Microfluidic chip detection structure, microfluidic chip and detection method

Abstract

The application provides a micro-fluidic chip detection structure, a micro-fluidic chip and a detection method, and relates to the technical field of biological fluid detection. In the micro-fluidic chip detection structure, under the action of centrifugal force or capillary force, the sample to be detected in the mixing groove flows into the first detection groove preloaded with reagents during rotation of the micro-fluidic chip; with high-speed rotation of the micro-fluidic chip, the sample to be detected and the preloaded reagents fully react in the first detection groove. The micro-fluidic chip detection structure can ensure that the sample to be detected and the preloaded reagents complete full reaction in the first detection groove and then enter the second detection groove for a second-step reaction. The application can effectively improve the accuracy of biological detection results in multi-step reactions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological fluid detection, in particular to a microfluidic chip detection structure, a microfluidic chip and a detection method. BACKGROUND

[0002] The centrifugal microfluidic chip is also called a microfluidic biochemical detection reagent disc. The centrifugal microfluidic chip separates cell components from a biological sample (such as whole blood) by using centrifugal action, measures a precise volume of a liquid sample (such as plasma), mixes the sample with a diluent, and then transports the diluted sample to a detection groove containing a preloaded reagent through a microfluidic channel for optical analysis and detection.

[0003] Some index analysis needs to be performed in multiple steps. For example, in the detection of creatinine content in serum or urine, before detection, the first step is to consume creatine in the sample through an enzymatic reaction to avoid interference with the subsequent creatinine detection. After the creatine is removed, the second step is to react with creatinine through a specific enzyme or chemical reagent to generate a quantifiable signal (such as color, absorbance, fluorescence, etc.), so as to calculate the creatinine concentration. The effect of creatine removal directly affects the effect of the second step of creatinine reaction.

[0004] In the prior art, various solutions have been proposed to solve this problem. For example, one solution sequentially arranges a first reaction groove, a buffer groove and a second reaction groove connected by a microfluidic channel in the paraxial direction of the chip: at a low rotation speed, the liquid first enters the first reaction groove, and the communication between the microfluidic channel and the buffer groove forms a gas-liquid interface, which generates back pressure to prevent the liquid from entering the second reaction groove at a low rotation speed. However, this type of solution relies on the Rayleigh-Taylor instability gas-liquid interface, which has obvious defects: on the one hand, the formation and collapse of the interface is directly controlled by the rotation speed of the chip, and a small disturbance on the interface (such as rotation speed fluctuations, flow channel flaws, etc.) can easily trigger instability, causing the liquid to flow into the second reaction groove too early and disrupting the reaction timing; on the other hand, in order to maintain the stability of the gas-liquid interface, the first reaction groove cannot be stirred, which can easily cause uneven mixing of the reaction system, insufficient reaction, and ultimately affect the reliability of the detection results.

[0005] Therefore, how to reliably ensure that the preloaded reagent and the sample to be detected are fully reacted before entering the next step of reaction, and improve the accuracy of the detection results, has become a technical problem to be solved by those skilled in the art. SUMMARY

[0006] Therefore, one of the purposes of the present application is to provide a microfluidic chip detection structure to solve the technical problem that the centrifugal detection flow channel used in the prior art cannot fully ensure that the preloaded reagent and the sample to be detected are fully reacted before entering the next step of reaction.

[0007] The second purpose of the present application is to provide a microfluidic chip containing the microfluidic chip detection structure.

[0008] The third object of the present application is to provide a detection method of a microfluidic chip.

[0009] To achieve one of the above objects, the present application provides a microfluidic chip detection structure, comprising at least one microfluidic unit, the microfluidic unit comprising a first detection groove, a first microfluidic channel and a second detection groove connected in sequence, the first detection groove and the second detection groove being arranged at two ends of the first microfluidic channel; a distribution channel is arranged in communication with the first detection groove, for supplying liquid to the first detection groove; the first microfluidic channel has at least one first elbow, the first elbow being directed towards a rotation center axis, the distance between the first elbow and the rotation center axis being less than the distance between the distribution channel and the rotation center axis.

[0010] Preferably, the first microfluidic channel is a first U-shaped microfluidic channel, and the first elbow is located on the first U-shaped microfluidic channel.

[0011] Preferably, the second detection groove is provided with a gas permeable hole on the near-center side, and the gas permeable hole is in communication with the second detection groove.

[0012] Preferably, a mixing groove for introducing liquid into the distribution channel is arranged in communication with the distribution channel, and a second microfluidic channel is arranged between the mixing groove and the distribution channel; the second microfluidic channel is in communication with the mixing groove and the distribution channel respectively to form a liquid transmission path.

[0013] Preferably, a baffle is arranged at the bottom of the far-center side of the mixing groove, and the baffle divides the bottom half of the mixing groove into two liquid containing spaces.

[0014] Preferably, the second microfluidic channel, the distribution channel, the first detection groove, the first microfluidic channel and the second detection groove are symmetrically arranged on both sides of the mixing groove.

[0015] Preferably, the mixing groove, the distribution channel and the first detection groove are arranged in sequence from the near-center side to the far-center side, and one end of the distribution channel is in communication with the second microfluidic channel.

[0016] Preferably, the first detection groove, the first microfluidic channel and the second detection groove are symmetrically arranged on both sides of the distribution channel.

[0017] Preferably, the distribution channel is arranged on the far-center side of the first detection groove, and the near-center side of the distribution channel is in communication with the first detection groove through a third microfluidic channel; the third microfluidic channel has at least one third elbow directed towards a rotation center axis, and the distance between the third elbow and the rotation center axis is greater than the distance between the first elbow and the rotation center axis.

[0018] Preferably, a fourth micro flow channel and a waste tank are further included, the fourth micro flow channel is a fourth U-shaped micro flow channel, the fourth micro flow channel has at least one fourth elbow, the fourth elbow is towards the rotating central axis, the distance between the fourth elbow and the rotating central axis is less than the distance between the third elbow and the rotating central axis, and the distance between the fourth elbow and the rotating central axis is greater than the distance between the first elbow and the rotating central axis.

[0019] To achieve the second of the above purposes, the application provides a micro fluidic chip, comprising a micro fluidic substrate, wherein at least one micro fluidic chip detection structure as described in any one of the above is arranged on the micro fluidic substrate.

[0020] To achieve the third of the above purposes, the application provides a detection method of the micro fluidic chip as described above, comprising the following steps:

[0021] (1) Control the chip to rotate at a high speed, under the action of centrifugal force, the sample enters the distribution channel and flows into the first detection tank through the distribution flow channel, and the chip is kept oscillating at a high speed so that the sample is fully reacted in the first detection tank;

[0022] (2) Reduce the rotating speed of the chip to a low speed or stop, after the sample in the first detection tank is filled into the first micro flow channel, control the chip to rotate at a high speed, so that the sample enters the second detection tank from the first micro flow channel;

[0023] (3) Keep the chip oscillating at a high speed, so that the sample is fully reacted in the second detection tank;

[0024] (4) Perform optical detection of the sample.

[0025] The micro fluidic chip detection structure provided by the application has the following technical effects:

[0026] When the micro fluidic chip detection structure of the application rotates, under the action of centrifugal force, the sample to be tested in the mixing tank flows into the first detection tank with preloaded reagent. Thanks to the high-speed oscillation of the chip, the sample to be tested and the preloaded reagent can be fully mixed and reacted in the first detection tank. At the same time, since the position of the first elbow of the first micro flow channel is higher than that of the distribution flow channel, the sample to be tested can flow into the straight end part of the first micro flow channel, but cannot pass the first elbow. This design not only ensures that the sample to be tested and the preloaded reagent are fully reacted in the first detection tank, but also prevents the sample from flowing into the second detection tank through the first micro flow channel in advance. After the reaction in the first detection tank is completed, the sample is controlled to enter the second detection tank, thereby effectively improving the accuracy of the detection result. BRIEF DESCRIPTION OF DRAWINGS

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a three-dimensional structural schematic diagram of the substrate of the microfluidic chip according to Embodiment 1 of the present invention;

[0029] Figure 2 yes Figure 1 Top view of the middle substrate;

[0030] Figure 3 yes Figure 2 Enlarged structural diagram at point A;

[0031] Figure 4 This is a three-dimensional structural schematic diagram of the substrate of a microfluidic chip according to Embodiment 2 of the present invention;

[0032] Figure 5 yes Figure 1 Top view of the middle substrate;

[0033] Figure 6 yes Figure 5 Enlarged structural diagram at point B;

[0034] Figure 7 This is a schematic diagram of the substrate structure of a microfluidic chip according to Embodiment 2 of the present invention;

[0035] Figure 8 This is a schematic diagram of the substrate of the microfluidic chip according to Embodiment 3 of the present invention;

[0036] Figure 9 yes Figure 8 First state diagram of the microfluidic chip detection structure on the substrate;

[0037] Figure 10 yes Figure 8 Second state diagram of the microfluidic chip detection structure on the substrate;

[0038] Figure 11 yes Figure 8 Third state diagram of the microfluidic chip detection structure on the substrate;

[0039] Figure 12 This is a centrifuge motor speed control diagram for the microfluidic chip detection method of Embodiment 4 of the present invention.

[0040] in, Figures 1-12 :

[0041] 100, microfluidic chip detection structure; 101, microfluidic unit; 1011, first microfluidic channel; 1011a, first elbow; 1012, first detection groove; 1013, second detection groove; 102, mixing groove; 1021, baffle; 103, second microfluidic channel; 1031, second elbow; 104, distribution channel; 105, overflow structure; 1051, waste liquid channel; 1052, waste liquid groove; 106, air vent; 1061, first air vent; 107, third microfluidic channel; 1071, third elbow; 108, fourth microfluidic channel; 1081, fourth elbow;

[0042] 200, microfluidic chip. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0044] It should be noted that the sample to be tested of the present application can be a blood sample, or a variety of other biological fluids, such as urine, sputum, semen, saliva, ocular lens fluid, cerebrospinal fluid, spinal fluid and amniotic fluid. Other testable fluids also include tissue culture medium, food and industrial chemicals, etc.

[0045] Taking a blood sample as an example, the microfluidic chip detection process is as follows: the whole blood sample is added to the sample addition groove, and the plasma and blood cells are separated by centrifugation. The plasma flows into the mixing groove through the microfluidic channel, and the diluent flows into the mixing groove through another set of channels. The two are mixed in the mixing groove to form a blood sample. Then, by controlling the rotation speed of the microfluidic chip, the blood sample flows into the microfluidic unit through the microfluidic channel, and reacts with the reagent in the first detection groove in the microfluidic unit for the first step. After the reaction is complete, it enters the second detection groove for the second step, and then receives optical detection to obtain biological index data.

[0046] In the prior art, the previous reaction is not fully performed, and the reagent enters the next step of reaction, resulting in inaccurate detection results.

[0047] Therefore, as Figures 1-11As shown, the present application provides a microfluidic chip 200, which comprises a substrate, and a microfluidic chip detection structure 100 is arranged on the upper surface of the substrate. Generally, the upper surface of the substrate, at least the upper surface of the microfluidic chip detection structure 100, needs to be provided with a film or plate structure to form a detection function area together with the microfluidic chip detection structure 100. The microfluidic chip 200 is a centrifugal microfluidic chip, which is usually designed as a disc. During the rotation of the microfluidic chip 200, the sample to be detected flows from the near-center side to the far-center side in the microfluidic chip detection structure 100 under the action of centrifugal force.

[0048] For the convenience of description, "near-center", "far-center" in the present application refer to the distance from the rotation center axis of the chip. In the following embodiments of the present application, the description method of gravity is used, and "up", "down", "high", "low" are used according to the distance from the rotation center axis, for example, "down" refers to moving to the far-center side in the same direction as the centrifugal force, and "up" refers to moving to the near-center side in the opposite direction of the centrifugal force, "higher" refers to being closer to the rotation center axis, and "lower" refers to being farther from the rotation center axis.

[0049] The microfluidic chip detection structure of the present application comprises a mixing groove 102, a distribution flow channel 104 and a microfluidic unit 101, the microfluidic unit 101 comprises a plurality of, the mixing groove 102 is communicated with the microfluidic unit 101 through the distribution flow channel 104, that is, the mixing groove 102 provides the microfluidic unit 101 with the sample to be detected through the distribution flow channel 104.

[0050] In detail, the microfluidic unit 101 comprises a first detection groove 1012, a first microfluidic channel 1011 and a second detection groove 1013 which are sequentially connected away from the rotation center axis, the first detection groove 1012 and the second detection groove 1013 are arranged at both ends of the first microfluidic channel 1011 and communicated with the first microfluidic channel 1011, wherein the first microfluidic channel 1011 is connected with the far-center side of the first detection groove 1012 and the near-center side of the second detection groove 1013 respectively.

[0051] The first microfluidic channel 1011 has at least one first elbow 1011a, and the first elbow 1011a faces the rotation center axis. The distance between the first elbow 1011a and the rotation center axis should be smaller than the distance between the distribution flow channel 104 and the rotation center axis.

[0052] The principle is: when the microfluidic chip is rotated and started, the sample to be tested (hereinafter referred to as liquid) enters the distribution flow channel from the mixing groove, and then enters the first detection groove under the action of centrifugal force. Since the first micro flow channel is in communication with the first detection groove, the liquid will also enter the first micro flow channel at the same time. Referring to the principle of communicating vessels, under high-speed centrifugation, the centrifugal force is greater than or equal to the capillary force, and the liquid surface entering the first micro flow channel cannot break through the first bend vertex, forming a "shut-off valve" at the first bend of the first micro flow channel. This "shut-off valve" prevents the liquid from flowing into the second detection groove in advance, effectively ensuring the full reaction of the first detection groove.

[0053] When the reaction in the first detection groove is completed, the rotation speed of the chip is reduced or stopped, at which time the capillary action in the first micro flow channel dominates - the liquid climbs along the straight end portion of the first micro flow channel to the first bend under the driving of the capillary force. When the centrifugal force is less than the capillary force, the liquid continues to rise and fills the first bend of the first micro flow channel, until the entire first micro flow channel is filled with liquid. Subsequently, the rotation speed of the chip is increased again, and the liquid in the first micro flow channel flows into the second detection groove under the action of centrifugal force and reacts with the preloaded reagent in the groove. Since the liquid in the first micro flow channel is in communication with the liquid in the first detection groove, under the action of continuous centrifugal force, the liquid in the first detection groove will also flow into the second detection groove, ensuring that the reaction system is completely transferred.

[0054] The structure can not only ensure that the liquid reacts fully in the first detection groove, but also avoid the liquid from entering the second detection groove and reacting with the preloaded reagent in the second detection groove in advance under the operation of a suitable centrifugal rotation speed.

[0055] It should be noted that the first micro flow channel 1011 of the present application is preferably a first U-shaped micro flow channel, and the first bend 1011a is located at the bend of the first U-shaped micro flow channel. It can also be a V-shaped flow channel, and the first bend 1011a is located at the tip of the first V-shaped micro flow channel.

[0056] In addition, as shown in Figures 1-11 In order to ensure that the liquid flows smoothly to the first detection groove 1012 and the second detection groove 1013, the second detection groove 1013 is provided with a gas permeable hole 106 near the heart side, and the gas permeable hole 106 is in communication with the second detection groove 1013.

[0057] When the liquid flows in the first micro flow channel 1011, it needs to resist the gas pressure in the pipeline. The gas permeable hole 106 discharges the gas from the pipeline and the reagent groove, that is, the liquid can smoothly enter the first detection groove 1012 and the second detection groove 1013.

[0058] Specifically, during centrifugation, when the liquid enters the second detection groove 1013 from the first detection groove 1012 through the first micro flow channel 1011, the gas permeable hole 106 allows the gas in the groove to flow outwards as the liquid flows in, avoiding the formation of a closed gas cavity to hinder the flow of the liquid.

[0059] Guided by the principles of this invention, this microfluidic unit can be further configured after the second detection tank as needed. For example, a third or fourth reagent tank can be configured after the second detection tank via a microchannel with an elbow to meet the needs of more steps in the reaction.

[0060] Based on the structure of the microfluidic unit described above, the microfluidic chip detection structure of the present invention will be described in detail below with reference to specific embodiments 1-4.

[0061] Example 1:

[0062] This embodiment provides a microfluidic chip detection structure 100, such as Figures 1-3 As shown, this embodiment includes a mixing tank 102, a second microchannel 103, and a microfluidic unit 101 arranged sequentially away from the rotation center axis. The second microchannel 103 and the microfluidic unit 101 are symmetrically arranged on both sides of the mixing tank 102. The proximal end of the second microchannel 103 is connected to the distal end of the mixing tank 102, and the distal end of the second microchannel 103 is connected to the corresponding microfluidic unit 101.

[0063] In this embodiment, the second microchannel 103 is preferably a second U-shaped microchannel. The second microchannel 103 has a second bend 1031, which is located at the end of the second U-shaped microchannel. The second bend 1031 faces the rotation center axis, and the distance between the second bend 1031 and the rotation center axis is less than the distance between the liquid surface formed in the mixing tank under centrifugal force and the rotation center axis. That is, the second bend 1031 is closer to the rotation center axis relative to the liquid surface in the mixing tank.

[0064] Since the liquid level in the mixing tank is higher than that in the first detection tank, the liquid will flow into the first detection tank under the action of centrifugal force and react with the pre-loaded reagent in the first detection tank.

[0065] like Figure 3 As shown, an overflow structure 105 is provided at the end of the distribution channel 104. The overflow structure 105 is used to collect excess liquid after the first detection tank 1012 has been filled. Specifically, the overflow structure 105 includes a waste liquid tank 1052 and a waste liquid channel 1051 communicating with the waste liquid tank 1052. The waste liquid channel 1051 is located at the end of the distribution channel 104 and extends away from the rotation center axis. The waste liquid tank 1052 is located at the distal end of the waste liquid channel 1051. To allow excess liquid to smoothly enter the waste liquid tank 1052, a vent hole 106 is provided on the proximal side of the end of the distribution channel, and the vent hole 106 communicates with the waste liquid channel 1051.

[0066] The distribution flow channel in this embodiment is located between the second micro flow channel 103 and the first detection groove, and its length can be designed according to the actual product. In this embodiment, a relatively short distribution flow channel 104 is designed, which is preferably in the form of a short linear arc structure, but it can be understood that its position is at least higher than that of the waste liquid passage 1051. Under the action of centrifugal force, the liquid flowing out of the mixing groove 102 enters the first detection groove 1012 through the second micro flow channel 103 and the distribution flow channel 104. When the first detection groove 1012 is filled, the excess liquid will flow into the waste liquid groove 1052 through the waste liquid passage 1051.

[0067] In this embodiment, the two microfluidic units are arranged on both sides of the mixing groove, and the distribution flow channel is physically isolated, which fundamentally solves the problem of cross contamination of reagents between microfluidic units in the liquid distribution process.

[0068] It should be noted that, in this embodiment, the excess liquid will not enter the second detection groove 1013 through the first micro flow channel 1011, because the first elbow 1011a is higher than the distribution flow channel 104. At this time, the liquid level in the first micro flow channel 1011 will not be higher than the distribution flow channel 104. When the excess liquid can flow away through the waste liquid passage 1051, the liquid level in the first micro flow channel 1011 will not continue to rise, and the first micro flow channel 1011 will not be filled. The liquid that has entered the first detection groove 1012 will be left in the first detection groove 1012 for reaction.

[0069] Continuing to refer to Figure 3 As shown in FIG. 1, the distal side bottom of the mixing groove 102 is provided with a baffle 1021 in the form of a convex tip structure, which separates the lower part of the mixing groove 102 into two spaces. The baffle 1021 has the following functions. On the one hand, it can play a stirring role when oscillating at high speed. On the other hand, when the liquid level in the mixing groove 102 drops to the baffle 1021, the baffle 1021 located in the middle position can uniformly distribute the liquid, so that the two microfluidic units 101 on the left and right sides with the same detection capacity obtain the same amount of liquid, and also avoid the problem of insufficient liquid in one side detection groove, which causes insufficient reaction.

[0070] It can be easily understood that if the detection capacities of the two microfluidic units 101 on both sides of the distribution flow channel are different, i.e., the capacities of the first detection grooves are different, the position of the baffle 1021 can be designed according to the needs of the two microfluidic units 101, so that the space capacities on the left and right sides of the baffle match the capacities of the two first detection grooves.

[0071] Embodiment 2:

[0072] This embodiment also provides a microfluidic chip detection structure 100, as shown in FIG. 2. Figures 4-7As shown, the embodiment also includes two microfluidic units 101, specifically, a mixing tank 102, a second microfluidic channel 103, a distribution channel 104 and the microfluidic units 101 are arranged away from the rotation center axis in sequence, wherein the liquid inlet of the second microfluidic channel 103 communicates with the distal side of the mixing tank 102, the liquid outlet communicates with the distribution channel 104, and one microfluidic unit 101 is arranged at each end of the distribution channel 104, i.e. the liquid of the mixing tank 102 first flows into the second microfluidic channel 103, then flows into the distribution channel 104, and then enters the two microfluidic units 101.

[0073] The same as embodiment 1, the second microfluidic channel 103 of the embodiment is preferably a second U-shaped microfluidic channel, and the second microfluidic channel 103 has a second elbow 1031, the second elbow 1031 is located at the end of the second U-shaped microfluidic channel, the second elbow 1031 faces the rotation center axis, and the distance between the second elbow 1031 and the rotation center axis is less than the distance between the liquid surface formed under the centrifugal action in the mixing tank 102 and the rotation center axis, i.e. the second elbow 1031 is closer to the rotation center axis than the liquid surface of the mixing tank 102.

[0074] The distribution channel 104 of the embodiment is preferably a long linear arc structure, and the distance between the distribution channel 104 and the rotation center axis gradually increases along the liquid flow direction, i.e. the distribution channel 104 gradually moves away from the rotation center axis from the liquid inlet end. In this way, the flow direction of the liquid is the same as the direction of the centrifugal force, and the liquid can flow more smoothly into the detection unit.

[0075] The distribution channel 104 is connected with the first detection tank through a connecting pipe, and the liquid in the second microfluidic channel 103 enters the two microfluidic units 101 through the distribution channel 104. Among them, the second microfluidic channel 103 can be connected with the distribution channel 104 at the middle position of the distribution channel 104, such as Figure 7 As shown, it can also be connected at one end of the distribution channel 104, such as Figure 6 As shown.

[0076] The cross-sectional area of the distribution channel 104 is preferably larger than the cross-sectional area of the second microfluidic channel 103.

[0077] As shown in Figure 6As shown, when the second micro-channel meets one end of the distribution channel, the distribution channel communicates with the first detection groove through the connecting pipeline. The first detection groove closer to the meeting point will be filled first. At this time, if the same volume of the first detection groove is to be filled simultaneously, the cross-sectional area of the connecting pipeline closer to the second flow channel should be designed to be smaller than that of the connecting pipeline farther away, so as to control the speed of liquid entering the closer first detection groove to be smaller than that of the farther first detection groove, so that the first detection grooves at both ends of the distribution channel are filled at the same time, and the risk of liquid mutual interference between the two first detection grooves is reduced. Alternatively, the cross-sectional areas of the two connecting pipelines are the same, and two first detection grooves with different volumes are designed. The relationship between the volume ratio of the detection grooves and the length, cross-sectional area and liquid flow rate of the distribution channel is reasonably designed, so that the first detection groove far from the second micro-channel is filled first or the two detection grooves are filled at the same time, avoiding the problem of reagent cross-contamination between the two first detection grooves.

[0078] As shown in Figure 7 As shown, when the second micro-channel meets the distribution channel at the middle position, the liquid flows from the meeting point to both sides, and the distribution channel moves away from the rotation center axis in the direction of liquid flow. The cross-sectional areas of the distribution channel at the same positions on both sides of the meeting point are as same as possible, so that the liquid can enter the two first detection grooves at the same time. The reagent cross-contamination between the two first detection grooves is reduced as much as possible.

[0079] As shown in Figure 6 As shown in the figure, in order to avoid liquid overflow from the first detection groove 1012, an overflow structure 105 is arranged at the end of the distribution channel 104 away from the second micro-channel 103. The overflow structure 105 is used to collect the excess liquid after the first detection groove 1012 is filled.

[0080] Specifically, the overflow structure 105 includes a waste liquid tank 1052 and a waste liquid channel 1051 communicating with the waste liquid tank 1052. The waste liquid channel 1051 is arranged at the end of the distribution channel 104 and extends away from the rotation center axis. The waste liquid tank 1052 is arranged at the end of the waste liquid channel 1051.

[0081] Under the action of centrifugal force, the liquid flowing out of the mixing tank 102 enters the first detection groove 1012 through the second micro-channel 103 and the distribution channel. When the first detection groove 1012 is filled, the excess liquid will flow into the waste liquid tank 1052 through the waste liquid channel 1051.

[0082] As shown in Figure 6 In order to enable the excess liquid to smoothly enter the waste liquid tank 1052, a gas permeable hole 106 is arranged on the heart side of the end of the distribution channel. The gas permeable hole 106 communicates with the waste liquid channel 1051.

[0083] Figure 7 In the embodiment of the application, overflow structures 105 are arranged at both ends of the distribution channel 104.

[0084] It should be noted that the excess liquid in the embodiment does not enter the second detection groove 1013 through the first micro-channel 1011, because the distance between the first bend 1011a of the first micro-channel 1011 and the rotation center axis is less than the distance between the distribution channel and the rotation center axis, so the liquid level in the first micro-channel 1011 is not higher than the first bend 1011a, and the first micro-channel 1011 is not filled.

[0085] Embodiment 3:

[0086] The embodiment also provides a micro-fluidic chip detection structure 100, as shown in the figure, the embodiment includes three micro-fluidic units 101, and further includes a mixing groove 102, a distribution channel 104 and a second micro-channel 103. Figures 8-11 The second micro-channel 103 is in communication with the mixing groove 102 and the distribution channel 104, that is, the liquid in the mixing groove 102 first flows into the second micro-channel 103, and then flows into the distribution channel 104, and the three micro-fluidic units 101 are sequentially arranged on the near center side of the distribution channel 104 along the liquid flow direction.

[0087] It should be noted that the micro-fluidic unit 101 in the embodiment is not limited to three, but can also be multiple.

[0088] The second micro-channel 103 in the embodiment can be a straight channel or a curved channel, and is preferably a second U-shaped micro-channel. The second micro-channel 103 has a second bend 1031 at the end of the second U-shaped micro-channel. The second bend 1031 faces the rotation center axis, and the distance between the second bend 1031 and the rotation center axis is less than the distance between the liquid level of the mixing groove and the rotation center axis, that is, the second bend 1031 is closer to the rotation center axis than the liquid level of the mixing groove.

[0089] Referring to Figures 8-11 As shown in the figure, the distribution channel 104 is arranged in an arc shape near the edge of the micro-fluidic chip 200. One end of the distribution channel 104 is in communication with the second micro-channel 103, and this end is the liquid inflow end. The other end of the distribution channel 104 is provided with a waste liquid groove 1052. In order to ensure smooth liquid flow under centrifugal operation, for example, to ensure that the liquid in the distribution channel is smoothly emptied after the first detection groove is filled, the distribution channel can gradually move away from the rotation center axis along the liquid flow direction.

[0090] Because the distance between the liquid level of the mixing groove and the rotation center axis is less than the distance between the distribution channel 104 and the rotation center axis, the liquid will flow to the distribution channel 104 under the action of the centrifugal force.

[0091] The third micro flow channel 107 is located at the near center side of the distribution flow channel 104, and the embodiment includes three third micro flow channels 107, which are in communication with the distribution flow channel 104 and the three micro flow control units 101.

[0092] The third micro flow channel 107 is preferably a U-shaped micro flow channel, and the third micro flow channel 107 has a third elbow 1071, which faces the rotation center axis, and the distance between the third elbow 1071 and the rotation center axis should be greater than the distance between the liquid surface of the mixing tank and the rotation center axis, so that the liquid in the mixing tank can enter the first detection tank.

[0093] When the micro flow control chip 200 rotates, the diluted sample to be tested enters the distribution flow channel 104 under the action of centrifugal force and fills the distribution flow channel 104, the third micro flow channel 107 and the first detection tank 1012. The sample to be tested reacts with the preloaded reagent in the first detection tank 1012.

[0094] As shown in FIG. 1, a waste tank 1052 is arranged at the end of the distribution flow channel 104, which is used to collect excess liquid. Figure 8

[0095] The fourth micro flow channel 108 is preferably a fourth U-shaped micro flow channel, and the fourth micro flow channel 108 has a fourth elbow 1081, which faces the rotation center axis.

[0096] In order to ensure that the blood sample fully fills the first detection tank and achieve the technical effects of the present application, the distance between the fourth elbow and the rotation center axis is less than the distance between the third elbow and the rotation center axis, and the distance between the fourth elbow and the rotation center axis is greater than the distance between the first elbow and the rotation center axis. Under the action of centrifugal force, the distribution flow channel is filled, and according to the principle of communicating vessels, the liquid will enter the third micro flow channel and the fourth micro flow channel. Because the liquid in the mixing tank continuously enters the third micro flow channel and the fourth micro flow channel, the liquid surface rises until it reaches the top of the third micro flow channel elbow, and the liquid enters the first detection tank. At this time, because the fourth micro flow channel elbow is higher than the third micro flow channel elbow, the liquid will preferentially fill the first detection tank.

[0097] ​When the first detection groove is filled, the liquid level will continue to rise along the first microchannel, and also along the fourth microchannel, but since the first microchannel bend apex is higher than the fourth microchannel apex, the liquid will not flow over the first microchannel bend, and when the liquid reaches the fourth microchannel bend, the fourth microchannel is filled. With the rotation of the chip, the liquid in the microfluidic chip, except for the first detection groove, flows into the waste liquid groove. With proper design of the size of each channel and the distribution channel structure, under the condition of ensuring that each microfluidic unit is filled and emptied synchronously, the liquid isolation between each unit can be accurately controlled, the cross-contamination between units is minimized, and the detection reliability is ensured.

[0098] In addition, to ensure that the first detection groove can be fully filled, the cross-sectional area or diameter of the fourth microchannel 108 is usually not greater than that of the second microchannel 103, the distribution channel 104 or the third microchannel 107, or the cross-sectional area or diameter of the fourth microchannel 108 is at least the same as that of the second microchannel. In a preferred embodiment, the cross-sectional area of each channel is in the following order: distribution channel > third microchannel > second microchannel ≥ fourth microchannel, wherein the cross-sectional area of the distribution channel is at least twice the cross-sectional area of the third microchannel. For example, when the channel is rectangular in cross-section, the cross-sectional area of the second microchannel is 0.15mm*0.2mm, the cross-sectional area of the third microchannel is 0.15mm*0.5mm, the cross-sectional area of the distribution channel is 0.3mm*0.5mm, and the cross-sectional area of the waste channel is 0.15mm*0.2mm.

[0099] As shown in Figure 9 and Figure 10 , the microfluidic chip 200 continues to rotate, and the liquid continues to flow from the distribution channel into the waste liquid groove 1052.

[0100] The third microchannel of the embodiment is arranged in a U shape, and the third bend 1071 is arranged close to the rotation center axis, so that when the distribution channel is emptied, the liquid in the connection part (between the distribution channel and the third bend) of the third microchannel and the distribution channel will flow back to the distribution channel, but the reaction liquid in the first detection groove 1012 will not flow away. In an embodiment, the third microchannel 107 is a U-shaped channel with an angle composed of three straight channels, as shown in Figure 8 The third bend 1071 is one of the angles of the U-shaped channel, and after the first detection groove is filled, the fluid is emptied from the distribution channel to the waste liquid groove, and the liquid in the third microchannel 107 is "broken" from the third bend 1071, so that the liquid is more easily emptied from the U-shaped channel.

[0101] As shown in Figure 11As shown, after the distribution flow channel is emptied, all the first detection grooves 1012 are filled and the reaction is completed, at which time the rotation speed of the chip is reduced. The liquid in the first micro flow channel 1011 flows to the first elbow 1011a under the action of capillary force, fills the first micro flow channel 1011, and then the high-speed centrifugation is started, so that the liquid enters the second detection groove 1013 under the action of centrifugal force.

[0102] In this embodiment, a first air vent 1061 is arranged in communication with the first detection groove 1012 and is arranged on the near-center side of the first detection groove 1012. After the reaction in the first detection groove 1012 is completed and the distribution flow channel 104 and the third micro flow channel 107 are partially emptied, the rotation speed of the chip is reduced or stopped, the liquid fills the first micro flow channel 1011, and then the rotation speed is increased, so that the liquid in the first detection groove 1012 and the first micro flow channel 1011 enters the second detection groove. If there is a liquid column that is not completely emptied in the third micro flow channel or other flow channels in communication with the third micro flow channel during this process, it may affect the filling of the first micro flow channel. The function of the first air vent 1061 is to balance the air pressure between the first detection groove and the second detection groove, so that the liquid can smoothly fill the first micro flow channel by capillary action.

[0103] It should be noted that the third elbows 1071 of the three third micro flow channels 107 in this embodiment are the same distance from the center axis of rotation, which can ensure that the liquid level in all the third micro flow channels 107 reaches the third elbows 1071 at the same time, and the liquid enters the first detection groove 1012 at the same time, and all the first detection grooves react at the same time.

[0104] Embodiment 4:

[0105] The embodiment provides a detection method of a microfluidic chip, which comprises the following steps:

[0106] Step 1: Perform normal operations such as sample addition and separation. After separation, the sample to be tested and the diluent flow into the mixing groove of the microfluidic chip, and the centrifuge is controlled to rotate at high speed, so that the sample and the diluent are mixed uniformly in the mixing groove. The motor speed of the high-speed vibration is varied between 3000-5000 rpm, and the time is 15 seconds.

[0107] Step 2: After the sample is mixed, the motor speed of the centrifuge is controlled, and the chip is rotated at low speed or stopped, as shown in Figure 12 The liquid sample enters the second micro flow channel, and because the cross-sectional area of the distribution flow channel is larger than that of the second micro flow channel, the capillary force is weakened when the sample reaches the distribution flow channel, and the sample is prevented at the junction of the second micro flow channel and the distribution flow channel.

[0108] Step 3: After the sample fills the second micro flow channel, the motor of the centrifuge is controlled to rotate at high speed, as shown in Figure 12As shown, the rotation speed is 5000 rpm, the sample enters the distribution channel under the centrifugal force and flows into the first detection groove through the third microfluidic channel, after high-speed rotation for 30 seconds, the motor rotation speed is high-speed oscillated between 3000-5000 rpm for 15 seconds, so that the sample is fully reacted; when the partial detection items are executed, the sample is reacted in the first detection groove, and the sample in the first detection groove can be monitored or detected by optical or other means;

[0109] Step 4, the rotation speed of the chip is reduced to low speed 0-300 rpm, the sample is waited to enter the first microfluidic channel, after the sample fills the first microfluidic channel, the centrifuge is controlled to increase the rotation speed and rotate at high speed for 30 seconds, so that the sample enters the second detection groove from the first microfluidic channel;

[0110] Step 5, the motor is kept high-speed oscillated between 3000-5000 rpm, and the sample is fully reacted in the second detection groove;

[0111] Step 6, the motor rotation speed is controlled to be constant at about 1200 rpm, and the optical detection of the sample is executed.

[0112] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0113] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0114] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A microfluidic chip, characterized in that, It includes a microfluidic substrate, on which a microfluidic chip detection structure is provided, the microfluidic chip detection structure being disposed on the upper surface of the microfluidic substrate; The microfluidic chip detection structure includes at least one microfluidic unit, and the microfluidic unit includes a first detection groove, a first microchannel and a second detection groove connected in sequence, with the first detection groove and the second detection groove located at both ends of the first microchannel; A distribution channel is provided in communication with the first detection tank for supplying liquid to the first detection tank; The first microchannel has at least one first bend, the first bend facing the rotation center axis, and the distance between the first bend and the rotation center axis is less than the distance between the distribution channel and the rotation center axis; The end of the distribution channel is provided with an overflow structure, which is used to collect excess liquid after the first detection tank is filled. The distribution channel is located on the distal side of the first detection groove, and the proximal side of the distribution channel is connected to the first detection groove through a third microchannel; the third microchannel has at least one third bend, the third bend faces the rotation center axis, and the distance between the third bend and the rotation center axis is greater than the distance between the first bend and the rotation center axis. The third microchannel has a third bend facing the rotation center axis. The third microchannel is a U-shaped channel with bends, consisting of three relatively straight channels. The third bend is one of the bends in this type of U-shaped channel. It is connected to the first detection groove and has a first vent hole. The first vent hole is located on the proximal side of the first detection groove. The channel between the first vent hole and the first detection groove is connected to the third bend.

2. The microfluidic chip according to claim 1, characterized in that, The first microchannel is a first U-shaped microchannel, and the first elbow is located on the first U-shaped microchannel.

3. The microfluidic chip according to claim 1, characterized in that, The second detection groove has a vent hole on the proximal side, and the vent hole is connected to the second detection groove.

4. The microfluidic chip according to claim 1, characterized in that, A mixing tank for introducing liquid into the distribution channel is provided in communication with the distribution channel. A second microchannel is provided between the mixing tank and the distribution channel. The second microchannel is connected to both the mixing tank and the distribution channel to form a liquid transport path.

5. The microfluidic chip according to claim 4, characterized in that, The bottom of the mixing tank on the distal side is provided with a baffle, which divides the bottom half of the mixing tank into two liquid-containing spaces.

6. The microfluidic chip according to claim 5, characterized in that, The second microchannel, the distribution channel, the first detection groove, the first microchannel and the second detection groove are symmetrically arranged on both sides of the mixing groove.

7. The microfluidic chip according to claim 4, characterized in that, The mixing tank, the distribution channel, and the first detection tank are arranged distally in sequence, and one end of the distribution channel is connected to the second microchannel.

8. The microfluidic chip according to claim 7, characterized in that, The first detection groove, the first microchannel, and the second detection groove are symmetrically arranged on both sides of the distribution channel.

9. The microfluidic chip according to claim 1, characterized in that, It also includes a fourth microchannel and a waste liquid tank connected to the distribution channel. The fourth microchannel is a fourth U-shaped microchannel with at least one fourth bend facing the rotation center axis. The distance between the fourth bend and the rotation center axis is less than the distance between the third bend and the rotation center axis, and the distance between the fourth bend and the rotation center axis is greater than the distance between the first bend and the rotation center axis.

10. A method for detecting a microfluidic chip as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Control the chip to rotate at high speed. Under the action of centrifugal force, the sample enters the distribution channel and flows into the first detection cell through the distribution channel. Keep the chip oscillating at high speed so that the sample can fully react in the first detection cell. (2) Reduce the chip rotation speed to a low speed or stop, wait for the sample in the first detection groove to fill the first microchannel, and then control the chip to rotate at high speed so that the sample enters the second detection groove from the first microchannel. (3) Maintain high-speed oscillation of the chip to ensure that the sample reacts fully in the second detection slot; (4) Perform optical inspection of the sample.

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