Double-plate micro-fluidic chip and sample pretreatment method based on same

Abstract

The invention relates to the technical field of microfluidics, in particular to a double-plate micro-fluidic chip and a sample pretreatment method based on the chip. The double-plate micro-fluidic chip comprises a heating plate, a lower polar plate is arranged on the heating plate, a liquid drop runner layer is arranged on one side, far away from the heating plate, of the lower polar plate, an upper polar plate is arranged on one side, far away from the lower polar plate, of the liquid drop runner layer, at least one communicating hole is formed in the upper polar plate, and the communicating hole penetrates through the upper polar plate. The array holes are formed in the upper electrode plate of the double-plate micro-fluidic chip, and meanwhile, the heating module is integrated, so that micro-fluid or liquid drops can heat and evaporate redundant solvents on the double-plate micro-fluidic chip in situ, and lossless concentration of a target sample is realized. Meanwhile, the device is simple in structure and convenient to operate, can be widely applied to various biochemical reactions, such as the fields of DNA directional assembly, polypeptide synthesis and the like, and has a relatively high market popularization value.

Description

Technical Field

[0001] The invention relates to the technical field of microfluidics, and in particular to a double-plate microfluidics chip and a sample pretreatment method based on the chip. Background Art

[0002] When conducting biochemical reactions such as DNA directed assembly and peptide synthesis based on a microfluidic chip platform, the fusion and mixing reaction mechanism of microfluids or droplets will cause a significant sample dilution effect. Specifically, the step-by-step advancement of the synthesis reaction will lead to a dynamic increase in the volume of the microfluids or droplets, causing the concentration of the target sample to decay exponentially. This concentration dilution mechanism places stringent requirements on subsequent detection links: lower detection limits, higher sensitivity, etc. Therefore, how to achieve enrichment and concentration of target samples while maintaining their stability in microfluidics or droplets has become a technical bottleneck restricting the expansion of microfluidic chips to high-throughput synthesis applications.

[0003] Microfluidics is an emerging technology that can manipulate and control fluids at the micrometer scale. It can integrate traditional laboratory operations (such as sample processing, reaction, separation and detection) on a small chip, which is usually called a "chip laboratory". Microfluidic chips mainly use methods such as fluid mechanics, electric fields, chemical reactions, physical filtration and thermal fields to achieve sample enrichment and concentration. Compared with traditional concentration technology, the concentrate obtained by microfluidic technology has a higher purity, and it can process trace samples without damaging the biological activity of the samples. Therefore, concentration technology based on microfluidic chips has become a research hotspot.

[0004] At present, the enrichment and concentration methods based on microfluidic chips are mainly divided into two categories: active and passive. Active technology achieves sample enrichment and concentration through external energy (such as electricity, magnetism, sound, light, heat, etc.) or specific physical and chemical means. For example, dielectrophoresis uses non-uniform electric fields to exert force on polarized particles, causing them to move and enrich in the electric field; electrowetting technology achieves the enrichment step by programming and controlling the movement, mixing and splitting of droplets, combined with magnetic beads or electric fields; evaporation concentration technology achieves sample concentration by heating combined with pressure regulation or light evaporation of solvents. These technologies have the advantages of high efficiency and rapidity, but the existing active concentration methods all require complex equipment and operating conditions, such as setting up non-uniform electric fields or using pressure, light, magnetic bead carriers, etc., and may cause damage to biological molecules. Passive technology achieves sample enrichment and concentration through the structural design or fluid dynamics of microfluidic chips without the need for external energy input. For example, centrifugal field uses centrifugal force to separate target molecules or particles; inertial migration uses the inertial force of the fluid to cause particles to migrate laterally in the channel; membrane filtration uses microporous membranes to filter samples and intercept target molecules or particles. These passive concentration technologies require complex microstructures, microchannel processing, or high-performance filter membrane materials, which greatly increase the complexity and cost of concentration.

[0005] Therefore, those skilled in the art are committed to developing a double-plate microfluidic chip that can be widely applied to various biochemical reactions and has simple operation and low cost, as well as a sample pretreatment method based on this chip. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a double-plate microfluidic chip and a sample pretreatment method based on this chip.

[0007] To achieve the above object, the present invention provides a double-plate microfluidic chip, including a heating plate, a lower plate is provided on the heating plate, a droplet flow channel layer is provided on a side of the lower plate away from the heating plate, an upper plate is provided on a side of the droplet flow channel layer away from the lower plate, at least one communication hole is provided on the upper plate, and the communication hole penetrates through the upper plate.

[0008] Preferably, the lower plate includes a first base layer, a first electrode layer, a dielectric layer, and a first hydrophobic layer sequentially arranged from bottom to top;

[0009] Preferably, the upper plate includes a second hydrophobic layer, a second electrode layer, and a second base layer sequentially arranged from bottom to top.

[0010] Preferably, the diameter of the communication hole is 0.05 mm - 0.75 mm.

[0011] Preferably, the droplet flow channel layer is filled with a continuous phase.

[0012] Preferably, the continuous phase is one of an oil phase or an air phase.

[0013] Preferably, the oil phase is any one of silicone oil, alkylated oil, fluorinated oil, or mineral oil.

[0014] Preferably, the first base layer and the second base layer are made of an inorganic material, an organic polymer material, a printed circuit board, or a paper-based material.

[0015] Preferably, at least two groups of micropore arrays composed of a plurality of the communication holes are provided on the upper plate, the number of communication holes in the subsequent micropore array is less than that in the previous micropore array, and so on for the subsequent arranged micropore arrays.

[0016] Preferably, at least two groups of micropore arrays composed of a plurality of the communication holes are provided on the upper plate, the diameter of the communication holes in the subsequent micropore array is smaller than that in the previous micropore array, and so on for the subsequent arranged micropore arrays.

[0017] The present invention also provides a sample pretreatment method based on a double-plate microfluidic chip, including the double-plate microfluidic chip described in any one of the above, and further including the following steps:

[0018] S1. Add a sample droplet on the lower plate;

[0019] S2. Drive the sample droplet in step S1 to be below a microporous array;

[0020] S3. Heat the sample droplet;

[0021] S4. When the sample droplet is tangent to the corner of the current microporous array, move it to be below the next microporous array, and so on until the concentration of the sample droplet is completed.

[0022] The beneficial effects of the present invention are as follows: By drilling array holes in the upper plate of the double-plate microfluidic chip and integrating a heating module at the same time, the present invention enables the in-situ heating and evaporation of excess solvent of the microfluid or droplet on the double-plate microfluidic chip, realizing the lossless concentration of the target sample. At the same time, the structure of the present application is simple and the operation is convenient, and it can be widely applied to various biochemical reactions, such as DNA directed assembly, polypeptide synthesis and other fields, and has great market promotion value.

[0023] Attached drawings of the invention

[0024] Figure 1 is a schematic cross-sectional structure diagram of a specific embodiment of the present invention.

[0025] Figure 2 is a schematic structure diagram of the sample droplet after concentration in a specific embodiment of the present invention.

[0026] Figure 3 is a schematic structure diagram of a specific embodiment of the present invention.

[0027] Figure 4 is a schematic flow chart of Embodiment 1 of the present invention.

[0028] Figure 5 is a schematic flow chart of Embodiment 2 of the present invention.

[0029] Figure 6 is a schematic flow chart of a specific embodiment of the present invention.

[0030] 1. Heating plate; 2. Lower plate; 2a. First base layer; 2b. First electrode layer; 2c. Dielectric layer; 2d. First hydrophobic layer; 3. Droplet flow channel layer; 4. Upper plate; 4a. Second hydrophobic layer; 4b. Second electrode layer; 4c. Second base layer; 5. Communication hole; 6. Microporous array; 6a. Previous microporous array; 6b. Next microporous array; 7. Sample droplet. Specific embodiments

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific manner, and therefore cannot be construed as a limitation to the present invention. Terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] As Figures 1-3 shown, a double-plate microfluidic chip includes a heating plate 1, and the heating plate 1, as the installation foundation, is mainly responsible for controlling the temperature of the double-plate microfluidic chip. A lower electrode plate 2 is provided on the heating plate 1, and the lower electrode plate 2 includes a first base layer 2a, a first electrode layer 2b, a dielectric layer 2c, and a first hydrophobic layer 2d arranged in sequence from bottom to top.

[0033] Among them, the first base layer 2a mainly provides mechanical support and can be made of inorganic materials, organic polymer materials, printed circuit boards or paper-based materials. Specifically, commercially available materials such as silicon, silicon dioxide, glass, quartz, polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), printed circuit boards (PCBs), etc. can be selected. The first electrode layer 2b can be made of commercially available indium tin oxide (ITO) or chromium (Cr). By setting the first electrode layer 2b, an electric field is applied to the chip to control the movement and merging of the sample droplets 7 on the chip. The dielectric layer 2c can be made of commercially available silicon nitride or aluminum oxide. By setting the dielectric layer 2c, the direct passage of current through the sample droplets 7 is prevented. The first hydrophobic layer 2d can be made of commercially available Teflon material. By setting the first hydrophobic layer 2d, the adhesion between the sample droplets 7 and the surface of the double-plate microfluidic chip described in the present application can be reduced, and the formation and movement of the sample droplets 7 can be promoted.

[0034] A droplet flow channel layer 3 is provided on the side of the lower electrode plate 2 away from the heating plate 1, and the droplet flow channel layer 3 provides a accommodation space for the sample droplets 7. A continuous phase 3a is filled in the droplet flow channel layer 3, and the continuous phase 3a is one of an oil phase or an air phase. By setting the continuous phase 3a in the droplet flow channel layer 3 to wrap the sample droplets 7, the resistance when the sample droplets 7 move is reduced. In this embodiment, the continuous phase 3a is selected as the oil phase, and in other embodiments, it can also be replaced with the air phase according to needs. Specifically, commercially available silicone oil, alkylated oil, fluorinated oil or mineral oil can be selected. Setting the oil phase can, on the one hand, provide lubrication and reduce the resistance of the sample droplets 7 moving, and on the other hand, prevent the steam from condensing in other non-punched areas of the double-plate microfluidic chip during the evaporation of the sample droplets 7.

[0035] On one side of the droplet flow channel layer 3 away from the lower electrode plate 2, there is an upper electrode plate 4. The upper electrode plate 4 includes a second hydrophobic layer 4a, a second electrode layer 4b, and a second base layer 4c arranged in sequence from bottom to top. By providing the second hydrophobic layer 4a, it can reduce the adhesion of the sample droplet 7 to the surface of the double-plate microfluidic chip described in this application and promote the formation and movement of the sample droplet 7. By providing the second electrode layer 4b, an electric field is applied to the chip to control the movement and merging of the sample droplet 7 on the chip. Specifically, in implementation, the second hydrophobic layer 4a can be made of commercially available Teflon material, the second electrode layer 4b can be made of commercially available indium tin oxide (ITO) or chromium (Cr), and the second base layer 4c can be made of commercially available materials such as silicon, silicon dioxide, glass, quartz, polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), printed circuit board (PCB), etc.

[0036] On the upper electrode plate 4, there is at least one communication hole 5 with a diameter of 0.05 mm - 0.75 mm. The communication hole 5 penetrates the upper electrode plate 4. By providing the communication hole 5, steam can be effectively discharged, enabling the microfluid or sample droplet 7 in the droplet flow channel layer 3 to be in-situ heated and evaporate the excess solvent on the double-plate microfluidic chip, thereby realizing the lossless concentration of the target sample.

[0037] Regarding the selection of the number and diameter of the communication holes 5, the present invention is further illustrated by the following two embodiments:

[0038] Embodiment 1

[0039] As Figure 4 shown, on the upper electrode plate 4, there are at least two groups of microhole arrays 6 composed of a number of communication holes 5. The number of communication holes 5 in the subsequent microhole array 6b is less than that in the previous microhole array 6a, and so on for the subsequent arranged microhole arrays 6.

[0040] Specifically in this embodiment, the microhole array 6 can be set to 4 groups. The 4 groups of microhole arrays 6 are respectively composed of 16, 9, 4, and 1 communication holes 5. In other embodiments, other numbers of microhole arrays 6 can also be set as needed. By gradually reducing the number of communication holes 5 in the microhole array 6 to reduce the area of the array microholes 6, the evaporation rate of the sample droplet 7 can be controlled. This design solves the problem that the sample droplet 7 is prone to emerging from the upper electrode plate 4 through the communication hole 5 or adsorbing around the pore diameter as the volume gradually shrinks during heating evaporation, and also solves the problem of loss of the target sample.

[0041] Embodiment 2

[0042] As Figure 5As shown in the figure, at least two groups of microporous arrays 6 composed of a number of communication holes 5 are provided on the upper plate 4. The diameter of the communication holes 5 in the subsequent microporous array 6b' is smaller than that in the previous microporous array 6a'. The subsequent arranged microporous arrays 6 follow this pattern.

[0043] Specifically in this embodiment, the microporous array can be set to 4 groups. The diameters of the communication holes 5 in the 4 groups of microporous arrays 6 are 0.75 mm, 0.6 mm, 0.45 mm, and 0.3 mm respectively. In other embodiments, other numbers of microporous arrays 6 can also be set as needed. And by gradually reducing the diameter of the communication holes 5 in the microporous array 6, the area of the array micropores 6 is reduced, so as to achieve the purpose of controlling the evaporation rate of the sample droplet 7. This design solves the problem that the sample droplet 7 is likely to emerge from the upper plate 4 through the communication holes 5 or adsorb around the pore diameter when the volume gradually shrinks during heating evaporation, and also solves the problem of loss of the target sample.

[0044] During specific use, first, a sample droplet 7 meeting the requirements is prepared by generation, splitting, merging, and moving in the operation area (not shown in the figure) on the lower plate 2. In other embodiments, the sample droplet 7 can also be directly added on the lower plate 2. The prepared sample droplet 7 is moved to the lower part of the previous microporous array 6a and the area is heated to reach the boiling point of the sample droplet 7 for evaporation and concentration. As the heating time increases, the volume of the sample droplet 7 decreases. Correspondingly, in the top view, the droplet area decreases. When the edge of the sample droplet 7 is tangent to the previous microporous array 6a, the droplet is moved to the lower part of the subsequent microporous array 6b to prevent the sample droplet 7 from emerging from the communication holes 5 in the microporous array 6 and causing loss. And so on, repeating the steps of moving the sample droplet 7 and evaporation and concentration until the sample droplet 7 with the final target concentration is obtained.

[0045] At the same time, for facilitating the real-time observation of the area of the sample droplet 7, a high-precision image recognition device (not shown in the figure) can also be integrated on the double-plate microfluidic chip. Through integrating the high-precision image recognition device, the real-time dynamic detection and automatic area recognition of the distributed sample droplets 7 on the double-plate microfluidic chip are realized. Further, the area of the recognized sample droplet 7 is multiplied by the standard distance between the first electrode layer 2b and the second electrode layer 4b, so as to realize the accurate calculation of the three-dimensional volume of the sample droplet 7. Based on this volume measurement method, the accurate regulation of the concentration of the sample droplet 7 in the microfluidic system can be realized, and then the time and temperature of heating and concentration can be controlled.

[0046] As Figure 6 shown, the present invention also provides a sample pretreatment method based on a double-plate microfluidic chip, which is realized by using any one of the above double-plate microfluidic chips, and specifically includes the following steps:

[0047] S1. Prepare a sample droplet 7 on the lower plate 2. In other embodiments, the prepared sample droplet 7 can also be directly added to the lower plate 2.

[0048] S2. Open at least two groups of microporous arrays 6 composed of a number of communicating holes 5 on the upper plate 4. In this embodiment, the microporous array is set to 4 groups. The number of communicating holes 5 in the latter microporous array 6b in the 4 groups of microporous arrays is less than that in the previous microporous array 6a. During use, drive the sample droplet 7 in step S1 to the lower part of a microporous array.

[0049] S3. Heat the sample droplet 7 through the heating plate 1 to make it reach the boiling point and start evaporation and concentration. The steam generated by evaporation escapes along the microporous array 6.

[0050] S4. As the heating time increases, the volume of the sample droplet 7 gradually decreases. When the sample droplet 7 is tangent to the current microporous array 6, move it to the lower part of the next microporous array 6 to prevent the sample droplet 7 from emerging from the communicating holes 5 in the microporous array 6 and causing losses. And so on until the concentration of the sample droplet 7 is completed. In this embodiment, by gradually reducing the number of communicating holes 5 in the microporous array 6, the area of the microporous array 6 is reduced, so as to precisely control the speed of the sample droplet 7 passing through the microporous array 6 and the evaporation rate. This design can achieve efficient concentration of high-throughput sample droplets 7 while avoiding cross-contamination.

[0051] Furthermore, the present invention also provides a sample pretreatment method based on a double-plate microfluidic chip, which is implemented by using any one of the above double-plate microfluidic chips, and specifically includes the following steps:

[0052] S1. Prepare a sample droplet 7 on the lower plate 2. In other embodiments, the prepared sample droplet 7 can also be directly added to the lower plate 2.

[0053] S2. Open at least two groups of microporous arrays 6 composed of a number of communicating holes 5 on the upper plate 4. In this embodiment, the microporous array is set to 4 groups. The diameter of the communicating holes 5 in the latter microporous array 6b' in the 4 groups of microporous arrays is smaller than that in the previous microporous array 6a'. During use, drive the sample droplet 7 in step S1 to the lower part of a microporous array 6.

[0054] S3. Heat the sample droplet 7 through the heating plate 1 to make it reach the boiling point and start evaporation and concentration. The steam generated by evaporation escapes along the microporous array 6.

[0055] S4. As the heating time increases, the volume of the sample droplet 7 gradually decreases. When the sample droplet 7 is tangent to the current micro-well array 6, it is moved below the next micro-well array 6 to prevent the sample droplet 7 from emerging from the communication holes 5 in the micro-well array 6 and causing losses, and so on until the concentration of the sample droplet 7 is completed. In this embodiment, the area of the micro-well array 6 is reduced by gradually decreasing the diameter of the communication holes 5 in the micro-well array 6, thereby precisely controlling the speed and evaporation rate of the sample droplet 7 passing through the micro-well array 6. This design can avoid cross-contamination while achieving efficient concentration of high-throughput sample droplets 7.

[0056] In addition to being applicable to the concentration of a single sample droplet 7, the present invention can also achieve the concentration operation of discrete sample droplets 7 and continuous-flow sample droplets 7 by adjusting the number of communication holes 5 on the upper plate 4.

[0057] By providing communication holes 5 on the upper plate of the double-plate microfluidic chip and integrating a heating module, the present invention enables in-situ heating and evaporation of excess solvent of the microfluid or sample droplet 7 on the double-plate microfluidic chip, realizing lossless concentration of the target sample. At the same time, the structure of the present application is simple and the operation is convenient, and it can be widely applied to various biochemical reactions, such as DNA directed assembly, polypeptide synthesis and other fields, and has great market promotion value.

[0058] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A double-plate microfluidic chip, characterized in that: It includes a heating plate (1), on which a lower electrode plate (2) is provided. On the side of the lower electrode plate (2) away from the heating plate (1), a droplet flow channel layer (3) is provided. On the side of the droplet flow channel layer (3) away from the lower electrode plate (2), an upper electrode plate (4) is provided. At least one communication hole (5) is provided on the upper electrode plate (4), and the communication hole (5) penetrates through the upper electrode plate (4).

2. The double-plate microfluidic chip according to claim 1, characterized in that: The lower electrode plate (2) includes a first base layer (2a), a first electrode layer (2b), a dielectric layer (2c), and a first hydrophobic layer (2d) arranged in sequence from bottom to top; The upper electrode plate (4) includes a second hydrophobic layer (4a), a second electrode layer (4b), and a second base layer (4c) arranged in sequence from bottom to top.

3. The double-plate microfluidic chip according to claim 1, characterized in that: The diameter of the communication hole (5) is 0.05 mm - 0.75 mm.

4. The double-plate microfluidic chip according to any one of claims 1-3, characterized in that: A continuous phase is filled in the droplet flow channel layer (3).

5. The double-plate microfluidic chip according to claim 4, characterized in that: The continuous phase (3a) is one of an oil phase or an air phase.

6. The double-plate microfluidic chip according to claim 5, wherein: The oil phase is any one of silicone oil, alkylated oil, fluorinated oil, or mineral oil.

7. The double-plate microfluidic chip according to claim 2, wherein: The first base layer (2a) and the second base layer (4c) are made of inorganic materials, organic polymer materials, printed circuit boards (PCBs), or paper-based materials.

8. The double-plate microfluidic chip according to claim 1, wherein: At least two groups of microporous arrays (6) composed of a number of the communication holes (5) are provided on the upper electrode plate (4). The number of communication holes (5) in the subsequent microporous array (6b) is less than the number of communication holes (5) in the previous microporous array (6a), and so on for the subsequently arranged microporous arrays (6).

9. The double-plate microfluidic chip according to claim 1, characterized in that: At least two groups of microporous arrays (6) composed of a number of the communication holes (5) are provided on the upper electrode plate (4). The diameter of the communication holes (5) in the subsequent microporous array (6b') is less than the diameter of the communication holes (5) in the previous microporous array (6a'), and so on for the subsequently arranged microporous arrays (6).

10. A sample pretreatment method based on a double-plate microfluidic chip, comprising the double-plate microfluidic chip according to any one of claims 1-9, characterized in that, It also includes the following steps: S1. Add a sample droplet on the lower electrode plate; S2. Drive the sample droplet in step S1 to the lower part of a microporous array; S3. Heat the sample droplet; S4. When the sample droplet is tangent to the corners of the current microporous array, move it to the lower part of the subsequent microporous array, and so on until the concentration of the sample droplet is completed.

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