An electrochemical detection device based on a spin-embedded centrifugal microfluidic chip and a working method thereof

Abstract

The application discloses an electrochemical detection device based on a spin-embedded centrifugal micro-fluidic chip and a working method thereof, which comprises an electrochemical detection chip, an electrode adaptation module, an electrochemical detection module, a driving module and a regulation and control module; a detection cavity is arranged in the chip base body, the inner electrode of the detection electrode is coincided with the bottom of the detection cavity, and the outer electrode is exposed; the contact electrode of the electrode adaptation module is in contact with the outer electrode, and a self-locking indexing pin is arranged at the bottom of the contact electrode; the electrochemical detection module realizes signal conduction between the electrode adaptation module and a detection circuit through an electric slip ring; the motor in the driving module drives the assembly to rotate through a transmission shaft; and the regulation and control module comprises a controller, a communication interface and a display. The electrochemical detection device has a highly integrated design, a stable contact mechanism, can realize rapid and accurate installation and dynamic rotation detection, and has high-precision signal transmission and processing, efficient driving and control functions.

Description

Technical Field

[0001] This invention relates to the field of electrochemical detection technology, and in particular to an electrochemical detection device and its working method based on a spin-embedded centrifugal microfluidic chip. Background Technology

[0002] With the rapid development of microfluidic technology, centrifugal microfluidic chip electrochemical detection devices, due to their advantages of high efficiency, low power consumption, and high integration, have shown broad application prospects in fields such as biomedical point-of-care diagnostics, rapid screening of environmental pollutants, and high-throughput analysis of food safety. Centrifugal microfluidic technology, through a precisely designed centrifugal chip structure combined with the high sensitivity of electrochemical detection methods, can achieve fully automated processing of nanoscale samples, including sample dispensing, reagent mixing, separation and enrichment, reaction, and detection, significantly improving detection efficiency and data reliability. However, existing designs still face the following challenges: (1) Insufficient dynamic detection capability: For example, CN105964314B relies on static electrode alignment after centrifugation stops, which requires precise mechanical control and limits its ability to analyze time-dependent biomarkers.

[0003] (2) Long-term stability defects: For example, CN212748794U simplifies installation with mechanical springs, but the components are numerous and prone to aging, causing positional deviations after long-term use.

[0004] (3) System complexity and high cost: For example, the integrated system of CN111982985A supports multi-data fusion, but relies on a high-power central processor and a multi-module collaborative architecture.

[0005] In addition, centrifugal microfluidic electrochemical detection technology is generally limited to a stepwise mode of "centrifugation-driven-static detection", which cannot capture the dynamic changes of the reaction in real time during the rotation process, making it difficult to meet the requirements of efficiency and data comprehensiveness for instant detection and high-throughput screening. Summary of the Invention

[0006] To address the problems of insufficient dynamic detection capability, long-term stability defects, and system complexity in existing centrifugal microfluidic electrochemical detection devices, this invention provides an electrochemical detection device and its working method based on a spin-embedded centrifugal microfluidic chip, which can achieve rapid and accurate positioning and dynamic rotation detection.

[0007] Specifically, the technical solution adopted in this invention is as follows: An electrochemical detection device based on a spin-embedded centrifugal microfluidic chip includes an electrochemical detection chip, an electrode adapter module, an electrochemical detection module, and a driving module. The electrochemical detection chip includes a chip substrate and a detection electrode located below the chip substrate. The chip substrate has at least one detection cavity. The detection electrode has at least one set of interconnected inner and outer electrodes. The detection area of ​​the inner electrode coincides with the bottom surface of the detection cavity. The outer electrode is exposed on the outside of the chip substrate. The upper surface of the detection electrode is tightly bonded to the bottom surface of the chip substrate. The electrode adapter module includes a fixing shell, which has a top opening. At least one slot is connected to the inner surface of the side wall of the fixing shell. The slot has an opening on its left or right side. A contact electrode is embedded in the inner wall of the top surface of the slot. A positioning hole is provided on the bottom surface of the slot, located directly below the contact electrode. A self-locking indexing pin for improving the tightness of the fit between the outer electrode and the contact electrode is installed in the positioning hole. The electrochemical detection chip is placed in the cavity of the fixing shell. When the electrochemical detection chip is not locked to the fixing shell, it can rotate to adjust its angle. When the outer electrode of the electrochemical detection chip is screwed into the slot and the chip is locked to the fixing shell, the outer electrode and the contact electrode are tightly fitted. The electrochemical detection module includes an electric slip ring and an electrochemical detection circuit; the electric slip ring is located below the fixed shell and is electrically connected to the fixed shell. The drive module includes a motor, which drives the chip substrate, detection electrodes, fixing shell and slip ring to rotate via a transmission shaft.

[0008] The chip substrate and the detection electrode each have a central through hole. The bottom surface of the fixing shell has a central through hole. A spring is installed in the through hole on the bottom surface of the fixing shell. The bottom of the spring contacts the fixing shell, and the top of the spring contacts the bottom surface of the electrochemical detection chip. The drive shaft passes through the spring.

[0009] The electrochemical detection circuit integrates a potentiostat, a signal generation circuit, a signal acquisition circuit, and a signal processing circuit; the signal acquisition circuit is electrically connected to the slip ring.

[0010] It also includes a control module, which includes a controller, a communication interface, and an interactive interface, the interactive interface being displayed on a monitor; the controller includes a motor driver and a microprocessor.

[0011] The chip substrate is made of materials such as polymethyl methacrylate, polydimethylsiloxane, or glass and has a microstructure design on the bottom surface. After being bonded to the detection electrode, it forms structures such as chambers, microchannels, and valves. The shape of the structure is determined by the sample to be tested and the functional requirements.

[0012] The number of detection cavities is the same as the number of inner electrodes, outer electrodes, contact electrodes, and self-locking indexing pins to ensure mutual cooperation.

[0013] The detection electrode is a two-electrode, three-electrode, or four-electrode system. The electrode material is a metal, carbon material, or semiconductor material. The electrode is fabricated by methods such as screen printing, vacuum evaporation, ion sputtering, or molecular beam epitaxy. The detection electrode and the contact electrode are matched in shape and can stably transmit electrical signals under close contact conditions.

[0014] The detection cavity of the chip substrate is matched with the inner electrode of the detection electrode, the bottom surface of the chip substrate is tightly bonded to the electrode surface of the detection electrode, and the detection cavity completely covers the inner electrode area of ​​the detection electrode.

[0015] The outer electrode, contact electrode, and self-locking indexing pin of the detection electrode are located on the same vertical axis, and the three are tightly fitted together in the locked state.

[0016] The contact electrode and the outer electrode of the detection electrode are coupled. When the electrochemical detection chip is inserted, the spring is pressed and the outer electrode is rotated into the slot where the contact electrode is located. After the spring is stopped, the electrochemical detection chip moves upward under the pressure of the spring, so that the contact electrode and the outer electrode fit together.

[0017] The self-locking indexing pin can be manually adjusted in height. In the unlocked state, the top of the self-locking indexing pin is not in contact with the bottom of the outer electrode. Manually rotating the bottom of the self-locking indexing pin clockwise by 90° will lock it in place. The top of the self-locking indexing pin will apply an upward force to the bottom of the outer electrode, making the top of the outer electrode fit tightly with the contact electrode. Therefore, in the high-speed rotation state, the electrochemical detection chip and the electrochemical detection module can achieve stable electrical signal transmission through the electrode adapter module.

[0018] The slip ring includes a rotor and a stator. The circuit of the rotor is connected to the electrode adapter module, and the circuit of the stator is connected to the electrochemical detection circuit, thereby achieving stable electrical signal communication between the rotating part and the stationary part.

[0019] The drive shaft and the slip ring are fixed with bolts and connected by lateral clamping force, which facilitates quick installation, replacement and regular maintenance. The fit between the drive shaft and the fixed housing and the electrochemical detection chip is arbitrary and can be interference fit, key connection, expansion sleeve connection, etc.

[0020] The rated speed of the motor is 4000 r / min, the rated torque is 0.48 Nm, and the relative error of the speed detected by the Hall sensor is ≤1%.

[0021] The electrochemical detection circuit integrates a potentiostat, a signal generation circuit, a signal acquisition circuit, and a signal processing circuit, and supports multiple electrochemical detection modes such as cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry.

[0022] The potentiostat can be adjusted to a potential range of ±5V with an accuracy of ±1mV, a current measurement range of ±1nA to ±100mA, and a scanning speed range of 0.1mV / s to 1V / s.

[0023] The signal generation circuit can output various excitation signals such as square waves, sine waves, and stepped waves, with a frequency range of 0.1Hz to 100kHz and a voltage amplitude of ±5V.

[0024] The sampling rate of the signal acquisition circuit is no less than 100kHz, and it supports 24-bit analog-to-digital conversion.

[0025] The signal processing circuit includes a low-pass filter and a programmable gain amplifier, which can capture current signals of 1nA-100mA to meet the requirements of rapid detection.

[0026] The control module serves as the core control hub of the entire device. It controls the operation of the motor and electrochemical detection circuit through the communication interface and controller, and displays parameters and receives instructions through the interactive interface to flexibly set the detection mode and detection parameters.

[0027] The communication interface is divided into a motor communication interface and an electrochemical detection circuit communication interface. The motor communication interface adopts the RS485 differential bus protocol with a baud rate of 9600. Through twisted-pair shielded cable and impedance matching terminal design, it ensures stable anti-electromagnetic interference capability when the motor rotates at high speed. The electrochemical detection circuit communication interface adopts the USB3.0 SuperSpeed ​​protocol with an actual transmission rate of ≥400Mbps and supports plug-and-play function and batch transmission mode.

[0028] The controller can adjust the motor speed and running time, with a speed adjustment range of ±4000 rpm and an adjustment accuracy of ±1 rpm. It can also set the detection method, detection time, scan rate and other related parameters of the electrochemical detection circuit.

[0029] The interactive interface of the display screen supports multi-touch operation, and can set parameters and display and save the motor running status and electrochemical detection results in real time, making it convenient for users.

[0030] The entire device is equipped with a housing.

[0031] The working method of the electrochemical detection device based on the spin-embedded centrifugal microfluidic chip of this invention is as follows: Align the central through hole of the electrochemical detection chip with the axis of the drive shaft to ensure that the chip is placed horizontally; press the electrochemical detection chip downward to compress the spring to its maximum stroke and maintain the pressed state; rotate the electrochemical detection chip to embed the outer electrode into the slot where the contact electrode is located; slowly release, the spring rebound pushes the electrochemical detection chip upward, and the outer electrode and the contact electrode initially adhere; manually rotate the self-locking indexing pin, the top of the self-locking indexing pin applies vertical upward pressure to the outer electrode to ensure tight adhesion; open the interactive interface, set the running process, perform electrochemical detection, after the detection is completed, rotate the self-locking indexing pin again to release the locking state, press, rotate and remove the electrochemical detection chip.

[0032] Compared with the prior art, the outstanding effect of the present invention is as follows: (1) The electrochemical detection device based on the spin-embedded centrifugal microfluidic chip of the present invention uses the coordinated design of fixed shell and electric slip ring to realize the synchronous coupling of centrifugal force drive and electrochemical detection, breaking through the traditional step detection mode of "centrifugal drive-static detection"; the axial displacement self-compensation mechanism constructed by spring and self-locking indexing pin suppresses the radial runout of electrochemical detection chip, improves positioning accuracy and ensures stable signal transmission during detection; the high integration of detection module, control module and interactive interface simplifies the structure, reduces cost, and displays the running status and detection results in real time, which is convenient for operation and adjustment.

[0033] (2) The device of the present invention realizes real-time electrochemical detection during centrifugation by synchronous signal transmission between rotation drive and electric slip ring; the combination of spin-embedded installation and electrode elastic adaptation means that during installation, only the rotating chip needs to be pressed and the self-locking indexing pin needs to be manually locked, which is simple to operate and reduces damage to the electrode; the embedded layout improves the system integration and portability, supports the full automation of "sample loading-detection-analysis", and is suitable for various real-time application scenarios such as precision medicine, environmental monitoring and food safety.

[0034] The electrochemical detection device and its working method based on a spin-embedded centrifugal microfluidic chip described in this invention will be further explained below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0035] Figure 1 This is an exploded view of the internal structure of an electrochemical detection device based on a spin-embedded centrifugal microfluidic chip.

[0036] Figure 2 This is a schematic diagram of the connection of an electrochemical detection device based on a spin-embedded centrifugal microfluidic chip.

[0037] Figure 3 This is a cross-sectional view of the internal structure of an electrochemical detection device based on a spin-embedded centrifugal microfluidic chip.

[0038] Figure 4 This is a schematic diagram of an electrochemical detection chip.

[0039] Figure 5 This is a schematic diagram of the fixed shell.

[0040] Figure 6 This is a schematic diagram of an electrochemical detection device based on a spin-embedded centrifugal microfluidic chip.

[0041] Figure 7 The results are from the potassium ferricyanide concentration dilution experiment.

[0042] Among them, 1-chip substrate, 101-detection cavity; 2-detection electrode, 201-inner electrode, 202-outer electrode; 3-fixed shell, 301-positioning hole, 302-contact electrode, 303-fixed outer shell, 304-slot; 4-self-locking indexing pin; 5-spring; 6-drive shaft; 7-electric slip ring; 8-motor; 9-electrochemical detection circuit; 10-control module; 11-device shell; 12-display. Detailed Implementation

[0043] like Figure 1-6 As shown, an electrochemical detection device based on a spin-embedded centrifugal microfluidic chip includes an electrochemical detection chip, an electrode adapter module, an electrochemical detection module, and a drive module.

[0044] The electrochemical detection chip includes a chip substrate 1 and a detection electrode 2 located below the chip substrate 1. Four detection cavities 101 are evenly distributed along the circumferential direction inside the chip substrate 1. Four sets of interconnected inner electrodes 201 and outer electrodes 202 are evenly distributed in the detection electrode 2. The detection areas of the four inner electrodes 201 coincide with the bottom surfaces of the four detection cavities 101. The outer electrodes 202 are exposed on the outside of the chip substrate 1. The upper surface of the detection electrode 2 is tightly bonded to the bottom surface of the chip substrate 1.

[0045] The electrode adapter module includes a fixing shell 3, which comprises a top-opening fixing outer shell 303. Four slots 304 are connected to the inner surface of the side wall of the fixing shell 303. The left or right side of each slot 304 is open. A contact electrode 302 is embedded in the inner wall of the top surface of each slot 304. A positioning hole 301 is provided on the bottom surface of each slot 304, located directly below the contact electrode 302. A self-locking indexing pin 4 for fixing the contact electrode 302 is installed inside the positioning hole 301. When the electrochemical detection chip is not locked to the fixing shell 3, the electrochemical detection chip can be rotated to adjust its angle. When the outer electrode 202 of the electrochemical detection chip is screwed into the slot 304 and locked to the fixing shell 3, the outer electrode 202 and the contact electrode 302 are tightly fitted. The top edge of the fixing shell 3 can be rounded to avoid sharp right angles or edges, reducing damage caused by collisions or scratches during use.

[0046] The electrochemical detection module includes an electric slip ring 7 and an electrochemical detection circuit 9; the electric slip ring 7 is located below the fixed shell 3 and is electrically connected to the fixed shell 3.

[0047] The drive module includes a motor 8, which drives the chip substrate 1, detection electrode 2, fixing shell 3 and slip ring 7 to rotate via a transmission shaft 6.

[0048] Both the chip substrate 1 and the detection electrode 2 have a central through hole. The bottom surface of the fixing shell 3 has a through hole. A spring 5 is installed in the through hole on the bottom surface of the fixing shell 3. The bottom of the spring 5 contacts the fixing shell 3, and the top of the spring 5 contacts the bottom surface of the electrochemical detection chip. The drive shaft 6 passes through the spring 5.

[0049] The electrochemical detection circuit 9 integrates a potentiostat, a signal generation circuit, a signal acquisition circuit, and a signal processing circuit; the signal acquisition circuit is electrically connected to the slip ring 7.

[0050] It also includes a control module 10, which includes a controller, a communication interface and a display 12; the controller includes a motor driver and a microprocessor.

[0051] The chip substrate 1 is made of materials such as polymethyl methacrylate, polydimethylsiloxane or glass, and has a microstructure design on the bottom surface.

[0052] The detection electrode 2 is shaped to match the contact electrode 302, enabling stable transmission of electrical signals under tight contact conditions. The detection electrode 2 is a two-, three-, or four-electrode system, and the electrode material is a metal, carbon material, or semiconductor material, etc. The electrode is fabricated using methods such as screen printing, vacuum evaporation, ion sputtering, or molecular beam epitaxy.

[0053] The electrochemical detection chip is formed by bonding a chip substrate 1 with a microstructure design and a detection electrode 2. During the bonding process, the detection cavity 101 is aligned with the inner electrode 201 of the detection electrode. After bonding, the bottom surface of the chip substrate 1 is tightly bonded to the electrode surface of the detection electrode 2, forming structures such as chambers, microchannels, and valves.

[0054] The number of detection cavities 101 in the electrochemical detection chip is the same as the number of inner electrodes 201, outer electrodes 202, contact electrodes 302, and self-locking indexing pins 4. The contact electrode 302 cooperates with the outer electrode 202 of the detection electrode. When the electrochemical detection chip is inserted, the spring 5 is pressed firmly and the outer electrode 202 is rotated into the slot 304 where the contact electrode 302 is located. After the spring 5 is stopped, the electrochemical detection chip moves upward under the pressure of the spring 5, so that the contact electrode 302 and the outer electrode 202 fit together.

[0055] The self-locking indexing pin 4 can be manually adjusted in height. In the unlocked state, the top of the self-locking indexing pin is not in contact with the bottom of the outer electrode 202. Manually rotating the self-locking indexing pin will lock it in place. The top of the self-locking indexing pin will apply an upward force to the bottom of the outer electrode 202, making the top of the outer electrode 202 fit tightly with the contact electrode 302. Therefore, even under high-speed rotation, the electrochemical detection chip and the electrochemical detection module can still achieve stable electrical signal transmission through the electrode adapter module.

[0056] The slip ring 7 includes a rotor and a stator. The circuitry of the rotor is connected to the electrode adapter module, and the circuitry of the stator is connected to the electrochemical detection circuit. The drive shaft and the slip ring are fixed together by bolts, and the connection is achieved through lateral clamping force, which facilitates quick installation, replacement, and regular maintenance. The fit between the drive shaft, the fixed housing, and the electrochemical detection chip is arbitrary and can be an interference fit, a key connection, an expansion sleeve connection, etc.

[0057] The motor has a rated speed of 4000 rpm and a rated torque of 0.48 Nm. The relative error of the Hall sensor in detecting the speed is ≤1%.

[0058] The electrochemical detection circuit integrates a potentiostat, signal generation circuit, signal acquisition circuit, and signal processing circuit, enabling various electrochemical detection modes such as cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry. The potentiostat is adjustable within a potential range of ±5V with an accuracy of ±1mV, measures currents from ±1nA to ±100mA, and has a scan speed range of 0.1mV / s to 1V / s. The signal generation circuit can output various excitation signals, including square waves, sine waves, and stepped waves, with a frequency range of 0.1Hz to 100kHz and a voltage amplitude of ±5V. The signal acquisition circuit has a sampling rate of at least 100kHz and supports 24-bit analog-to-digital conversion. The signal processing circuit includes a low-pass filter and a programmable gain amplifier, capable of capturing current signals from 1nA to 100mA to meet rapid detection requirements.

[0059] The control module, as the core control hub of the entire device, regulates the operation of the motor and electrochemical detection circuit through the communication interface and controller. It displays parameters and receives instructions through the interactive interface to flexibly set detection modes and parameters.

[0060] The communication interface is divided into a motor communication interface and an electrochemical detection circuit communication interface. The motor communication interface adopts the RS485 differential bus protocol with a baud rate of 9600. It uses twisted-pair shielded cable and impedance matching terminal design to ensure stable electromagnetic interference resistance when the motor is rotating at high speed. The electrochemical detection circuit communication interface adopts the USB3.0 SuperSpeed ​​protocol with an actual transmission rate of ≥400Mbps and supports plug-and-play function and batch transmission mode.

[0061] The controller can adjust the motor speed and running time, with a speed adjustment range of ±4000 rpm and an adjustment accuracy of ±1 rpm. It can also set the detection method, detection time, scan rate and other related parameters of the electrochemical detection circuit.

[0062] The interactive interface of display screen 12 supports multi-touch operation, and can set parameters and display and save the motor running status and electrochemical detection results in real time, making it convenient for users.

[0063] The entire device is equipped with a housing 11.

[0064] The working method of this electrochemical detection device is as follows: Align the central through hole of the electrochemical detection chip with the axis of the drive shaft to ensure that the chip is placed horizontally. Press the electrochemical detection chip downward to compress the spring to its maximum stroke and maintain the pressed state. Rotate the electrochemical detection chip to embed the outer electrode into the slot where the contact electrode is located. Slowly release the spring, and the spring rebound will push the electrochemical detection chip upward, and the outer electrode and the contact electrode will initially fit together. Manually rotate the self-locking indexing pin, and the top of the self-locking indexing pin will apply vertical upward pressure to the outer electrode to ensure a tight fit. Open the interactive interface, set the running process, and perform electrochemical detection. After the detection is completed, rotate the self-locking indexing pin counterclockwise to release the locking state, press and rotate, and remove the electrochemical detection chip.

[0065] Its working principle is as follows: the sample is injected into the electrochemical detection chip through the sample application port. The motor in the drive module drives the electrochemical detection chip, electrode adapter module and electric slip ring to rotate through the transmission shaft. Under the action of centrifugal force, the sample flows along the microstructure and enters the detection chamber to complete the reagent mixing and reaction. At the same time, the electrochemical detection module collects the electrical signal on the inner electrode in real time through the electrode adapter module and electric slip ring. After the signal is processed by the potentiostat, signal generation circuit and signal acquisition circuit, it is transmitted to the control module for data analysis and result display.

[0066] Application Example (Potassium Ferricyanide Concentration Dilution Experiment)

[0067] The purpose of this experiment is to use a centrifugal microfluidic chip to dilute a 100 mM potassium ferricyanide solution and to use this device to determine the concentration of potassium ferricyanide solutions of different concentrations after dilution by differential pulse voltammetry.

[0068] 1. Fabrication of electrochemical detection chip (1) Chip substrate fabrication: The chip structure mold was designed using Solidworks 3D software and saved as an STL file; the file was imported into a high-precision photopolymerization 3D printer, and after SLA resin was placed in it, the mold was printed layer by layer; after printing, the mold was placed in a 75% alcohol solution, ultrasonically cleaned for 10 minutes, dried and then placed in a UV curing chamber for 10 minutes, and placed in a 60℃ oven for 12 hours to ensure complete curing. Then, transparent tape was wrapped around the edges; the PDMS prepolymer and curing agent were mixed in a 10:1 ratio and stirred evenly. The mixture was slowly poured into the mold to ensure complete filling of the microstructure on the surface of the mold. After vacuum degassing for 30 minutes, the micro air bubbles were removed; the mold and the mixture were placed in a 60℃ oven to dry for 12 hours to ensure complete curing of PDMS. After cooling, the PDMS chip substrate was carefully peeled off and the integrity of the microchannels was checked.

[0069] (2) Fabrication of detection electrodes: Electrodes are fabricated on polymethyl methacrylate substrates using screen printing. First, conductive silver paste is printed on the polymethyl methacrylate substrate to form electrode strips, which are then cured in an oven at 70°C for 30 minutes. Next, conductive carbon paste is printed to form working electrodes and auxiliary counter electrodes, which are then cured in an oven at 70°C for 20 minutes. Finally, silver / silver chloride reference electrodes are printed and cured at room temperature for 12 hours.

[0070] (3) Bonding of chip substrate and detection electrode: After cleaning the chip substrate and detection electrode surface with anhydrous ethanol, apply UV curing agent to the chip substrate with a thickness of 5-10 μm, taking care to avoid microstructures to prevent blockage; attach the detection electrode to the chip substrate precisely at the preset position and angle, and irradiate with UV lamp for 15 min to allow the adhesive layer to fully cure, ensuring stable bonding strength between the chip substrate and the detection electrode.

[0071] 2. Instrument preparation and testing (1) Detection preparation: Place the electrochemical detection chip into the detection device and align its central through hole with the axis of the drive shaft to ensure that the chip is placed horizontally. Press down on the electrochemical detection chip to compress the spring to the maximum stroke and keep pressing. Rotate the electrochemical detection chip to embed the outer electrode into the groove where the contact electrode is located. Slowly release the pressure. The spring rebounds and pushes the electrochemical detection chip upward. The outer electrode and the contact electrode are initially in contact. Rotate the bottom of the self-locking indexing pin clockwise by 90° to make its top pop out and apply vertical upward pressure to the outer electrode to ensure that the outer electrode and the contact electrode are in close contact. After installation, use a pipette to add 0.5 ml of 100 mmol / L potassium ferricyanide solution from the sample addition port and add 1 ml of 0.1 mol / L potassium chloride solution from the diluent addition port.

[0072] (2) Detection process: Open the interactive interface, check that the communication is normal, and set the running process and detection parameters; the running process is to run at 1000 rpm for 3 minutes, then at 2500 rpm for 3 minutes, so that the potassium ferricyanide solution and potassium chloride solution enter the quantitative chamber to achieve quantification, and then run at 3500 rpm for 5 minutes, so that the potassium ferricyanide solution and potassium chloride solution in the quantitative chamber enter the detection chamber and mix thoroughly; the detection parameters are set as differential pulse voltammetry, initial potential -0.2V, termination potential 0.4V, potential increment 0.004V, pulse amplitude 0.05V, pulse width 0.05s, sampling width 0.016s, pulse period 0.5s, rest time 2s, and sensitivity 1e-4 / V; click start running, and the interface displays the real-time running speed curve of the motor and the detection result curve; after the run ends, save the results (e.g. Figure 7 Rotate the self-locking indexing pin counterclockwise 90° to release the locking state, press and rotate to remove the electrochemical detection chip.

[0073] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An electrochemical detection device based on a spin-embedded centrifugal microfluidic chip, characterized in that: It includes an electrochemical detection chip, an electrode adapter module, an electrochemical detection module, and a drive module; The electrochemical detection chip includes a chip substrate (1) and a detection electrode (2) located below the chip substrate (1). The chip substrate (1) has at least one detection cavity (101). The detection electrode (2) has at least one set of interconnected inner electrodes (201) and outer electrodes (202). The detection area of ​​the inner electrode (201) coincides with the bottom surface of the detection cavity (101). The outer electrode (202) is exposed on the outside of the chip substrate (1). The upper surface of the detection electrode (2) is tightly bonded to the bottom surface of the chip substrate (1). The electrode adapter module includes a fixing shell (3), which includes a fixing outer shell (303) with a top opening. At least one slot (304) is connected to the inner surface of the side wall of the fixing outer shell (303). The left or right side of the slot (304) is open. A contact electrode (302) is embedded in the inner wall of the top surface of the slot (304). A positioning hole (301) is provided on the bottom surface of the slot (304). The positioning hole (301) is located directly below the contact electrode (302). The positioning hole (301) is equipped with a self-locking indexing pin (4) for improving the tightness of the fit between the outer electrode (202) and the contact electrode (302); the electrochemical detection chip is placed in the cavity of the fixing shell (3). When the electrochemical detection chip is not locked to the fixing shell (3), the electrochemical detection chip can be rotated to adjust the angle; when the outer electrode (202) of the electrochemical detection chip is screwed into the slot (304) and the electrochemical detection chip is locked to the fixing shell (3), the outer electrode (202) and the contact electrode (302) are tightly fitted. The chip substrate (1) and the detection electrode (2) are both provided with a central through hole. The bottom surface of the fixing shell (3) is provided with a through hole. A spring (5) is provided in the through hole on the bottom surface of the fixing shell (3). The bottom of the spring (5) is in contact with the fixing shell (3), and the top of the spring (5) is in contact with the bottom surface of the electrochemical detection chip. The electrochemical detection module includes an electric slip ring (7) and an electrochemical detection circuit (9); the electric slip ring (7) is located below the fixed shell (3) and is electrically connected to the fixed shell (3); The drive module includes a motor (8), which drives the chip substrate (1), detection electrode (2), fixed shell (3) and electric slip ring (7) to rotate via a transmission shaft (6). The transmission shaft (6) passes through a spring (5).

2. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: The electrochemical detection circuit (9) integrates a potentiostat, a signal generation circuit, a signal acquisition circuit, and a signal processing circuit; the signal acquisition circuit is electrically connected to the slip ring (7).

3. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: It also includes a control module (10), which includes a controller, a communication interface and a display (12); the controller includes a motor driver and a microprocessor.

4. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: The electrochemical detection chip is formed by bonding a chip substrate (1) with a microstructure design and a detection electrode (2), which together form a chamber, a microchannel, and a valve structure. The number of detection chambers (101) of the electrochemical detection chip is the same as the number of inner electrodes (201), outer electrodes (202), contact electrodes (302), and self-locking indexing pins (4).

5. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: The chip substrate is made of polymethyl methacrylate, polydimethylsiloxane, or glass.

6. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: The detection electrode is a two-electrode, three-electrode, or four-electrode system. The electrode material is a metal, carbon material, or semiconductor material. The electrode fabrication method is screen printing, vacuum evaporation, ion sputtering, or molecular beam epitaxy.

7. The electrochemical detection device based on a spin-embedded centrifugal microfluidic chip according to claim 1, characterized in that: The slip ring (7) includes a rotor and a stator. The circuit of the rotor is connected to the electrode adapter module, and the circuit of the stator is connected to the electrochemical detection circuit.

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