Microfluidic chip and microfluidic device

Abstract

A microfluidic chip (100) comprises a plurality of microcavities, at least two of which have different volumes.

Description

Technical Field

[0001] The present disclosure relates to the field of microfluidics, and in particular to a microfluidic chip and a microfluidic device comprising the microfluidic chip. Background Art

[0002] Polymerase Chain Reaction (PCR) is a molecular biology technique used to amplify specific DNA fragments. It can replicate trace amounts of DNA in large quantities, greatly increasing their number. During the PCR reaction, the double-stranded structure of the DNA fragment denatures at high temperatures (e.g., 95°C) to form a single-stranded structure. At low temperatures (e.g., 60°C), the primers and single strands combine according to the principle of base complementary pairing. At the most suitable temperature for DNA polymerase (e.g., 70°C), base binding and extension are achieved. DNA polymerase synthesizes complementary chains along the direction from phosphate to pentose (5'-3'). The above process is the temperature cycle of denaturation-annealing-extension. Through multiple temperature cycles of denaturation-annealing-extension, DNA fragments can be replicated in large quantities. Digital polymerase chain reaction (dPCR) technology is a quantitative analysis technology developed on the basis of PCR that can provide digital DNA quantitative information. It can further improve the sensitivity and accuracy of detection, and therefore has received increasing attention. Summary of the invention

[0003] According to one aspect of the present disclosure, a microfluidic chip is provided. The microfluidic chip includes a plurality of microcavities, at least two of the plurality of microcavities having different volumes.

[0004] In some embodiments, the plurality of microcavities include at least three types of microcavities with different volumes, and the ratio of the volumes of the at least three types of microcavities with different volumes is 1:2-4:3-8.

[0005] In some embodiments, the ratio of the volumes of the at least three types of microcavities with different volumes is 1:4:8.

[0006] In some embodiments, the multiple microcavities include at least one first microcavity, at least one second microcavity, and at least one third microcavity, the first microcavity, the second microcavity, and the third microcavity have the same depth, and the area of ​​the bottom of the first microcavity: the area of ​​the bottom of the second microcavity: the area of ​​the bottom of the third microcavity is equal to 1:4:8.

[0007] In some embodiments, the shapes of the orthographic projections of the bottom of the first microcavity, the bottom of the second microcavity, and the bottom of the third microcavity on the microfluidic chip are all circular.

[0008] In some embodiments, the radius of the bottom of the first microcavity is 20-30 μm, the radius of the bottom of the second microcavity is 40-60 μm, and the radius of the bottom of the third microcavity is 56.57-84.85 μm.

[0009] In some embodiments, the depths of the first microcavity, the second microcavity, and the third microcavity are all 30-70 μm.

[0010] In some embodiments, the first microcavity, the second microcavity and the third microcavity are arranged in an array, and in the first direction, a row of second microcavities is arranged between two adjacent rows of third microcavities, and in the second direction, a column of second microcavities is arranged between two adjacent columns of third microcavities.

[0011] In some embodiments, the spacing between the centers of the bottoms of two adjacent first microcavities in the first direction is equal to the spacing between the centers of the bottoms of two adjacent first microcavities in the second direction. The spacing between the centers of the bottoms of two adjacent second microcavities in the first direction is equal to the spacing between the centers of the bottoms of two adjacent second microcavities in the second direction. The spacing between the centers of the bottoms of two adjacent third microcavities in the first direction is equal to the spacing between the centers of the bottoms of two adjacent third microcavities in the second direction.

[0012] In some embodiments, the intersection of two adjacent rows of third microcavities and two adjacent columns of third microcavities includes four third microcavities, the lines connecting the centers of the bottoms of the four third microcavities form a square, a second microcavity is arranged at the center of the four third microcavities, and the center of the bottom of the second microcavity coincides with the midpoint of the diagonal of the square. In the first direction or the second direction, a first microcavity is arranged between any two adjacent third microcavities, and the center of the bottom of the first microcavity coincides with the midpoint of the line connecting the centers of the bottoms of the two adjacent third microcavities; and, in the first direction or the second direction, a first microcavity is arranged between any two adjacent second microcavities, and the center of the bottom of the first microcavity coincides with the midpoint of the line connecting the centers of the bottoms of the two adjacent second microcavities.

[0013] In some embodiments, an area of ​​an orthographic projection of the plurality of microcavities on the microfluidic chip accounts for 76.82% of an area of ​​the microfluidic chip.

[0014] In some embodiments, the ratio of the volumes of the at least three types of microcavities with different volumes is 1:2:3.

[0015] In some embodiments, the multiple microcavities include at least one first microcavity, at least one second microcavity and at least one third microcavity, the first microcavity, the second microcavity and the third microcavity have the same depth, the shape of the orthographic projection of the first microcavity on the microfluidic chip is an equilateral triangle, the shape of the orthographic projection of the second microcavity on the microfluidic chip is a parallelogram, the shape of the orthographic projection of the third microcavity on the microfluidic chip is a trapezoid, and the area of ​​the equilateral triangle: the area of ​​the parallelogram: the area of ​​the trapezoid is equal to 1:2:3.

[0016] In some embodiments, the first microcavity, the second microcavity and the third microcavity are arranged in an array, and in a first direction, each row is arranged alternately in the order of the first microcavity, the second microcavity and the third microcavity, and in a second direction, the microcavities in the same column have the same shape.

[0017] In some embodiments, in each row, the first side of the parallelogram and the first side of the adjacent equilateral triangle are parallel to each other and spaced at a first spacing, the second side of the parallelogram and the first side of the adjacent trapezoid are parallel to each other and spaced at a second spacing, the second side of the adjacent trapezoid and the second side of the adjacent equilateral triangle are parallel to each other and spaced at a third spacing, and the first spacing, the second spacing, and the third spacing are equal.

[0018] In some embodiments, the lengths of the four sides of the parallelogram are equal to the length of the side of the equilateral triangle, the length of the upper base of the trapezoid is equal to the length of the side of the equilateral triangle and the length of the lower base of the trapezoid is twice the length of the side of the equilateral triangle, and the parallelogram is composed of two equilateral triangles, and the trapezoid is composed of three equilateral triangles.

[0019] In some embodiments, the depths of the first microcavity, the second microcavity, and the third microcavity are all 30-70 μm.

[0020] In some embodiments, an area of ​​an orthographic projection of the plurality of microcavities on the microfluidic chip accounts for 72.90% of an area of ​​the microfluidic chip.

[0021] In some embodiments, the ratio of the volumes of the at least three types of microcavities with different volumes is 1:2:4.

[0022] In some embodiments, the plurality of microcavities include at least one first microcavity, at least one second microcavity, and at least one third microcavity, and the bottoms of the first microcavity, the second microcavity, and the third microcavity have the same bottom area.

[0023] In some embodiments, the depth of the first microcavity is 25-40 μm, the depth of the second microcavity is 50-80 μm, and the depth of the third microcavity is 100-160 μm.

[0024] In some embodiments, the shapes of the orthographic projections of the bottom of the first microcavity, the bottom of the second microcavity, and the bottom of the third microcavity on the microfluidic chip are all circular, and the radius of the bottom of the first microcavity, the radius of the bottom of the second microcavity, and the radius of the bottom of the third microcavity are equal.

[0025] In some embodiments, the plurality of microcavities are arranged in a two-dimensional hexagonal close-packed or two-dimensional square lattice manner, and the interval between any two adjacent microcavities is 10-80 μm.

[0026] In some embodiments, an area of ​​an orthographic projection of the plurality of microcavities on the microfluidic chip accounts for 24.67% to 68.43% of an area of ​​the microfluidic chip.

[0027] In some embodiments, the multiple microcavities are arranged in a two-dimensional hexagonal close-packed manner, the interval between any two adjacent microcavities is 50 μm, and the area of ​​the orthographic projections of the multiple microcavities on the microfluidic chip accounts for 40.18% of the area of ​​the microfluidic chip.

[0028] According to another aspect of the present disclosure, a microfluidic device is provided, which includes the microfluidic chip described in any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly describe the technical solutions in the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of a lower substrate of a microfluidic chip according to an embodiment of the present disclosure is shown;

[0031] Figure 2 A schematic diagram of the structure of a microfluidic chip according to an embodiment of the present disclosure is shown;

[0032] Figure 3 The figure shows the arrangement of the microcavities of the microfluidic chip according to an embodiment of the present disclosure;

[0033] Figure 4 Shown along Figure 3 A cross-sectional view taken along the line A-A' in FIG.

[0034] Figure 5 Shown along Figure 3 The cross-sectional view taken along the line BB' in FIG.

[0035] Figure 6 The figure shows the arrangement of microcavities of a microfluidic chip according to another embodiment of the present disclosure;

[0036] Figure 7 Shown along Figure 6 The cross-sectional view taken along the C-C' line in FIG.

[0037] Figure 8 The figure shows the arrangement of the microcavities of the microfluidic chip according to another embodiment of the present disclosure;

[0038] Fig. 9 Shows Figure 8 An arrangement of microcavities of a microfluidic chip;

[0039] Fig.10 Shows Figure 8 Another arrangement of the microcavities of the microfluidic chip;

[0040] Fig.11 Shown along Fig.10 A cross-sectional view taken along the line D-D' in FIG.

[0041] Fig.12 A block diagram of a microfluidic device according to another embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0043] dPCR is widely used in clinical diagnosis, gene instability analysis, single-cell gene expression, environmental microbial detection, and prenatal diagnosis due to its advantages of high sensitivity, strong specificity, high detection throughput, and accurate quantification. dPCR technology is a nucleic acid molecule absolute quantification technology, and its principle can be roughly described as follows: the sample solution containing the target nucleic acid molecule (the target nucleic acid molecule that the present application hopes to study, such as the nucleic acid molecule of cancer cells) is fully diluted, and then the diluted sample solution is distributed to a large number of tiny reaction units of the microfluidic chip, so that each reaction unit contains one or zero nucleic acid molecules. Then, single-molecule PCR amplification is performed in each reaction unit to form a solution to be detected. Then, a fluorescence microscope or flow cytometer is used to detect the fluorescence intensity of the solution to be detected in each reaction unit. Finally, the number of target nucleic acid molecules (or concentration) of the original sample can be calculated by the number of positive reaction units and the Poisson distribution statistical method, thereby achieving absolute quantification.

[0044] In the dPCR reaction, the number of nucleic acid molecules in the diluted sample solution is usually less than the number of reaction units in the microfluidic chip, so that the distribution of the number of nucleic acid molecules in each reaction unit satisfies the Poisson distribution probability model. According to the Poisson distribution formula, it can be deduced that: N=-ln(1-P), where N represents the number of nucleic acid molecules contained in each reaction unit, and P represents the proportion of negative units in all reaction units. The upper limit of dPCR quantification mainly depends on the volume and number of reaction units, while the lower limit of detection is related to the total volume of the sample solution.

[0045] The term "dynamic range" refers to the linear dynamic range, specifically, within a concentration range, the known concentration of the sample and the concentration of the sample obtained by measurement present an acceptable linear relationship. The unit of dynamic range is usually expressed in logs. For example, the sample solution is diluted several times in a row, such as 5 times of 10-fold serial dilution, to obtain a total of 6 serial dilution sample solutions (100000X, 10000X, 1000X, 100X, 10X, 1X), and then the 6 serial dilution sample solutions are detected to obtain their detection concentrations (such as mmol / mL), and then the linearity between the concentrations of the 6 known dilution ratio sample solutions and their respective detection concentrations is calculated. If the linearity reaches the predetermined threshold requirement, it means that the detection can achieve a dynamic range of 6 logs.

[0046] The inventors of the present application have found that in conventional technology, whether it is droplet dPCR or microwell dPCR, the volumes of multiple reaction units of the microfluidic chip are consistent. Since the volume of each reaction unit is the same, the number of nucleic acid molecules contained in the sample solution contained in each reaction unit is theoretically basically the same. In order to contain at most one nucleic acid molecule in each reaction unit, the sample solution needs to be diluted to a fixed concentration (i.e., a fixed multiple). However, this will result in the dynamic range and sensitivity of dPCR being unable to be adjusted, thereby greatly reducing the experimental efficiency. Moreover, in the case of such a single volume reaction unit, in order to make the sample concentration fall into the concentration range applicable to dPCR, it is usually necessary to dilute the sample multiple times in a row, but this continuous dilution method increases the use of related reagents and brings the risk of cross-contamination (e.g., cross-contamination with pollutants in the environment).

[0047] In view of this, an embodiment of the present disclosure provides a microfluidic chip, which includes a plurality of microcavities, at least two of which have different volumes.

[0048] The microfluidic chip provided by the embodiment of the present disclosure can achieve a multi-dynamic range, because the microfluidic chip can allow the dilution concentration of the sample solution to have a larger selection range, rather than being able to be diluted to a fixed concentration. When the diluted sample solution is applied to the microfluidic chip, since the microcavity of the microfluidic chip includes a large-volume microcavity and a small-volume microcavity, the large-volume microcavity should contain more nucleic acid molecules contained in the sample solution than the small-volume microcavity. Therefore, if the concentration of the diluted sample solution is low, since the microfluidic chip includes a large-volume microcavity, the solution contained in the large-volume microcavity can satisfy the requirement of containing one nucleic acid molecule in the microcavity (the number of nucleic acid molecules in the large-volume microcavity = the concentration of the diluted sample solution (mmol / mL*microcavity volume (mL)); if the concentration of the diluted sample solution is high, the number of nucleic acid molecules contained in the large-volume microcavity may have exceeded the threshold requirement, but since the microfluidic chip also includes a small-volume microcavity, the solution contained in the small-volume microcavity may satisfy the requirement of containing one nucleic acid molecule in the microcavity (the number of nucleic acid molecules in the small-volume microcavity = the concentration of the diluted sample solution (mmol / mL*microcavity volume (mL)). Therefore, whether the concentration of the diluted sample solution is slightly higher or lower, the microfluidic chip can be adapted, thereby achieving a multi-dynamic range without the need to dilute the sample solution to a fixed multiple as in the related art.

[0049] For example, if a solution with a concentration of C1 is added to each microcavity, the C1 concentration can satisfy the requirement of containing one nucleic acid molecule for a large-volume microcavity, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the large-volume microcavity; if a solution with a concentration of C2 (C2>C1) is added to each microcavity, the concentration C2 may be too high for a large-volume microcavity, so that the number of nucleic acid molecules contained in the sample solution in each large-volume microcavity exceeds the threshold requirement, but the C2 concentration may satisfy the requirement of containing one nucleic acid molecule for a small-volume microcavity, and therefore the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the small-volume microcavity. Compared with a microcavity with a larger volume, a microcavity with a smaller volume is essentially equivalent to diluting the sample solution to a greater extent, so it can adapt to a solution with a higher concentration. In this way, the sample solution can be diluted within a wider concentration range (for example, it can be diluted to a concentration of C1 or C2), instead of being diluted to a fixed multiple as in the related art. Therefore, compared with the microfluidic chip in the related art, the microfluidic chip provided by the embodiment of the present disclosure achieves an expansion of the dynamic range and improves the sensitivity of detection, and at the same time realizes multiple detection lines on a single microfluidic chip, thereby improving the experimental efficiency. In addition, compared with the conventional technology that requires multiple continuous dilutions of samples to meet the concentration requirements of a single volume microcavity, the microfluidic chip provided by the embodiment of the present disclosure avoids multiple continuous dilutions of samples, thereby avoiding the waste of reagents and the risk of cross contamination.

[0050] Microfluidic chips usually include an upper cover plate with an integrated gas valve structure, a lower base plate, a temperature control module, a program-controlled voltage unit, a sample reagent mixed liquid inlet and outlet, and other structures. Figure 1 A schematic diagram showing the lower substrate of the microfluidic chip, Figure 2 A schematic diagram of a microfluidic chip after the upper cover plate and the lower substrate are combined is shown. As shown in the figure, a reaction zone is arranged in the center of the lower substrate, and a plurality of microcavities as described above are arranged in the reaction zone. The plurality of microcavities include at least three types of microcavities with different volumes, and the volume ratio of the at least three types of microcavities with different volumes can be 1:2~4:3~8.

[0051] Several specific embodiments are used below to describe the arrangement of microcavities with different volumes of a microfluidic chip.

[0052] Figure 3 A partial top view of the microfluidic chip 100 is shown. Figure 4 Shown along Figure 3 The cross-sectional view taken along the line A-A' in Figure 5 Shown along Figure 3 Cross-sectional view taken along line BB'.

[0053] like Figure 3-Figure 5 As shown, the microfluidic chip 100 includes a plurality of microcavities, which include at least one first microcavity 101, at least one second microcavity 102, and at least one third microcavity 103. The first microcavity 101, the second microcavity 102, and the third microcavity 103 are all cylindrical and have the same depth, for example, the depths of the first microcavity 101, the second microcavity 102, and the third microcavity 103 are all 30-70 μm. In one example, the depths of the first microcavity 101, the second microcavity 102, and the third microcavity 103 are all 50 μm. The volume of the first microcavity 101: the volume of the second microcavity 102: the volume of the third microcavity 103 is less than or equal to 1:4:8. In one example, the volume of the first microcavity 101: the volume of the second microcavity 102: the volume of the third microcavity 103 is equal to 1:4:8. In another example, the volume of the first microcavity 101: the volume of the second microcavity 102: the volume of the third microcavity 103 is equal to 1:4:6. In another example, the volume of the first microcavity 101: the volume of the second microcavity 102: the volume of the third microcavity 103 is equal to 1:3:5. The embodiment of the present disclosure does not specifically limit the specific ratio of the volumes of the first microcavity 101, the second microcavity 102, and the third microcavity 103, as long as the ratio is less than or equal to 1:4:8.

[0054] Since the first microcavity 101, the second microcavity 102 and the third microcavity 103 are all cylindrical, the bottoms of the first microcavity 101, the second microcavity 102 and the third microcavity 103 are all circular. The radius of the bottom of the first microcavity is 20-30 μm, the radius of the bottom of the second microcavity is 40-60 μm, and the radius of the bottom of the third microcavity is 56.57-84.85 μm. In one example, the radius of the bottom of the first microcavity 101 is 25 μm, the radius of the bottom of the second microcavity 102 is 50 μm, and the radius of the bottom of the third microcavity 103 is 70.71 μm, that is, the area of ​​the bottom of the first microcavity 101: the area of ​​the bottom of the second microcavity 102: the area of ​​the bottom of the third microcavity 103 is equal to 1:4:8.

[0055] As shown in the figure, the first microcavity 101, the second microcavity 102 and the third microcavity 103 are arranged in an array. In the first direction X, a row of second microcavities 102 is arranged between two adjacent rows of third microcavities 103, and in the second direction Y, a row of second microcavities 102 is arranged between two adjacent columns of third microcavities 103, and in the first direction X or the second direction Y, a first microcavity 101 is arranged between any two adjacent second microcavities 102, and a first microcavity 101 is arranged between any two adjacent third microcavities 103. The distance between the centers of the bottoms of two adjacent first microcavities 101 in the first direction X is equal to the distance between the centers of the bottoms of two adjacent first microcavities 101 in the second direction Y; the distance between the centers of the bottoms of two adjacent second microcavities 102 in the first direction X is equal to the distance between the centers of the bottoms of two adjacent second microcavities 102 in the second direction Y; the distance between the centers of the bottoms of two adjacent third microcavities 103 in the first direction X is equal to the distance between the centers of the bottoms of two adjacent third microcavities 103 in the second direction Y. In one example, in the first direction X, the spacing between the centers of the bottoms of two adjacent first microcavities 101 is 200 μm, and in the second direction Y, the spacing between the centers of the bottoms of two adjacent first microcavities 101 is 200 μm; in the first direction X, the spacing between the centers of the bottoms of two adjacent second microcavities 102 is 200 μm, and in the second direction Y, the spacing between the centers of the bottoms of two adjacent second microcavities 102 is 200 μm; in the first direction X, the spacing between the centers of the bottoms of two adjacent third microcavities 103 is 200 μm, and in the second direction Y, the spacing between the centers of the bottoms of two adjacent third microcavities 103 is 200 μm. That is, the intersection of the Nth row and the (N+2)th row (N≥1) of the first microcavities 101 and the two adjacent columns of the first microcavities 101 includes four first microcavities 101, and the line connecting the centers of the bottoms of the four first microcavities 101 forms a square with a side length of 200 μm; the intersection of the two adjacent rows of the second microcavities 102 and the two adjacent columns of the second microcavities 102 includes four second microcavities 102, and the line connecting the centers of the bottoms of the four second microcavities 102 forms a square with a side length of 200 μm; the intersection of the two adjacent rows of the third microcavities 103 and the two adjacent columns of the third microcavities 103 includes four third microcavities 103, and the line connecting the centers of the bottoms of the four third microcavities 103 forms a square with a side length of 200 μm.

[0056] As shown in the figure, the intersection of two adjacent rows of third microcavities 103 and two adjacent columns of third microcavities 103 includes four third microcavities 103, the lines connecting the centers of the bottoms of the four third microcavities 103 form a square (for example, the side length of the square is 200 μm), a second microcavity 102 is arranged at the center of the four third microcavities 103, and the center of the bottom of the second microcavity 102 coincides with the midpoint of the diagonal of the square. In the first direction X or the second direction Y, a first microcavity 101 is arranged between any two adjacent third microcavities 103, and the center of the bottom of the first microcavity 101 coincides with the midpoint of the line connecting the centers of the bottoms of the two adjacent third microcavities 103; and, in the first direction X or the second direction Y, a first microcavity 101 is arranged between any two adjacent second microcavities 102, and the center of the bottom of the first microcavity 101 coincides with the midpoint of the line connecting the centers of the bottoms of the two adjacent second microcavities 102. Therefore, it can be concluded through calculation that the distance between the bottom center of any third microcavity 103 of the four third microcavities 103 forming a square and the bottom center of the second microcavity 102 arranged at the center of the square is 141.4 μm, the distance between the bottom center of the third microcavity 103 and the bottom center of the first microcavity 101 adjacent thereto is 100 μm, and the distance between the bottom center of the second microcavity 102 and the bottom center of the first microcavity 101 adjacent thereto is 100 μm. Therefore, the third microcavity 103 and the first microcavity 101, the third microcavity 103 and the second microcavity 102, and the first microcavity 101 and the second microcavity 102 are all spaced apart from each other. This distribution method can prevent mutual interference between different microcavities, and is also conducive to the effective identification of each microcavity through a fluorescence microscope.

[0057] In some embodiments, the area of ​​the orthographic projection of the plurality of microcavities on the microfluidic chip 100 on the microfluidic chip 100 accounts for 76.82% of the area of ​​the microfluidic chip 100 .

[0058] It should be noted that although Figure 3 In the figure, the first microcavity 101, the second microcavity 102 and the third microcavity 103 are all cylindrical, but this is only an example, and the embodiments of the present disclosure do not limit the specific shapes of the first microcavity 101, the second microcavity 102 and the third microcavity 103. For example, the shapes of the first microcavity 101, the second microcavity 102 and the third microcavity 103 include but are not limited to cubes, quadrangular prisms, regular polyhedrons, etc.

[0059] The microfluidic chip 100 has three microcavities of different volumes, namely, a first microcavity 101, a second microcavity 102, and a third microcavity 103, which have the same depth but different bottom areas, and the volume ratio of the first microcavity 101, the second microcavity 102, and the third microcavity 103 is 1:4:8. The microfluidic chip 100 can allow a wider range of selection for the dilution concentration of the sample solution, without being restricted to diluting to a fixed concentration. For example, if a solution with a concentration of C1 is added to each microcavity, the C1 concentration can satisfy the requirement that the third microcavity 103 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 103; if a solution with a concentration of C2 (C2>C1) is added to each microcavity, the concentration C2 may be too high for the third microcavity 103, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 103 exceeds the threshold requirement, but the C2 concentration may satisfy the requirement that the second microcavity 102 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 103; The initial number of target nucleic acid molecules in the sample solution is calculated based on the value measured by the sample solution in the second microcavity 102; if a solution with a concentration of C3 (C3>C2>C1) is added to each microcavity, the concentration C3 may be too high for the third microcavity 103 and the second microcavity 102, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 103 and each second microcavity 102 exceeds the threshold requirement, but the C3 concentration may satisfy the requirement of containing one nucleic acid molecule for the first microcavity 101, so the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the first microcavity 101. Compared with a microcavity with a larger volume, a microcavity with a smaller volume is essentially equivalent to diluting the sample solution to a greater extent, so it can adapt to a solution with a higher concentration. In this way, the sample solution can be diluted in a wider concentration range (for example, it can be diluted to a concentration of C1, C2 or C3), instead of being diluted to a fixed multiple as in the related art. Therefore, compared with the microfluidic chip in the related art, the microfluidic chip 100 achieves an expansion of the dynamic range and improves the sensitivity of detection, and at the same time realizes multiple detection lines on a single microfluidic chip, thereby improving the experimental efficiency. In addition, compared with the conventional technology that requires multiple continuous dilutions of samples to meet the concentration requirements of a single volume microcavity, the microfluidic chip 100 avoids multiple continuous dilutions of the sample, thereby avoiding the waste of reagents and the risk of cross-contamination. Moreover, the arrangement of the various microcavities of the microfluidic chip 100 as described above can prevent mutual interference between different microcavities, which is conducive to the effective identification of each microcavity through a fluorescence microscope.

[0060] like Figure 4 and Figure 5As shown, the microfluidic chip 100 may also include structures such as a substrate 104, an insulating layer 105, a limiting layer 106, a hydrophilic layer 107, a conductive layer 108, and a heating electrode 109. The substrate 104 may be a glass substrate. The insulating layer 105 is located on the substrate 104. In one example, the insulating layer 105 is a SiO2 layer with a thickness of about 3000Å. The limiting layer 106 is located on the side of the insulating layer 105 away from the substrate 104, which defines each microcavity structure. For example, a plurality of grooves are formed in the limiting layer 106 by patterning the limiting layer 106, and the plurality of grooves constitute a plurality of microcavities of the microfluidic chip 100. In one example, the material of the limiting layer 106 is photoresist. The hydrophilic layer 107 is located on the side of the limiting layer 106 away from the substrate 104 and covers the bottom and sidewalls of the microcavity. The hydrophilic layer 107 has the characteristics of being hydrophilic and oleophobic. By setting the hydrophilic layer 107, the hydrophilic properties of the interior of the microcavity (the sidewalls and bottom of the microcavity) can be improved, which is conducive to making it easier for the reaction system solution to enter each microcavity. In one example, the material of the hydrophilic layer 107 is SiO2. The conductive layer 108 is located on the substrate 104 and is covered by the insulating layer 105. The conductive layer 108 is electrically connected to the heating electrode 109. The conductive layer 108 is configured to apply an electrical signal (e.g., a voltage signal) to the heating electrode 109. After receiving the electrical signal, the heating electrode 109 can generate heat under the action of the electrical signal, thereby heating the microcavity to promote the dPCR reaction. In one example, the material of the heating electrode 109 is indium tin oxide (ITO).

[0061] Figure 6 2 shows a side view of a microfluidic chip 200, Figure 7 Shown along Figure 6 The cross-sectional view taken along the C-C' line. Figure 6 and Figure 7 Except for the different microcavity structures, the microfluidic chip 200 has substantially the same structure as the microfluidic chip 100 described in the above embodiment, that is, the microfluidic chip 200 also includes a substrate 104, an insulating layer 105, a limiting layer 106, a hydrophilic layer 107, a conductive layer 108, and a heating electrode 109. Below, for the purpose of brevity, only the differences between the microfluidic chip 200 and the microfluidic chip 100 are introduced, and the similarities are not repeated.

[0062] like Figure 6 and Figure 7 As shown, the microfluidic chip 200 includes a plurality of microcavities, including at least one first microcavity 201, at least one second microcavity 202, and at least one third microcavity 203, and the volume of the first microcavity 201: the volume of the second microcavity 202: the volume of the third microcavity 203 is equal to 1:2:3.

[0063] The first microcavity 201, the second microcavity 202 and the third microcavity 203 have the same depth. The depths of the first microcavity 201, the second microcavity 202 and the third microcavity 203 are all 30-70 μm. In one example, the depths of the first microcavity 201, the second microcavity 202 and the third microcavity 203 are all 50 μm. The shape of the orthographic projection of the first microcavity 201 on the microfluidic chip 200 is an equilateral triangle, the shape of the orthographic projection of the second microcavity 202 on the microfluidic chip 200 is a parallelogram, and the shape of the orthographic projection of the third microcavity 203 on the microfluidic chip 200 is a trapezoid. Since the volume ratio of the first microcavity 201, the second microcavity 202 and the third microcavity 203 is 1:2:3 and the three have the same depth, the area of ​​the equilateral triangle: the area of ​​the parallelogram: the area of ​​the trapezoid is equal to 1:2:3. The lengths of the four sides of the parallelogram are all equal to the lengths of the sides of the equilateral triangle, the length of the upper base of the trapezoid is equal to the length of the sides of the equilateral triangle, and the length of the lower base of the trapezoid is twice the length of the sides of the equilateral triangle. In one example, the length of the side of the equilateral triangle is 100 μm, the lengths of the four sides of the parallelogram are all 100 μm, and the parallelogram is composed of two equilateral triangles, the length of the upper base of the trapezoid is 100 μm, the length of the lower base is 200 μm, and the trapezoid is composed of three equilateral triangles.

[0064] The first microcavity 201, the second microcavity 202 and the third microcavity 203 are arranged in an array. Figure 6 The first direction X is the row direction, and the second direction Y is the column direction. As shown in the figure, in each row, from left to right, the microcavities are alternately arranged in the order of the first microcavity 201, the second microcavity 202, and the third microcavity 203. In each column, the microcavities in the same column have the same shape. Figure 6 Taking the first row in as an example, the first four figures from left to right are an equilateral triangle, a parallelogram, a trapezoid, and an equilateral triangle. The first side of the parallelogram (i.e., the left side of the parallelogram in the figure) is adjacent to and parallel to the first side of the equilateral triangle on its left (i.e., the side of the equilateral triangle closest to the parallelogram), the second side of the parallelogram (i.e., the right side of the parallelogram in the figure) is adjacent to and parallel to the first side of the trapezoid on its right (i.e., the left side of the trapezoid closest to the parallelogram), the second side of the trapezoid (i.e., the right side of the trapezoid) is adjacent to and parallel to the second side of the equilateral triangle on its right (i.e., the side of the equilateral triangle closest to the trapezoid), the first spacing is the spacing between the first side of the parallelogram and the first side of the equilateral triangle on its left, the second spacing is the spacing between the second side of the parallelogram and the first side of the trapezoid on its right, the third spacing is the spacing between the second side of the trapezoid and the second side of the equilateral triangle on its right, and the first spacing, the second spacing, and the third spacing are equal. In one example, the first pitch, the second pitch, and the third pitch are all 12.50 μm.

[0065] In one example, the area of ​​the orthographic projection of the plurality of microcavities of the microfluidic chip 200 on the microfluidic chip 200 accounts for 72.90% of the area of ​​the microfluidic chip 200 .

[0066] The microfluidic chip 200 has three microcavities of different volumes, namely, a first microcavity 201, a second microcavity 202, and a third microcavity 203 having the same depth but different bottom areas, and the volume ratio of the first microcavity 201, the second microcavity 202, and the third microcavity 203 is 1:2:3. The microfluidic chip 200 can allow a wider range of selection for the dilution concentration of the sample solution, without being restricted to diluting to a fixed concentration. For example, if a solution with a concentration of C1 is added to each microcavity, the C1 concentration can satisfy the requirement that the third microcavity 203 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 203; if a solution with a concentration of C2 (C2>C1) is added to each microcavity, the concentration C2 may be too high for the third microcavity 203, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 203 exceeds the threshold requirement, but the C2 concentration may satisfy the requirement that the second microcavity 202 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 203. The initial number of target nucleic acid molecules in the sample solution is calculated based on the value measured by the sample solution in the second microcavity 202; if a solution with a concentration of C3 (C3>C2>C1) is added to each microcavity, the concentration C3 may be too high for the third microcavity 203 and the second microcavity 202, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 203 and each second microcavity 202 exceeds the threshold requirement, but the C3 concentration may satisfy the requirement of containing one nucleic acid molecule for the first microcavity 201, so the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the first microcavity 201. Compared with a microcavity with a larger volume, a microcavity with a smaller volume is essentially equivalent to diluting the sample solution to a greater extent, so it can adapt to a solution with a higher concentration. In this way, the sample solution can be diluted within a wider concentration range (for example, it can be diluted to a concentration of C1, C2 or C3), instead of being diluted to a fixed multiple as in the related art. Therefore, compared with the microfluidic chip in the related art, the microfluidic chip 200 achieves an expansion of the dynamic range and improves the sensitivity of detection, and at the same time realizes multiple detection lines on a single microfluidic chip, thereby improving the experimental efficiency. In addition, compared with the conventional technology that requires multiple continuous dilutions of samples to meet the concentration requirements of a single volume microcavity, the microfluidic chip 200 avoids multiple continuous dilutions of the sample, thereby avoiding the waste of reagents and the risk of cross-contamination. Moreover, the arrangement of the various microcavities of the microfluidic chip 200 as described above can prevent mutual interference between different microcavities, which is conducive to the effective identification of each microcavity through a fluorescence microscope.

[0067] Figure 8 FIG. 3 shows a side view of the microfluidic chip 300. Figure 8 Except for the different microcavity structures, the microfluidic chip 300 has substantially the same structure as the microfluidic chip 100 described in the above embodiment, that is, the microfluidic chip 300 also includes a substrate 104, an insulating layer 105, a limiting layer 106, a hydrophilic layer 107, a conductive layer 108, and a heating electrode 109. Below, for the purpose of brevity, only the differences between the microfluidic chip 300 and the microfluidic chip 100 are introduced, and the similarities are not repeated.

[0068] like Figure 8 As shown, the microfluidic chip 300 includes a plurality of microcavities, and the plurality of microcavities 300 include at least one first microcavity 301, at least one second microcavity 302, and at least one third microcavity 303. The volume of the first microcavity 301: the volume of the second microcavity 302: the volume of the third microcavity 303 is equal to 1:2:4. The first microcavity 301, the second microcavity 302, and the third microcavity 303 are all cylindrical and have the same bottom area. In one example, the radius of the bottom of the first microcavity 301, the radius of the bottom of the second microcavity 302, and the radius of the bottom of the third microcavity 303 are all 50 μm. Therefore, that is to say, the depths of the first microcavity 301, the second microcavity 302, and the third microcavity 303 are different, and the depth ratio of the three is 1:2:4. The depth of the first microcavity 301 is 25-40 μm, the depth of the second microcavity 302 is 50-80 μm, and the depth of the third microcavity 303 is 100-160 μm. In one example, the depth of the first microcavity 301 is 25 μm, the depth of the second microcavity 302 is 50 μm, and the depth of the third microcavity 303 is 100 μm.

[0069] Fig. 9 An arrangement of multiple microcavities of a microfluidic chip 300 on the microfluidic chip 300 is shown. As shown in the figure, multiple microcavities are arranged on the microfluidic chip 300 in a two-dimensional hexagonal close-packed manner, and the interval between any two adjacent microcavities is 10 to 80 μm. The area of ​​the orthographic projections of the multiple microcavities on the microfluidic chip 300 accounts for 24.67% to 68.43% of the area of ​​the microfluidic chip 300. The term "two-dimensional hexagonal close-packed" means that multiple microcavities are arranged in a honeycomb-like manner on the microfluidic chip 300 to maximize the use of spatial area, but it is necessary to ensure that there is a suitable interval between each microcavity to avoid mutual interference between each microcavity. As shown Fig. 9As shown in the dotted box in the figure, the two-dimensional hexagonal close-packed arrangement is made so that the line connecting the bottom centers of six adjacent microcavities forms a regular hexagon, and another microcavity is arranged in the exact center of the regular hexagon, and the center of the bottom of the microcavity in the exact center coincides with the center of the regular hexagon. In one example, the multiple microcavities of the microfluidic chip 300 are arranged in a two-dimensional hexagonal close-packed manner, the interval between any two adjacent microcavities is 50μm, and the area of ​​the positive projection of the multiple microcavities on the microfluidic chip 300 accounts for 40.18% of the area of ​​the microfluidic chip 300. It should be noted that the "interval" here does not refer to the distance between the centers of the bottoms of two adjacent microcavities, but refers to the distance between the sides of two adjacent microcavities that are closest to each other, with a spacing of 1.5 m. Fig. 9 Taking the seven microcavities (i.e., seven circles) in the dotted frame in FIG. 1 as an example, the interval between the tangent line of the lowest arc of the uppermost circle and the tangent line of the uppermost arc of the circle located at the center of the regular hexagon is 50 μm.

[0070] Fig.10 Another arrangement of multiple microcavities of the microfluidic chip 300 on the microfluidic chip 300 is shown. Fig.11 Shown along Fig.10 The cross-sectional view is taken along the D-D' line. As shown in the figure, multiple microcavities are arranged in a two-dimensional square lattice on the microfluidic chip 300, and the interval between any two adjacent microcavities is 10-80 μm. The area of ​​the orthographic projection of the multiple microcavities on the microfluidic chip 300 accounts for 24.67%-68.43% of the area of ​​the microfluidic chip 300. It should be noted that the "interval" here does not refer to the distance between the centers of the bottoms of two adjacent microcavities, but refers to the distance between the sides of two adjacent microcavities that are closest to each other, with the interval being 10-80 μm. Fig.10 Taking the first two microcavities (i.e., the first two circles) in the first column on the left side from top to bottom as an example, the interval between the tangent of the lowest arc of the first circle and the tangent of the highest arc of the second circle is 10-80 μm.

[0071] The term "two-dimensional square lattice" means that multiple microcavities are regularly arranged on the microfluidic chip 300, and the intersection of two adjacent rows of microcavities and two adjacent columns of microcavities is four microcavities, and the lines connecting the centers of the bottoms of the four microcavities form a square. This arrangement of microcavities can maximize the use of the space area, while ensuring that there is a suitable spacing between the microcavities to avoid mutual interference between the microcavities. Fig.10 and Fig.11 As shown, along the direction of line DD', a plurality of microcavities are alternately arranged in the order of first microcavity 301, second microcavity 302, and third microcavity 303. In one example, the depth of first microcavity 301 is 25 μm, the depth of second microcavity 302 is 50 μm, and the depth of third microcavity 303 is 100 μm.

[0072] It should be noted that although Figure 8-Figure 10 In the figure, the first microcavity 301, the second microcavity 302 and the third microcavity 303 are all shown as cylindrical, but this is only an example, and the embodiments of the present disclosure do not limit the specific shapes of the first microcavity 301, the second microcavity 302 and the third microcavity 303. For example, the shapes of the first microcavity 301, the second microcavity 302 and the third microcavity 303 include but are not limited to cubes, quadrangular prisms, regular polyhedrons, etc.

[0073] The microfluidic chip 300 has three microcavities of different volumes, namely, a first microcavity 301, a second microcavity 302, and a third microcavity 303, which have the same bottom area but different depths, and the volume ratio of the first microcavity 301, the second microcavity 302, and the third microcavity 303 is 1:2:4. The microfluidic chip 300 can allow a wider range of selection for the dilution concentration of the sample solution, without being restricted to diluting to a fixed concentration. For example, if a solution with a concentration of C1 is added to each microcavity, the C1 concentration can satisfy the requirement that the third microcavity 303 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 303; if a solution with a concentration of C2 (C2>C1) is added to each microcavity, the concentration C2 may be too high for the third microcavity 303, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 303 exceeds the threshold requirement, but the C2 concentration may satisfy the requirement that the second microcavity 302 contains one nucleic acid molecule, and the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the third microcavity 303. The initial number of target nucleic acid molecules in the sample solution is calculated based on the value measured by the sample solution in the second microcavity 302; if a solution with a concentration of C3 (C3>C2>C1) is added to each microcavity, the concentration C3 may be too high for the third microcavity 303 and the second microcavity 302, so that the number of nucleic acid molecules contained in the sample solution in each third microcavity 303 and each second microcavity 302 exceeds the threshold requirement, but the C3 concentration may satisfy the requirement of containing one nucleic acid molecule for the first microcavity 301, so the initial number of target nucleic acid molecules in the sample solution can be calculated mainly based on the value measured by the sample solution in the first microcavity 301. Compared with a microcavity with a larger volume, a microcavity with a smaller volume is essentially equivalent to diluting the sample solution to a greater extent, so it can adapt to a solution with a higher concentration. In this way, the sample solution can be diluted within a wider concentration range (for example, it can be diluted to a concentration of C1, C2 or C3), instead of being diluted to a fixed multiple as in the related art. Therefore, compared to the microfluidic chip in the related art, the microfluidic chip 300 achieves an expansion of the dynamic range and improves the sensitivity of detection, and at the same time realizes multiple detection lines on a single microfluidic chip, thereby improving the experimental efficiency. In addition, compared to the conventional technology that requires multiple continuous dilutions of samples to meet the concentration requirements of a single volume microcavity, the microfluidic chip 300 avoids multiple continuous dilutions of the sample, thereby avoiding the waste of reagents and the risk of cross-contamination. Moreover, the arrangement of the various microcavities of the microfluidic chip 300 as described above can prevent mutual interference between different microcavities, which is conducive to the effective identification of each microcavity through a fluorescence microscope.

[0074] According to another aspect of the present disclosure, a microfluidic device 400 is provided. Fig.12 4 shows a block diagram of the microfluidic device 400. The microfluidic device 400 includes the microfluidic chip described in any of the above embodiments.

[0075] Since the microfluidic device 400 can have substantially the same technical effects as the microfluidic chips described in the previous embodiments, the technical effects of the microfluidic device 400 will not be described repeatedly herein for the purpose of brevity.

[0076] Another aspect of the present disclosure provides a method 500 for manufacturing a microfluidic chip, which can be applied to the microfluidic chip described in any of the above embodiments. Figure 4 and Figure 5 The method 500 is described below.

[0077] Step 501: Provide a substrate 104. The substrate 104 may be made of any suitable material. In one example, the substrate 104 is made of glass.

[0078] Step 502: Form a conductive film layer on the substrate 104 at about 125°C. In one example, a molybdenum (Mo) layer with a thickness of 200Å, an aluminum (Al) layer with a thickness of 3000Å, and a molybdenum (Mo) layer with a thickness of 800Å are sequentially deposited on the substrate 104 to form the conductive film layer. The conductive film layer is patterned, such as by exposure, development, etching, etc., to form a conductive layer 108.

[0079] Step 503: Deposit an insulating film layer on the conductive layer 108 at about 200° C., and pattern the insulating film layer to form an insulating layer 105 covering the conductive layer 108. In one example, the insulating layer 105 is a SiO2 layer with a thickness of about 3000Å.

[0080] Step 504 : patterning the insulating layer 105 to form at least one via hole penetrating the insulating layer 105 , wherein the at least one via hole exposes a portion of the conductive layer 108 . In one example, the insulating layer 105 is etched in a dry etching machine to form a via, and the specific process is described as follows: etching for 10 seconds at a pressure of about 150 mtorr, a power of about 800 w, and a volume flow rate of O2 of about 400 sccm (standard cubic centimeter per minute); etching for 200 seconds at a pressure of about 60 mtorr, a power of about 800 w, and a gas volume flow rate ratio of CF4 to O2 of about 200:50; etching for 30 seconds at a pressure of about 130 mtorr, a power of about 800 w, and a gas volume flow rate ratio of O2 to CF4 of about 400:40; and etching for 160 seconds at a pressure of about 60 mtorr, a power of about 800 w, and a gas volume flow rate ratio of CF4 to O2 of about 200:50.

[0081] Step 505: deposit a conductive film layer on the side of the insulating layer 105 away from the substrate 104, and then perform exposure, development, etching, stripping and other processes on the conductive film layer to form a patterned heating electrode 109. In one example, the material of the heating electrode 109 is ITO. In one example, the heating electrode 109 may include a plurality of sub-parts separated from each other.

[0082] Step 506: Deposit another insulating film layer on the side of the heating electrode 109 away from the substrate 104, and pattern the other insulating film layer to form another insulating layer (not shown in the figure) that at least partially covers the heating electrode 109. In one example, the material of the other insulating layer is SiO2. In another example, the other insulating layer includes a SiO2 layer with a thickness of about 1000Å and a SiN layer with a thickness of about 2000Å stacked in sequence. x layer.

[0083] Step 507: A shielding film layer may be coated on one side of the other insulating layer away from the substrate 104, and the shielding film layer may be patterned to form a shielding layer defined with an opening (not shown in the figure). In one example, the specific steps of forming the shielding layer may include: coating a shielding film layer on one side of the other insulating layer away from the substrate 104, and then exposing, developing, and etching the shielding film layer through a mask. Finally, the etched shielding film layer is post-cured at 230°C for about 30 minutes to form a shielding layer defined with an opening. The opening of the shielding layer may correspond to the position of the microcavity to be formed later. In one example, the material forming the shielding layer includes chromium, chromium oxide, and black resin.

[0084] Step 508: Coat a defining film layer on the side of the shielding layer away from the substrate 104, and pattern the defining film layer to form a defining layer 106 defining a plurality of microcavities. In one example, the process of forming the defining layer 106 is described as follows: First, at a pressure of 30 Kpa, spin-coat an optical adhesive at a speed of 300 rpm on the surface of the shielding layer away from the substrate 104 for about 10 seconds, and then cure the optical adhesive at a temperature of 90°C for 120 seconds. Repeat the above process twice to obtain a defining film layer. Next, expose the defining film layer through a mask, and then develop the exposed defining film layer with a developer for 100 seconds, and then etch. At a temperature of 230°C, cure the etched defining film layer for 30 minutes to finally obtain a defining layer 106 defining a plurality of microcavities. The process steps used to form the multiple microcavities of the microfluidic chip 100, the multiple microcavities of the microfluidic chip 200 and the multiple microcavities of the microfluidic chip 300 are the same, but different shapes of masks are used to form microcavities of different shapes. The material of the definition layer 106 includes photoresist.

[0085] Step 509: At 200°C, an insulating film layer is deposited on the surface of the limiting layer 106 away from the substrate 104, and the insulating film layer is exposed, developed, and etched to form a patterned layer. The patterned layer is treated with a 0.4% KOH solution for about 15 minutes to perform hydrophilic modification on the patterned layer, thereby forming a hydrophilic layer 107. The hydrophilic layer 107 covers the surface of the limiting layer 106 away from the substrate 104, and covers the bottom and sidewalls of each microcavity. In one example, the hydrophilic layer 107 is a SiO2 layer with a thickness of about 3000Å.

[0086] It should be noted that the manufacturing method may further include more steps, which may be determined according to actual needs, and the embodiments of the present disclosure do not limit this. The technical effects achieved by the manufacturing method can refer to the description of the microfluidic chip above, which will not be repeated here.

[0087] In the description of the present disclosure, the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present disclosure rather than requiring that the present disclosure must be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present disclosure.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "another embodiment", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory. In addition, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0089] As will be appreciated by those skilled in the art, although the various steps of the method in the present disclosure are described in a particular order in the accompanying drawings, this does not require or imply that the steps must be performed in this particular order unless the context clearly indicates otherwise. Additionally or alternatively, multiple steps may be combined into one step for execution, and / or a step may be decomposed into multiple steps for execution. In addition, other method steps may be inserted between steps. The inserted steps may represent improvements to the method such as described herein, or may be unrelated to the method. In addition, a given step may not be fully completed before the next step begins.

[0090] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A microfluidic chip comprising a plurality of microcavities, wherein: The plurality of microcavities include at least one first microcavity, at least one second microcavity, and at least one third microcavity, the volumes of the first microcavity, the second microcavity, and the third microcavity are different, the bottom areas of the first microcavity, the second microcavity, and the third microcavity are the same, and the plurality of microcavities are arranged in a two-dimensional hexagonal close-packed or two-dimensional square lattice manner, wherein The two-dimensional hexagonal close-packed arrangement is such that the line connecting the bottom centers of six adjacent microcavities forms a regular hexagon, and another microcavity is arranged at the exact center of the regular hexagon, and the center of the bottom of the microcavity at the exact center coincides with the center of the regular hexagon. The two-dimensional square lattice arrangement is such that the intersection of two adjacent rows of microcavities and two adjacent columns of microcavities is four microcavities, and the lines connecting the bottom centers of the four microcavities form a square.

2. The microfluidic chip according to claim 1, wherein: The ratio of the volumes of the first microcavity, the second microcavity, and the third microcavity is 1:2:

4.

3. The microfluidic chip according to claim 2, wherein: The depth of the first microcavity is 25-40 μm, the depth of the second microcavity is 50-80 μm, and the depth of the third microcavity is 100-160 μm.

4. The microfluidic chip according to claim 1, wherein: The shapes of the orthographic projections of the bottom of the first microcavity, the bottom of the second microcavity, and the bottom of the third microcavity on the microfluidic chip are all circular, and the radius of the bottom of the first microcavity, the radius of the bottom of the second microcavity, and the radius of the bottom of the third microcavity are equal.

5. The microfluidic chip according to claim 1, wherein: The interval between any two adjacent microcavities is 10-80 μm.

6. The microfluidic chip according to claim 5, wherein: The orthographic projection area of ​​the plurality of microcavities on the microfluidic chip accounts for 24.67% to 68.43% of the area of ​​the microfluidic chip.

7. The microfluidic chip according to claim 5, wherein: The multiple microcavities are arranged in a two-dimensional hexagonal close-packed manner, the interval between any two adjacent microcavities is 50 μm, and the area of ​​the orthographic projections of the multiple microcavities on the microfluidic chip accounts for 40.18% of the area of ​​the microfluidic chip.

8. A microfluidic device, comprising the microfluidic chip according to any one of claims 1 to 7.

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