Addressable droplet impedance measurement digital microfluidic system and droplet measurement and control circuit

Abstract

This invention provides an addressable digital microfluidic system for droplet impedance measurement and a droplet measurement and control circuit. The droplet measurement and control circuit includes an impedance detection subcircuit, a droplet driving subcircuit, a mode switching subcircuit, and a main control chip. The impedance detection subcircuit is connected to a first electrode of the digital microfluidic chip through the mode switching subcircuit. The droplet driving subcircuit is connected to multiple second electrodes of the digital microfluidic chip through the mode switching subcircuit. The mode switching subcircuit is electrically connected to the main control chip. The main control chip sends a switching command to the mode switching subcircuit to switch the mode switching subcircuit between an impedance measurement state and a droplet driving state. This allows for simultaneous impedance detection and droplet control, and improves the accuracy of droplet impedance detection in the digital microfluidic chip.

Description

Technical Field

[0001] This invention relates to the field of digital microfluidics, and in particular to an addressable digital microfluidic system for measuring droplet impedance and a droplet measurement and control circuit. Background Technology

[0002] Digital microfluidics (DMF) is a novel technology that uses electric and electrostatic forces to precisely drive and control discrete droplets. It offers advantages such as miniaturization, high efficiency, automation, and ease of integration, and is widely used in various fields including biology, chemical analysis, medical testing, immunoassay, and optical devices. For example, it can be applied to cell culture and analysis, protein sample processing and analysis, nucleic acid detection, glucose concentration detection, and the fabrication of microlenses with adjustable focal lengths based on droplet shape.

[0003] Digital microfluidics can not only prepare, move, separate, and mix droplets to be tested, but also drive two sample reagents to conduct reaction experiments. That is, a single droplet to be tested is used as a micro-container, and the two reagents are driven to react in it, thereby reducing the amount of sample used, reducing the reaction time of the experiment, and achieving the goal of saving costs.

[0004] The driving and control methods for the droplets to be detected in digital microfluidic chips include pneumatic methods, surface acoustic wave methods, and dielectric wetting methods. Among them, dielectric wetting methods have the advantages of simple structure and easy control.

[0005] like Figure 1 , 3 As shown, when using the dielectric wetting method, the corresponding digital microfluidic chip has a pair of electrodes placed parallel to each other at a certain distance. Electrode A includes a substrate 1, an electrode layer 11 and a hydrophobic layer 12, and electrode B includes a hydrophobic layer 21, a dielectric layer 22, an electrode layer 23 and a substrate 24.

[0006] The essential circuit property between the two plates of a digital microfluidic chip is capacitance. Based on the structure of the digital microfluidic chip, an equivalent circuit model of a droplet located between the two plates can be established. See details... Figure 2 Z drop Part of it is the equivalent circuit formed by the droplet to be detected and the digital microfluidic chip, where C htd It is the equivalent capacitance of the hydrophobic layer of plate B, C hbd R is the equivalent capacitance of the hydrophobic layer and the dielectric layer of plate A. d With C d The parallel circuit is the equivalent circuit of the droplet to be detected, and it is related to the physicochemical properties of the droplet, including conductivity, dielectric constant, volume, temperature, pH value, and salt concentration, etc. aIt is the distance between the plates, and also the height of the droplet to be detected, d ht and d hb These refer to the insulation layer thickness of the two electrodes of the digital flow control chip. In practical applications, the theoretical calculation formula for the droplet impedance on the electrodes can be derived, providing a theoretical basis for impedance detection. Electrode-related parameters include d... a C htd C hbd Since the impedance signal between the plates can be considered fixed, the measured impedance signal and its changes can be used to detect the physicochemical properties of the droplets, thereby enabling the development of various biochemical detection methods based on droplet properties and their changes that are integrated into digital microfluidic chips.

[0007] To achieve impedance detection of droplets in digital microfluidics, the electrode of plate A in the digital microfluidic chip is usually used as the interface for the excitation signal, and the electrode of plate B is used as the interface for the measurement of the response signal. The driving voltage of the droplet to be detected is also used as the excitation signal for impedance detection. The response signal is converted from current to voltage at the measurement interface using a resistor. The problems with this configuration method include: (1) Since droplet control requires a high driving voltage (usually 60 V to 300 V), a boost circuit is required. The excitation signal generated by the boost circuit is difficult to reach a high frequency. Therefore, it is difficult to collect high-frequency characteristic information when measuring droplet impedance; (2) The voltage output obtained by the boost circuit has low accuracy and high noise, which makes it difficult to guarantee the accuracy and repeatability of impedance measurement; (3) The dielectric layer and hydrophobic layer of the digital microfluidic chip may be broken down during use, which will cause the resistance between the plates to drop significantly, resulting in the risk of high voltage directly acting on the measurement circuit and causing it to be damaged; (4) The measurement circuit based on resistor voltage division has the problem of low input impedance. The circuit itself will affect the signal to be measured, thus having a large error.

[0008] In summary, traditional impedance measurement methods and circuit systems in digital microfluidics are difficult to achieve high measurement accuracy and have many problems in practical applications. They are only suitable for qualitative applications with low sensitivity requirements, such as whether a droplet is in place, and are not suitable for quantitative analysis with high precision requirements, such as the physicochemical properties of droplets. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the problems of low measurement accuracy, poor repeatability, low detection frequency and circuit complexity of the impedance detection circuit of the prior art digital microfluidics when performing droplet impedance detection, and to provide a digital microfluidic system with addressable droplet impedance measurement.

[0010] The present invention solves the above-mentioned technical problems through the following technical solution:

[0011] In a first aspect, a droplet measurement and control circuit for a digital microfluidic chip is provided, the droplet measurement and control circuit comprising an impedance detection sub-circuit, a droplet driving sub-circuit, a mode switching sub-circuit, and a main control chip;

[0012] The impedance detection subcircuit is connected to the first electrode included in the digital microfluidic chip through the mode switching subcircuit, the droplet driving subcircuit is connected to the multiple second electrodes included in the digital microfluidic chip through the mode switching subcircuit, and the mode switching subcircuit is electrically connected to the main control chip.

[0013] The main control chip is used to send switching commands to the mode switching sub-circuit, so that the mode switching sub-circuit switches between impedance measurement state and droplet driving state.

[0014] When in the impedance measurement state, the first electrode is connected to the impedance detection sub-circuit through the mode switching sub-circuit, and the first target electrode among the plurality of second electrodes is grounded through the mode switching sub-circuit; the impedance detection sub-circuit is used to output an excitation signal to the first electrode and acquire the response signal generated by the excitation signal between the first electrode and the first target electrode;

[0015] When in the droplet-driven state, the first electrode is grounded through the mode switching sub-circuit, and the second target electrode among the plurality of second electrodes is connected to the droplet-driven sub-circuit through the mode switching sub-circuit; the droplet-driven sub-circuit is used to output a driving signal to the second target electrode to drive the sample to be tested in the digital microfluidic chip to move.

[0016] Optionally, the impedance detection subcircuit includes a transimpedance amplifier and a signal processor; the mode switching subcircuit includes a first switch;

[0017] The positive input terminal of the transimpedance amplifier is connected to the output terminal of the signal processor, the negative input terminal of the transimpedance amplifier is connected to the first terminal of the first switch, and the output terminal of the transimpedance amplifier is connected to the input terminal of the signal processor.

[0018] The second terminal of the first switch is grounded, and the third terminal of the first switch is connected to the first electrode; when in the impedance measurement state, the third terminal is connected to the first terminal; when in the droplet driving state, the third terminal is connected to the second terminal.

[0019] Optionally, the impedance detection subcircuit further includes a calibration component; the calibration component is connected to the fourth terminal of the first switch;

[0020] When in the droplet-driven state, the first end is connected to the fourth end.

[0021] Optionally, the calibration component includes a resistor and a plurality of capacitors, wherein the resistor and a portion of the plurality of capacitors are connected in parallel and then connected in series with the remaining capacitors; the calibration component has a standard impedance.

[0022] Optionally, the droplet driving sub-circuit includes a driving signal generator; the mode switching sub-circuit includes a plurality of second switches, the first end of the second switch is used to connect to a second electrode, the second end of the second switch is connected to the driving signal generator, and the third end of the second switch is grounded;

[0023] When in the impedance measurement state, the first terminal of the second switch connected to the first target electrode is connected to the third terminal;

[0024] When in the droplet-driven state, the first end of the second switch connected to the second target electrode is connected to the second end.

[0025] Optionally, the drive signal generator includes a boost circuit and a high-speed optocoupler switch connected to the boost circuit;

[0026] The boost circuit is used to convert the input voltage into a target voltage, and output the target voltage to the second electrode through the high-speed optocoupler switch; wherein the amplitude of the target voltage ranges from [50V, 300V], and the frequency ranges from [1Hz, 10kHz].

[0027] Optionally, the main control chip includes a communication component, through which the main control chip communicates with external devices.

[0028] In a second aspect, an addressable digital microfluidic system for measuring droplet impedance is provided, the digital microfluidic system comprising a digital microfluidic chip and a droplet measurement and control circuit as described in any of the above claims;

[0029] The droplet measurement and control circuit is connected to the digital microfluidic chip.

[0030] Optionally, the digital microfluidic chip includes a first electrode plate and a second electrode plate disposed parallel to the first electrode plate;

[0031] The first electrode plate includes a first substrate, a first electrode, and a first hydrophobic layer disposed sequentially.

[0032] The second electrode plate includes a second hydrophobic layer, a dielectric layer, a second electrode, and a second substrate arranged sequentially.

[0033] There is a gap between the first hydrophobic layer and the second hydrophobic layer, which is used to accommodate the sample to be tested.

[0034] Optionally, both the first substrate and the second substrate are made of a first insulating material, the dielectric layer is made of a second insulating material, the insulation of the second insulating material is higher than that of the first insulating material, and both the first hydrophobic layer and the second hydrophobic layer are made of hydrophobic materials.

[0035] The positive and progressive effects of the present invention are as follows: the droplet measurement and control circuit of the present invention can simultaneously realize impedance detection and droplet control, and improves the accuracy of droplet impedance detection in digital microfluidic chips. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a digital microfluidic chip in the prior art.

[0037] Figure 2 This is a schematic diagram of the electrode equivalent circuit of a digital microfluidic chip in the prior art.

[0038] Figure 3 This is a schematic diagram of the structure of a digital microfluidic system with addressable droplet impedance measurement in the prior art.

[0039] Figure 4 This is a schematic diagram of the structure of a droplet measurement and control circuit of a digital microfluidic chip provided in an embodiment of the present invention.

[0040] Figure 5 The circuit diagram of an addressable droplet impedance measurement digital microfluidic system provided in an embodiment of the present invention.

[0041] Figure 6 This invention relates to a digital microfluidic system with addressable droplet impedance measurement. The data curves and linear fitting results obtained by measuring the impedance of pure water droplets of different volumes using an excitation signal of 400 mV and 30 kHz with a 1.6 mm electrode spacing are described. Detailed Implementation

[0042] The present invention will be described more clearly and completely below with reference to a preferred embodiment and the accompanying drawings.

[0043] This invention provides a droplet measurement and control circuit for a digital microfluidic chip. This circuit can simultaneously achieve impedance detection and motion control of droplets in the digital microfluidic chip, and improves the accuracy of droplet impedance detection in the digital microfluidic chip. The sample to be tested is encapsulated in an oil phase or an aqueous phase to form a droplet. The sample to be tested may include, but is not limited to, DNA and RNA.

[0044] See Figure 4 and Figure 5The droplet measurement and control circuit includes an impedance detection sub-circuit 11, a droplet driving sub-circuit 12, a main control chip 13, and a mode switching sub-circuit 14. The impedance detection sub-circuit 11 is connected to a first electrode included in the digital microfluidic chip through the mode switching sub-circuit 14. The droplet driving sub-circuit 12 is connected to multiple second electrodes included in the digital microfluidic chip through the mode switching sub-circuit 14. The mode switching sub-circuit 14 is electrically connected to the main control chip 13.

[0045] See Figure 5 The digital microfluidic chip includes a pair of parallel electrodes, a first electrode A and a second electrode B, with a certain distance between them, allowing a droplet to move within this distance. The first electrode A includes a first substrate, a first electrode, and a first hydrophobic layer arranged sequentially. The second electrode B includes a second hydrophobic layer, a dielectric layer, a second electrode, and a second substrate arranged sequentially. There can be multiple second electrodes, and the number of first electrodes can be one or more. The area formed by the vertical projection of the first electrode onto the second electrode B coincides with the second electrode area of ​​the second electrode on the second electrode B.

[0046] The droplet measurement and control circuit provided by this invention includes two operating states: impedance measurement state and droplet driving state. The main control chip 13 sends a switching command to the mode switching sub-circuit 14, causing the mode switching sub-circuit 14 to switch between the impedance measurement state and the droplet driving state, thus switching the droplet measurement and control circuit between the two states. In addition to controlling mode switching, the main control chip 13 can also participate in controlling impedance measurement, controlling droplet movement, and data communication.

[0047] When in droplet-driven state, the first electrode is grounded through mode switching sub-circuit 14, and the second target electrode among the multiple second electrodes is connected to the droplet-driven sub-circuit 12 through mode switching sub-circuit 14; the droplet-driven sub-circuit 12 is used to output a driving signal to the second target electrode to drive the movement of the sample under test in the digital microfluidic chip.

[0048] The second target electrode is different at different times. The second target electrode is determined according to the target running path of the droplet. There can be one or more second target electrodes.

[0049] When in impedance measurement state, the first electrode is connected to the impedance detection sub-circuit 11 through the mode switching sub-circuit 14, and the first target electrode among the multiple second electrodes is grounded through the mode switching sub-circuit 14; the impedance detection sub-circuit 11 is used to output the excitation signal to the first electrode and acquire the response signal generated by the excitation signal between the first electrode and the first target electrode.

[0050] The response signal is related to the impedance of the sample to be tested in the digital microfluidic chip and can be used to characterize information such as the size, location, composition and concentration of the sample to be tested. This information can then be used for automated biological, chemical and environmental detection based on digital microfluidics, such as nucleic acid detection, immunoassay, pathogen detection, and heavy metal pollutant detection.

[0051] The droplet measurement and control circuit of this invention can simultaneously realize impedance detection and droplet control, and improves the accuracy of droplet impedance detection in digital microfluidic chips. It solves the challenge of simultaneously realizing high-precision impedance detection and droplet control, and can realize impedance measurement of droplets at low voltage and high frequency.

[0052] In one embodiment, the impedance detection subcircuit 11 includes a transimpedance amplifier 112 and a signal processor 111. The mode switching subcircuit 14 includes a first switch 141; the positive input terminal of the transimpedance amplifier 112 is connected to the output terminal of the signal processor 111, the negative input terminal of the transimpedance amplifier 112 is connected to the first terminal of the first switch 141, and the output terminal of the transimpedance amplifier 112 is connected to the input terminal of the signal processor 111; the second terminal of the first switch 141 is grounded, and the third terminal of the first switch 141 is connected to a first electrode.

[0053] In one embodiment, the droplet driving sub-circuit 12 includes a driving signal generator 121; the mode switching sub-circuit 14 includes a plurality of second switches 142, the first end of the second switch 142 is used to connect to a second electrode, the second end of the second switch 142 is connected to the driving signal generator, and the third end of the second switch 142 is grounded.

[0054] The main control chip 13 achieves addressable control of any droplet in the microfluidic chip by arbitrarily switching the second electrode of the second plate B in the following states: drive signal input, grounding, and floating.

[0055] When in droplet-driven state, the main control chip 13 controls the first switch 141 to switch on and off, so that the third terminal of the first switch 141 is connected to the second terminal, thereby grounding the first electrode. The main control chip 13 controls the second switch 142 to switch on and off, so that the first terminal of the second switch 142 connected to the second target electrode is connected to the second terminal, thereby connecting the second target electrode to the signal drive generator 121.

[0056] According to the droplet control requirements, the signal drive generator 121 applies a high voltage (drive signal) to the second target electrode of the corresponding second plate B, while the other second electrodes are grounded. This causes the droplet to generate dielectric wetting, forming a lateral force and moving it in a specified direction. The signal drive generator can addressably control the voltage applied to each second electrode on the second plate, causing the droplet to move along the target path.

[0057] When in impedance measurement mode, the main control chip 13 controls the first switch 141 to switch so that the third terminal of the first switch 141 is connected to the first terminal 1, thereby connecting the first electrode to the transimpedance amplifier 112. The main control chip 13 also controls the first switch 141 to switch so that the first terminal of the second switch 142 connected to the first target electrode is connected to the third terminal, thereby grounding the first target electrode and leaving the other second electrodes floating, thus forming a signal path between the first electrode and the first target electrode. At this time, the signal processor 111 applies an excitation signal to the first electrode through the transimpedance amplifier 112, and the impedance detection sub-circuit 11 synchronously measures the response signal generated by the excitation signal in this signal path and converts it into impedance information between the two plates, including amplitude and phase.

[0058] The signal processor 111 generates the excitation signal required for impedance measurement. The amplitude of the excitation signal ranges from [10mV to 10V] and the frequency ranges from [1kHz to 50MHz]. Simultaneously, it measures and acquires the response signal generated between the two plates of the digital microfluidic chip under the application of the excitation signal, and converts the response signal into impedance information between the plates.

[0059] The signal processor 111 further processes the output signal of the transimpedance amplifier 112 to condition the signal to a suitable voltage range. Then, using the lock-in amplification principle and with the excitation signal as a reference, it analyzes and obtains the impedance amplitude and phase, and outputs them to the main control chip 13. The signal processor 111 can adjust the frequency of impedance measurement and the amplitude of the excitation voltage according to the instructions of the main control chip 13.

[0060] The transimpedance amplifier 112 is implemented by configuring an operational amplifier in a resistive feedback amplification manner, so as to simultaneously output the impedance excitation signal and amplify and convert the response signal.

[0061] In one embodiment, the impedance detection subcircuit 11 further includes a calibration component 113, which is connected to the fourth terminal of the first switch 141.

[0062] When in droplet-driven state, the first terminal of the first switch 141 is connected to the fourth terminal, thereby connecting the transimpedance amplifier 112 to the calibration component 113. The calibration component 113 floats in the droplet-driven state. This calibration component 113 has a standard impedance and can calibrate the impedance measurement results of the impedance detection sub-circuit 11. The calibration results can compensate for subsequent actual impedance measurements.

[0063] In one embodiment, calibration component 113 includes a resistor and a plurality of capacitors, wherein the resistor and a portion of the plurality of capacitors are connected in parallel and then connected in series with the remaining capacitors; both the resistor and capacitors are standard components, so calibration component 113 has a standard impedance.

[0064] In one embodiment, the drive signal generator 121 includes a boost circuit and a high-speed optocoupler switch connected to the boost circuit. The boost circuit is used to convert the input voltage into a target voltage and output the target voltage to the second electrode through the high-speed optocoupler switch; wherein the amplitude of the target voltage ranges from [50V, 300V] and the frequency ranges from [1Hz, 10kHz].

[0065] The target voltage is the high voltage required for the droplet dielectric wetting effect. The boost circuit can convert DC power below 10 V to a high voltage range of 50 V to 300 V, and convert the voltage from DC to AC through a high-voltage high-speed optocoupler switch. Its high-voltage output frequency range is 1 Hz to 10 kHz.

[0066] In one embodiment, the main control chip 13 includes a communication component. The main control chip 13 communicates with an external device through the communication component, thereby enabling the main control chip 13 to receive control commands sent by the external device and send impedance measurement results to the external device. The communication component may include, but is not limited to, Bluetooth, WiFi, Zigbee, etc.

[0067] In this embodiment, the impedance detection subcircuit is connected to the first plate A of the digital microfluidic chip, providing both the excitation and response signal measurement functions required for impedance detection. A transimpedance amplifier is used to amplify and convert the response signal, enabling impedance measurement of the droplet under high-frequency, low-voltage excitation. This not only improves the accuracy of the impedance measurement but also makes the measurement results more suitable for analysis of droplet temperature, size, composition, and physicochemical properties. Furthermore, in the impedance detection subcircuit, the excitation signal is independent of the driving signal applied to the droplet, achieving a frequency scanning function, further enhancing the frequency range for impedance measurement of the droplet and the accuracy of the final measurement results.

[0068] Figure 5 This is a schematic diagram of an addressable droplet impedance measurement digital microfluidic system provided in an embodiment of the present invention. The digital microfluidic system includes a digital microfluidic chip and a droplet measurement and control circuit provided in any of the above embodiments. The droplet measurement and control circuit is connected to the digital microfluidic chip.

[0069] Figure 6This invention presents a digital microfluidic system with addressable droplet impedance measurement. Under a 1.6 mm electrode spacing, using a 400 mV and 30 kHz excitation signal, the impedance measurement data curves and linear fitting results of pure water droplets of different volumes are obtained. As can be seen from the figure, the digital microfluidic system can accurately measure the droplet size in the digital microfluidic chip.

[0070] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A droplet measurement and control circuit for a digital microfluidic chip, characterized in that, The droplet measurement and control circuit includes an impedance detection sub-circuit, a droplet driving sub-circuit, a mode switching sub-circuit, and a main control chip. The impedance detection subcircuit is connected to the first electrode included in the digital microfluidic chip through the mode switching subcircuit, the droplet driving subcircuit is connected to the multiple second electrodes included in the digital microfluidic chip through the mode switching subcircuit, and the mode switching subcircuit is electrically connected to the main control chip. The main control chip is used to send switching commands to the mode switching sub-circuit, so that the mode switching sub-circuit switches between impedance measurement state and droplet driving state. When in the impedance measurement state, the first electrode is connected to the impedance detection sub-circuit through the mode switching sub-circuit, and the first target electrode among the plurality of second electrodes is grounded through the mode switching sub-circuit; the impedance detection sub-circuit is used to output an excitation signal to the first electrode and acquire the response signal generated by the excitation signal between the first electrode and the first target electrode; When in the droplet-driven state, the first electrode is grounded through the mode switching sub-circuit, and the second target electrode among the plurality of second electrodes is connected to the droplet-driven sub-circuit through the mode switching sub-circuit; the droplet-driven sub-circuit is used to output a driving signal to the second target electrode to drive the sample to be tested in the digital microfluidic chip to move. The impedance detection subcircuit includes a transimpedance amplifier and a signal processor; the mode switching subcircuit includes a first switch; The positive input terminal of the transimpedance amplifier is connected to the output terminal of the signal processor, the negative input terminal of the transimpedance amplifier is connected to the first terminal of the first switch, and the output terminal of the transimpedance amplifier is connected to the input terminal of the signal processor. The second terminal of the first switch is grounded, and the third terminal of the first switch is connected to the first electrode; when in the impedance measurement state, the third terminal is connected to the first terminal; when in the droplet driving state, the third terminal is connected to the second terminal. The droplet driving sub-circuit includes a driving signal generator; the mode switching sub-circuit includes a plurality of second switches, the first end of the second switch is used to connect to a second electrode, the second end of the second switch is connected to the driving signal generator, and the third end of the second switch is grounded.

2. The droplet measurement and control circuit of the digital microfluidic chip as described in claim 1, characterized in that, The impedance detection subcircuit further includes a calibration component; the calibration component is connected to the fourth terminal of the first switch. When in the droplet-driven state, the first end is connected to the fourth end.

3. The droplet measurement and control circuit of the digital microfluidic chip as described in claim 2, characterized in that, The calibration component includes a resistor and multiple capacitors, wherein the resistor and a portion of the multiple capacitors are connected in parallel and then connected in series with the remaining capacitors; the calibration component has a standard impedance.

4. The droplet measurement and control circuit of the digital microfluidic chip as described in claim 1, characterized in that, When in the impedance measurement state, the first terminal of the second switch connected to the first target electrode is connected to the third terminal; When in the droplet-driven state, the first end of the second switch connected to the second target electrode is connected to the second end.

5. The droplet measurement and control circuit of the digital microfluidic chip as described in claim 4, characterized in that, The drive signal generator includes a boost circuit and a high-speed optocoupler switch connected to the boost circuit. The boost circuit is used to convert the input voltage into a target voltage, and output the target voltage to the second electrode through the high-speed optocoupler switch; wherein the amplitude of the target voltage ranges from [50V, 300V], and the frequency ranges from [1Hz, 10kHz].

6. The droplet measurement and control circuit of the digital microfluidic chip as described in claim 1, characterized in that, The main control chip includes a communication component, through which the main control chip communicates with external devices.

7. An addressable digital microfluidic system for measuring droplet impedance, characterized in that, The digital microfluidic system includes a digital microfluidic chip and a droplet measurement and control circuit as described in any one of claims 1-6; The droplet measurement and control circuit is connected to the digital microfluidic chip.

8. The addressable droplet impedance measurement digital microfluidic system as described in claim 7, characterized in that, The digital microfluidic chip includes a first electrode plate and a second electrode plate arranged parallel to the first electrode plate; The first electrode plate includes a first substrate, a first electrode, and a first hydrophobic layer disposed sequentially. The second electrode plate includes a second hydrophobic layer, a dielectric layer, a second electrode, and a second substrate arranged sequentially. There is a gap between the first hydrophobic layer and the second hydrophobic layer, which is used to accommodate the sample to be tested.

9. The addressable droplet impedance measurement digital microfluidic system as described in claim 8, characterized in that, Both the first substrate and the second substrate are made of a first insulating material, the dielectric layer is made of a second insulating material, the insulation of the second insulating material is higher than that of the first insulating material, and both the first hydrophobic layer and the second hydrophobic layer are made of hydrophobic materials.

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