Digital micro-fluidic chip

Abstract

The utility model relates to the technical field of microfluidics, and provides a digital micro-fluidic chip which comprises a substrate, an electrode layer, a dielectric layer and a hydrophobic layer, the electrode layer is located on the substrate, the electrode layer comprises a liquid storage electrode, execution electrodes and a circuit, the execution electrodes are arranged in a plurality of rings with different radiuses in the same center, each ring is provided with a plurality of execution electrodes, and the execution electrodes in the same ring radius are connected in series through the same circuit to form an annular circuit; the execution electrode comprises a first driving electrode, a second driving electrode, a reagent electrode and a reaction electrode, and the liquid storage electrode, the first driving electrode, the reaction electrode, the second driving electrode and the reagent electrode are radially arranged in the direction away from the annular center to form a liquid drop flowing channel. According to the utility model, through the design of the annular radial circuit, one line and a plurality of electrodes are simultaneously connected in series, so that one pin point position can simultaneously control a plurality of electrodes, the number of pins is reduced, and the problem of difficulty in wiring of a chip is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of microfluidics, and particularly relates to a digital microfluidic chip. Background Art

[0002] Digital microfluidics (DMF for short) is a technology based on the principle of electrowetting. By changing the electrode voltage, the contact angle of droplets on the chip surface can be changed to achieve the directional movement, splitting, and merging of droplets. This technology can precisely control the volume, flow rate, and flow direction of fluids, realizing precise control of fluids. Since the operation is carried out automatically on the micron scale, digital microfluidics can greatly reduce the consumption of experimental reagents, improve the reaction efficiency, and shorten the operation time. At the same time, the chip size is small, which is convenient for carrying and integrating into various devices. Currently, digital microfluidics has been used in many fields such as chemical synthesis, biological analysis, disease diagnosis, and drug screening.

[0003] Digital microfluidics is a technology that precisely manipulates the movement of trace amounts of liquid on a chip using electrical signals through an electrode array. Therefore, the chip circuit design plays a crucial role in microfluidics technology, directly determining the accuracy and efficiency of droplet manipulation on the chip. The design principles and objectives mainly focus on achieving precise control of droplets, high chip integration, and low power consumption.

[0004] In the existing technology for the design of digital microfluidic chips, each electrode corresponds one by one to each pin position, the chip design is relatively cumbersome, and wiring is difficult within the limited chip area. At the same time, on a single digital microfluidic chip, it is difficult to control the movement and reaction of multiple droplets simultaneously, the throughput is low, and the reaction speed is slow. Moreover, under the limited chip area and the number of pins, the scalability of the chip is poor. Summary of the Utility Model

[0005] To solve the deficiencies in the above-mentioned existing technology, the utility model provides a digital microfluidic chip, which includes a substrate; an electrode layer located above the substrate. The electrode layer includes a liquid storage electrode, an execution electrode, and a circuit. The execution electrodes are arranged in a plurality of concentric circles with different radii around the same center. Each circle is provided with a plurality of execution electrodes. A plurality of execution electrodes within the same circular radius are connected in series using the same circuit to form a circular circuit. The liquid storage electrode is located at the center of the circle; the execution electrode includes a first driving electrode, a second driving electrode, a reagent electrode, and a reaction electrode. The liquid storage electrode, the first driving electrode, the reaction electrode, the second driving electrode, and the reagent electrode are arranged radially away from the center of the circle to form a droplet flow channel; a dielectric layer located above the electrode layer; and a hydrophobic layer located above the dielectric layer.

[0006] Further, each annular circuit of the digital microfluidic chip is externally connected to a pin point, and the externally connected voltage of the pin point can regulate the power supply.

[0007] Further, the voltage regulation range of the voltage-regulatable power supply is 0 V to 180 V AC.

[0008] Further, the electrode distances between different rings in the droplet flow channel are different.

[0009] Further, the electrode distances between different rings in the droplet flow channel are the same.

[0010] Further, the electrode distances between different rings in the droplet flow channel are 0.02 mm to 0.08 mm.

[0011] Further, the distance between the reaction electrodes needs to be greater than a preset value.

[0012] Further, the reaction electrodes and the reagent electrodes are arranged in a circle.

[0013] Further, the first driving electrode and the second driving electrode have at least one circle.

[0014] Further, the area of the liquid storage electrode is equal to the total area of the first driving electrodes close to the liquid storage electrode.

[0015] Based on the above, compared with the prior art, the digital microfluidic chip provided by the present utility model, through the annular radial circuit design, connects a single line in series with multiple electrodes simultaneously, enabling a single pin point to control multiple electrodes simultaneously without interference, reducing the number of pins, improving the flexibility of chip design, significantly reducing the wiring complexity, and solving the problem of difficult chip wiring. At the same time, without increasing the pins and chip area, the number and complexity of electrodes can be conveniently increased without significantly changing the circuit design, having strong scalability.

[0016] Other features and beneficial effects of the present utility model will be described in the subsequent specification, and, in part, will become apparent from the specification or be understood by implementing the present utility model. The objectives and other beneficial effects of the present utility model can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. Brief Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings; the positional relationships described in the following drawings are based on the directions shown by the components in the drawings unless otherwise specified.

[0018] Figure 1 It is a schematic structural diagram of the digital microfluidic chip provided by the present invention;

[0019] Figure 2 It is a schematic structural diagram of the electrode distribution of the digital microfluidic chip provided by the present invention;

[0020] Figure 3 It is another schematic structural diagram of the electrode distribution of the digital microfluidic chip provided by the present invention;

[0021] Figure 4 It is another schematic structural diagram of the electrode distribution of the digital microfluidic chip provided by the present invention.

[0022] Reference numerals:

[0023] Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention; the technical features designed in different implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that all the terms (including technical terms and scientific terms) used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs, and should not be construed as a limitation to the present invention; it should be further understood that the terms used in the present invention should be understood as having meanings consistent with their meanings in the context of this specification and the relevant technical fields, and should not be understood in an idealized or overly formal sense, unless clearly defined as such in the present invention.

[0026] The present utility model provides a digital microfluidic chip, as Figure 1 shown, which includes a substrate 10, an electrode layer 20, a dielectric layer 30, and a hydrophobic layer 40 that are in contact with each other in sequence from bottom to top.

[0027] Specifically, the substrate 10 is made of glass, the electrode layer 20 is made of chromium, the dielectric layer 30 is made of SU-8 photoresist, the hydrophobic layer 40 is made of Teflon, and the pin points 50 provide a variable voltage for the electrode layer 20.

[0028] Process flow of the digital microfluidic chip: First, a nanoscale chromium metal thin film is sputtered on a cleaned glass substrate. Through a designed mask plate and using photolithography technology, a photoresist coating with a specific pattern is formed on the surface of the metal layer. Then, the metal layer is etched. At this time, the metal film not protected by the photoresist will be etched away, leaving a pattern the same as that of the photolithography mask plate. After removing the photoresist, the electrode layer 20 with the specified pattern can be obtained. Then, SU-8 photoresist is coated, and the dielectric layer 30 is obtained through the same photolithography process, exposure development, and hard baking. Then, a hydrophobic layer 40 made of Teflon is coated on the surface of the chip, and finally, it is tested on the machine.

[0029] In an embodiment, as Figure 2 shown, the electrode layer 20 includes a liquid storage electrode 21, an execution electrode 22, and a circuit 23. The execution electrodes 22 are arranged in a plurality of concentric rings with different radii. Each ring is provided with a plurality of execution electrodes 22. A plurality of execution electrodes 22 within the same ring radius are connected in series using the same circuit 23 to form a ring circuit 60, and the liquid storage electrode 21 is located at the center of the ring.

[0030] It should be noted that a ring refers to the shape formed by connecting the execution electrodes 22 at the same center and the same radius. The rings formed by multiple circles of execution electrodes 22 share a common center.

[0031] The execution electrode 22 includes a first driving electrode 221, a second driving electrode 223, a reagent electrode 224, and a reaction electrode 222. The liquid storage electrode 21, the first driving electrode 221, the reaction electrode 222, the second driving electrode 223, and the reagent electrode 224 are arranged radially in a direction away from the center of the ring to form a droplet flow channel 70.

[0032] Specifically, the droplets are stored in the liquid storage electrode 21, and the reagent is stored in the reagent electrode 224. The liquid storage electrode 21 is located at the annular center, and the reagent electrode 224 is located in the outermost annular circuit 60. The first driving electrode 221 is disposed close to the liquid storage electrode 21, the second driving electrode 223 is disposed close to the reagent electrode 224, and the reaction electrode 222 is disposed between the first driving electrode 221 and the second driving electrode 223. The droplets are moved to the reaction electrode 222 by the action of the first driving electrode 221, and then the second driving electrode 223 moves the reagent droplets on the reagent electrode 224 to the reaction electrode 222.

[0033] In one embodiment, special structures such as detection windows, liquid inlets, and liquid outlets can be added at the positions required by the microfluidic chip to ensure the accurate connection of the microchannel network composed of the detection windows, liquid inlets, liquid outlets, and the droplet flow channel 70.

[0034] In one embodiment, the electrode distances between different rings in the droplet flow channel are different. Specifically, the electrode distances between different rings can increase or decrease, and even the distances between different electrodes can be different. For example, the distance between the second ring electrode and the third ring electrode can be greater than the distance between the third ring electrode and the fourth ring electrode.

[0035] In one embodiment, the electrode distances between different rings in the droplet flow channel are the same.

[0036] Preferably, the distance between the electrode distances between different rings in the droplet flow channel is 0.02 mm to 0.08 mm, which is applicable to the case where the electrode distances between different rings are different and can also be applicable to the case where the electrode distances between different rings are the same. Specifically, when the electrode distance between different rings is less than 0.02 mm, due to the electric field effect, different electrodes will be connected, affecting the experimental results; when the distance between the electrodes is greater than 0.08 mm, the droplets cannot be transferred from the first ring electrode to the second ring electrode, causing the droplet movement to stop. Preferably, the distance between the electrodes is 0.04 mm, which can ensure that different electrodes are not affected by each other's electric fields and does not affect the movement of droplets between different ring electrodes.

[0037] In one embodiment, the reaction electrode 222 and the reagent electrode 224 are provided in one circle.

[0038] Preferably, the distance between the reaction electrodes 222 needs to be greater than a preset value. Specifically, when the distance between the reaction electrodes 222 is less than the preset value, there is a possibility of droplet fusion between different reaction electrodes 222, which will affect the experimental results. And the size of the preset value needs to be determined specifically according to the actual size of the droplets. If the droplets are larger, the distance between the reaction electrodes 222 also needs to be increased; if the droplets are smaller, the distance between the reaction electrodes 222 can be correspondingly decreased. At the same time, the number of turns of the first driving electrode 221 is determined according to the distance between the reaction electrodes 222. Since the first driving electrode 221 is located inside the reaction electrodes 222, when the number of reaction electrodes 222 in the ring circuit 60 where the reaction electrodes 222 are located is fixed, the number of turns of the ring circuit 60 of the first driving electrode 221 needs to be determined according to the distance between the reaction electrodes 222, and the number of turns of the first driving electrode 221 is at least one turn.

[0039] In one embodiment, the area of the liquid storage electrode 21 is equal to the total area of the first driving electrodes 221 adjacent to the liquid storage electrode 21. When the area of the liquid storage electrode 21 is equal to the total area of the first driving electrodes 221 adjacent to the liquid storage electrode 21, the first driving electrodes 221 in the first circle of the multiple droplet flow channels 70 connected to the liquid storage electrode 21 can apply the same five component forces to the droplets on the surface of the liquid storage electrode 21, and can divide the droplets into five equal parts completely, ensuring that the sizes of the droplets in each droplet flow channel 70 are the same.

[0040] As Figure 2 、 Figure 3 and Figure 4 shown, the liquid storage electrode 21 can be semi-circular, circular, fan-shaped, and fan-ring-shaped. In a preferred embodiment, as Figure 3 shown, the liquid storage electrode 21 is composed of three fan-ring shapes, and each fan-ring shape is connected to 5 droplet flow channels 70. The total area of all the electrodes in the 5 droplet flow channels 70 is equal to the area of the single fan-ring-shaped liquid storage electrode 21 they are currently connected to.

[0041] As Figure 1 shown, the pin point 50 is connected to the electrode layer 20 through the line 23.

[0042] Specifically, each ring circuit 60 is connected to a pin point 50, and the pin point 50 is externally connected to a voltage-adjustable power supply. The voltage adjustment range of the voltage-adjustable power supply is 0 V to 180 V AC.

[0043] Specifically, the voltage input to each ring circuit 60 and the liquid storage electrode 21 is determined according to the actual characteristics of the droplets. If the droplets are fragile, a small voltage is required for control; when the droplets have high viscosity, a large voltage is required to control their movement.

[0044] In one embodiment, multiple liquid storage electrodes 21 can also be connected to the same pin point 50, or a single liquid storage electrode 21 can be connected to one pin point 50. Preferably, a single liquid storage electrode 21 is connected to one pin point 50, which can better control different liquid storage electrodes 21.

[0045] Specifically, the pin point 50 uses a PIN needle, and the electrode is connected to the pin point 50 through a line 23. The pin point 50 outputs a variable voltage to the electrode, and the adjustable power supply controls the voltage and frequency output to the electrodes of different annular circuits 60 through programming and control algorithms to achieve complex droplet manipulation tasks.

[0046] The specific working principle is as follows: First, the droplets on the liquid storage electrode 21 are separated. Specifically, the first loop of the first driving electrode 221 of the annular circuit 60 is energized, and the first driving electrode 221 generates a force to suck the droplets from the liquid storage electrode 21 to the first loop of the first driving electrode 221. After the droplets enter the first loop of the first driving electrode 221, the second loop of the first driving electrode 221 is energized, and the first loop of the first driving electrode 221 is de-energized. The second loop of the first driving electrode 221 generates a force to suck the droplets from the first loop of the first driving electrode 221 to the second loop of the first driving electrode 221, and so on, until the droplets are sucked to the reaction electrode 222. After the droplets on the liquid storage electrode 21 are sucked to the reaction electrode 222, the second driving electrode 223 starts to suck the reagent on the surface of the reagent electrode 224 and transfer it to the reaction electrode 222, and finally the droplets and the reagent react at the reaction electrode 222.

[0047] In summary, compared with the prior art, the digital microfluidic chip provided by the present utility model has the following advantages:

[0048] 1. Reducing manufacturing costs: Using one line to control multiple electrodes can reduce the number of independent control pins required, thereby reducing the number of pins on the chip and the overall manufacturing cost.

[0049] 2. Reducing wiring complexity: By using one line to control multiple electrodes, the number of wirings can be reduced, the wiring complexity can be lowered, and the integration and reliability of the chip can be improved.

[0050] 3. Improving design flexibility: Through programming and control algorithms, the voltage and frequency on different electrodes can be flexibly adjusted to achieve complex droplet manipulation tasks.

[0051] 4. Improving energy efficiency: Since the number of control pins and lines is reduced, it helps to reduce the power consumption and heat generation of the chip, and improve the stability and reliability of the system.

[0052] 5. High-throughput feature: The annular radial line can ensure that multiple projects or experiments can be carried out simultaneously on the same chip, thereby greatly improving the throughput of detection and analysis.

[0053] 6. Enhanced scalability: The annular radial circuit can easily increase the number of electrodes and complexity without significantly changing the circuit design.

[0054] 7. Reaction units are isolated from each other: In a digital microfluidic chip, each reaction electrode is isolated from each other, which means that each reaction electrode does not interfere with each other, thus avoiding cross - contamination or interference between different reactions.

[0055] In addition, those skilled in the art should understand that although there are many problems in the prior art, each embodiment or technical solution of the present utility model can be improved in only one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or the background art at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be regarded as a limitation to that claim.

[0056] Although terms such as substrate, electrode layer, liquid storage electrode, execution electrode, first drive electrode, reaction electrode, second drive electrode, reagent electrode, circuit, dielectric layer, hydrophobic layer, pin position, annular circuit and droplet flow channel are used more in this article, the possibility of using other terms is not excluded. Using these terms is only to more conveniently describe and explain the essence of the present utility model; interpreting them as any additional limitation is contrary to the spirit of the present utility model; the terms "first", "second", etc. (if any) in the specification, claims and above - mentioned drawings of the embodiments of the present utility model are used to distinguish similar objects and do not have to be used to describe a specific order or sequence.

[0057] Finally, it should be noted that: The above - mentioned embodiments are only used to illustrate the technical solutions of the present utility model, rather than to limit it; Although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A digital microfluidic chip, characterized in that: including a substrate; An electrode layer, located on the substrate, the electrode layer includes a liquid storage electrode, an execution electrode and a circuit, the execution electrodes are arranged in a plurality of rings with different radii at the same center, each ring is provided with a plurality of the execution electrodes, and a plurality of the execution electrodes within the same ring radius are connected in series using the same circuit to form a ring circuit, and the liquid storage electrode is located at the center of the ring; The execution electrode includes a first driving electrode, a second driving electrode, a reagent electrode and a reaction electrode, and the liquid storage electrode, the first driving electrode, the reaction electrode, the second driving electrode and the reagent electrode are radially arranged in a direction away from the center of the ring to form a droplet circulation channel; a dielectric layer, located on the electrode layer; The hydrophobic layer is located on the medium layer.

2. The digital microfluidic chip according to claim 1, characterized in that: Each of the ring circuits of the digital microfluidic chip is externally connected to a pin point, and the pin point is externally connected to a voltage-adjustable power supply.

3. The digital microfluidic chip according to claim 2, characterized in that: The voltage control range of the voltage controllable power supply is AC 0 V to 180 V.

4. The digital microfluidic chip according to claim 1, characterized in that: The electrode distances between different rings in the droplet circulation channel are different.

5. The digital microfluidic chip according to claim 1, characterized in that: The electrode distances between different rings in the droplet circulation channel are the same.

6. The digital microfluidic chip according to claim 4 or 5, characterized in that: The electrode distance between different rings in the droplet circulation channel is 0.02 mm to 0.08 mm.

7. The digital microfluidic chip according to claim 1, characterized in that: The distance between the reaction electrodes needs to be greater than a preset value.

8. The digital microfluidic chip according to claim 1, characterized in that: The reaction electrode and the reagent electrode are arranged in a circle.

9. The digital microfluidic chip according to claim 1, characterized in that: The first driving electrode and the second driving electrode have at least one turn.

10. The digital microfluidic chip according to claim 1, characterized in that: The area of ​​the liquid storage electrode is equal to the sum of the areas of the first driving electrodes close to the liquid storage electrode.

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