Microporous chip design method for efficient fluid distribution and displacement

Abstract

The invention relates to the technical field of design of microporous chips, in particular to a design method of a microporous chip capable of efficiently distributing and displacing fluid. Comprising the following steps: S1, simulating a microporous chip with a blind hole structure; s2, simulating and applying fluid driving pressure to the blind hole structure, and determining an optimal driving pressure range according to a fluid displacement sampling effect; s3, performing differential hydrophilic and hydrophobic modification on the wall surface of the blind hole structure, and determining an optimal contact angle combination according to a fluid displacement sampling effect; and S4, based on the optimal contact angle combination, simulating the depth-to-width ratio of the blind hole structure, and determining the optimal depth-to-width ratio according to the fluid displacement sampling effect. In the application, the microporous chip with the blind hole structure only needs an opening in a single side, so that compared with a microporous chip with a through hole structure, the sample introduction process is more convenient, the operation process is simpler, and the process complexity is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of microchannel chip design, and particularly relates to a design method for a microchannel chip with efficient fluid distribution and displacement. Background Art

[0002] The microchannel chip mainly adopts through-hole and blind-hole sample distribution schemes. The through-hole structure has upper and lower surfaces communicating with each other, and the sample injection is relatively simple. However, in practical applications, it is necessary to consider the oil seal for double-sided samples, which puts higher requirements on the packaging of the rear flow channels and reduces the heat conduction efficiency. After using through-hole injection and sealing one side by means of film sticking or the like, although the sealing can be simplified while ensuring the injection effect, it is necessary to introduce high-precision film sticking equipment and ensure the stability and consistency of film sticking. The operation process is relatively cumbersome, increasing the process complexity and cost. Moreover, there is a lack of a design method for a microchannel chip for the blind-hole sample distribution scheme. Summary of the Invention

[0003] In view of this, the present invention provides a design method for a microchannel chip with efficient fluid distribution and displacement to solve the problems of relatively complex process caused by the existing through-hole sample distribution scheme and the lack of a design method for a microchannel chip for the blind-hole sample distribution scheme in the prior art.

[0004] The present invention provides a design method for a microchannel chip with efficient fluid distribution and displacement, including:

[0005] S1, simulating a microchannel chip with a blind-hole structure;

[0006] S2, simulating and applying a fluid driving pressure on the blind-hole structure, and determining an optimal driving pressure range according to the fluid displacement injection effect;

[0007] S3, performing differential hydrophilic-hydrophobic modification on the wall surface of the blind-hole structure, and determining an optimal contact angle combination according to the fluid displacement injection effect;

[0008] S4, based on the optimal contact angle combination, simulating the depth-width ratio of the blind-hole structure, and determining an optimal depth-width ratio according to the fluid displacement injection effect.

[0009] In the present application, the microchannel chip with a blind-hole structure only needs to be opened on one side. Compared with the microchannel chip with a through-hole structure, the injection process is more convenient, the operation process is relatively simple, and the process complexity is reduced. The present application also selects the driving pressure of the fluid, the contact angle combination of the wall surface, and the depth-width ratio through the fluid displacement injection effect, so that the fluid displacement injection effect of the microchannel chip meets the design requirements.

[0010] In an alternative embodiment, the blind hole structure includes a flow channel layer and a microporous layer. The microporous layer is a blind hole, and the opening of the microporous layer communicates between the inlet and the outlet of the flow channel layer. The fluid driving pressure is applied at the inlet position of the flow channel layer.

[0011] In the present application, the microporous layer only needs to have a single-sided opening, and the flow channel layer is independently responsible for fluid transmission, avoiding the need for double-sided sealing (such as the film pasting process for through holes), and reducing the packaging complexity. The driving pressure is applied to the inlet of the flow channel layer and directly acts on the microporous opening through the flow channel, ensuring uniform pressure distribution to all blind holes and avoiding local overpressure leading to bubbles.

[0012] In an alternative embodiment, the flow channel layer and the microporous layer are filled with a non-gas-permeable material. The non-gas-permeable material has a relatively low cost, can completely block gas exchange, avoid steam escape and intrusion of external pollutants, significantly reduce the bubble problem, and has better high-temperature resistance performance.

[0013] In an alternative embodiment, the step S2 includes:

[0014] S21, selecting a sample solution to perform a displacement simulation on air;

[0015] S22, applying a plurality of driving pressures at the inlet position of the flow channel layer and respectively recording the displacement injection effect of the sample solution on air;

[0016] S23, eliminating the driving pressures that do not meet the requirements based on the phenomenon of wrapped bubbles to obtain the optimal driving pressure range.

[0017] In the present application, by applying a plurality of driving pressures to the inlet position of the flow channel layer respectively to obtain the displacement injection effects under different driving pressures, a suitable driving pressure can be selected as the optimal driving pressure range according to the phenomenon of wrapped bubbles in the displacement injection effect.

[0018] In an alternative embodiment, in the step S23, the phenomenon of wrapped bubbles includes the ease of generation and discharge of wrapped bubbles.

[0019] In the present application, the phenomenon of wrapped bubbles can be used to judge whether the displacement injection effect meets the requirements.

[0020] In an alternative embodiment, the flow channel layer is located above the microporous layer. The wall surface above the fluid in the flow channel layer is the upper wall surface, and the wall surface below the fluid in the flow channel layer is the lower wall surface.

[0021] In the present application, the upper wall surface and the upper wall surface can isolate the fluid in the flow channel layer and the microporous layer from the outside world, preventing the fluid in the flow channel layer and the microporous layer from permeating or being contaminated by the outside world. The microporous layer can store the sample solution for performing PCR reactions. The flow channel layer can retain the dispensing liquid to seal the sample solution in the microporous layer.

[0022] In an alternative embodiment, step S3 includes:

[0023] S31, selecting a sample solution to perform a displacement simulation on air;

[0024] S32, arranging and combining the contact angle combinations between the sample solution and the upper wall surface and the lower wall surface respectively, and respectively recording the displacement injection effect of the sample solution on air;

[0025] S33, eliminating the contact angle combinations that do not meet the requirements based on the phenomenon of bubble wrapping to obtain the first optimal contact angle combination.

[0026] In the present application, the hydrophilicity or hydrophobicity of the upper wall surface and the lower wall surface can be characterized by setting the contact angle combinations on the simulation software. The hydrophilic contact angle and the hydrophobic contact angle are sequentially set on the upper wall surface and the lower wall surface in the form of permutation and combination. By observing and recording the displacement injection effect of the sample solution on air, the contact angle combinations that do not meet the requirements are eliminated.

[0027] In an alternative embodiment, step S3 further includes:

[0028] S34, selecting a dispensing liquid to perform a displacement simulation on the sample solution;

[0029] S35, arranging and combining the contact angle combinations between the dispensing liquid and the upper wall surface and the lower wall surface respectively, and respectively recording the displacement injection effect of the dispensing liquid on the sample solution;

[0030] S36, eliminating the contact angle combinations that do not meet the requirements based on the retention volume ratio of the sample solution and the sealing and layering of the dispensing liquid to obtain the second optimal contact angle combination.

[0031] In an alternative embodiment, step S4 includes:

[0032] S41, based on the second optimal contact angle combination, selecting a dispensing liquid to perform a displacement simulation on the sample solution;

[0033] S42, simulating multiple depth-to-width ratios of the microporous layer and respectively recording the displacement injection effect of the dispensing liquid on the sample solution;

[0034] S43, obtaining the depth-to-width ratio that meets the requirements based on the retention volume ratio of the sample solution.

[0035] In the present application, displacement simulation is performed on the sample solution using the dispensing liquid, enabling the dispensing liquid to displace a portion of the sample solution and perform layered sealing. It is necessary to retain a certain proportion of the sample solution to meet the requirements of subsequent PCR reactions.

[0036] In an alternative embodiment, step S4 further includes:

[0037] S44, based on the aspect ratio that meets the requirements, sequentially select the sample solution to perform displacement simulation on the air, and respectively record the displacement injection effect of the sample solution on the air;

[0038] S45, based on the phenomenon of bubble encapsulation, eliminate the aspect ratios that do not meet the requirements to obtain the optimal aspect ratio.

[0039] In the present application, the obtained aspect ratio that meets the requirements also needs to enable the sample solution to meet the displacement requirements of the sample solution when displacing the air, and be able to completely displace the air from the microporous layer and the flow channel layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings 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.

[0041] Figure 1 Schematic diagram of the principle of the embodiment of the present invention;

[0042] Figure 2 Schematic diagram of the principle of step S2 of the embodiment of the present invention;

[0043] Figure 3 Schematic diagram of the displacement of the sample solution on the air when the driving pressure of the embodiment of the present invention is 200 Pa to 1000 Pa;

[0044] Figure 4 Schematic diagram of the displacement of the sample solution on the air when the driving pressure of the embodiment of the present invention is 1000 Pa to 3000 Pa;

[0045] Figure 5 Schematic diagram of the displacement of the sample solution on the air when the driving pressure of the embodiment of the present invention is greater than 3000 Pa;

[0046] Figure 6 Schematic diagram of the microporous chip structure of the embodiment of the present invention;

[0047] Figure 7 Schematic diagram of the principle of step S3 of the embodiment of the present invention;

[0048] Figure 8 Schematic diagram of the contact angle in the embodiment of the present invention;

[0049] Figure 9 Schematic diagram of the displacement of the sample solution by air when the sample solution has a hydrophobic contact angle with both the upper and lower wall surfaces in the embodiment of the present invention;

[0050] Figure 10 Schematic diagram of the displacement of the sample solution by air when the sample solution has a hydrophobic contact angle with the upper wall surface and a hydrophilic contact angle with the lower wall surface in the embodiment of the present invention;

[0051] Figure 11 Schematic diagram of the displacement of the sample solution by air when the sample solution has a hydrophilic contact angle with both the upper and lower wall surfaces in the embodiment of the present invention;

[0052] Figure 12 Schematic diagram of the displacement of the sample solution by the dispensing liquid when the dispensing liquid has a hydrophobic contact angle with both the upper and lower wall surfaces 4 in the embodiment of the present invention;

[0053] Figure 13 Schematic diagram of the displacement of the sample solution by the dispensing liquid when the dispensing liquid has a hydrophilic contact angle with the upper wall surface 3 and a hydrophobic contact angle with the lower wall surface 4 in the embodiment of the present invention;

[0054] Figure 14 Schematic diagram of the displacement of the sample solution by the dispensing liquid when the dispensing liquid has a hydrophobic contact angle with the upper wall surface 3 and a hydrophilic contact angle with the lower wall surface 4 in the embodiment of the present invention;

[0055] Figure 15 Schematic diagram of the principle of step S4 in the embodiment of the present invention;

[0056] Figure 16 Schematic diagram of the aspect ratio of the micro - pores in the embodiment of the present invention;

[0057] Figure 17 Schematic diagram of the displacement of the sample solution by the dispensing liquid when the aspect ratio of the micro - pores in the embodiment of the present invention is 1:1;

[0058] Figure 18 Schematic diagram of the displacement of the sample solution by air when the aspect ratio of the micro - pores in the embodiment of the present invention is 2:1.

[0059] Explanation of the reference numerals:

[0060] 1, flow channel layer; 2, micro - pore layer; 3, upper wall surface; 4, lower wall surface. Detailed implementation manners

[0061] 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 accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0062] Digital PCR (dPCR) divides a sample into dozens to tens of thousands of parts and distributes them to different reaction units. The target molecules are respectively amplified by PCR in each unit, and the concentration of the original sample is obtained by collecting and statistically analyzing the signals of each reaction unit. It is an absolute quantitative nucleic acid amplification technology, and the key to its quantitative accuracy lies in how to achieve efficient sample distribution. There are mainly two types of dPCR sample distribution methods: droplet-based and microchamber-based. The droplet-based method disperses the sample into tens of thousands to millions of nanoliter water-in-oil microdroplets, and each microdroplet is used as an independent reaction unit for subsequent PCR reactions; the microchamber-based method uses physical segmentation to distribute the sample into a fixed number of microholes, and each microhole independently conducts PCR reactions. The microchamber-based method has a stable physically isolated space, and the cavity volume is fixed and uniform, with higher uniformity compared to the droplet-based method. It can also effectively avoid signal interference problems caused by droplet fusion or rupture. At the same time, the microchamber-based method does not rely on droplet generation and is more convenient to operate, especially suitable for scenarios with high requirements for precision and reliability such as trace nucleic acid analysis, pathogen quantification, and clinical diagnosis.

[0063] The following will describe the embodiments of the present invention in conjunction with Figures 1 to 18 , describe the embodiments of the present invention.

[0064] According to the embodiments of the present invention, as Figure 1 shown, a design method for a microhole chip for efficient fluid distribution and displacement is provided, including:

[0065] S1, simulating a microhole chip with a blind hole structure; specifically, simulation software such as COMSOL Multiphysics or Anasys Fluent can be used to achieve this.

[0066] S2, simulating and applying a fluid driving pressure on the blind hole structure, and determining the optimal driving pressure range according to the fluid displacement injection effect;

[0067] S3, performing differential hydrophilic and hydrophobic modification on the wall surface of the blind hole structure, and determining the optimal contact angle combination according to the fluid displacement injection effect;

[0068] S4, based on the optimal contact angle combination, simulating the depth-to-width ratio of the blind hole structure, and determining the optimal depth-to-width ratio according to the fluid displacement injection effect.

[0069] In this application, the microporous chip with a blind hole structure only needs a single-side opening, so the injection process is more convenient and the operation process is relatively simple compared to the microporous chip with a through-hole structure, which reduces the process complexity. This application also selects the fluid driving pressure, the contact angle combination of the wall surface, and the depth-to-width ratio through the fluid displacement injection effect, so that the fluid displacement injection effect of the microporous chip meets the design requirements.

[0070] Among them, micro-cavity chips mainly use through-hole and blind-hole sample distribution schemes. The through-hole structure is connected to the upper and lower surfaces, and the injection is relatively simple, but in practical applications, it is necessary to consider the oil sealing of double-sided samples, which puts higher requirements on the back-end flow channel packaging and reduces the heat conduction efficiency. After the through-hole injection, one side is sealed by film pasting, etc. Although it can simplify the sealing while ensuring the injection effect, it is necessary to introduce high-precision film pasting equipment, and the stability and consistency of the film pasting must be ensured. The operation process is relatively cumbersome, which increases the process complexity and cost. In comparison, the blind hole structure only requires a single-side opening, so the injection process is the most convenient. A blind hole is a structure that is open only on one side of the microcavity (such as a microporous layer 2, which is open only on one side and connected to the flow channel layer 1, and the rest is isolated by the wall). The bottom of the microcavity is closed, and the sample solution needs to be filled through a single opening, and cannot penetrate the entire chip; a through hole is a microcavity structure that runs through the upper and lower surfaces of the chip, and the two ends of the microcavity are open (the microporous layer 2 of the through hole structure is provided with two openings, which can be regarded as an opening at the bottom of the microporous layer 2 of the blind hole structure, and a second flow channel layer 1 is provided to connect it, and the two openings of the microporous layer 2 in the through hole structure are sealed through the two flow channel layers 1), allowing fluid to flow in from one side and out from the other side. Blind hole chips can seal the reaction environment to prevent reagent contamination and reagent evaporation, etc.

[0071] In an optional embodiment, the blind hole structure includes a flow channel layer 1 and a microporous layer 2, the microporous layer 2 is a blind hole, the opening of the microporous layer 2 is connected between the inlet and outlet of the flow channel layer 1, and the fluid driving pressure is applied at the inlet position of the flow channel layer 1.

[0072] The flow channel layer 1 and the microporous layer 2 can be bonded to form a chip. The flow channel layer 1 can be machined to dig out flow channels for reagent flow, diffusion and oil sealing; the microporous layer 2 can be machined to dig out micropores for storing sample solutions.

[0073] In this application, the microporous layer 2 only needs to be opened on one side, and the flow channel layer 1 is independently responsible for fluid transmission, avoiding the need for double-sided sealing (such as the film lamination process of the through hole) and reducing the complexity of packaging. The driving pressure is applied to the inlet of the flow channel layer 1, and directly acts on the microporous opening through the flow channel to ensure that the pressure is evenly distributed to all blind holes, avoiding excessive local pressure and bubbles.

[0074] In an alternative embodiment, the flow channel layer 1 and the microporous layer 2 are filled with a non-permeable material. The non-permeable material has a relatively low cost, can completely block gas exchange, prevent steam from escaping and external pollutants from invading, significantly reduce the bubble problem, and has better high-temperature resistance performance.

[0075] The realization of efficient fluid injection in the blind hole structure depends on the collaborative design of material properties and displacement mechanisms. Blind holes made of permeable materials (such as PDMS, etc.) can achieve self-driven injection through gas permeation to generate negative pressure. However, in practical applications, there are still problems of consistency and cost, and the material cost is high. Since permeable materials allow gas to pass through, it may cause water vapor diffusion, resulting in bubbles or liquid evaporation during the PCR process. The non-permeable material has a low cost, and the airtight encapsulation design can completely block gas exchange, prevent steam from escaping and external pollutants from invading, significantly reduce the bubble problem, and has better high-temperature resistance performance.

[0076] It should be noted that for non-permeable materials (such as thermoplastic polymers, silicon, or glass, etc.), how efficient the digital distribution of blind hole fluid displacement is, what the correlation is with the modification effect of the interface, external driving pressure, etc., and how to guide the structural design of the microcavity need to be systematically analyzed.

[0077] This application designs the key factors affecting efficient fluid injection in blind holes, including driving pressure, wall contact angle modification, and microporous structure. The driving fluid adopts a positive pressure driving method, and the pressure magnitude is closely related to the fluid injection state. If the pressure is too high, bubbles are likely to be generated in the fluid; if the pressure is too low, the injection efficiency will be affected. The wall modification should set the corresponding modified contact angle according to the cooperation mode of different fluids with the upper and lower walls 4 of the micropores. Under pressure driving, the fluid autonomously selects to enter the pores and displace through the difference in the modified structure. The aspect ratio of the micropores affects the fluid displacement effect. Appropriately increasing the aspect ratio is more conducive to fluid displacement and can retain more sample solutions. However, if the aspect ratio is too large, it will affect the sample entry process into the pores. Through this design of the efficient displacement method, it is used to guide the preparation process of the dPCR micropore chip. Among them, the displacement process is divided into two steps. The first step is to inject the sample solution to displace the air in the micropores, and the second step is to inject the dispensing solution to displace the sample solution. In the present invention, a classic micropore morphology is adopted, which is divided into a flow channel layer 1 and a microporous layer 2. The upper wall of the flow channel layer 1 is the upper wall surface 3, and the lower wall of the flow channel layer 1 and the inner wall surface of the microporous layer 2 are the lower wall surface 4. The sample solution is used to enter the micropores and perform PCR reactions, and the dispensing solution is used to displace the sample solution in the flow channel layer 1 and seal the micropores.

[0078] In an alternative embodiment, as Figure 2 shown, the step S2 includes:

[0079] S21, select a sample solution to perform a displacement simulation on the air;

[0080] S22. Apply multiple driving pressures at the inlet position of the flow channel layer 1, and record the displacement injection effect of the sample solution on air respectively.

[0081] S23. Eliminate the driving pressures that do not meet the requirements based on the bubble wrapping phenomenon, and obtain the optimal driving pressure range.

[0082] In this application, by applying multiple driving pressures at the inlet position of the flow channel layer 1 respectively to obtain the displacement injection effects under different driving pressures, the appropriate driving pressure can be selected as the optimal driving pressure range according to the bubble wrapping phenomenon in the displacement injection effect.

[0083] It should be noted that the ideal displacement injection effect is that the microchannel layer 2 is the sample solution for subsequent PCR reactions; the flow channel layer 1 is the dispensing solution to seal the microchannel layer 2 and prevent the sample solution from flowing out of the microchannels during the PCR reaction.

[0084] This application proposes a method for determining the critical pressure. The pressure is a positive pressure used to drive fluid injection. By simulation under different pressure conditions, the fluid injection effect is investigated. As Figures 3 to 5 shown, this application successively uses driving pressures of 200 Pa to 1000 Pa, 1000 Pa to 3000 Pa, and greater than 3000 Pa to simulate the displacement of air by the sample solution and its entry into the microchannel layer 2. As Figure 3 shown, when the driving pressure is 200 Pa to 1000 Pa, the sample solution slowly enters the microchannel layer 2 along the wall and displaces the air in the pores. As Figure 4 shown, when the driving pressure is 1000 Pa to 3000 Pa, although the sample solution can displace the air, the sample wrapping bubble phenomenon is very likely to occur during the displacement process, and it may also be difficult to discharge the wrapped bubbles during the actual injection process. As Figure 5 shown, when the driving pressure is greater than 3000 Pa, when the sample solution displaces the air, the sample wrapping bubble phenomenon is very likely to occur during the displacement process, and it may also be difficult to discharge the wrapped bubbles during the actual injection process. It can be seen that when the driving pressure ≤ 1000 Pa, the fluid can uniformly enter the microchannels along the wall. If the pressure is too small, the fluid flow cannot be driven, reducing the injection efficiency. It should be noted that the optimal driving pressure range is applicable to the process of displacing the sample solution with the dispensing solution.

[0085] In an alternative embodiment, in step S23, the bubble wrapping phenomenon includes the ease of generation and discharge of wrapped bubbles. Specifically, the driving pressure without the generation of wrapped bubbles can be considered to meet the conditions. If wrapped bubbles are generated, the driving pressure with a relatively short discharge time can be considered to meet the conditions.

[0086] In this application, the bubble wrapping phenomenon can be used to judge whether the displacement injection effect meets the requirements.

[0087] In an alternative embodiment, as Figure 6 shown, the flow channel layer 1 is located above the microporous layer 2. The wall surface above the fluid in the flow channel layer 1 is the upper wall surface 3, and the wall surface below the fluid in the flow channel layer 1 is the lower wall surface 4.

[0088] In the present application, the upper wall surface 3 and the upper wall surface 3 can isolate the fluids in the flow channel layer 1 and the microporous layer 2 from the outside world, preventing the fluids in the flow channel layer 1 and the microporous layer 2 from permeating or being contaminated by the outside world. The microporous layer 2 can store the sample solution for performing PCR reactions. The flow channel layer 1 can retain the dispensing liquid to seal the sample solution in the microporous layer 2.

[0089] In an alternative embodiment, as Figure 7 shown, the step S3 includes:

[0090] S31, selecting a sample solution to perform a displacement simulation on air; specifically, the displacement simulation can be performed on the basis of the optimal driving pressure range.

[0091] S32, arranging and combining the contact angle combinations between the sample solution and the upper wall surface 3 and the lower wall surface 4 respectively, and recording the displacement injection effects of the sample solution on air respectively; wherein, as Figure 8 shown, in the simulation software, the contact angle of the upper wall surface 3 can be marked as α, and the contact angle of the lower wall surface 4 can be marked as θ. The hydrophobic contact angle can be considered as a contact angle greater than 90°, and the hydrophilic contact angle can be considered as a contact angle less than 90°, which can be set at 50°. When the fluid flows in the flow channel, due to the hydrophilic and hydrophobic properties, a certain angle, that is, the hydrophilic / hydrophobic angle, will be formed.

[0092] S33, eliminating the contact angle combinations that do not meet the requirements based on the phenomenon of bubble wrapping to obtain the first optimal contact angle combination.

[0093] In the present application, the hydrophilicity or hydrophobicity of the upper wall surface 3 and the lower wall surface 4 can be characterized by setting the contact angle combinations on the simulation software. The hydrophilic contact angle and the hydrophobic contact angle are sequentially set on the upper wall surface 3 and the lower wall surface 4 in the form of arrangement and combination, and the contact angle combinations that do not meet the requirements are eliminated by observing and recording the displacement injection effects of the sample solution on air.

[0094] Based on the optimal driving pressure range, the present application proposes a method for modifying the microporous wall surface, which enables the fluid to enter the pores and be displaced autonomously by using the difference in the modification structure. Different hydrophilic and hydrophobic treatments are performed on the microporous wall surface through simulation, and the injection displacement effects of the sample solution are investigated. Specifically, in the present application, during the process of the sample solution displacing air, as Figures 9 to 11As shown, the sample solution and the upper and lower wall surfaces 4 are set to have hydrophobic contact angles in sequence, the sample solution and the upper wall surface 3 have a hydrophobic contact angle and the lower wall surface 4 has a hydrophilic contact angle, and the sample solution and the upper and lower wall surfaces 4 both have hydrophilic contact angles. Among them, as Figure 9 shown, the sample solution and the upper and lower wall surfaces 4 both have hydrophobic contact angles, and the sample solution cannot completely displace the air, and the air accumulates at the bottom of the micropores; as Figure 10 shown, α≥90°, θ≤50°, the sample solution and the upper wall surface 3 have a hydrophobic contact angle, and the lower wall surface 4 has a hydrophilic contact angle. The sample solution completely displaces the air, and the sample solution enters the micropores; as Figure 11 shown, α≤90°, θ≤50°, the sample solution and the upper and lower wall surfaces 4 both have hydrophilic contact angles. Although the sample solution can completely displace the air, the phenomenon of the sample solution wrapping the bubbles is very likely to occur during the displacement process, and it may also be difficult to discharge the wrapped bubbles during the actual sample injection process. It can be seen that during the process of the sample solution entering the pores, the sample solution and the upper wall surface 3 have a hydrophobic contact angle, and the lower wall surface 4 has a hydrophilic contact angle. The sample solution mainly adheres to the lower wall surface 4 and enters the micropores and completely displaces the air in the pores, effectively ensuring the uniform sample solution entering the pores.

[0095] In an alternative embodiment, the step S3 further includes:

[0096] S34, selecting a dispensing liquid to perform a displacement simulation on the sample solution; specifically, the displacement simulation can be performed on the basis of the optimal driving pressure range.

[0097] S35, arranging and combining the contact angle combinations between the dispensing liquid and the upper wall surface 3 and the lower wall surface 4 respectively, and respectively recording the displacement injection effects of the dispensing liquid on the sample solution;

[0098] S36, eliminating the contact angle combinations that do not meet the requirements based on the retention volume ratio of the sample solution and the sealed stratification of the dispensing liquid, and obtaining the second optimal contact angle combination.

[0099] Specifically, in this application, during the process of the dispensing liquid displacing the sample solution and sealing the micropores, as Figures 12 to 14 shown, the dispensing liquid and the upper and lower wall surfaces 4 are set to have hydrophobic contact angles in sequence, the dispensing liquid and the upper wall surface 3 have a hydrophilic contact angle and the lower wall surface 4 has a hydrophobic contact angle, and the dispensing liquid and the upper wall surface 3 have a hydrophobic contact angle and the lower wall surface 4 has a hydrophilic contact angle. Among them, as Figure 12 shown, α≥90°, θ≥90°, the dispensing liquid and the upper and lower wall surfaces 4 both have hydrophobic contact angles, and the dispensing liquid displaces the sample in the micropores, and only ±10% of the sample solution remains; as Figure 13 shown, the dispensing liquid and the upper wall surface 3 have a hydrophilic contact angle, and the lower wall surface 4 has a hydrophobic contact angle. The dispensing liquid displaces part of the sample in the micropores, and 60% of the sample solution remains, and a sealing layer is formed on the upper layer of the sample; as Figure 14As shown, the contact angle between the dispensing liquid and the upper wall surface 3 is hydrophobic, and the contact angle with the lower wall surface 4 is hydrophilic. The dispensing liquid displaces all the samples in the micropores, making it impossible to carry out subsequent PCR reactions. It can be seen that during the process of the dispensing liquid displacing the sample solution, the contact angle between the dispensing liquid and the upper wall surface 3 is hydrophilic, and the contact angle with the lower wall surface 4 is hydrophobic. The dispensing liquid mainly adheres to the upper wall surface 3 and flows, displacing and dividing the sample solution in the flow channel layer 1. The retained volume ratio of the sample solution in the pores is 60%, and the dispensing liquid forms a sealing layer on the upper layer of the sample solution.

[0100] It should be noted that the hydrophilic and hydrophobic degrees of the upper wall surface 3 and the lower wall surface 4 with respect to the sample solution and the dispensing liquid are determined by their own characteristics, and the hydrophilic and hydrophobic degrees of the same wall surface with respect to the sample solution and the dispensing liquid can be different. Before bonding the flow channel layer 1 and the microporous layer 2, different hydrophilic modification treatments can be performed, such as plasma cleaning.

[0101] In an alternative embodiment, as Figure 15 shown, step S4 includes:

[0102] S41, based on the optimal contact angle combination, select a dispensing liquid to perform a displacement simulation on the sample solution;

[0103] S42, simulate the aspect ratios of multiple microporous layers 2, and respectively record the displacement injection effects of the dispensing liquid on the sample solution; among them, as Figure 16 shown, the pore depth can be marked as h, and the pore width can be marked as d. The aspect ratio of the micropore is h:d.

[0104] S43, based on the retained volume ratio of the sample solution, obtain the aspect ratio that meets the requirements.

[0105] In this application, selecting a dispensing liquid to perform a displacement simulation on the sample solution can make the dispensing liquid displace a part of the sample solution and perform layered sealing. It is necessary to keep a certain proportion of the sample solution to meet the requirements of subsequent PCR reactions.

[0106] This application proposes a design scheme for the aspect ratio of the microporous structure to reduce the displacement effect between fluids. By setting different aspect ratio conditions, the effects of the dispensing liquid displacing the sample solution under different conditions are simulated. As Figure 17 shown, simulating the dispensing liquid displacing the sample solution and sealing the micropores, the aspect ratio of the micropores increases from 1:2 to 1:1. The contact angle between the dispensing liquid and the upper wall surface is hydrophilic, and the contact angle with the lower wall surface is hydrophobic. The dispensing liquid displaces some of the samples in the micropores. 85% of the sample solution is retained, and a sealing layer is formed on the upper layer of the sample. Appropriately increasing the aspect ratio of the micropores is beneficial for the dispensing liquid to divide the sample units and seal the micropores. It can be seen that the results show that when the aspect ratio is 1:1, the retained volume ratio of the sample solution in the micropores after displacement is relatively large and meets the requirements.

[0107] As Figure 18As shown, the simulation sample solution displaces air and enters the micro-pores. The depth-to-width ratio of the micro-pores increases from 1:2 to 2:1. The sample solution has a hydrophobic contact angle with the upper wall surface and a hydrophilic contact angle with the lower wall surface (the first optimal contact angle combination). The sample solution cannot completely displace the air, and the air accumulates at the bottom of the micro-pores. It can be seen that the depth-to-width ratio should not be increased excessively. When the depth-to-width ratio is increased by 2 times, it affects the process of the sample solution entering the pores, and the sample solution cannot fill the micro-pores completely. It should be noted that when the depth-to-width ratio of the micro-pores is 2:1, the dispensing liquid can also achieve layered sealing of the micro-pores during the process of displacing the sample solution.

[0108] The present invention discloses that it has important guiding significance for the preparation process of the dPCR micro-pore chip. By appropriately applying a positive pressure, the fluid can be effectively driven to inject uniformly, eliminating the interference of air bubbles and ensuring the fluid injection efficiency. According to the different fluid characteristics, the wall surface contact angles are modified differentially. During the process of the sample solution displacing air and entering the pores, the sample solution has a hydrophobic contact angle with the upper wall surface and a hydrophilic contact angle with the lower wall surface. Due to the different upper and lower contact angles, the sample solution mainly adheres to the lower wall surface and enters the micro-pores to displace the air in the pores. During the process of the dispensing liquid displacing the sample solution, the dispensing liquid has a hydrophilic contact angle with the upper wall surface and a hydrophobic contact angle with the lower wall surface of the sample solution, so that the dispensing liquid mainly adheres to the upper wall surface and flows to displace and divide the sample solution in the flow channel layer and seal the micro-pores. By increasing the depth-to-width ratio of the micro-pores, during the process of the dispensing liquid displacing the sample solution, the volume ratio of the sample solution retained in the pores increases correspondingly.

[0109] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A design method for a microporous chip for efficient fluid distribution and displacement, characterized in that Including: S1, simulating a micro-hole chip with a blind-hole structure; S2, simulating the application of a fluid driving pressure on the blind-hole structure, and determining the optimal driving pressure range according to the fluid displacement injection effect; S3, performing differential hydrophilic and hydrophobic modification on the wall surface of the blind-hole structure, and determining the optimal contact angle combination according to the fluid displacement injection effect; S4, based on the optimal contact angle combination, simulating the depth-to-width ratio of the blind-hole structure, and determining the optimal depth-to-width ratio according to the fluid displacement injection effect.

2. The method for designing a microporous chip for efficient fluid distribution and displacement according to claim 1, wherein The blind-hole structure includes a flow channel layer (1) and a micro-hole layer (2). The micro-hole layer (2) is a blind hole. The opening of the micro-hole layer (2) communicates between the inlet and the outlet of the flow channel layer (1). The fluid driving pressure is applied at the inlet position of the flow channel layer (1).

3. The method for designing a microchannel chip for efficient fluid distribution and displacement according to claim 2, wherein The flow channel layer (1) and the micro-hole layer (2) are filled with non-breathable materials.

4. The method for designing a microchannel chip for efficient fluid distribution and displacement according to claim 2, characterized in that, The step S2 includes: S21, selecting a sample solution to perform a displacement simulation on air; S22, applying multiple driving pressures at the inlet position of the flow channel layer (1), and respectively recording the fluid displacement injection effect of the sample solution on air; S23, eliminating the driving pressures that do not meet the requirements based on the phenomenon of bubble entrapment, and obtaining the optimal driving pressure range.

5. The method for designing a microchannel chip for efficient fluid distribution and displacement according to claim 4, characterized in that, In the step S23, the phenomenon of bubble entrapment includes the ease of generation and discharge of entrapped bubbles.

6. The method for designing a microporous chip for efficient fluid distribution and displacement according to claim 2, wherein The flow channel layer (1) is located above the micro-hole layer (2). The wall surface above the fluid in the flow channel layer (1) is the upper wall surface (3), and the wall surface below the fluid in the flow channel layer (1) is the lower wall surface (4).

7. The method for designing a microporous chip for efficient fluid distribution and displacement according to claim 6, wherein The step S3 includes: S31, selecting a sample solution to perform a displacement simulation on air; S32, arranging and combining the contact angle combinations between the sample solution and the upper wall surface (3) and the lower wall surface (4) respectively, and respectively recording the fluid displacement injection effect of the sample solution on air; S33, eliminating the contact angle combinations that do not meet the requirements based on the phenomenon of bubble entrapment, and obtaining the first optimal contact angle combination.

8. The method for designing a microchannel chip for efficient fluid distribution and displacement according to claim 7, wherein The step S3 further includes: S34, selecting a dispensing liquid to perform a displacement simulation on the sample solution; S35, arranging and combining the contact angle combinations between the dispensing liquid and the upper wall surface (3) and the lower wall surface (4) respectively, and respectively recording the fluid displacement injection effect of the dispensing liquid on the sample solution; S36, eliminating the contact angle combinations that do not meet the requirements based on the retention volume ratio of the sample solution and the sealed stratification of the dispensing liquid, and obtaining the second optimal contact angle combination.

9. The method for designing a microporous chip for efficient fluid distribution and displacement according to claim 8, characterized in that, The step S4 includes: S41, based on the second optimal contact angle combination, selecting a dispensing liquid to perform a displacement simulation on the sample solution; S42, simulating multiple depth-to-width ratios of the micro-hole layer (2), and respectively recording the fluid displacement injection effect of the dispensing liquid on the sample solution; S43, obtaining the depth-to-width ratio that meets the requirements based on the retention volume ratio of the sample solution.

10. The method for designing a microporous chip for efficient fluid distribution and displacement according to claim 9, characterized in that The step S4 further includes: S44, based on the depth-to-width ratio that meets the requirements, sequentially selecting a sample solution to perform a displacement simulation on air, and respectively recording the fluid displacement injection effect of the sample solution on air; S45, eliminating the depth-to-width ratios that do not meet the requirements based on the phenomenon of bubble entrapment, and obtaining the optimal depth-to-width ratio.

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