A microfluidic chip for precise quantification of reagents

Abstract

The present invention provides a microfluidic chip for accurate quantification of reagents, belonging to the field of microfluidic technology, comprising: an upstream cavity; a quantitative cavity, the quantitative cavity is located on a side away from the rotation center compared to the upstream cavity, the upstream cavity is directly or indirectly connected to the entrance of the quantitative cavity, and the quantitative cavity also has an overflow channel; a quantitative auxiliary protrusion, the quantitative auxiliary protrusion is located on the inner wall of the quantitative cavity close to the rotation center, the quantitative auxiliary protrusion is located between the overflow channel and the entrance of the quantitative cavity; there is a gap between the upper surface and / or lower surface of the quantitative auxiliary protrusion and the inner wall of the quantitative cavity, and when the liquid is filled, the liquid enters the gap. The present invention uses centrifugal force as a driving force, and designs a "concave" type special structure quantitative cavity with a quantitative auxiliary protrusion on a centrifugal microfluidic chip, and breaks the liquid-gas interfacial tension at low speed, thereby ensuring the accuracy of quantitative diversion at low speed.

Description

Technical Field

[0001] The present application relates to the field of microfluidics technology, and in particular to a microfluidics chip for precise quantification of reagents. Background Art

[0002] With the continuous development and innovation of microfluidic technology, the application of microfluidic chips is gradually becoming a hot topic in various research fields. Due to the advantages of microfluidic chips such as miniaturization, integration and high automation, they have been widely used in the field of biomedical testing (including biochemistry, immunology and molecular diagnosis, etc.). Microfluidic chip kits used to load and run various detection reagents are gradually becoming the most effective carrier form for achieving "point-of-care testing" (POCT) at the patient's bedside.

[0003] To meet the detection needs, microfluidic chip test kits need to perform various processing, mixing, separation and transfer operations on liquid components such as samples and reagents. Among them, the diversion, quantification and sequential release of liquid reagents are important links for various microfluidic chip test kits to achieve internal fluid manipulation and operation, and are often also the key to ensuring the sensitive and efficient operation of microfluidic chips. For example, when there are multiple parallel reaction chambers (such as multiple PCR amplification chambers) downstream, accurate and consistent quantification and diversion are often required upstream. For example, when sequential reactions of reagents are required downstream (such as nucleic acid extraction and purification), sequential release of reagents is often required upstream.

[0004] At present, although some microfluidic solutions have made certain design optimizations and performance improvements in subdivided technical strategies such as quantitative diversion and sequential release, there is still a large space and demand for technical improvement in the accuracy of quantitative diversion and the feasibility and simplicity of sequential release operations in the field of microfluidics. Existing reagent quantitative diversion strategies often require the use of a semi-open quantitative cavity connected to a common flow channel, or directly rely on a quantitative pipeline with an inlet and an outlet to achieve it, but these technical strategies may cause inaccurate quantitative diversion due to factors such as bubble cavities, wall slip or surface tension; and the existing reagent sequential release strategies are either completed by the sequential opening and closing of multiple active or passive valves, or by using multi-level, interconnected siphon pipelines, but these strategies either require complex valve control systems or fluid drive systems, or have high requirements for the processing technology of various flow channels, and often require more operating steps in the process of sequential release, which is often time-consuming, labor-intensive and costly. It is also worth noting that the existing technical solutions have not been able to combine quantitative diversion with sequential release order, and thus have not been able to further achieve precise and orderly diversion of liquid reagents, which to a certain extent limits the application flexibility of the microfluidic test kit, or when it is necessary to achieve precise and orderly diversion of reagents, some additional complex processes or procedures have to be added, making the production and use process of the microfluidic test kit too complicated and costly. Summary of the invention

[0005] The purpose of the present invention is to provide a microfluidic chip for accurate reagent quantification. Centrifugal force is used as the driving force for liquid reagents, and a "concave" special structure quantitative cavity with quantitative auxiliary protrusions is designed on the centrifugal microfluidic chip, and the surface tension of the liquid in the gap is used as a constraint, thereby fundamentally ensuring the accuracy of quantitative diversion at low speed.

[0006] The present invention adopts the following technical solution:

[0007] A microfluidic chip for precise quantification of reagents, comprising: an upstream cavity; a quantitative cavity, wherein the quantitative cavity is located on a side away from a rotation center compared to the upstream cavity, the upstream cavity is directly or indirectly connected to an entrance of the quantitative cavity, and the quantitative cavity also has an overflow channel; a quantitative auxiliary protrusion, wherein the quantitative auxiliary protrusion is located on an inner wall of the quantitative cavity on a side close to the rotation center, and the quantitative auxiliary protrusion is located between the overflow channel and the entrance of the quantitative cavity; a gap is provided between the upper surface and / or lower surface of the quantitative auxiliary protrusion and the inner wall of the quantitative cavity, and when liquid filling is completed, the liquid enters the gap.

[0008] Furthermore, the minimum distance between the distal end of the quantitative auxiliary protrusion and the rotation center is greater than the minimum distance between the inner wall of the overflow channel away from the rotation center and the rotation center, and the minimum distance between the distal end of the quantitative auxiliary protrusion and the rotation center is greater than the maximum distance between the inlet and the rotation center.

[0009] Furthermore, the quantitative auxiliary protrusion and the first inner wall of the quantitative cavity on the liquid inlet side have a first minimum width S1, the quantitative auxiliary protrusion and the second inner wall of the quantitative cavity on the overflow channel side have a second minimum width S2, and the distal end side of the quantitative auxiliary protrusion and the distal end side of the quantitative cavity form a third minimum width S3; the first minimum width S1, the second minimum width S2 and the third minimum width S3 satisfy: S1<S3 and S2<S3.

[0010] Furthermore, the inner wall of the overflow channel away from the rotation center is an arc or a slope, and the angle between the tangent of the arc or the slope and the line connecting the rotation center along the liquid flow direction is greater than 90° and gradually increases; on the distal end side of the overflow channel, the relationship between the first minimum width S1 and the second minimum width S2 satisfies: S2<S1.

[0011] Furthermore, the first minimum width S1, the second minimum width S2 and the third minimum width S3 satisfy:

[0012] ;

[0013] ;

[0014] in, The value of is 0.7-0.5, The value of is 0.2-0.4; the size range of the third minimum width S3 does not exceed 3mm.

[0015] Furthermore, when the quantitative cavity is filled, the ratio of the arc length of the gap to the arc length of the liquid surface is not less than 0.8; and the size range of the gap is 0.2mm-2mm.

[0016] Furthermore, a return air passage is provided at the proximal end of the quantitative chamber; and the overflow passage of the final quantitative chamber recycles the excess liquid into the waste liquid pool through the waste liquid passage.

[0017] Furthermore, it also includes a downstream chamber, which is arranged on a side farther away from the rotation center than the quantitative chamber, and the proximal end of the downstream chamber is connected to the distal end of the quantitative chamber.

[0018] Furthermore, the quantitative chambers include at least two; the number of the downstream chambers is the same as that of the quantitative chambers, and the quantitative chambers are respectively connected to the corresponding downstream chambers; the quantitative chambers are arranged in a spiral line and gradually move away, and the upstream chamber is connected to the quantitative chamber with the smallest spiral radius; the distal end of the quantitative chamber is connected to the downstream chamber through an infusion channel with different resistances, and the resistance of the infusion channel gradually increases along the direction in which the liquid fills the quantitative chamber, and a connecting channel is provided between the downstream chambers.

[0019] Furthermore, it also includes a blocking cavity, which is connected to the connecting channel and the infusion channel respectively, the distance between the connection between the infusion channel and the blocking cavity and the rotation center is less than the distance between the side of the blocking cavity away from the rotation center and the rotation center, and the distance between the connection between the connecting channel and the blocking cavity and the rotation center is not greater than the distance between the side of the blocking cavity away from the rotation center and the rotation center; with the rotation center as the center of the circle, an arc is formed with a radius that is not less than the distance between the connection between the infusion channel and the blocking cavity and the rotation center and less than the distance between the side of the blocking cavity away from the rotation center and the rotation center, the arc intersects with the blocking cavity to form a first intersection, the rotation center and the connection between the infusion channel and the blocking cavity form a first straight line, the arc intersects with the first straight line to form a second intersection, and the length of the arc formed between the first intersection and the second intersection is not greater than 5 mm; the width of the blocking cavity is not greater than 1 mm.

[0020] Compared with the prior art, the beneficial technical effects of the present invention include:

[0021] 1. First, the present invention solves the problem that the surface tension dominates and affects the quantitative accuracy of liquid reagents under low speed conditions by designing a "concave" special structure quantitative cavity with quantitative auxiliary protrusions on the centrifugal microfluidic chip. By breaking the liquid-gas interfacial tension at low speed to reduce the wall slip phenomenon, the accuracy of quantitative diversion at low speed is fundamentally guaranteed; secondly, the gap formed between the quantitative auxiliary protrusion and the inner wall of the quantitative cavity can restrain the free surface of the liquid, inhibit the microfluidic chip from causing liquid surface fluctuations under speed fluctuations, acceleration or deceleration, and further improve the accuracy in the quantitative process, especially for the open quantitative cavity in this application; thirdly, when the quantitative cavity is filled, part or all of the liquid flows through the gap to avoid the formation of obstruction causing the liquid to flow along the bottom of the quantitative auxiliary protrusion, resulting in poor liquid surface stability and low quantitative accuracy; finally, the quantitative auxiliary protrusion and the first inner wall, the second inner wall and the third inner wall of the quantitative cavity have a certain width, forming a pipeline-like structure, which can discharge the bubbles generated during quantitative measurement from the quantitative cavity, further increasing the accuracy of the quantitative process.

[0022] 2. Secondly, the present invention utilizes a circulation path composed of interconnected fan-shaped connecting channels and capillary channels with different resistances to successively play the multiple roles of the capillary channels as a fluid valve, liquid flow path and gas loop. It can not only achieve simultaneous blocking of multiple fluids at a low speed, but also achieve sequential release of multiple liquid reagents at a single constant speed, thereby broadening the scope of application, increasing the flexibility of microfluidic chip design, and reducing the requirements for the performance of supporting instruments and equipment and the precision of the assembly system.

[0023] 3. Again, the present invention not only solves the problem of easy stratification of liquid reagents that are easy to settle during centrifugal quantitative distribution, but also realizes the sequential release of multiple precisely quantified liquids. Through ingenious structural design and the control of centrifugal speed, the technical solution of the present application can achieve precise quantification of liquids at a minimum speed of 200r / min, and at the same time, only a single constant speed of 800r / min is required to achieve the sequential release of three liquid reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A structural diagram of a microfluidic chip for precise quantification of reagents provided in an embodiment of the present invention;

[0026] Figure 2 for Figure 1 AA view in;

[0027] Figure 3 for Figure 1 Another schematic diagram of a quantitative auxiliary protrusion structure in;

[0028] Figure 4 A local enlarged view of the quantitative cavity provided in an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of a quantitative cavity after filling is completed provided in an embodiment of the present invention;

[0030] Figure 6 A structural diagram of another microfluidic chip with connecting channels provided by an embodiment of the present invention;

[0031] Figure 7 A partial enlarged view of another microfluidic chip with connecting channels provided by an embodiment of the present invention;

[0032] Figure 8Schematic diagram of different stages of the microfluidic chip provided in an embodiment of the present invention, a is the state after the reagent is added to the upstream chamber, b is the state of the reagent in the upstream chamber entering the quantitative chamber, c is the state of the rightmost downstream chamber being filled, d is the state of the middle downstream chamber being filled, and e is the state of the leftmost downstream chamber being filled.

[0033] Figure markings: 001, sample addition port; 01, first channel; 02, return air passage; 03, waste liquid channel; 04, connecting channel; 041, blocking cavity; 05, infusion channel; 1, upstream cavity; 2, quantitative cavity; 20, inlet; 21, overflow channel; 22, first side wall; 23, second side wall; 3, quantitative auxiliary protrusion; 4, waste liquid pool; 5, downstream cavity. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the embodiment of the present invention, the "distal end" and the "proximal end" are obtained by comparing the distances relative to the rotation center O. For example, the side of a chamber close to the rotation center is the proximal end, and the side away from the rotation center is the distal end.

[0040] The present invention discloses a microfluidic chip for accurate quantification of reagents. Figure 1 and 2 As shown, it includes: an upstream cavity 1; a quantitative cavity 2, wherein the quantitative cavity 2 is located on a side away from the rotation center O compared to the upstream cavity 1, the upstream cavity 1 is directly or indirectly connected to the inlet 20 of the quantitative cavity 2, and the quantitative cavity 2 also has an overflow channel 21; a quantitative auxiliary protrusion 3, wherein the quantitative auxiliary protrusion 3 is located on the inner wall of the quantitative cavity 2 close to the rotation center O, and the quantitative auxiliary protrusion 3 is located between the overflow channel 21 and the inlet 20 of the quantitative cavity 2; there is a gap L between the upper surface and / or lower surface of the quantitative auxiliary protrusion 3 and the inner wall of the quantitative cavity 2, and when the liquid is filled, the liquid enters the gap L.

[0041] The technical solution provided by the present invention uses centrifugal force as the driving force of the liquid reagent. First, by designing a "concave" special structure quantitative cavity with a quantitative auxiliary protrusion on the centrifugal microfluidic chip, the liquid-gas interfacial tension at low speed is broken to reduce the wall slip phenomenon, thereby fundamentally ensuring the accuracy of quantitative diversion; secondly, the gap formed between the quantitative auxiliary protrusion and the inner wall of the quantitative cavity can constrain the free surface of the liquid, weaken the liquid surface fluctuation caused by the speed fluctuation, acceleration or deceleration of the microfluidic chip, and further improve the accuracy of the quantitative process, especially for the open quantitative cavity in this application; thirdly, when the quantitative cavity is filled, part or all of the liquid flows through the gap to avoid the formation of flow obstruction causing the liquid to flow along the bottom of the quantitative auxiliary protrusion 3, such as Figure 1 The X-direction movement in the quantitative chamber leads to worse liquid surface stability and low quantitative accuracy; finally, the quantitative auxiliary protrusion and the first inner wall, the second inner wall and the third inner wall of the quantitative chamber have a certain width, forming a pipeline-like structure, which can discharge the bubbles generated during quantitative measurement into the quantitative chamber, thereby further increasing the accuracy of the quantitative process.

[0042] Figure 1 In the embodiment of the invention, the upstream chamber 1 is used to store liquids, such as buffer solutions or reagents, and is a fan-shaped ring structure. Its distal end is connected to the quantitative chamber, and a feeding port is provided for adding buffer solutions or reagents. There are three quantitative chambers in the embodiment of the invention, but it should be noted that the quantitative chambers can be selectively set to 1, 2 or n based on the reagent requirements, and the number is not limited here. The upstream chamber 1 is directly or indirectly connected to the inlet 20 of the quantitative chamber 2. If there is only one quantitative chamber in the embodiment of the invention, the upstream chamber 1 is directly connected to the inlet 20 of the quantitative chamber 2; if Figure 1 As shown, when there are multiple quantitative chambers, the other quantitative chambers need to be filled after the first quantitative chamber is filled, which can be understood as an indirect connection. There is a gap L between the upper surface and / or lower surface of the quantitative auxiliary protrusion 3 and the inner wall of the quantitative chamber 2, such as Figure 2 As shown, there is a gap L between the upper surface of the quantitative auxiliary protrusion 3 and the inner wall of the quantitative cavity, as shown in FIG. Figure 3 As shown, there is a gap L between the upper and lower surfaces of the quantitative auxiliary protrusion 3 and the quantitative cavity 2. In order to improve the stability of the quantitative auxiliary protrusion 3, a support portion can be set in the gap L to accurately position the quantitative auxiliary protrusion 3. Similarly, it can be understood that there is a gap L between the lower surface of the quantitative auxiliary protrusion 3 and the quantitative cavity 2. When the gap L is immersed in liquid, under the action of surface tension, the gap can restrain the free surface of the liquid, weaken the liquid surface fluctuation caused by the speed fluctuation, acceleration or deceleration of the microfluidic chip, and further improve the accuracy of the quantitative process.

[0043] The "upstream chamber 1" in the embodiment of the present invention may be provided with a sample addition port or not, which depends on the position of the upstream chamber in the predetermined process. For example, when it is used as a chamber for adding liquids such as reagents and samples, a sample addition port 001 is required. Figure 1 As shown; when the upstream chamber 1 is an intermediate chamber, there is no need to set a sample addition port.

[0044] The "inlet 20" and "overflow channel 21" in the embodiment of the present invention are relative. For example, for the leftmost quantitative chamber 2, the distal end of the upstream chamber 1 is connected to the proximal end of the quantitative chamber 2 through the first channel 01, and the connection point is the inlet 20. After the liquid quantitative measurement is completed, the excess liquid is discharged through the overflow channel 21; for the middle quantitative chamber 2, its inlet 20 is the liquid discharged from the overflow channel 21 of the leftmost quantitative chamber 2. After the middle quantitative chamber 2 is filled, the overflow channel 21 on the right is used to discharge the excess liquid to the next quantitative chamber, and so on.

[0045] Specifically, Figure 1As shown, the minimum distance L1 between the distal end of the quantitative auxiliary protrusion 3 and the rotation center O is greater than the minimum distance L2 between the inner wall of the overflow channel 21 away from the rotation center O and the rotation center, and the minimum distance L1 between the distal end of the quantitative auxiliary protrusion 3 and the rotation center O is greater than the maximum distance L3 between the inlet 20 and the rotation center O. Through the above-mentioned structural setting, it is ensured that the liquid after filling can fill the gap, and the liquid in the gap is pressurized under the dual effects of centrifugal force and surface tension, thereby improving the bonding strength between the liquid and the quantitative cavity 2 and further reducing the probability of wall slip.

[0046] Specifically, Figure 4 As shown, the quantitative auxiliary protrusion 3 and the first inner wall of the quantitative cavity 2 on the liquid inlet side have a first minimum width S1, the quantitative auxiliary protrusion 3 and the second inner wall of the quantitative cavity 2 on the overflow channel 21 side have a second minimum width S2, and the distal end side of the quantitative auxiliary protrusion 3 and the distal end side of the quantitative cavity 2 form a third minimum width S3; the first minimum width S1, the second minimum width S2 and the third minimum width S3 satisfy: S1<S3 and S2<S3. Setting S1 and S2 to be smaller can, on the one hand, reduce the size of the free surface and weaken the fluctuation of the liquid surface. At the same time, after filling, there is still a free interface at the first minimum width S1 and the second minimum width S2, which can apply pressure to the liquid in the direction away from the rotation center, further reducing the wall slip phenomenon; secondly, after filling, the liquid in the cavity will be subject to the resistance of the first maximum width S1 and the second minimum width S2 when flowing out from the inlet or overflow channel, avoiding large fluctuations in the liquid surface during acceleration, deceleration and speed fluctuations, resulting in poor quantitative effect.

[0047] Specifically, Figure 1 As shown, the inner wall of the overflow channel 21 on the side away from the rotation center O is an arc or a slope, and the angle α between the tangent of the arc or the slope and the line connecting the rotation center O along the liquid flow direction is greater than 90° and gradually increases; the relationship between the first minimum width S1 and the second minimum width S2 satisfies: S2<S1. During the liquid quantitative process, due to the fluctuation of the liquid level in the quantitative chamber, that is, the fluctuation of the liquid level on the side close to the rotation center, the liquid level fluctuation at the initial quantitative stage causes excess liquid to overflow into the downstream quantitative chamber, but at this time the upstream quantitative chamber can still be supplemented by the liquid in the upstream chamber, which will not cause the problem of insufficient quantitative quantity in the upstream quantitative chamber. After the quantitative measurement is completed, the upstream quantitative chamber will not be supplemented by the liquid in the upstream chamber, resulting in insufficient quantitative quantity. Based on the above problems, the present application proposes S2<S1, which further increases the outflow resistance of the liquid from the overflow channel and avoids the above problems.

[0048] Preferably, the first minimum width S1, the second minimum width S2 and the third minimum width S3 satisfy:

[0049] ;

[0050] ;

[0051] in, The value of is 0.7-0.5, The value of is 0.2-0.4; the size range of the third minimum width S3 does not exceed 3 mm. Within the above size range, it can be achieved under the existing technology that there will be no problem of quantitative under- or over-quantity, and the quantitative error does not exceed 1%.

[0052] Preferably, Figure 5 As shown, when the quantitative cavity is filled, the dotted line indicates the position of the liquid level. In the embodiment of the present invention, there is a gap L between the upper surface of the quantitative auxiliary protrusion 3 and the inner wall of the quantitative cavity 2, and the ratio of the arc length L4 of the gap to the arc length L5 of the liquid level is not less than 0.8; the size range of the gap is 0.2mm-2mm. A gap that is too large or too small will affect the pressure effect of surface tension. Specifically, if the size is too small, the flow resistance is more serious, causing the liquid to flow from the bottom of the quantitative auxiliary protrusion, and the liquid stability is poor, which can easily lead to inaccurate quantification. If the gap size is too large, the surface tension of the liquid will become smaller, affecting the pressure effect. Based on the above considerations, this application limits the size range and ratio of the gap to further improve the accuracy of quantification. After experimental measurement, the liquid volume measured by the above technical solution is less than the design value, and the error is no more than 1%, and the accuracy is extremely high.

[0053] like Figure 5 As shown, the entrance of the quantitative chamber 2 has a first side wall 22, and the overflow channel 21 of the quantitative chamber 2 has a second side wall 23. The first side wall 22, the second side wall 23 and the bottom together constitute the quantitative chamber 2. The rotation center O and the two sides of the bottom of the quantitative chamber 2 are connected to form R1 and R2, and the first side wall 22 and the second side wall 23 are inclined inwardly relative to R1 and R2. When the microfluidic chip accelerates, decelerates or the speed fluctuates, the liquid acts on the first side wall and the second side wall under the action of inertia. By setting the first side wall 22 and the second side wall 23 to be inclined inwardly relative to R1 and R2, the opening of the quantitative chamber 2 is contracted, so that the kinetic energy is digested inside the quantitative chamber 2, and the liquid reagent is prevented from splashing out at the first minimum width S1 and the second minimum width S2, causing inaccurate quantification.

[0054] Specifically, Figure 1As shown, the proximal end of the quantitative chamber 2 is provided with a return air passage 02; the overflow channel 21 of the final quantitative chamber 2 recycles the excess liquid into the waste liquid pool 4 through the waste liquid passage 03. When the liquid is transported from the upstream chamber 1 to the leftmost quantitative chamber 2 through the first channel 01, the pressure in the quantitative chamber 2 increases, and the gas is transported to the upstream chamber 1 through the return air passage 02, and a circulation passage is formed at this time, which facilitates the smooth progress of the filling process. The depth and width of the return air passage 02 are at the level of hundreds of microns (μm), which is used to provide a reliable gas circuit for the quantitative measurement of liquid reagents at low speed (<1000rpm), ensuring the smoothness of the quantitative filling of liquid reagents in sequence.

[0055] like Figure 1 As shown, it also includes a downstream chamber 5, which is arranged on the side farther away from the rotation center O than the quantitative chamber 2, and the proximal end of the downstream chamber 5 is connected to the distal end of the quantitative chamber 2.

[0056] Specifically, the quantitative chamber 2 includes at least two, Figure 1 Three quantitative chambers are shown in the figure; the number of the downstream chambers 5 is the same as that of the quantitative chambers 2, and the quantitative chambers 2 are connected to the corresponding downstream chambers 5 respectively; the quantitative chambers 2 are arranged in a spiral line, and the upstream chamber 1 is connected to the quantitative chamber 2 with the smallest spiral radius; the distal end of the quantitative chamber 2 is connected to the downstream chamber 5 through an infusion channel 05 with different resistances, and along the direction in which the liquid fills the quantitative chamber 2, the resistance of the infusion channel gradually increases, and a connecting channel 04 is provided between the downstream chambers. Arranging multiple quantitative chambers 2 in a spiral line makes it easier to fill the quantitative chambers 2 one by one, Figure 1 The filling direction is from left to right; on the other hand, when the quantitative liquid in the quantitative chamber is released into the downstream chamber, since the terminal quantitative chamber 2 is farthest from the rotation center O, the centrifugal force on the liquid in the rightmost quantitative chamber is the largest, and the liquid is preferentially transported to the downstream chamber 5 through the infusion channel 05, and multiple downstream chambers 5 are connected by the connecting channel 04, so that after the transfer of the rightmost liquid is completed, a circulation passage is formed between the connecting channel 04, the infusion channel 05 of the rightmost quantitative chamber 2 and the quantitative chamber 2, so that the liquid in the subsequent quantitative chambers can be transferred according to the preset order.

[0057] The resistance of each infusion channel 05 can be adjusted by designing different pipe lengths, widths, depths and curvatures, or by treating the pipe surface with different degrees of hydrophilicity / hydrophobicity. The depth and width of each capillary channel are in the order of tens to hundreds of micrometers (μm).

[0058] Specifically, Figure 1As shown, the connecting channel 04 is fan-shaped and is arranged on one side of the downstream cavity 5 close to the rotation center O; the infusion channel 05 is connected with the downstream cavity 5 through the connecting channel 04; the relationship between the depth h1 of the connecting channel 04 and the depth h2 of the downstream cavity satisfies: , where The maximum value of is 1 / 8. In order to facilitate processing, the embodiment of the present invention sets the connecting channel 04 to be fan-shaped, and secondly limits the size of the connecting channel and the downstream cavity. The purpose is that under the dual effects of Coriolis force and surface tension, in the process of quantitative cavity liquid transfer, the connecting channel needs to be used as a valve for the gas passage to achieve the sequential release of liquids between different cavities; secondly, the above structure can be used to fill the fan-shaped connecting channel 04 with an isolation liquid to avoid the problem of cross-contamination of the downstream cavity during the reaction process. The isolation liquid is made of mineral oil and the like, which has a lower density than the reagent liquid, and the two are incompatible. Preferably, the width of the connecting channel 04 in the embodiment of the present invention is preferably not more than 1 mm and not less than 0.1 mm, which can be understood as Figure 1 The width dimension range perpendicular to the paper surface, h1 and h2, is from several millimeters (mm) to several centimeters (cm).

[0059] As a preferred embodiment, Figure 6 As shown, different downstream chambers 5 are connected by a connecting channel 04, and the connecting channel is arranged closer to the rotation center than the downstream chamber 5, so it is more difficult for problems such as liquid cross-contamination to occur. Secondly, the connecting channel 04 can be set to be thin enough or coated with a liquid-repellent coating inside to further solve the problem of cross-contamination between different downstream chambers.

[0060] Specifically, Figure 6 and 7As shown, it also includes a blocking cavity 041, which is connected to the connecting channel 04 and the infusion channel 05 respectively, and the distance L6 between the connection between the infusion channel 05 and the blocking cavity 041 and the rotation center O is less than the distance L7 between the side of the blocking cavity 041 away from the rotation center O and the rotation center O, and the distance L8 between the connection between the connecting channel 04 and the blocking cavity 041 and the rotation center O is not greater than the distance L7 between the side of the blocking cavity 041 away from the rotation center O and the rotation center O; with the rotation center O as the center of the circle, the distance L8 between the connecting channel 04 and the blocking cavity 041 and the rotation center O is not greater than the distance L7 between the side of the blocking cavity 041 away from the rotation center O and the rotation center O; with the rotation center O as the center of the circle, the distance L8 between the connecting channel 04 and the blocking cavity 041 and the rotation center O is not less than the distance L7 between the side of the blocking cavity 041 away from the rotation center O and the rotation center O; The distance L6 between the connection of cavity 041 and the rotation center O is less than the distance between the side of the blocking cavity 041 away from the rotation center O and the rotation center O, forming an arc Ar with a radius. The arc Ar intersects with the blocking cavity to form a first intersection P1. The connection between the rotation center O, the infusion channel 05 and the blocking cavity 041 forms a first straight line Li. The arc Ar intersects with the first straight line Li to form a second intersection P2. The arc length L9 formed between the first intersection P1 and the second intersection P2 is not greater than 5mm; the width of the blocking cavity 041 is not greater than 1mm. Figure 6 As shown, the leftmost downstream cavity 5 is about to be filled, the middle downstream cavity 5 is being filled, and the rightmost downstream cavity has been filled. When the chip rotates counterclockwise, under the action of the Coriolis force, the liquid rotates clockwise relative to the chip. At this time, the liquid enters the blocking cavity 041, thus only constituting a return air passage between the middle and rightmost downstream cavities. Since the return air passage on the left is blocked, a large resistance can still be maintained to limit the leftmost quantitative cavity 2 from filling the leftmost downstream cavity 5 with liquid through the infusion channel 05. Only when the liquid in the middle quantitative cavity 2 completely fills the downstream cavity 5, the liquid filled in the blocking cavity 041 then enters the downstream cavity 5, and the blocking cavity 041 used to block the leftmost gas passage is opened to start filling the leftmost downstream cavity. Figure 6 The solution shown in FIG. 1 is to achieve the filling of multiple downstream cavities in the clockwise direction only when the chip rotates counterclockwise. If it is necessary to achieve the filling of the downstream cavities in both directions, it is necessary to set a blocking cavity 041 on the left side of the infusion channel 05, but the filling direction is opposite to the rotation direction of the chip.

[0061] It can be understood that the blocking cavity 041 can be a part of the connecting channel 04, as long as it meets the above technical requirements, that is, Figure 1 implementation method in . Figure 1 The chip can be rotated in both directions to fill the downstream chambers in sequence, but the filling direction is still opposite to the chip rotation direction.

[0062] The present invention is provided with a first channel 01, a waste liquid channel 03, a connecting channel 04 and an infusion channel 05. The above channels or pipelines can use active valves or passive valves. Specifically, a manually operated mechanical valve or a phase change valve in the prior art can be used, or a capillary that is opened or closed under centrifugal action can be used. In order to reduce production costs while maintaining detection accuracy, it is preferred to use a capillary for control. The size of the capillary is in the range of hundreds of microns to microns, and different diameters and lengths can be used to achieve the effect of opening or closing under different centrifugal forces; preferably, the depth and width of the first channel 01 are at the level of several millimeters (mm), ensuring that the liquid reagent can flow out of the upstream cavity 1 at a relatively low speed (<1000rpm), and the depth and width of the waste liquid channel 03 are at the level of several millimeters (mm), which is used to promptly and smoothly export the excess liquid reagent after quantification.

[0063] In order to better understand the design ideas and operating principles of this technical solution, the specific implementation methods and operating procedures for achieving precise and orderly diversion of liquid reagents in a microfluidic chip are described as follows:

[0064] (1) Add a certain amount of liquid reagent to the upstream chamber 1 through the sample injection port 001, such as Figure 8 As shown in a, the microfluidic chip is in a static state at this time.

[0065] (2) Apply a first centrifugal speed of 200 rpm to the microfluidic chip, such as Figure 8 As shown in Figure b, at this time, under the action of centrifugal force and with the help of the special structure of the quantitative chamber and the design of the return air passage, the liquid reagent will be accurately quantified in the three quantitative chambers from left to right at a low speed, and the excess liquid reagent will enter the waste liquid pool. At the same time, the infusion channel at the distal end of the quantitative chamber acts as a capillary valve to prevent the liquid in the quantitative chamber from entering the downstream chamber, ensuring the accuracy of the quantification.

[0066] (3) Increase the speed of the microfluidic chip to the second centrifugal speed of 800 rpm, such as Figure 8 As shown in Figure c, at this time, the centrifugal force on the liquid reagent in the rightmost quantitative cavity is greater than the resistance of the infusion channel connected to it, and finally the liquid reagent completely enters the corresponding downstream cavity from the rightmost quantitative cavity. At this time, since the resistance on the liquid reagent in the two quantitative cavities on the left is greater than the centrifugal force, the liquid reagent in both will not be released.

[0067] (4) When the liquid reagent in the rightmost quantitative cavity is completely transferred to the downstream cavity, the infusion channel connected to the rightmost quantitative cavity can be used as a gas circuit to provide gas circulation for the middle quantitative cavity. Finally, the liquid in the middle quantitative cavity completely enters the corresponding downstream cavity, such as Figure 8As shown in d. During the liquid transfer process of the middle quantitative cavity, the connecting channel 04 is filled with liquid and cannot provide a gas passage for the liquid reagent in the left quantitative cavity. Therefore, the resistance it encounters is still greater than the centrifugal force it encounters, so the liquid reagent therein will not be released.

[0068] (5) Similarly, when the liquid reagent in the middle quantitative cavity is completely transferred to the downstream cavity, the infusion channel connected to the middle quantitative cavity and the right quantitative cavity can be used as a gas circuit to provide gas circulation for the left quantitative cavity. Finally, the liquid reagent in the leftmost quantitative cavity completely enters the corresponding downstream cavity, such as Figure 8 As shown in FIG. 4 , the precise quantitative diversion of the liquid reagent is now completed.

[0069] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A microfluidic chip for precise quantification of reagents, characterized in that: include: upstream cavity; A quantitative chamber, wherein the quantitative chamber is located at a side away from the rotation center compared to the upstream chamber, the upstream chamber is directly or indirectly connected to the inlet of the quantitative chamber, and the quantitative chamber also has an overflow channel; A quantitative auxiliary protrusion, the quantitative auxiliary protrusion is located on the inner wall of the quantitative cavity close to the rotation center, and the quantitative auxiliary protrusion is located between the overflow channel and the entrance of the quantitative cavity; there is a gap between the upper surface and / or the lower surface of the quantitative auxiliary protrusion and the inner wall of the quantitative cavity, and when the liquid is filled, the liquid enters the gap; The quantitative auxiliary protrusion and the first inner wall of the quantitative cavity on the liquid inlet side have a first minimum width S1, the quantitative auxiliary protrusion and the second inner wall of the quantitative cavity on the overflow channel side have a second minimum width S2, and the distal end side of the quantitative auxiliary protrusion and the distal end side of the quantitative cavity form a third minimum width S3; The first minimum width S1 , the second minimum width S2 , and the third minimum width S3 satisfy: S1 < S3 and S2 < S3 .

2. The microfluidic chip according to claim 1, characterized in that: include: The minimum distance between the distal end of the quantitative auxiliary protrusion and the rotation center is greater than the minimum distance between the inner wall of the overflow channel away from the rotation center and the rotation center, and the minimum distance between the distal end of the quantitative auxiliary protrusion and the rotation center is greater than the maximum distance between the inlet and the rotation center.

3. The microfluidic chip according to claim 1, characterized in that: The inner wall of the overflow channel on the side away from the rotation center is an arc or an inclined surface, and the angle between the tangent of the arc or the inclined surface and the line connecting the rotation center along the liquid flow direction is greater than 90° and gradually increases; On the distal end side of the overflow channel, the relationship between the first minimum width S1 and the second minimum width S2 satisfies: S2<S1.

4. The microfluidic chip according to claim 3, characterized in that: The first minimum width S1, the second minimum width S2 and the third minimum width S3 satisfy: S1=λ1S3; S2=λ2S3; The value of λ1 is 0.7-0.5, the value of λ2 is 0.2-0.4; and the size range of the third minimum width S3 does not exceed 3 mm.

5. The microfluidic chip according to claim 1, characterized in that: When the quantitative cavity is filled, the ratio of the arc length of the gap to the arc length of the liquid surface is not less than 0.8; The size of the gap ranges from 0.2 mm to 2 mm.

6. The microfluidic chip according to claim 1, characterized in that: The proximal end of the quantitative cavity is provided with an air return passage; The overflow channel of the final quantitative chamber passes through the waste liquid channel to recycle the excess liquid into the waste liquid pool.

7. The microfluidic chip according to claim 1, characterized in that: It also includes a downstream chamber, which is arranged farther away from the rotation center than the quantitative chamber, and the proximal end of the downstream chamber is connected to the distal end of the quantitative chamber.

8. The microfluidic chip according to claim 7, characterized in that: The quantitative chamber comprises at least two; The number of the downstream chambers is the same as that of the quantitative chambers, and the quantitative chambers are respectively connected to the corresponding downstream chambers; The quantitative chambers are arranged in a spiral line and gradually move away from each other, and the upstream chamber is connected to the quantitative chamber with the smallest radius of the spiral line; The distal end of the quantitative cavity is connected to the downstream cavity through an infusion channel with different resistances, and the resistance of the infusion channel gradually increases along the direction in which the quantitative cavity is filled with liquid. A connecting channel is provided between the downstream cavities.

9. The microfluidic chip according to claim 8, characterized in that: It also includes a blocking cavity, the blocking cavity is connected to the communication channel and the infusion channel respectively, the distance between the connection between the infusion channel and the blocking cavity and the rotation center is smaller than the distance between the side of the blocking cavity away from the rotation center and the rotation center, and the distance between the connection between the communication channel and the blocking cavity and the rotation center is not greater than the distance between the side of the blocking cavity away from the rotation center and the rotation center; An arc is formed with the rotation center as the center and a radius that is not less than the distance between the connection between the infusion channel and the blocking cavity and the rotation center and less than the distance between the side of the blocking cavity away from the rotation center and the rotation center. The arc intersects with the blocking cavity to form a first intersection. The rotation center and the connection between the infusion channel and the blocking cavity form a first straight line. The arc intersects with the first straight line to form a second intersection. The length of the arc formed between the first intersection and the second intersection is not greater than 5 mm. The width of the blocking cavity is not greater than 1 mm.

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