PCB-based dielectric wetting digital microfluidic system and control method

Abstract

This invention discloses a PCB-based dielectric wetting digital microfluidic system and control method. The system adopts a modular layered architecture, including a main control board, a driver board, and a microfluidic chip card. The main control board integrates a high-voltage boost module and a main control unit, and is connected to the driver board via a flexible connection component. The driver board integrates an independent microcontroller as a drive control unit, a high-voltage drive array, and a magnetic control module, and is pluggably connected to the microfluidic chip card via an edge connector. The microfluidic chip card is fabricated using PCB technology, and a temperature control module is integrated on the back. This system, through its modular three-layer structure design, utilizes low-cost PCB technology to replace expensive photolithography technology, and features low cost, high integration, and strong real-time control, making it suitable for point-of-care testing (POCT) applications.

Description

Technical Field

[0001] This invention relates to the fields of microfluidics and biochemical analysis technology, specifically to a PCB-based dielectric wetting digital microfluidic system and control method. Background Technology

[0002] Digital microfluidics technology, with its advantages of flexible droplet manipulation, low reagent consumption, and high analytical efficiency, has demonstrated significant application value in fields such as point-of-care testing (POCT), biochemical analysis, and nucleic acid detection. The core of this technology is to apply electrical signals to an electrode array, utilizing the dielectric wetting effect to drive, separate, and fuse micro-droplets, thereby completing complex biochemical experimental procedures.

[0003] Currently, microfluidic chips in digital microfluidic systems are mostly fabricated using photolithography to prepare electrode arrays. This process involves multiple steps such as photoresist coating, exposure, and development. Furthermore, microfluidic systems often adopt a single main control unit architecture, where the main control unit must simultaneously undertake multiple tasks such as high-voltage drive control, temperature control algorithm calculation, and human-computer interaction processing. In addition, the magnetic control module and temperature control module are usually designed as external independent devices, used separately from the microfluidic chip.

[0004] However, the high cost of fabricating electrode arrays using photolithography leads to high chip mass production costs. The generation of high-voltage drive signals and the execution of PID temperature control algorithms consume a large amount of computing resources, which can easily cause resource conflicts, resulting in poor temperature control accuracy and droplet drive response delays. This fails to meet the real-time and accuracy requirements of biochemical experiments, and the control architecture lacks real-time performance. Furthermore, the use of external independent devices results in low integration. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a PCB-based dielectric wetting digital microfluidic system and control method, aiming to solve the technical problems of high manufacturing cost, low integration of multiple physical fields, and insufficient real-time control of current digital microfluidic devices.

[0006] To achieve the above objectives, the present invention proposes a PCB-based dielectric wetting digital microfluidic system, which includes a main control component, a driving component disposed on the main control component, and a microfluidic chip component disposed on the driving component.

[0007] The main control component includes a main control board and a main control unit disposed on the main control board;

[0008] The drive assembly includes a drive board connected to the main control board, a drive control unit, a high-voltage drive array, and a magnetic control mechanism disposed on the drive board, wherein the magnetic control mechanism is disposed between the drive board and the main control board;

[0009] The drive board is provided with a connector slot, and the microfluidic chip assembly is movably connected to the connector slot through an edge connector set at the edge. The high-voltage boost module is used to generate the high-voltage signal required to drive the droplet. The magnetic control mechanism is used to generate a controllable magnetic field to penetrate the card body and act on the droplet. The main control unit and the drive control unit are connected through the IIC bus.

[0010] According to one aspect of the above technical solution, the main control component further includes a high-voltage boost module for generating the high-voltage signal required to drive the droplets, a human-machine interaction unit, and a feedback detection module electrically connected to the main control unit.

[0011] The human-computer interaction unit includes a display screen and an audio feedback circuit integrated on the main control board. The main control unit and the high-voltage boost module are connected by an optocoupler and a high-voltage isolation safety device.

[0012] According to one aspect of the above technical solution, the magnetic control mechanism includes a stepper motor fixedly mounted on the drive plate and a magnet connected to the output shaft of the stepper motor. The drive control unit is connected to the drive circuit of the stepper motor through an input / output interface, and the drive control unit controls the stepper motor to drive the magnet to move.

[0013] According to one aspect of the above technical solution, the high voltage boost module includes a DC-DC boost circuit and a high voltage switching circuit. The DC-DC boost circuit is configured to output an adjustable DC high voltage from 50V to 300V, and the high voltage switching circuit is configured to convert the DC high voltage into an AC high voltage with an adjustable frequency.

[0014] The high-voltage drive array includes several high-voltage serial-to-parallel conversion chips, configured to receive control signals and output multiple high-voltage signals in parallel to the microfluidic chip assembly.

[0015] According to one aspect of the above technical solution, the microfluidic chip assembly is covered with a conductive cover plate. The microfluidic chip assembly includes a card plate body, an electrode array and a temperature control mechanism respectively disposed on the upper and lower surfaces of the card plate body, the electrode array being provided with a dielectric layer and a hydrophobic layer, and the conductive cover plate and the electrode array forming a cavity for accommodating droplets.

[0016] According to one aspect of the above technical solution, the temperature control mechanism includes a heating element and a temperature sensor mounted on the card plate body, and the electrical connection lines of the heating element and the temperature sensor are led out to the edge connector and electrically connected to the drive assembly through the connector slot.

[0017] The modular portable digital microfluidic system based on PCB provided in this application utilizes a modular three-layer structure design, replacing expensive photolithography processes with low-cost PCB technology. Specifically, this invention employs a distributed control architecture based on the IIC bus, integrating an independent drive control unit (MCU) on the driver board. This MCU is specifically responsible for PID temperature control calculations and underlying hardware I / O driving, effectively reducing the burden on the main control board and ensuring the real-time performance and accuracy of temperature control. By combining magnetic control with temperature control, multi-physics collaborative operation of droplet driving, precise temperature control, and magnetic bead separation is achieved simultaneously on a single portable device.

[0018] This invention also provides a PCB-based digital microfluidic control method for dielectric wetting, which is used to implement the PCB-based digital microfluidic system for dielectric wetting as described above. The method includes:

[0019] The droplet movement path, preset temperature parameters, and magnetic control timing are obtained to generate a control command sequence containing electrode indexes and status information.

[0020] Based on the control command sequence, the high-voltage boost module is controlled to generate a driving voltage, and the high-voltage driving array is used to activate specific electrodes on the microfluidic chip assembly in a time sequence to drive the droplet to move.

[0021] When the droplet moves into the temperature control area, a write command containing the target temperature value is obtained, the PID algorithm is executed to control the heating power, and real-time temperature data fed back by the drive control unit is periodically obtained;

[0022] When magnetic bead separation is required, a magnetic control register configuration command is sent to drive a stepper motor to move a magnet to the bottom of the microfluidic chip assembly, adsorbing the magnetic beads in the droplets and achieving solid-liquid separation.

[0023] According to one aspect of the above technical solution, the step of controlling the high-voltage boost module to generate a drive voltage based on the control command sequence is as follows:

[0024] The voltage amplitude and frequency parameters in the control command sequence are analyzed, and the duty cycle of the DC-DC boost circuit is adjusted to output the target DC voltage. If the command is AC drive, the high voltage switching circuit is controlled to invert the DC voltage at a preset frequency and output an AC drive signal.

[0025] After outputting the AC drive signal, the impedance or capacitance feedback data of the electrode is collected in real time. Based on the feedback data, it is determined whether the droplet has moved into place. If the droplet has not moved into place, an alarm prompt or an automatic oscillation repair strategy is executed.

[0026] According to one aspect of the above technical solution, in the steps of obtaining a write instruction containing the target temperature value when the droplet moves to the temperature control area, executing a PID algorithm to control the heating power, and periodically obtaining real-time temperature data fed back by the drive control unit, the execution of the PID algorithm to control the heating power is performed by the drive control unit in a local loop:

[0027] Read the real-time analog signal from the temperature sensor and convert it into a real-time temperature value; calculate the deviation between the real-time temperature value and the target temperature value sent by the main control unit.

[0028] Based on the aforementioned deviation, the proportional (P), integral (I), and derivative (D) control quantities are calculated, and a PWM control signal is output to adjust the on / off duty cycle of the heating element.

[0029] The system responds to the main control unit's query request via IIC interrupt or polling mechanism, and sends the current real-time temperature value.

[0030] According to one aspect of the above technical solution, the step of sending a magnetic control register configuration command to drive a stepper motor to move a magnet to the bottom of the microfluidic chip assembly to adsorb the magnetic beads in the droplets and achieve solid-liquid separation when magnetic bead separation is required is as follows:

[0031] The drive control unit receives the IIC magnetic control command, controls the stepper motor to rotate in the forward direction, drives the magnet to rise vertically to the adsorption position, maintains the preset adsorption time, and allows the magnetic field generated by the magnet to penetrate the card plate body and act on the magnetic beads in the droplet.

[0032] The main control unit controls the electrode array to drive the droplet to move along a preset path. The magnetic field's attraction to the magnetic beads is greater than the drag force generated by the droplet's movement, causing the liquid phase in the droplet to leave the magnetic field range, while the solid magnetic beads are retained by the magnetic field.

[0033] The drive control unit receives a release command, controls the stepper motor to rotate in the opposite direction, drives the magnet to descend vertically to the reset position, and removes the magnetic field.

[0034] The PCB-based digital microfluidic control method for dielectric wetting provided in this application enables the digital programming and automated execution of complex biochemical experimental processes (such as "sample addition-lysis-magnetic attraction-elution-amplification") through visual interaction and automated control. In particular, by incorporating distributed control logic, it solves the resource conflict problem of traditional single MCU systems when dealing with high-voltage drive and complex PID calculations, thereby improving the efficiency and accuracy of POCT detection.

[0035] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the PCB-based dielectric wetting digital microfluidic system in Embodiment 1 of the present invention;

[0037] Figure 2 This is a block diagram of the hardware circuit architecture of the microfluidic system in Embodiment 1 of the present invention;

[0038] Figure 3 This is a schematic diagram of the driving component in Embodiment 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of the assembly of the communication interface and the high-voltage drive array in Embodiment 1 of the present invention;

[0040] Figure 5 This is an assembly diagram of the card plate body, electrode array, and edge connector in Embodiment 1 of the present invention;

[0041] Figure 6 This is a schematic diagram of the temperature control mechanism in Embodiment 1 of the present invention;

[0042] Figure 7 This is a schematic diagram of the host computer visual control software interface in Embodiment 1 of the present invention;

[0043] Figure 8 This is a flowchart of the PCB-based digital microfluidic control method for dielectric wetting in Embodiment 2 of the present invention.

[0044] Component symbol explanation in the attached diagram:

[0045] 100. Digital microfluidic system; 10. Main control board; 11. Main control unit; 12. High-voltage boost module; 13. High-voltage isolation safety device; 14. Display screen; 15. Communication interface; 20. Driver board; 21. High-voltage drive array; 22. Magnetic control mechanism; 221. Stepper motor; 222. Magnet; 23. Connector slot; 24. Drive control unit; 30. Cardboard body; 31. Electrode array; 32. Edge connector; 33. Temperature control mechanism; 331. Heating resistor; 332. NTC thermistor; 40. Host computer control terminal. Detailed Implementation

[0046] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0047] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "upper," "lower," and similar expressions used herein are for illustrative purposes only and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0049] Example 1

[0050] Please see Figures 1-7 The diagram shows a schematic of a PCB-based dielectric wetting digital microfluidic system according to Embodiment 1 of the present invention. The PCB-based dielectric wetting digital microfluidic system 100 adopts a three-layer modular stacked structure, including a main control component, a drive component disposed on the main control component, and a microfluidic chip component disposed on the drive component, wherein:

[0051] The main control component includes a main control board 10, a main control unit 11 integrated on the main control board 10, a high-voltage boost module 12 for generating the high-voltage signal required to drive the droplet, a communication interface 15, a human-machine interface unit, and a feedback detection module electrically connected to the main control unit 11. The high-voltage boost module 12 is used to generate the high-voltage signal required to drive the droplet, and the main control unit 11 is used to process system logic and communicate with the host computer. The feedback detection module is electrically connected to the main control unit 11 and is used to detect the impedance or capacitance changes of the electrode array 31 in real time to provide feedback on the position status of the droplet. The main control board 10 is the control core of the system. The main control board 10 integrates the main control unit 11 (e.g., a 32-bit microprocessor, such as STM32 or SAMD series), the high-voltage boost module 12, the high-voltage isolation safety device 13, the display screen 14 (e.g., an OLED screen), and the communication interface 15 (e.g., a USB Type-C interface). The high-voltage isolation safety device 13 is connected between the main control unit 11 and the high-voltage boost module 12 via an optocoupler.

[0052] Furthermore, the human-machine interface unit includes a display screen 14 integrated on the main control board 10 and an audio feedback circuit. A high-voltage isolation safety device 13 is connected between the main control unit 11 and the high-voltage boost module 12 via an optocoupler. The high-voltage boost module 12 includes a DC-DC boost circuit configured to boost the input 5V voltage to an adjustable DC high voltage of 50V~300V, and integrates a full-bridge switching circuit capable of outputting AC high voltage at frequencies up to 1kHz to accommodate reagents with different dielectric constants and prevent electrode polarization. The high-voltage isolation safety device 13 uses an optocoupler to optically isolate the low-voltage logic signals of the main control unit 11 from the high-voltage drive section, preventing high-voltage backflow from damaging the main control chip or the host computer. The display screen 14 is used to display the system status in real time, such as the current voltage value, temperature value, and operating steps. In addition, the main control board 10 can also integrate an audio amplifier and a speaker to provide operational feedback audio effects.

[0053] The driving assembly includes a driving board 20 connected to the main control board 10, a driving control unit 24, a high-voltage driving array 21, and a magnetic control mechanism 22 mounted on the driving board 20. The magnetic control mechanism 22 is located in the area below the microfluidic chip assembly on the driving board 20 and is used to generate a controllable magnetic field that penetrates the card body 30 to act on the droplets. The driving board 20 is connected to the main control board 10 via a flexible connection assembly. The high-voltage driving array 21 is used to distribute high-voltage signals to multiple output channels. The magnetic control mechanism 22 includes a stepper motor 221 fixedly mounted on the driving board 20 and a magnet 222 connected to the output shaft of the stepper motor 221. The driving control unit 24 is connected to the driving circuit of the stepper motor 221 via an input / output interface and controls the stepper motor 221 to drive the magnet 222 to move. The high-voltage driving array 21 includes several high-voltage serial-to-parallel converter chips configured to receive control signals and output multiple high-voltage signals to the microfluidic chip assembly in parallel. The master control unit 11 and the drive control unit 24 are connected via the IIC (Inter-Integrated Circuit) bus to form a master-slave distributed control architecture. The master control unit 11 is configured as the IIC master and sends target control commands. The drive control unit 24 is configured as the IIC slave and receives commands and independently executes the underlying PID temperature control algorithm and hardware port (GPIO) control.

[0054] Furthermore, the driver board 20, as an intermediate layer, is mainly responsible for high voltage distribution, magnetic field control, and execution of the underlying temperature control algorithm. The driver board 20 integrates a high voltage drive array 21, which consists of multiple high voltage serial-to-parallel chips (such as HV507).

[0055] Specifically, the driver board 20 also integrates an independent drive control unit 24 (such as a microcontroller with an Arduino M0 / Zero architecture). This drive control unit 24 communicates with the main control board 10 as an IIC slave, and is responsible for performing real-time PID temperature control calculations, reading sensor data, and controlling the onboard GPIO ports.

[0056] The drive board 20 also integrates a magnetic control mechanism 22. The magnetic control mechanism 22 includes a stepper motor 221 fixed to the back of the drive board 20 and a magnet 222 located on the front of the drive board 20 (below the card body 30). The stepper motor 221 is controlled by the drive control unit 24 (which controls the motor drive chip via GPIO), and can drive the magnet 222 to move up and down in the vertical direction (Z-axis) via the linkage assembly.

[0057] Furthermore, a conductive cover plate covers the microfluidic chip assembly. The microfluidic chip assembly includes a card body 30 fabricated using printed circuit board technology, an electrode array 31 disposed on the front side of the card body 30, and a temperature control mechanism 33 disposed on the back side of the card body 30. The electrode array 31 is provided with a dielectric layer and a hydrophobic layer. The conductive cover plate and the electrode array 31 form a chamber for containing droplets. The card body 30 is a consumable carrier for droplet reaction. The card body 30 is fabricated using standard PCB technology, with a two-dimensional electrode array 31 etched on the front side, and the surface covered with a dielectric layer (such as Parylene) and a hydrophobic layer (such as Teflon).

[0058] Specifically, a temperature control mechanism 33 is integrated on the back of the card body 30. The temperature control mechanism 33 includes a surface mount heating resistor 331 and an NTC thermistor 332 and a temperature sensor mounted on the back of the card body 30. The electrical connection lines of the heating element and the temperature sensor are led out to the edge connector 32 and electrically connected to the drive assembly through the connector slot 23.

[0059] The drive control unit 24 has an independent PID temperature control program running internally. It is configured to directly acquire the real-time analog signal from the temperature sensor and, based on the target temperature command sent by the main control unit 11 via the IIC bus, calculate the control quantity and adjust the pulse width modulation (PWM) signal output to the heating element to achieve closed-loop constant temperature control. The drive control unit 24 is also configured to feed back real-time temperature data to the main control unit 11 via the IIC bus. Specifically, when the card body 30 is inserted into the drive board 20, the temperature control mechanism 33 is connected to the drive board 20 circuit via the edge connector 32. The drive control unit 24 on the drive board 20 acquires the analog signal from the NTC thermistor 332, calculates the control quantity using the built-in PID algorithm, and outputs a PWM signal to adjust the power of the heating resistor 331. The main control board 10 only needs to send the target temperature value (e.g., 95°C) via the IIC bus, and the drive board 20 can automatically maintain this temperature and send the real-time temperature back to the main control board 10 for display. Experimental data show that the system can heat up to 100°C within 5 seconds and stabilize completely within the 1% error band within 8 seconds.

[0060] In addition, the system is equipped with a host computer control terminal 40. This terminal runs visual software developed using Web or Processing languages. The software interface provides an intuitive graphical operation area, allowing users to directly edit the droplet's movement path, set the duration of each frame, configure multiple temperature setpoints, and control the on / off state of the magnetic control mechanism 22 by dragging and dropping with a mouse. The software communicates with the main control board 10 via USB or wirelessly, sending commands in real time and displaying droplet position feedback.

[0061] The modular portable digital microfluidic system based on PCB provided in this application utilizes a modular three-layer structure design, replacing expensive photolithography processes with low-cost PCB technology. Specifically, this invention employs a distributed control architecture based on the IIC bus, integrating an independent drive control unit (MCU) on the driver board. This MCU is specifically responsible for PID temperature control calculations and underlying hardware I / O driving, effectively reducing the burden on the main control board and ensuring the real-time performance and accuracy of temperature control. By combining magnetic control with temperature control, multi-physics collaborative operation of droplet driving, precise temperature control, and magnetic bead separation is achieved simultaneously on a single portable device.

[0062] Example 2

[0063] Please see Figure 8 The figure shows a PCB-based digital microfluidic control method for dielectric wetting provided in Embodiment 2. This PCB-based digital microfluidic control method includes the following steps S01-S04, wherein:

[0064] S01. Obtain the droplet movement path, preset temperature parameters and magnetic control timing, and generate a control command sequence containing electrode index and status information;

[0065] S02. Based on the control command sequence, control the high-voltage boost module to generate a driving voltage, and activate specific electrodes on the microfluidic chip assembly in sequence through the high-voltage driving array to drive the droplet to move.

[0066] S03. When the droplet moves to the temperature control area, a write command containing the target temperature value is obtained, the PID algorithm is executed to control the heating power, and the real-time temperature data fed back by the drive control unit is periodically obtained.

[0067] S04. When magnetic bead separation is required, a magnetic control register configuration instruction is sent to drive the stepper motor to move the magnet to the bottom of the microfluidic chip assembly, adsorbing the magnetic beads in the droplet and realizing solid-liquid separation.

[0068] The user draws the droplet movement path in the host computer software and sets the heating temperature (such as pyrolysis temperature and elution temperature) and the magnet action sequence (such as adsorption time and release time). After obtaining the droplet movement path drawn by the user in the host computer visualization interface, the set temperature parameters, and the magnetocontrol timing, a control command sequence containing electrode indexes and status information is generated. The current driving voltage and temperature values ​​are displayed in real time on the display screen. When the command sequence is received, the operation is completed, or an error occurs, feedback sound effects are emitted through the audio feedback circuit.

[0069] The voltage amplitude and frequency parameters in the control command sequence are analyzed, and the duty cycle of the DC-DC boost circuit is adjusted to output the target DC voltage. If the command is AC drive, the high-voltage switching circuit is controlled to invert the DC voltage at a preset frequency to output an AC drive signal. The main control unit controls the high-voltage boost module to generate the drive voltage. After the drive voltage is generated, the impedance or capacitance feedback data of the electrodes is collected in real time, and specific electrodes on the microfluidic chip assembly are activated sequentially through the high-voltage drive array. The dielectric wetting effect is used to drive the droplet to move. Based on the feedback data, it is determined whether the droplet has moved to the correct position. If the droplet has not moved to the correct position, an alarm prompt or automatic oscillation repair strategy is executed.

[0070] When the droplet moves to the temperature control area, the main control unit sends a write command containing the target temperature value to the drive control unit via the IIC bus. After receiving the command, the drive control unit executes a PID algorithm to control the heating power in a local loop. The main control unit periodically obtains the real-time analog signal from the temperature sensor fed back by the drive control unit via the IIC read command and converts it into a real-time temperature value. It calculates the deviation between the real-time temperature value and the target temperature value issued by the main control unit. Based on the deviation, it calculates the proportional (P), integral (I), and derivative (D) control quantities and outputs a PWM control signal to adjust the on / off duty cycle of the heating element. It responds to the query request from the main control unit through the IIC interrupt or polling mechanism and sends the current real-time temperature value.

[0071] When magnetic bead separation is required, the main control unit sends a magnetic control register configuration command to the drive control unit via the IIC bus. The drive control unit receives the IIC magnetic control command (such as configuring the GPIO register), parses the magnetic control command, and controls the onboard GPIO port to flip, driving the magnet to rise vertically to the adsorption position. The magnet is raised to the bottom of the microfluidic chip assembly, adsorbing the magnetic beads in the droplet. The preset adsorption time is maintained, allowing the magnetic field generated by the magnet to penetrate the card body and act on the magnetic beads in the droplet. The main control unit controls the electrode array to drive the droplet to move along a preset path. The magnetic field's adsorption force on the magnetic beads is greater than the drag force generated by the droplet's movement, causing the liquid phase in the droplet to leave the magnetic field range, while the solid phase magnetic beads are retained by the magnetic field. The drive control unit receives the release command, controls the stepper motor to rotate in the opposite direction, and drives the magnet to descend vertically to the reset position, removing the magnetic field. The magnetic beads are then resuspended in the eluent, completing the separation and liquid replacement process.

[0072] The PCB-based digital microfluidic control method for dielectric wetting provided in this application enables the digital programming and automated execution of complex biochemical experimental processes (such as "sample addition-lysis-magnetic attraction-elution-amplification") through visual interaction and automated control. In particular, by incorporating distributed control logic, it solves the resource conflict problem of traditional single MCU systems when dealing with high-voltage drive and complex PID calculations, thereby improving the efficiency and accuracy of POCT detection.

[0073] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0074] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A PCB-based dielectrophoretic wetting digital microfluidics system, characterized in that, The PCB-based dielectric wetting digital microfluidic system includes a main control component, a driving component disposed on the main control component, and a microfluidic chip component disposed on the driving component. The main control component includes a main control board, a main control unit mounted on the main control board, a high-voltage boost module for generating the high-voltage signal required to drive the droplets, a human-machine interaction unit, and a feedback detection module electrically connected to the main control unit. The human-machine interaction unit includes a display screen and an audio feedback circuit integrated on the main control board. A high-voltage isolation safety device is connected between the main control unit and the high-voltage boost module via an optocoupler. A microfluidic chip assembly is provided, the microfluidic chip assembly is covered with a conductive cover plate, the microfluidic chip assembly includes a card plate body, an electrode array and a temperature control mechanism respectively disposed on the upper and lower surfaces of the card plate body, the electrode array is provided with a dielectric layer and a hydrophobic layer, the conductive cover plate and the electrode array form a cavity for containing droplets, and the card plate body is fabricated using standard PCB process; The drive assembly includes a drive board connected to the main control board, a drive control unit, a high-voltage drive array, and a magnetic control mechanism disposed on the drive board, wherein the magnetic control mechanism is disposed between the drive board and the main control board; The drive board is provided with a connector slot, and the microfluidic chip assembly is movably connected to the connector slot through an edge connector set at the edge. The high-voltage boost module is used to generate the high-voltage signal required to drive the droplet. The magnetic control mechanism is used to generate a controllable magnetic field to penetrate the card body and act on the droplet. The main control unit and the drive control unit are connected through the IIC bus.

2. The PCB-based dielectrowetting digital microfluidics system of claim 1, wherein, The magnetic control mechanism includes a stepper motor fixedly mounted on the drive board and a magnet connected to the output shaft of the stepper motor. The drive control unit is connected to the drive circuit of the stepper motor through an input / output interface, and the drive control unit controls the stepper motor to drive the magnet to move.

3. The PCB-based dielectrowetting digital microfluidics system of claim 2, wherein, The high-voltage boost module includes a DC-DC boost circuit and a high-voltage switching circuit. The DC-DC boost circuit is configured to output an adjustable DC high voltage from 50V to 300V, and the high-voltage switching circuit is configured to convert the DC high voltage into an AC high voltage with an adjustable frequency. The high-voltage drive array includes several high-voltage serial-to-parallel conversion chips, configured to receive control signals and output multiple high-voltage signals in parallel to the microfluidic chip assembly.

4. The PCB-based dielectrowetting digital microfluidics system of claim 1, wherein, The temperature control mechanism includes a heating element and a temperature sensor mounted on the card plate body. The electrical connection lines of the heating element and the temperature sensor are led out to the edge connector and electrically connected to the drive assembly through the connector slot.

5. A PCB-based dielectrophoretic wetting digital microfluidic control method, characterized in that, The PCB-based dielectric wetting digital microfluidic control method is used to implement the PCB-based dielectric wetting digital microfluidic system as described in any one of claims 1-4, the method comprising: The droplet movement path, preset temperature parameters, and magnetic control timing are obtained to generate a control command sequence containing electrode indexes and status information. Based on the control command sequence, the high-voltage boost module is controlled to generate a driving voltage, and the high-voltage driving array is used to activate specific electrodes on the microfluidic chip assembly in a time sequence to drive the droplet to move. When the droplet moves into the temperature control area, a write command containing the target temperature value is obtained, the PID algorithm is executed to control the heating power, and real-time temperature data fed back by the drive control unit is periodically obtained; When magnetic bead separation is required, a magnetic control register configuration command is sent to drive a stepper motor to move a magnet to the bottom of the microfluidic chip assembly, adsorbing the magnetic beads in the droplets and achieving solid-liquid separation.

6. The PCB-based dielectrowetting digital microfluidic control method of claim 5, wherein, The step of controlling the high-voltage boost module to generate the drive voltage based on the control command sequence is as follows: The voltage amplitude and frequency parameters in the control command sequence are analyzed, and the duty cycle of the DC-DC boost circuit is adjusted to output the target DC voltage. If the command is AC drive, the high voltage switching circuit is controlled to invert the DC voltage at a preset frequency and output an AC drive signal. After outputting the AC drive signal, the impedance or capacitance feedback data of the electrode is collected in real time. Based on the feedback data, it is determined whether the droplet has moved into place. If the droplet has not moved into place, an alarm prompt or an automatic oscillation repair strategy is executed.

7. The PCB-based digital microfluidic control method for dielectric wetting according to claim 5, characterized in that, In the steps of obtaining a write instruction containing the target temperature value when the droplet moves to the temperature control area, executing a PID algorithm to control the heating power, and periodically obtaining real-time temperature data fed back by the drive control unit, the execution of the PID algorithm to control the heating power is performed by the drive control unit in a local loop: Read the real-time analog signal from the temperature sensor and convert it into a real-time temperature value; calculate the deviation between the real-time temperature value and the target temperature value sent by the main control unit. Based on the aforementioned deviation, the proportional (P), integral (I), and derivative (D) control quantities are calculated, and a PWM control signal is output to adjust the on / off duty cycle of the heating element. The system responds to the main control unit's query request via IIC interrupt or polling mechanism, and sends the current real-time temperature value.

8. The PCB-based dielectrowetting digital microfluidic control method of claim 5, wherein, When magnetic bead separation is required, a magnetic control register configuration command is sent to drive a stepper motor to move a magnet to the bottom of the microfluidic chip assembly, adsorbing the magnetic beads in the droplets, thus achieving solid-liquid separation. The steps are as follows: The drive control unit receives the IIC magnetic control command, controls the stepper motor to rotate in the forward direction, drives the magnet to rise vertically to the adsorption position, maintains the preset adsorption time, and allows the magnetic field generated by the magnet to penetrate the card plate body and act on the magnetic beads in the droplet. The main control unit controls the electrode array to drive the droplet to move along a preset path. The magnetic field's attraction to the magnetic beads is greater than the drag force generated by the droplet's movement, causing the liquid phase in the droplet to leave the magnetic field range, while the solid magnetic beads are retained by the magnetic field. The drive control unit receives a release command, controls the stepper motor to rotate in the opposite direction, drives the magnet to descend vertically to the reset position, and removes the magnetic field.

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