CN-122006829-A - Preparation method of digital micro-fluidic chip and digital micro-fluidic chip

Abstract

The invention relates to a preparation method of a digital microfluidic chip and the digital microfluidic chip, the method comprises the following steps of S10, S20, S30, assembling the first polar plate and the second polar plate, S20, sequentially preparing a second electrode layer, a hydrophilic layer, a stripping photoresist, a starting layer and a positive photoresist on a second substrate, exposing and developing the positive photoresist, the starting layer and the stripping photoresist, removing the positive photoresist, the starting layer and the stripping photoresist in a preset micropore 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 gas phase activation on the second hydrophobic layer, removing the stripping photoresist, the starting layer, the positive photoresist and the second hydrophobic layer covered by the surface of the positive photoresist, and obtaining the second hydrophobic layer with a plurality of micropores arranged on the surface of the hydrophilic layer.

Inventors

• MAO HONGJU
• YANG WEIDONG

Assignees

• 上海市浦东医院（复旦大学附属浦东医院）

Dates

Publication Date

20260512

Application Date

20260408

Claims (10)

1. 1. The preparation method of the digital micro-fluidic chip is characterized by comprising the following steps of: S10, preparing a first polar plate; S20, preparing a second polar plate; s30, assembling the first polar plate and the second polar plate, so that the first polar plate and the second polar plate are arranged oppositely, a plate cavity is formed between the first polar plate and the second polar plate, and the first polar plate and the second polar plate jointly drive the liquid to be detected to move in the plate cavity; The step S20 specifically includes the following steps: S21, depositing a second electrode layer on a second substrate; s22, depositing a hydrophilic layer on the second electrode layer; s23, stripping photoresist on the hydrophilic layer in a spin coating way; s24, spin coating a starting layer on the stripped photoresist; s25, spin-coating positive photoresist on the starting layer; S26, exposing and developing the positive photoresist, the starting layer and the stripping photoresist, and removing the positive photoresist, the starting layer and the stripping photoresist in a preset micropore pattern area to obtain a substrate structure with a photoresist micro-column array; s27, spin-coating a second hydrophobic layer on the substrate structure with the photoresist micro-column array, wherein the second hydrophobic layer covers the surface of the positive photoresist and the surface of the hydrophilic layer in the photoresist micro-column gap; s28, performing gas-phase activation on the second hydrophobic layer; And S29, removing the stripping photoresist, the starting layer, the positive photoresist and the second hydrophobic layer covered on the surface of the positive photoresist after the gas-phase activation, and reserving the second hydrophobic layer on the surface of the hydrophilic layer to obtain a second hydrophobic layer with a plurality of micropores, wherein the second hydrophobic layer is arranged on the surface of the hydrophilic layer.
2. 2. The method for manufacturing a digital microfluidic chip according to claim 1 wherein the first plate comprises a first substrate, a first electrode layer and a first hydrophobic layer, the first electrode layer and the first hydrophobic layer being sequentially disposed on the first substrate, the first hydrophobic layer being closer to the second plate than the first substrate.
3. 3. The method for manufacturing a digital microfluidic chip according to claim 2, wherein the first electrode layer includes a ground electrode region for grounding and a droplet driving electrode region for driving the liquid to be detected to move, and the second electrode layer is connected to the ground electrode region.
4. 4. The method of manufacturing a digital microfluidic chip according to claim 3 wherein the second electrode layer is connected to the ground electrode region of the first electrode layer by a conductive tape.
5. 5. The method of manufacturing a digital microfluidic chip according to claim 3 wherein said droplet drive electrode region comprises a pretreatment region electrode, a transition region electrode, a waste liquid storage region electrode, and a distribution region electrode, said distribution region electrode being disposed opposite each microwell, said transition region electrode being adjacent to said pretreatment region electrode, said waste liquid storage region electrode, and said distribution region electrode, respectively.
6. 6. The method for manufacturing a digital microfluidic chip according to claim 5 wherein said distribution area electrode comprises a plurality of electrode units, each of said electrode units being disposed adjacent one another in sequence, each of said electrode units comprising a first electrode block and a second electrode block disposed adjacent one another, the first electrode block and the second electrode block being connected in parallel with one another, and an interdigital structure being formed between adjacent sides of said first electrode block and said second electrode block.
7. 7. The method of manufacturing a digital microfluidic chip according to claim 6 wherein an inter-digitated structure is formed between adjacent sides of two adjacent electrode blocks of any two adjacent electrode units.
8. 8. The method of claim 1, wherein the thickness of the stripped photoresist is greater than 5 microns, the initiation layer is a silane coupling agent, and the thickness of the initiation layer is less than 10 nanometers.
9. 9. The method of manufacturing a digital microfluidic chip according to claim 1 wherein the spacing between any two adjacent microwells is equal to or less than the size of the microwells.
10. 10. A digital micro-fluidic chip is characterized in that, the method for preparing the digital micro-fluidic chip according to claim 1.

Description

Preparation method of digital micro-fluidic chip and digital micro-fluidic chip Technical Field The invention relates to the technical field of biological detection, in particular to a preparation method of a digital micro-fluidic chip and the digital micro-fluidic chip. Background The digital microfluidic chip (Digital Microfluidic Chip, DMFC) is used as an important branch of a microfluidic technology, realizes precise driving, segmentation, fusion and mixing of discrete liquid drops through electrowetting, dielectrophoresis and other electric control modes, has the remarkable advantages of low reagent consumption, high reaction integration level, high automation degree, low cross contamination risk and the like, and is widely applied to biological detection, such as nucleic acid detection, protein detection, cell detection and the like. The digital micro-fluidic technology can realize operations such as automatic movement, splitting, mixing and the like of liquid drops by means of electrowetting effect, and has important application value in the fields of biochemical analysis, nucleic acid detection, microsphere separation and the like, but is limited by the number of electrodes, the cost of chips and the difficulty in controlling the size of the liquid drops, so that nano-liter or even picoliter small liquid drops are difficult to generate in high flux, and the liquid drop micro-array technology realizes capturing and arrangement of micro-liquid drops by means of the surface hydrophilic-hydrophobic wettability difference, so that the liquid drops with small volumes can be obtained, but generally depends on manual operation, has low automation and integration degree, is easy to introduce artificial errors, and is difficult to meet the multivariable control requirement of high-flux experiments. In order to solve the technical pain point, the Chinese patent application with publication number of CN118751301A proposes to combine a liquid drop microarray with a digital microfluidic, and constructs a hydrophilic-hydrophobic array on a polar plate of the digital microfluidic chip, so that when a mother liquid drop is driven to pass through the hydrophilic-hydrophobic array by utilizing an electrowetting effect, sub liquid drops are adhered and separated at hydrophilic vacant sites by means of wettability difference, and automatic generation of the micro liquid drop array is realized. The technology can realize the advantages of automatic control of digital microfluidics and micro-droplet generation of a droplet microarray, and realize the preparation of droplets with different picoliter to nanoliter, but has the key technical defects in the preparation technology of a hydrophilic-hydrophobic array, the arrangement density of hydrophilic vacancy sites is strictly limited, the preparation of a high-density hydrophilic-hydrophobic array cannot be realized, and the high-flux performance of the droplet microarray is further restricted. Specifically, the adjacent hydrophilic vacancy site spacing of the hydrophilic-hydrophobic array in the prior art needs to be larger than 1.5 times of the vacancy site size, and only the hydrophilic vacancy site array with low density can be prepared. The core reason for this limitation is that when the existing process prepares hydrophilic vacant sites by photoresist forming a patterned sacrificial layer, spin coating a hydrophobic layer and then photoresist removing, teflon (polytetrafluoroethylene, PTFE) is directly spin coated and cured on the photoresist, forming a dense, chemically inert barrier that is difficult to penetrate or dissolve by conventional photoresist removing solutions. If the distance between adjacent vacant sites is reduced, the Teflon is more likely to form root wrapping or sealing at the bottom of the microcolumn, and the wrapping body cannot be completely removed in the subsequent conventional liquid phase photoresist stripping (such as solvent soaking) due to the fact that the solvent is difficult to permeate the compact Teflon wrapping layer, so that the photoresist is not completely removed, and permanent residues are formed. Therefore, how to break through the limitation of the existing technology and realize the stable preparation of the hydrophilic-hydrophobic array with high-density vacancy sites is a technical problem to be solved by the technicians in the field. Disclosure of Invention The invention aims to provide a preparation method of a digital micro-fluidic chip and the digital micro-fluidic chip so as to solve the technical problems. Based on the above object, the present invention provides a method for preparing a digital microfluidic chip, which includes the following steps: S10, preparing a first polar plate; S20, preparing a second polar plate; s30, assembling the first polar plate and the second polar plate, so that the first polar plate and the second polar plate are arranged oppositely, a plate cavity is formed between the first polar p