of the fluid.

[0004] The method based on acoustic waves can provide a non-contact and more flexible control means for the mass transfer and diffusion of substances in the channel. There is an electrochemical detection device based on surface acoustic waves on the market, which can be used to enhance the response current of electrochemistry in detection, but serious heating problems occur during the detection process, which has a serious impact on the biochemical sensing detection results, and the substrate processing based on lithium niobate interdigital microstructure is required for the surface acoustic wave generation component part, which has a complex processing technology. The electrochemical detection microfluidic chip based on ultrasonic waves can also be used to improve the detection performance of electrochemistry, but it involves the manufacture of a complex ultrasonic wave component, which is expensive, and also produces serious heating problems during the detection process, which affects the properties of biochemical molecules and thus affects the detection results. SUMMARY

[0005] The purpose of the present application is to provide a preparation and detection method of an electrochemical detection microfluidic chip based on bulk acoustic wave enhancement, which can simplify the microchip preparation process and improve the electrochemical detection performance.

[0006] To achieve the above object, in a first aspect, the disclosure provides a method for preparing an electrochemical detection microfluidic chip based on a bubble array, comprising: designing a three-dimensional structure diagram of a top layer structure, a middle layer structure and a bubble capture structure mold, the top layer structure and the middle layer structure both comprising a communicating solution inlet and a solution outlet, the middle layer structure comprising a detection chamber, the detection chamber being connected with the solution inlet and the solution outlet through a straight channel respectively; using polymethyl methacrylate as a material to process the top layer structure and the middle layer structure; using polydimethylsiloxane and the bubble capture structure mold to prepare the bubble capture structure; assembling the microchip, the top layer structure and the middle layer structure being sequentially arranged from top to bottom, the bubble capture structure being fixed on the top layer structure and covering the detection chamber.

[0007] As a preferred embodiment, the method further comprises designing a substrate structure, the substrate structure being provided with a clamping groove for mounting an electrochemical electrode; the electrochemical electrode comprising a working electrode, a counter electrode and a reference electrode; an area of the detection chamber covering at least a working area of the three electrodes in the electrochemical electrode; and using polymethyl methacrylate as a material to process the substrate structure.

[0008] As a preferred embodiment, a nanomaterial is modified on the working electrode as a catalyst, the nanomaterial being a transition metal-based nanomaterial, which is modified on the working electrode of a screen-printed electrode by means of dropwise addition and air drying to obtain a screen-printed electrode modified with the nanomaterial; the electrochemical electrode is mounted into the clamping groove and connected with an electrochemical workstation.

[0009] As a preferred embodiment, the top layer structure, the middle layer structure and the substrate structure all comprise a plurality of screw holes, and the top layer structure, the middle layer structure and the substrate structure are detachably connected through the screw holes.

[0010] As a preferred embodiment, the method for preparing the bubble capture structure comprises the following steps:

[0011] According to the designed bubble capture structure mold, a 3D printer is used for printing; and a mold post-processing is performed; and polydimethylsiloxane and the bubble capture structure mold are used to prepare the bubble capture structure.

[0012] As a preferred embodiment, the mold post-processing comprises the following steps:

[0013] The printed mold is cleaned in ethanol and subjected to ultraviolet light curing for 1 hour; the processed mold is cleaned in a plasma cleaning machine for 180 seconds; and a release agent is spin-coated on the surface of the mold by using a spin coater, so that the surface of the mold is silanized.

[0014] As a preferred embodiment, the bubble capture structure is prepared by using polydimethylsiloxane and the bubble capture structure mold, comprising the following steps:

[0015] The polydimethylsiloxane prepolymer and the curing agent are mixed at a ratio of 1:10, degassed in a vacuum chamber, then poured into a mold, placed in an oven for 45 minutes, and then taken out; the cured polydimethylsiloxane bubble trapping structure layer is peeled off from the mold and stored for use.

[0016] As an implementable preferred solution, the microfluidic chip is assembled, including installing the piezoelectric transducer, specifically as follows:

[0017] The piezoelectric transducer is bonded to the top layer structure, and the electrodes of the piezoelectric transducer are electrically connected to the voltage amplifier and the signal generator; and the signal quality on the entire link from the signal generator output to the input end of the piezoelectric transducer is checked.

[0018] As an implementable preferred solution, the solution enters the detection chamber; the bubbles are also captured into the bubble trapping structure to form a micro-bubble array; after the solution fills the detection chamber, the acoustic field excitation is loaded; the electrochemical workstation connected with the electrochemical electrode is turned on, and the electrochemical detection is started; the electrochemical detection method is differential pulse voltammetry.

[0019] As an implementable preferred solution, the acoustic field excitation is loaded, specifically including:

[0020] The signal generator and the voltage amplifier are used to generate an acoustic field signal; the signal is loaded onto the piezoelectric transducer to make it oscillate, causing the micro-bubble array attached below it to oscillate and generate micro-flow, and the signal is one of a sine wave, a square wave or a triangular wave, the loading frequency range is 1 kHz-20 kHz, and the loading voltage range is 40 Vpp-100 Vpp.

[0021] Advantages of the scheme: in the technical solution, the microchip is arranged as multiple independent structures, each structure can be used repeatedly and replaced according to actual needs, reducing the use cost. The bubble trapping structure is also an independent structure and can be used repeatedly, avoiding repeated preparation, and can also be flexibly disassembled and replaced according to actual needs, without the need to replace the entire structure of the microchip, reducing the use cost. At the same time, the entire chip preparation process is very simple, reducing the difficulty of electrochemical detection and improving the detection efficiency.

[0022] In the technical solution, the micro flow channels such as the solution inlet, the solution outlet and the detection chamber have hydrophilicity, the bubble capturing structure has hydrophobicity, the solution can easily enter the detection chamber from the solution inlet and fill the detection chamber, the bubble capturing structure can capture and discharge the bubbles in the solution, the bubbles are prevented from interfering with the liquid flow, the solution is more likely to fill the entire detection chamber, the contact between the to-be-detected substance and the electrode surface is enhanced, and a micro pump does not need to be connected to continuously sample. Due to this characteristic, the volume of the detection chamber can also be designed to be smaller, the sample solution can be added dropwise through the solution inlet to fill the detection chamber, and the detection complexity is reduced. Meanwhile, because an additional ultrasonic assembly does not need to be used, compared with an existing surface acoustic wave electrochemical microfluidic chip, the temperature rise is small (less than 3 DEG C) during the detection process, and a serious temperature rise problem can also be avoided.

[0023] In addition, the synergistic effect of the mass transfer enhancement effect based on the acoustic flow and the excellent electrocatalytic activity of the nano material modified on the electrode also plays an important role in improving the electrochemical detection performance.

[0024] In addition, the acoustic field generated by the piezoelectric transducer is mild, and continuous sampling flow is not needed, the continuous sampling flow of the fluid can be prevented from washing away the modified material, the nano material modified on the electrode is not affected, and therefore the stability of the detection signal is ensured.

[0025] In addition, the top layer structure and the middle layer structure use polymethyl methacrylate as the material, the material has excellent optical performance, the user can directly observe the experimental process inside the chip, and the experimental process is convenient to observe and control. Meanwhile, the polymethyl methacrylate also has good chemical stability and can resist the erosion of various chemical reagents. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a logic diagram of a preparation method of the electrochemical detection microfluidic chip based on the bubble array;

[0027] Figure 2 It is a schematic diagram of the bubble capturing structure;

[0028] Figure 3 It is a three-dimensional exploded view of the electrochemical detection microfluidic chip based on the bubble array;

[0029] Figure 4 It is a logic diagram of an electrochemical detection method based on the bubble array;

[0030] Figure 5 It is a response curve of detection of 30 muM dopamine by differential pulse voltammetry (DPV) in different states;

[0031] Figure 6Temperature change in the chip within the DPV detection time of 120s for loading the sound field signal;

[0032] Figure 7 10 mu M dopamine DPV response curve diagram before and after the sound wave loading;

[0033] Figure 8 The structural schematic diagram of the electronic equipment of the embodiment of the application. DETAILED DESCRIPTION

[0034] In order to make the technical solutions of the present application and their advantages clearer, the technical solutions of the present application will be further described in detail below with reference to the drawings. It can be understood that the specific embodiments described herein are only part of the embodiments of the present application, and are only used to explain the present application, but not to limit the present application. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, and they can be combined with each other to achieve better technical effects. The same reference numerals appearing in the drawings of the following embodiments represent the same features or components, which can be applied to different embodiments.

[0035] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the general meanings understood by the general technical personnel in the field to which the present application belongs.

[0036] In addition, it should be noted that in the description of the present application, the terms "first", "first", "second" and the like are only used for differentiation and description, and cannot be understood as indicating or implying relative importance.

[0037] The present application will be further described in detail below with reference to the drawings:

[0038] Legend: piezoelectric transducer 100, top layer structure 200, first solution inlet 201, first solution outlet 202, first screw hole 203, bubble trapping structure 204, first through hole 205, middle layer structure 300, second solution inlet 301, second solution outlet 302, second screw hole 303, detection chamber 304, substrate 400, third screw hole 401, electrochemical electrode 402, clamping groove 403, electronic equipment 500, processor 501, communication interface 502, memory 503, bus 504.

[0039] Reference Figure 1 A method for preparing an electrochemical detection microfluidic chip based on a bubble array, comprising:

[0040] Step S100, design the three-dimensional structure diagram of the top layer structure 200, the middle layer structure 300, the substrate structure 400 and the bubble trapping structure 204 mold, specifically including:

[0041] Step S101, design the bubble trapping structure 204 mold, refer to Figure 2 The bubble trapping structure 204 includes an array of several cylindrical micro-pits, and in this embodiment, the interval between the micro-pits is 1 mm, and the number is 51. The diameter of a single bubble trapping structure can be 0.1 mm-5 mm. The number of pits can be determined according to the size of the detection chamber, the diameter of a single bubble trapping structure, and the arrangement, and the number of pits can be 1-100.

[0042] In another embodiment, the arrangement of the bubbles can also be optimized, and a mixed arrangement of bubbles with different diameters can be used to improve the mass transfer of substances in the chip by using the different acoustic streaming intensities of bubbles with different diameters.

[0043] Step S103, design the top layer structure 200, including the first through hole 205, the first solution inlet 201 and the first solution outlet 202, the size of the first through hole 205 matches the size of the bubble trapping structure 204, and is used to fix the bubble trapping structure. The first solution inlet and the first solution outlet are respectively arranged on both sides of the first through hole. It also includes a plurality of first screw holes for assembling the chip, and the first screw holes are symmetrically arranged around the first through hole. In this embodiment, the number of first screw holes is 4, which are symmetrically arranged around the first through hole. The top layer structure is made of polymethyl methacrylate.

[0044] Step S104, design the middle layer structure 300, the middle layer structure 300 is a micro-channel layer, refer to Figure 5 , including a plurality of second screw holes 303, the number and size of the second screw holes 303 are the same as those of the first screw holes 203, and the positions of the second screw holes 303 correspond to those of the first screw holes 203. It also includes a second solution inlet 301 and a second solution outlet 302, the position of the second solution inlet 301 corresponds to that of the first solution inlet 201, and the position of the second solution outlet 302 corresponds to that of the first solution outlet 202. It also includes a detection chamber 304, which corresponds to the position of the through hole 205 of the top layer structure 200. The detection chamber 304 is connected to the second solution inlet 301 and the second solution outlet 302 through two straight passages, and the area of the detection chamber 304 covers at least the working area of three electrodes in the electrochemical electrode 402. The detection chamber 304 is preferably elliptical, and in this embodiment, the major axis of the detection chamber 304 is 10 mm, and the minor axis is 9 mm. The length of the two straight passages is 5 mm, and the width is 1 mm. The depth of the micro-channel of the entire middle layer structure 300 is 500 μm.

[0045] Step S105, design the substrate structure 400, refer to Figure 6, including several third screw holes 401, the number and size of the third screw holes 401 are the same as the second screw holes 303, and the positions of the third screw holes 401 correspond to the second screw holes 303. It also includes a clamping groove 403 for installing and fixing the electrochemical electrode 402. In this embodiment, the length of the clamping groove 403 is 16mm, and the width is 6mm.

[0046] Step S200, according to the designed top layer structure 200, middle layer structure 300 and substrate structure 400, using polymethyl methacrylate as the material, using numerical control machine tool for processing.

[0047] Step S300, preparing the bubble trapping structure 204, specifically including:

[0048] Step S301, according to the designed bubble trapping structure 204 mold, using 3D printer to print with light curing resin.

[0049] Step S302, after printing, mold post-processing, specifically including:

[0050] Step S301-1, clean the printed mold in ethanol, and perform ultraviolet curing for 1 hour, preferably 355nm light source (80Wcm -2 ).

[0051] Step S302-2, place the treated mold in the plasma cleaning machine and clean for 180s.

[0052] Step S302-3, use the spin coater to spin the release agent on the surface of the mold, and silanize the surface of the mold.

[0053] Step S303, using polydimethylsiloxane (PDMS) and bubble trapping structure 204 mold to make bubble trapping structure 204, specifically including:

[0054] Step S303-1, mix the PDMS prepolymer and the curing agent in a ratio of 1:10, and place them in a vacuum chamber for degassing. Then pour them into the mold, and put them into the oven for curing for 45 minutes.

[0055] Step S303-2, use tweezers to peel off the cured PDMS bubble trapping structure 204 layer from the mold, and store it for later use.

[0056] Step S400, assemble the microchip, refer to Figure 3 , from top to bottom in order, top layer 200, middle layer 300 and substrate 400, specifically including:

[0057] Step S401, fix the bubble trapping structure 204 to the through hole 205 of the top layer 200, to ensure that it can cover the detection chamber 304.

[0058] Step S402, install an electrochemical electrode 402, the electrochemical electrode 402 is a screen-printed electrode. The screen-printed electrode is a three-electrode system, the working electrode is carbon, the counter electrode is carbon, and the reference electrode is Ag / AgCl. A nanomaterial is modified on the working electrode to improve the performance of the electrochemical electrode 402. In the technical solution, the electrochemical electrode 402 is independent, facilitating electrode disassembly, and facilitating users to modify the working electrode with a nanomaterial outside the chip according to needs, and then assembling and using with the chip, thereby expanding the application range of the device. Specifically, it includes:

[0059] Step S402-1: The nanomaterial can be any nanomaterial, preferably a transition metal-based nanomaterial. In the embodiment, a nickel phosphide nanomaterial is prepared, a 5mg / mL nickel phosphide solution is prepared with isopropanol, and the nickel phosphide solution and Nafion solution are mixed at a ratio of 9:1.

[0060] Step S402-2, 4 microliters of the nickel phosphide solution are sucked by a pipette and dropped onto the working electrode, and then naturally air-dried to obtain a nickel phosphide modified screen-printed electrode.

[0061] Step S402-3, install the electrochemical electrode 402 into the clamping groove 403 of the substrate structure 400, and connect the electrochemical workstation.

[0062] Step S403, install the piezoelectric transducer 100 on the top layer structure 200. In the embodiment, the piezoelectric transducer 100 is a buzzer composed of a metal sheet and a piezoelectric ceramic sheet. The metal sheet can be a brass sheet, an iron sheet or a steel sheet, and the working frequency of the piezoelectric transducer 100 is ensured to be within the acoustic wave range. The piezoelectric transducer 100 is adhered to the top layer structure 200 by strong glue. At the same time, the electrodes of the piezoelectric transducer 100 are electrically connected with the voltage amplifier and the voltage generator. After the connection is completed, a signal measuring instrument such as an oscilloscope can be used to check the signal quality on the entire link from the voltage generator output to the input end of the piezoelectric transducer 100, to confirm whether the signal waveform is correct and has no obvious distortion, and whether the amplified voltage reaches the expected level.

[0063] Step S404, align the first screw hole 103, the first screw hole 203, the second screw hole 303 and the third screw hole 401, and fix them by bolts.

[0064] The technical solution combines the micro-flow effect of the bubbles with the electrocatalytic properties of the nanomaterial, significantly improving the sensitivity of the electrochemical detection and reducing the detection lower limit of the target.

[0065] Reference Figure 4 An electrochemical detection method based on a bubble array, comprising:

[0066] Step S500, use the pipette to add the test solution from the solution inlet, and in this embodiment, the amount added is 30 μL. Since the detection chamber 304 is made of PMMA material, it has hydrophilicity, and the solution will automatically enter the detection chamber 304.

[0067] Step S600, while the solution is filling the detection chamber 304, the bubble capturing structure 204 has hydrophobicity, and the bubbles are also automatically captured into the bubble capturing structure 204 to form a micro-bubble array.

[0068] Step S700, after the solution fills the detection chamber 304, the sound field excitation is loaded, specifically including:

[0069] Step S701, use the signal generator and voltage amplifier to generate a sound field signal.

[0070] Step S702, load the signal onto the piezoelectric transducer 100 to make it oscillate, causing the micro-bubble array attached below it to oscillate, generating micro-flow, enhancing the contact of the test substance with the electrode surface, and the signal can be a sine wave, a square wave or a triangular wave. In this embodiment, the signal is a sine wave. The frequency range of the loaded signal is 1 kHz-20 kHz, and the optimal frequency range is related to the bubble size. The voltage range of the loaded signal is 40 Vpp-100 Vpp, and the preferred voltage is 80 Vpp.

[0071] Step S800, turn on the electrochemical workstation connected to the electrochemical electrode 402 to start the electrochemical detection. The electrochemical detection method is preferably differential pulse voltammetry (DPV).

[0072] A 30 μM dopamine solution prepared with a phosphate buffer solution is used as the test solution for the electrochemical measurement.

[0073] 30 μL of the test solution is added to the detection chamber in the chip using a pipette. The test solution will automatically fill the detection chamber due to the hydrophilicity of the detection chamber, and the bubbles will also be automatically captured into the bubble capturing structure due to the hydrophobicity of the bubble capturing structure, forming a micro-bubble array.

[0074] When the working electrode surface of the screen-printed electrode is modified with nickel phosphide nanocomposite, the loading frequency is 13 kHz, and the loading voltage is 80 Vpp. The detection results for 30 μM dopamine are shown in Figure 4 The results show that the current response of the constructed electrochemical detection chip for dopamine is significantly improved with the assistance of the sound field compared with the case without the sound field.

[0075] The temperature change of the chip within 120 s of DPV detection under the loading frequency of 13 kHz and the loading voltage of 80 Vpp sound field signal is collected by an infrared camera, and the temperature change of the chip within 120 s of DPV detection under the loading frequency of 13 kHz and the loading voltage of 80 Vpp sound field signal is obtained. Figure 6For the temperature change value extracted from the infrared camera, the results show that the temperature rise is less than 3℃ during the whole detection process.

[0076] After loading the 13 kHz, 80 Vpp acoustic field signal for 30 minutes, stop, then 10 μM dopamine DPV detection, the results are shown in Figure 7 The results show that compared with the DPV response signal before loading the acoustic field, the difference is negligible, indicating that the microflow caused by the loaded acoustic wave does not affect the modified nanomaterial on the electrode surface.

[0077] The embodiments of the present disclosure also provide a storage medium, wherein the storage medium stores a computer program, and the computer program is executed by a processor to realize all steps of the above-mentioned electrochemical detection method based on a bubble array.

[0078] Those skilled in the art can understand that all or part of the process of implementing an electrochemical detection method based on a bubble array can be completed by a computer program instructing related hardware, and the program can be stored in a non-volatile computer readable storage medium. When the program is executed, it can include the processes of each embodiment of the electrochemical detection method based on a bubble array. Any reference to memory, storage, database or other medium used in each embodiment provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM) and the like.

[0079] The embodiments of the present application also provide an electronic device, which includes a memory, a processor and a computer program stored in the memory and executable on the processor. The processor executes the program to realize the steps of the electrochemical detection method based on a bubble array in any of the above-mentioned embodiments. In the embodiments of the present application, the processor is the control center of the computer system, which can be the processor of a physical machine or the processor of a virtual machine.

[0080] Reference is made to Figure 8The electronic device 500 comprises at least one processor 501, at least one communication interface 502, at least one memory 503 and at least one bus 504. The bus 504 is used to realize the connection communication between the components, the communication interface 502 is used to communicate with other node devices, and the memory 503 stores machine readable instructions executable by the processor 501. When the electronic device 500 runs, the processor 501 communicates with the memory 503 through the bus 504, and the machine readable instructions are executed by the processor 501 to perform the steps of the above-mentioned any one embodiment of the electrochemical detection method based on the bubble array.

[0081] The above is only an embodiment of the present application, and the common knowledge of specific structures and characteristics in the scheme is not described in detail. The ordinary skilled person in the art knows all the ordinary technical knowledge in the field of the present application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply conventional experimental means before that date. The ordinary skilled person in the art can improve and implement the present scheme based on the disclosure given in the present application, and some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be noted that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be considered as the protection scope of the present application, and these will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode in the specification can be used to explain the content of the claims.

Claims

1. A method for preparing a bubble array-based electrochemical detection microfluidic chip, characterized in that: The application relates to a microfluidic chip and a preparation method thereof. A three-dimensional structure diagram of a top layer structure, a middle layer structure and a bubble capturing structure mold is designed, the top layer structure and the middle layer structure both comprise a solution inlet and a solution outlet which are communicated, the middle layer structure comprises a detection chamber which is connected with the solution inlet and the solution outlet through straight channels respectively; polymethyl methacrylate is used as a material to process the top layer structure and the middle layer structure; polydimethylsiloxane and the bubble capturing structure mold are used to prepare the bubble capturing structure; the microfluidic chip is assembled, and the top layer structure and the middle layer structure are sequentially arranged from top to bottom, the bubble capturing structure is fixed on the top layer structure and covers the detection chamber, and the bubble capturing structure is an independent structure which can be detached and replaced; The application further relates to a substrate structure which is provided with a clamping groove for mounting an electrochemical electrode; the electrochemical electrode comprises a working electrode, a counter electrode and a reference electrode; the area of the detection chamber covers at least the working area of the three electrodes in the electrochemical electrode; and polymethyl methacrylate is used as a material to process the substrate structure; Nano materials are modified on the working electrode as catalysts, the nano materials are transition metal-based nano materials, and the nano materials are modified on the working electrode of a screen-printed electrode in a manner of dropwise adding and air drying to obtain a screen-printed electrode modified with the nano materials; The electrochemical electrode is mounted into the clamping groove and connected with an electrochemical workstation; The top layer structure, the middle layer structure and the substrate structure all comprise a plurality of screw holes, and the top layer structure, the middle layer structure and the substrate structure are detachably connected through the screw holes; The microfluidic chip is assembled, and a piezoelectric transducer is mounted, and the specific steps are as follows: The piezoelectric transducer is bonded to the top layer structure, the electrode of the piezoelectric transducer is electrically connected with a voltage amplifier and a signal generator, and the signal quality of the entire link from the signal generator to the input end of the piezoelectric transducer is checked.

2. The method for preparing a bubble array-based electrochemical detection microfluidic chip according to claim 1, characterized in that: The bubble capturing structure is prepared, and the specific steps are as follows: The bubble capturing structure mold is designed, a 3D printer is used for printing, and mold post-processing is conducted; and the bubble capturing structure is prepared by using polydimethylsiloxane and the bubble capturing structure mold.

3. The method of claim 2, wherein the method further comprises: The mold post-processing comprises the following steps: The printed mold is cleaned in ethanol and subjected to ultraviolet light curing for 1 hour; The processed mold is cleaned in a plasma cleaning machine for 180 seconds; A release agent is spin-coated on the surface of the mold by using a spin coater to silanize the surface of the mold.

4. The method of claim 1, wherein the method further comprises: The bubble capturing structure is prepared by using polydimethylsiloxane and the bubble capturing structure mold, and the specific steps are as follows: Polydimethylsiloxane prepolymer and a curing agent are mixed at a ratio of 1:10, and then placed in a vacuum chamber for degassing; then the mixture is poured into the mold, placed in an oven for curing for 45 minutes, and then taken out; and the cured polydimethylsiloxane bubble capturing structure layer is peeled off from the mold and stored for use.

5. A method for electrochemical detection based on bubble array, using a microfluidic chip prepared by the method for preparing a microfluidic chip for electrochemical detection based on bubble array according to any one of claims 1-4, characterized in that: The sample liquid is added from the solution inlet by using a pipette gun; the solution enters the detection chamber; and bubbles are also captured into the bubble capturing structure to form a micro-bubble array; After the detection chamber is filled with the solution, a sound field is loaded for excitation; the electrochemical workstation connected with the electrochemical electrode is turned on to start electrochemical detection; and the electrochemical detection method is differential pulse voltammetry.

6. The method of claim 5, wherein: Load sound field excitation, specifically includes: Use signal generator and voltage amplifier to generate sound field signal; load the signal to the piezoelectric transducer to make it oscillate, cause the microbubble array attached below it to oscillate, produce microflow, the signal is one of sine wave, square wave or triangle wave, the frequency range of loading is 1kHz-20kHz, and the voltage range of loading is 40Vpp-100Vpp.

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