A method for preparing a digital microfluidic chip and a digital microfluidic chip

Abstract

This invention relates to a method for fabricating a digital microfluidic chip and the digital microfluidic chip itself. The method includes the following steps: S10: fabricating a first electrode plate; S20: fabricating a second electrode plate; S30: assembling the first electrode plate and the second electrode plate; Step S20 includes: sequentially fabricating a second electrode layer, a hydrophilic layer, a release photoresist, a activation layer, and a positive photoresist on a second substrate; exposing and developing the positive photoresist, the activation layer, and the release photoresist to remove the positive photoresist, the activation layer, and the release photoresist in a preset micro-hole pattern area to obtain a substrate structure with a photoresist micropillar array; spin-coating a second hydrophobic layer on the substrate structure with the photoresist micropillar array; performing vapor phase activation on the second hydrophobic layer; removing the release photoresist, the activation layer, the positive photoresist, and the second hydrophobic layer covering the surface of the positive photoresist to obtain a second hydrophobic layer with multiple micropores disposed on the surface of the hydrophilic layer.

Description

Technical Field

[0001] This invention relates to the field of biological detection technology, and more specifically to a method for preparing a digital microfluidic chip and the digital microfluidic chip itself. Background Technology

[0002] Digital microfluidic chips (DMFCs), as an important branch of microfluidics technology, achieve precise driving, segmentation, fusion, and mixing of discrete droplets through electro-manipulation methods such as electrowetting and dielectrophoresis. They have significant advantages such as low reagent consumption, high reaction integration, high degree of automation, and low risk of cross-contamination, and have been widely used in biological detection, such as nucleic acid detection, protein detection, and cell detection.

[0003] Digital microfluidics, leveraging the electrowetting effect, enables automated movement, splitting, and mixing of droplets, demonstrating significant application value in fields such as biochemical analysis, nucleic acid detection, and microsphere separation. However, it is limited by the number of electrodes, chip cost, and difficulty in controlling droplet size, making it difficult to generate nanoliter or even picoliter-sized droplets in high throughput. Droplet microarray technology, on the other hand, relies on the difference in surface hydrophilicity and hydrophobicity to capture and arrange microdroplets, obtaining droplets of minute volume. However, it generally relies on manual operation, has low automation and integration levels, is prone to introducing human error, and cannot meet the multivariate control requirements of high-throughput experiments.

[0004] To address the aforementioned technical challenges, Chinese patent application CN118751301A proposes combining droplet microarrays with digital microfluidics. This involves constructing a hydrophilic-hydrophobic array on a digital microfluidic chip using electrodes. The electrowetting effect drives the mother droplet through the array, and the difference in wettability causes the sub-droplets to adhere and separate at hydrophilic vacancy sites, thus automating the generation of microdroplet arrays. While this technology combines the automated control of digital microfluidics with the advantages of microdroplet array generation, enabling the fabrication of droplets at the picoliter to nanoliter level, its hydrophilic-hydrophobic array fabrication process suffers from a key technical defect: the density of hydrophilic vacancy sites is strictly limited, preventing the fabrication of high-density hydrophilic-hydrophobic arrays and thus hindering the improvement of high-throughput performance of droplet microarrays.

[0005] Specifically, in existing technologies, the spacing between adjacent hydrophilic vacancies in hydrophilic-phobic arrays needs to be greater than 1.5 times the vacancies size, which only allows for the fabrication of low-density hydrophilic vacancies arrays. The core reason for this limitation is that in existing processes, when preparing hydrophilic vacancies by forming a patterned sacrificial layer with photoresist, then spin-coating a hydrophobic layer, and finally removing the photoresist, Teflon (polytetrafluoroethylene, PTFE) is directly spin-coated and cured onto the photoresist, forming a dense, chemically inert barrier that is difficult to penetrate or dissolve with conventional photoresist removers. If the spacing between adjacent vacancies is reduced, Teflon is more likely to form a "root encapsulation" or seal at the bottom of the micropillar. During subsequent conventional liquid-phase photoresist removal (such as solvent immersion), the solvent has difficulty penetrating the dense Teflon encapsulation layer, resulting in the photoresist not being completely removed and forming permanent residues.

[0006] Therefore, how to overcome the limitations of existing processes and achieve stable fabrication of hydrophilic and hydrophobic arrays with high-density vacancy sites is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method for fabricating a digital microfluidic chip and a digital microfluidic chip, so as to solve the above-mentioned technical problems.

[0008] To achieve the above objectives, the present invention provides a method for fabricating a digital microfluidic chip, comprising the following steps:

[0009] S10: Preparation of the first electrode plate;

[0010] S20: Preparation of the second electrode plate;

[0011] S30: Assemble the first electrode plate and the second electrode plate so that the first electrode plate and the second electrode plate are positioned opposite each other, and form an interplate cavity between the first electrode plate and the second electrode plate. The first electrode plate and the second electrode plate together drive the liquid to be tested to move in the interplate cavity.

[0012] Step S20 specifically includes the following steps:

[0013] S21: Deposit a second electrode layer on the second substrate;

[0014] S22: Deposit a hydrophilic layer on the second electrode layer;

[0015] S23: Spin-coat the hydrophilic layer with a release photoresist;

[0016] S24: Spin-coat an activation layer onto the stripped photoresist;

[0017] S25: Spin-coat positive photoresist onto the activation layer;

[0018] S26: Expose and develop the positive photoresist, the activation layer and the stripping photoresist to remove the positive photoresist, the activation layer and the stripping photoresist in the preset micro-hole pattern area to obtain a substrate structure with a photoresist micropillar array;

[0019] S27: Deposit a second hydrophobic layer on the substrate structure with the photoresist micropillar array, the second hydrophobic layer simultaneously covering the surface of the positive photoresist and the surface of the hydrophilic layer within the gaps between the photoresist micropillars;

[0020] S28: Perform vapor phase activation on the second hydrophobic layer;

[0021] S29: After the vapor phase activation, the stripping photoresist, the activation layer, the positive photoresist, and the second hydrophobic layer covering the surface of the positive photoresist are removed, while the second hydrophobic layer on the surface of the hydrophilic layer is retained, resulting in a second hydrophobic layer with multiple micropores disposed on the surface of the hydrophilic layer.

[0022] Optionally, the first electrode plate includes a first substrate, a first electrode layer, and a first hydrophobic layer, wherein the first electrode layer and the first hydrophobic layer are sequentially disposed on the first substrate, and the first hydrophobic layer is closer to the second electrode plate than the first substrate.

[0023] Optionally, the first electrode layer includes a ground electrode region and a droplet driving electrode region. The ground electrode region is used for grounding, and the droplet driving electrode region is used for driving the liquid to be detected to move. The second electrode layer is connected to the ground electrode region.

[0024] Optionally, the second electrode layer is connected to the ground electrode area of ​​the first electrode layer by a conductive tape.

[0025] Optionally, the droplet-driven electrode region includes a pretreatment zone electrode, a transition zone electrode, a waste liquid storage zone electrode, and a distribution zone electrode. The distribution zone electrode is disposed opposite to each micropore, and the transition zone electrode is adjacent to the pretreatment zone electrode, the waste liquid storage zone electrode, and the distribution zone electrode, respectively.

[0026] Optionally, the distribution area electrode includes multiple electrode units, which are arranged adjacent to each other in sequence. Each electrode unit includes a first electrode block and a second electrode block arranged adjacent to each other. The first electrode block and the second electrode block are connected in parallel, and an interdigital structure is formed between the adjacent sides of the first electrode block and the second electrode block.

[0027] Optionally, an interdigitated structure is formed between the adjacent sides of the two adjacent electrode blocks of any two adjacent electrode units.

[0028] Optionally, the thickness of the stripped photoresist is greater than 5 micrometers, the activation layer is a silane coupling agent, and the thickness of the activation layer is less than 10 nanometers.

[0029] Optionally, the interval between any two adjacent micropores is less than or equal to the size of the micropore.

[0030] Another aspect of the present invention provides a digital microfluidic chip, which is prepared by the digital microfluidic chip preparation method described above. Attached Figure Description

[0031] Figure 1 A cross-sectional view of a digital microfluidic chip according to an embodiment of the present invention;

[0032] Figure 2 This is a top view of the first electrode layer of a digital microfluidic chip according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the electrode unit of the distribution region electrode of the first electrode layer of a digital microfluidic chip according to an embodiment of the present invention;

[0034] Figure 4 A cross-sectional view of a digital microfluidic chip according to another embodiment of the present invention;

[0035] Figure 5 A flowchart illustrating a method for fabricating a digital microfluidic chip according to another embodiment of the present invention;

[0036] Figure 6 This is a flowchart of step S20 of the method for fabricating a digital microfluidic chip according to an embodiment of the present invention. Detailed Implementation

[0037] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0038] like Figure 1 As shown, this embodiment of the invention provides a digital microfluidic chip, which includes a first electrode plate 100 and a second electrode plate 200. The first electrode plate 100 and the second electrode plate 200 are connected by a conductive tape and are arranged opposite to each other, forming an interplate cavity 300 between the first electrode plate 100 and the second electrode plate 200. The first electrode plate 100 and the second electrode plate 200 jointly drive the liquid to be tested to move within the interplate cavity 300. The side of the second electrode plate 200 facing the first electrode plate 100 has a plurality of micropores 231 (equivalent to vacancy sites in the prior art). Each micropore 231 is configured to retain at least a portion of the liquid to be tested within the micropore 231 when the liquid to be tested passes through the micropore 231, thereby distributing the liquid to be tested within different micropores 231 and achieving automatic distribution.

[0039] The first electrode plate 100 may include a first substrate 110, a first electrode layer 120, and a first hydrophobic layer 130. The first electrode layer 120 and the first hydrophobic layer 130 are sequentially disposed on the first substrate 110. The first hydrophobic layer 130 is closer to the second electrode plate 200 than the first substrate 110. By energizing the first electrode layer 120, the movement of the test liquid in the interplate cavity 300 can be controlled. When the test liquid passes through the micropore 231, the difference in wettability causes some of the test liquid to be retained in the micropore 231.

[0040] The first substrate 110 can be made of any suitable substrate material, such as glass, silicon, or other substrate materials. The first electrode layer 120 can be made of any suitable metallic material, such as indium tin oxide, chromium, gold, or other metallic materials. The first hydrophobic layer 130 can be made of any suitable hydrophobic material, such as polytetrafluoroethylene (PTFE), perfluoropolyether (PFPE), Teflon (Teflon AF), or other hydrophobic materials.

[0041] The second electrode plate 200 may include a second substrate 210, a second electrode layer 220, and a second hydrophobic layer 230. The second electrode layer 220 and the second hydrophobic layer 230 are sequentially disposed on the second substrate 210. The second hydrophobic layer 230 has a plurality of micropores 231. The second hydrophobic layer 230 is disposed toward the first hydrophobic layer 130. The space between the first hydrophobic layer 130 and the second hydrophobic layer 230 is formed as an interplate cavity 300.

[0042] The micropores 231 on the second hydrophobic layer 230 can be arranged in any suitable manner, such as in an array to form a micropore array. The shape of the micropores 231 can be arbitrarily set as needed, such as circular, square, rectangular, elliptical, or irregular shapes. The spacing between any two adjacent micropores 231 is unrestricted and can be less than 1.5 times the micropore size, for example, it can be 0.5 times the micropore size.

[0043] The second substrate 210 can be made of any suitable substrate material, such as glass, silicon, or other substrate materials. The second electrode layer 220 can be made of any suitable metallic material, such as indium tin oxide, chromium, gold, or other metallic materials. The second hydrophobic layer 230 can be made of a spin-coated hydrophobic material, such as Teflon AF, or other hydrophobic materials.

[0044] like Figure 2 As shown, the first electrode layer 120 includes a ground electrode area 121 and a droplet driving electrode area. The ground electrode area 121 is used for grounding, and the droplet driving electrode area is used for driving the liquid to be tested to move. The second electrode layer 220 is connected to the ground electrode area 121 of the first electrode layer 120. For example, the two can be connected together by conductive tape 400, so as to achieve both physical fixation and electrical connection.

[0045] like Figure 2 As shown, the droplet-driven electrode region includes a pretreatment zone electrode 122, a transition zone electrode 123, a waste liquid storage zone electrode 124, and a distribution zone electrode 125. The distribution zone electrode 125 is disposed opposite to each micropore. The transition zone electrode 123 is adjacent to the pretreatment zone electrode 122, the waste liquid storage zone electrode 124, and the distribution zone electrode 125, respectively. Through the transition zone electrode 123, the pretreatment zone electrode 122, the waste liquid storage zone electrode 124, and the distribution zone electrode 125 can be connected, so that the liquid to be detected can move between the electrode regions.

[0046] The distribution area electrode 125 includes multiple electrode units, which are arranged adjacent to each other in sequence. For example... Figure 3 As shown, each electrode unit includes a first electrode block 1251 and a second electrode block 1252 arranged adjacently. The first electrode block 1251 and the second electrode block 1252 are connected in parallel (i.e., they are both excited by the same electrical signal). Multiple first protrusions 1251a are provided on the side adjacent to the first electrode block 1251 and the second electrode block 1252. A first groove is formed between any two adjacent first protrusions 1251a. Multiple second protrusions 1252a are provided on the side adjacent to the first electrode block 1251. A second groove is formed between any two adjacent second protrusions 1252a. Each first protrusion 1251a corresponds one-to-one with each second groove, and each second protrusion 1252a corresponds one-to-one with each first groove. Each of the first protrusions 1251a is inserted into the corresponding second groove, and there is a gap between the first protrusion 1251a and the two second protrusions 1252a forming the second groove. Each second protrusion 1252a is inserted into the corresponding first groove, and there is a gap between the second protrusion 1252a and the two first protrusions 1251a forming the first groove. This makes the first electrode block 1251 and the second electrode block 1252 form an interdigital structure. In this way, when the liquid to be tested moves on the first protrusion 1251a of the first electrode block 1251, it can contact the second protrusion 1252a of the second electrode block 1252 in advance, avoiding the liquid to be tested from getting stuck on the edge of the first electrode block 1251 and not being able to smoothly transition to the second electrode block 1252, thereby effectively preventing the pinning effect.

[0047] Interdigitated structures can also be formed between adjacent electrode blocks of any two adjacent electrode units, allowing the test liquid to transition smoothly between different electrode units.

[0048] Each of the pretreatment zone electrode 122, the transition zone electrode 123, and the waste liquid storage zone electrode 124 includes multiple independent electrode blocks, which are arranged adjacent to each other in sequence. Each electrode block is connected to the signal control module to receive the timed electrical signal (voltage / potential signal) output by the signal control module. By controlling the on / off state and potential level of each electrode block, an electric field gradient can be formed between the electrode blocks, driving the liquid to be tested to move along the desired path.

[0049] The size of the micropores 231 can be set arbitrarily as needed. For example, the diameter of the circular micropores can be between 20 and 1000 micrometers. For example, micropores 231 with a diameter of 20-50 micrometers can be used for single-cell level analysis, micropores 231 with a diameter of 50-200 micrometers can be used for micro-biochemical reactions, and micropores 231 with a diameter of 200-1000 micrometers can be used for more complex biological systems.

[0050] like Figure 4 As shown, in some embodiments, a hydrophilic layer 240 may be provided between the second electrode layer 220 and the second hydrophobic layer 230 of the second electrode plate 200, and the micropore 231 is a through hole penetrating the second hydrophobic layer 230. In this way, when the test liquid moves in the interplate cavity 300 and passes through the micropore 231, the hydrophilic layer 240 will adsorb the test liquid, thereby adsorbing at least a portion of the test liquid in the micropore 231. That is, without applying an additional voltage, a portion of the test liquid can be automatically separated into the micropore 231.

[0051] The hydrophilic layer 240 can be made of any suitable hydrophilic material, such as polyethylene glycol, polyvinyl alcohol or other hydrophilic materials.

[0052] It should be noted that, although in Figure 1 and Figure 4 In this embodiment, the first electrode 100 is located below the second electrode 200. However, in actual use, the second electrode 200 can also be located below the first electrode 100. This embodiment of the invention does not limit this. Preferably, the first electrode 100 can be located below the second electrode 200. Figure 1 The second electrode plate 200 is located below the first electrode plate 100. This allows the micropore 231 to be located below the inter-plate cavity 300. When the liquid to be tested moves in the inter-plate cavity 300, it can be better retained in the micropore 231 due to gravity, that is, the liquid retention effect of the micropore 231 will be better.

[0053] The following is a brief description of the process of nucleic acid detection using the digital microfluidic chip of this invention:

[0054] First, the lysis buffer, magnetic beads, and sample are sequentially fed into the pretreatment zone of the interplate cavity 300, corresponding to the pretreatment zone electrode 122. The lysis buffer, magnetic beads, and sample are then formed into a large droplet by the pretreatment zone electrode 122, which rotates and moves within it. After the magnetic beads adsorb nucleic acids from the sample, a magnet is placed below the first electrode 100 to hold the magnetic beads stationary in the pretreatment zone. The mixture is then moved to the waste liquid storage zone via the pretreatment zone electrode 122, the transition zone electrode 123, and the waste liquid storage zone electrode 124. Washing buffer is then added twice to the pretreatment zone to wash the magnetic beads, and the washed mixture is also moved to the waste liquid storage zone. Elution buffer is then added to the pretreatment zone to elute the nucleic acids from the magnetic beads, which are then removed by the magnet. Finally, primers, probes, and PCR premix are thoroughly mixed with the nucleic acids to obtain the pretreated mixture.

[0055] After pretreatment, the pretreated mixture is moved to the distribution zone via the pretreatment zone electrode 122 and the transition zone electrode 123. Then, the pretreated mixture is moved within the distribution zone via the distribution zone electrode 125 to distribute it into different micropores 231. Through multiple experiments on micropores with a diameter of 100 micrometers, it was found that the mixture can be distributed into more than 30,000 micropores.

[0056] After partitioning, the digital microfluidic chip is placed on a slab PCR instrument for nucleic acid amplification. After amplification, the chip is imaged using a scanning fluorescence microscope, and the original sample can be absolutely quantified based on the imaging results using a deep learning algorithm.

[0057] The digital microfluidic chip of this invention, by setting a plurality of micropores 231 on the second electrode plate 200, allows at least a portion of the liquid to be tested to be retained in the micropores 231 when the first electrode plate 100 drives the liquid to be tested to move between the interplate cavity 300 between the first electrode plate 100 and the second electrode plate 200, thereby realizing automatic distribution of the liquid to be tested. The spacing between any two adjacent micropores 231 is not limited, and its density is higher than that of the prior art, and its throughput is also higher.

[0058] like Figure 5 As shown, another embodiment of the present invention provides a method for fabricating a digital microfluidic chip, which includes the following steps:

[0059] S10: Prepare the first electrode plate 100;

[0060] S20: Preparation of the second electrode plate 200;

[0061] S30: Assemble the first electrode plate 100 and the second electrode plate 200 so that the first electrode plate 100 and the second electrode plate 200 are positioned opposite each other, and an inter-plate cavity is formed between the first electrode plate 100 and the second electrode plate 200 to obtain the digital microfluidic chip described in the previous embodiment.

[0062] like Figure 6 As shown, step S20 specifically includes the following steps:

[0063] S21: Deposit a second electrode layer 220 on the second substrate 210;

[0064] S22: Deposit a hydrophilic layer 240 on the second electrode layer 220;

[0065] S23: Spin-coat lift-off resist (LOR) 250 onto the hydrophilic layer 240; the thickness of LOR 250 is greater than 5 micrometers;

[0066] S24: Spin-coat the initiation layer 260 onto LOR 250; the initiation layer 260 can be made of silane coupling agent and its thickness is less than 10 nanometers;

[0067] S25: Spin-coat positive photoresist 270 onto the activation layer 260;

[0068] S26: Expose and develop the positive photoresist 270, the activation layer 260 and the LOR 250 to remove the positive photoresist 270, the activation layer 260 and the LOR 250 in the preset micro-hole pattern area to obtain a substrate structure with a photoresist micropillar array;

[0069] S27: Deposit a second hydrophobic layer 230 on a substrate structure with a photoresist micropillar array. The second hydrophobic layer 230 simultaneously covers the surface of the positive photoresist 270 and the surface of the hydrophilic layer 240 in the gaps between the photoresist micropillars.

[0070] S28: Perform vapor-phase activation on the second hydrophobic layer 230;

[0071] S29: After vapor phase activation, remove LOR 250, start-up layer 260, positive photoresist 270 and the second hydrophobic layer 230 covering the surface of positive photoresist 270, and retain the second hydrophobic layer 230 on the surface of hydrophilic layer 240 to obtain a second hydrophobic layer 230 with multiple micropores 231 disposed on the surface of hydrophilic layer 240.

[0072] As described in the background section, conventional fabrication processes using ordinary photoresist inevitably lead to incomplete photoresist removal when the micropore density is significantly increased, a defect that is difficult to overcome. To overcome this defect, this invention proposes a process combining a three-layer composite sacrificial layer (i.e., LOR 250, activation layer 260, and positive photoresist 270) with vapor-phase activation. This process ensures that sacrificial layer residue does not occur even when the micropore density increases, thus making it possible to increase the micropore density. The principle of the fabrication process of this invention is as follows:

[0073] 1) The dissolution rate of LOR 250 in the developer is generally higher than that of the top layer of positive photoresist. In step S26, LOR dissolves more laterally, resulting in a mushroom-shaped inverted trapezoidal overhang structure. If there is only a single layer of positive photoresist, the sidewalls after development are usually vertical or slightly trapezoidal. When spin-coating or depositing Teflon, Teflon continuously and uniformly covers the entire photoresist sidewall like a blanket. During photoresist stripping, the stripping solution is physically blocked by the dense Teflon on the outside and cannot reach the internal photoresist, making it completely "impossible to strip". The undercut of LOR disrupts the continuity of the Teflon film, leaving a "breakthrough" for the stripping solution to penetrate.

[0074] 2) The start-up layer 260 is located between LOR 250 and positive photoresist 270. Since LOR 250 and positive photoresist 270 usually require different solvents, or are prone to interpenetration of polymer chains during multiple baking (pre-baking) processes, the start-up layer 260 can prevent the LOR 250 and positive photoresist 270 from dissolving together, making development controllable and forming a perfect undercut profile; it also prevents the second hydrophobic layer 230 at the edge from breaking due to the interpenetration between LOR 250 and positive photoresist 270, resulting in photoresist removal failure.

[0075] 3) The second hydrophobic layer 230 has extremely low surface energy and is a superhydrophobic / oleophobic material. Even if the undercut gap is successfully created by LOR 250, when the wafer is immersed in the liquid resist remover, due to the extremely high surface tension of the liquid, a large contact angle will be formed when it encounters the second hydrophobic layer 230. It cannot squeeze into the micron or even nanometer-scale undercut gap to contact the photoresist at the bottom, and therefore cannot dissolve the photoresist, resulting in incomplete resist removal. By performing vapor phase activation on the second hydrophobic layer 230, the purpose is to modify the surface of the second hydrophobic layer 230 through plasma technology to form a pore structure or increase the surface roughness, creating conditions for the subsequent resist removal steps, so that the photoresist can be removed efficiently and thoroughly.

[0076] Through the above three points, the present invention successfully solves the problems of difficult photoresist removal and photoresist residue in the preparation of high-density micro-hole arrays in existing processes, so that the density of micro-holes is no longer limited, and micro-hole arrays of arbitrary size and spacing can be prepared, thereby enabling digital microfluidic chips to have higher throughput.

[0077] Because the micropore density can be significantly increased, the area occupied by the micropore array is smaller for the same number of micropores. Correspondingly, the area of ​​the distribution zone electrode is also smaller. Therefore, the droplet-driven electrode area has enough space to set up the pretreatment zone electrode, the transition zone electrode, and the waste liquid storage zone electrode, thereby realizing fully enclosed automated processing of liquids. The waste liquid and the sample are physically separated to prevent cross-contamination.

[0078] Step S10 can be prepared using any existing suitable process, which may include the following steps:

[0079] S11: Deposit a first electrode layer 120 on the first substrate 110;

[0080] S12: Deposit a first hydrophobic layer 130 on the first electrode layer 120.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for fabricating a digital microfluidic chip, characterized by, Includes the following steps: S10: Preparation of the first electrode plate; S20: Preparation of the second electrode plate; S30: Assemble the first electrode plate and the second electrode plate so that the first electrode plate and the second electrode plate are positioned opposite each other, and form an interplate cavity between the first electrode plate and the second electrode plate. The first electrode plate and the second electrode plate together drive the liquid to be tested to move in the interplate cavity. Step S20 specifically includes the following steps: S21: Deposit a second electrode layer on the second substrate; S22: Deposit a hydrophilic layer on the second electrode layer; S23: Spin-coat the hydrophilic layer with a release photoresist; S24: Spin-coat an activation layer onto the stripped photoresist; S25: Spin-coat positive photoresist onto the activation layer; S26: Expose and develop the positive photoresist, the activation layer and the stripping photoresist to remove the positive photoresist, the activation layer and the stripping photoresist in the preset micro-hole pattern area to obtain a substrate structure with a photoresist micropillar array; S27: Spin-coat a second hydrophobic layer onto the substrate structure with the photoresist micropillar array, wherein the second hydrophobic layer simultaneously covers the surface of the positive photoresist and the surface of the hydrophilic layer within the gaps between the photoresist micropillars; S28: Perform vapor phase activation on the second hydrophobic layer; S29: After the vapor phase activation, the stripping photoresist, the activation layer, the positive photoresist, and the second hydrophobic layer covering the surface of the positive photoresist are removed, while the second hydrophobic layer on the surface of the hydrophilic layer is retained, resulting in a second hydrophobic layer with multiple micropores disposed on the surface of the hydrophilic layer.

2. The method for fabricating a digital microfluidic chip according to claim 1, characterized in that, The first electrode plate includes a first substrate, a first electrode layer and a first hydrophobic layer, the first electrode layer and the first hydrophobic layer are sequentially disposed on the first substrate, and the first hydrophobic layer is closer to the second electrode plate than the first substrate.

3. The method for fabricating a digital microfluidic chip according to claim 2, characterized in that, The first electrode layer includes a ground electrode region and a droplet driving electrode region. The ground electrode region is used for grounding, and the droplet driving electrode region is used for driving the liquid to be detected to move. The second electrode layer is connected to the ground electrode region.

4. The method of claim 3, wherein the method further comprises: The second electrode layer is connected to the ground electrode area of ​​the first electrode layer by conductive tape.

5. The method of claim 3, wherein the method further comprises: The droplet-driven electrode region includes a pretreatment zone electrode, a transition zone electrode, a waste liquid storage zone electrode, and a distribution zone electrode. The distribution zone electrode is disposed opposite to each micropore, and the transition zone electrode is adjacent to the pretreatment zone electrode, the waste liquid storage zone electrode, and the distribution zone electrode, respectively.

6. The method of claim 5, wherein the method further comprises: The distribution area electrode includes multiple electrode units, which are arranged adjacent to each other in sequence. Each electrode unit includes a first electrode block and a second electrode block arranged adjacent to each other. The first electrode block and the second electrode block are connected in parallel, and an interdigital structure is formed between the adjacent sides of the first electrode block and the second electrode block.

7. The method of claim 6, wherein the method further comprises: An interdigitated structure is formed between the adjacent sides of the two adjacent electrode blocks of any two adjacent electrode units.

8. The method of claim 1, wherein the method further comprises: The thickness of the stripped photoresist is greater than 5 micrometers, and the activation layer is a silane coupling agent with a thickness of less than 10 nanometers.

9. The method of claim 1, wherein the method further comprises: The spacing between any two adjacent micropores is less than or equal to the size of the micropore.

10. A digital microfluidics chip, characterized by, It was prepared using the fabrication method of the digital microfluidic chip as described in claim 1.

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