Microfluidic chip, microfluidic system and processing method

Abstract

Disclosed are a microfluidic chip, a microfluidic system and a processing method. The microfluidic chip comprises a first flow channel, and a first buffer solution flow channel, a first waste liquid flow channel and a washing flow channel group communicating with the first flow channel, wherein the washing flow channel group comprises at least two washing flow channels arranged sequentially along a flow direction, and the diameter of an inlet of each washing flow channel is smaller than the diameter of a first target object; the microfluidic system further comprises microvalves provided corresponding to respective flow channels. When a first microvalve and a first waste liquid microvalve are in an open state, once a single first target object has flowed to a first region, the first microvalve and the first waste liquid microvalve are switched to a closed state, and a first buffer solution microvalve and a washing microvalve are in an open state, so as to allow the single first target object to flow to an inlet of one of the washing flow channels and stop at the inlet, and to allow liquid in the first region to flow out through other washing flow channels. The present invention is capable of screening out a single first target object from a first carrier liquid containing first target objects A and non-target objects.

Description

Microfluidic chips, microfluidic systems and processing methods Technical Field

[0001] This invention relates to the field of single-cell sequencing technology, and in particular to a microfluidic chip, a microfluidic system, and a processing method. Background Technology

[0002] Circulating tumor cells (CTCs) are a rare type of cancer cell commonly found in the circulatory system of cancer patients, typically present in the blood or lymph. CTCs detach from the primary tumor and enter the circulatory system, where they can act as seeds for secondary tumors. Strong heterogeneity is observed in CTCs during this metastatic process. Phenotypic variations between CTCs and molecular characteristics indicate the existence of specific CTC subsets, and these variations may result in different metastatic potentials. Analyzing CTCs at the single-cell level in breast cancer patients can reveal the internal heterogeneity of cancer-related gene expression, further elucidating molecular pathways activated or altered during tumor and metastatic evolution. This allows researchers to obtain crucial information about metastatic mechanisms and genomic alterations, which will contribute to drug resistance research, enhanced cancer treatment, and cancer management.

[0003] Circulating tumor cells are scarce in samples. When facing the need for single-cell sequencing with low sample volumes, valve-based single-cell sequencing systems offer advantages such as low cost and high RNA capture efficiency. Currently, commercial single-cell sequencing technologies based on droplets or micropores have high single-cell capture efficiency and cell throughput. However, in addition to circulating tumor cells, samples also contain other cells such as red blood cells and white blood cells. The large amount of contamination from red blood cells and white blood cells reduces the accuracy of single-cell gene sequencing and increases the cost of sequencing.

[0004] Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a microfluidic chip that can reduce contamination of the target object by non-target objects.

[0006] This invention also proposes a microfluidic system and processing method.

[0007] According to the microfluidic chip of the first embodiment of the present invention, it is applied to the screening of a first target. The microfluidic chip includes a first flow channel and a first buffer flow channel, a first waste liquid flow channel and a cleaning flow channel group respectively connected to the first flow channel. The first flow channel is used for the liquid containing the first target to flow through. Along the flow direction of the liquid in the first flow channel, the first waste liquid flow channel and the cleaning flow channel group are both disposed downstream of the first buffer flow channel. The cleaning flow channel group includes at least two cleaning channels arranged sequentially along the flow direction. The diameter of the inlet of the cleaning channel is smaller than the diameter of the first target.

[0008] The microfluidic system further includes a first microvalve corresponding to the first flow channel, a first buffer microvalve corresponding to the first buffer solution flow channel, a first waste liquid microvalve corresponding to the first waste liquid flow channel, and a cleaning microvalve corresponding to each of the cleaning flow channels. The first microvalve is used to control the opening and closing of the first flow channel, the first buffer solution microvalve is used to control the opening and closing of the first buffer solution flow channel, the first waste liquid microvalve is used to control the opening and closing of the first waste liquid flow channel, and the cleaning microvalve is used to control the opening and closing of each of the cleaning flow channels.

[0009] Wherein, the first channel between the first buffer solution channel and the cleaning channel group is defined as the first region, and the microfluidic chip is configured to: when the first microvalve and the first waste liquid microvalve are in the open state to allow a single first target object to flow into the first region, the first microvalve and the first waste liquid microvalve switch to the closed state, and the first buffer solution microvalve and the cleaning microvalve are in the open state to allow the single first target object to flow to the inlet of one of the cleaning channels and stop at the inlet, and to allow the liquid in the first region to flow out through the other cleaning channels.

[0010] The microfluidic system according to embodiments of the present invention has at least the following beneficial effects:

[0011] The microfluidic chip in this embodiment sets up corresponding flow channels and valves, and filters out a single first target object from a first carrier liquid containing a first target object A and non-target objects by switching the valves, thereby reducing contamination by non-target objects and improving the accuracy of subsequent detection.

[0012] In other embodiments of the present invention, the first waste liquid channel and the cleaning channel are independent channels, and the diameter of the first waste liquid channel is larger than the diameter of the cleaning channel.

[0013] In other embodiments of the present invention, the first buffer solution channel, the first waste liquid channel, and the cleaning channel group are arranged sequentially along the flow direction;

[0014] Wherein, the first flow channel between the first buffer solution flow channel and the first waste liquid flow channel is defined as the second region. The step of switching the first microvalve and the first waste liquid microvalve to the closed state and the first buffer solution microvalve and the cleaning microvalve to the open state after the first microvalve and the first waste liquid microvalve are in the open state and a single first target object flows into the second region, and the first microvalve and the first waste liquid microvalve to the closed state and the first buffer solution microvalve and the cleaning microvalve to the open state.

[0015] In other embodiments of the present invention, at least one of the cleaning channels is the first waste liquid channel, and the cleaning microvalve is the first waste liquid microvalve.

[0016] In other embodiments of the present invention, the cleaning channel includes a first cleaning section communicating with the first channel, the first cleaning section having the inlet at one end facing the first channel, and the cross-sectional area of ​​the first cleaning section gradually increasing from the end having the inlet along the flow direction of the liquid in the cleaning channel.

[0017] In other embodiments of the present invention, along the flow direction of the liquid in the cleaning channel, the cleaning channel further includes a second cleaning section communicating with the first cleaning section, wherein the cross-sectional area of ​​the second cleaning section is greater than or equal to the maximum cross-sectional area of ​​the first cleaning section.

[0018] In other embodiments of the invention, the diameter of the inlet of the first waste liquid channel is 5 micrometers to 10 micrometers.

[0019] In other embodiments of the present invention, the microfluidic chip further includes a connecting channel, one end of which is connected to the first channel and the other end of which is connected to each cleaning channel. The length of the connecting channel is 3 micrometers to 8 micrometers along the flow direction of the liquid in the connecting channel.

[0020] In other embodiments of the present invention, the microfluidic chip further includes a second flow channel, an oil flow channel, a second buffer flow channel, and a paired flow channel. The paired flow channel is connected to the oil flow channel. The first flow channel, the second flow channel, and the second buffer flow channel are all connected to the paired flow channel. The second flow channel is used to allow liquid containing the second target to flow through.

[0021] The microfluidic chip further includes a pairing microvalve corresponding to the paired flow channel, a second microvalve corresponding to the second flow channel, an oil microvalve corresponding to the oil flow channel, and a second buffer microvalve corresponding to the second buffer flow channel. The pairing microvalve is used to control the opening and closing of the paired flow channel, the second microvalve is used to control the opening and closing of the second flow channel, the oil microvalve is used to control the opening and closing of the oil flow channel, and the second buffer microvalve is used to control the opening and closing of the second buffer flow channel.

[0022] When a single first target object from the first flow channel and a single second target object from the second flow channel are present in the paired flow channel, the first microvalve, the second microvalve, the first buffer microvalve, the first waste liquid microvalve, and the cleaning microvalve are all in a closed state, and the paired microvalve and the second buffer microvalve are in an open state, so as to send the single first target object and the single second target object in the paired flow channel into the oil in the oil flow channel to form droplets.

[0023] In other embodiments of the present invention, the microfluidic system further includes a second waste liquid channel and a second waste liquid microvalve corresponding to the second waste liquid channel. The second waste liquid channel is connected to the paired channel. The second waste liquid microvalve is used to control the opening and closing of the second waste liquid channel. The microfluidic chip is further configured such that when the single first target object stops at the inlet of one of the cleaning channels, the first microvalve, the first waste liquid microvalve, the cleaning microvalve, the second buffer channel, and the paired microvalve are all in a closed state, and the first buffer microvalve and the second waste liquid microvalve are in an open state, the liquid in the first channel can flow out through the paired channel and the second waste liquid channel, so that the single first target object enters the paired channel from the first channel.

[0024] In other embodiments of the present invention, the microfluidic chip is further configured to: when the single first target object stops at the inlet of one of the cleaning channels, and after the first buffer microvalve and the cleaning microvalve remain in the open state for a set time, the cleaning microvalve switches to the closed state, and the second waste liquid microvalve switches to the open state, so that the single first target object enters the paired channel from the first channel.

[0025] In other embodiments of the present invention, the microfluidic system further includes a second waste liquid channel and a second waste liquid microvalve disposed corresponding to the second waste liquid channel. The second waste liquid channel is connected to the paired channel, and the second waste liquid microvalve is used to control the opening and closing of the second waste liquid channel.

[0026] When the first microvalve, the first waste liquid microvalve, the cleaning microvalve, and the paired microvalve are all in the closed state, and the first buffer microvalve and the second waste liquid microvalve are in the open state, the liquid in the first flow channel can flow out through the paired flow channel and the second waste liquid flow channel.

[0027] And / or, when the paired microvalve is in the closed state and the second microvalve and the second waste liquid microvalve are in the open state, the liquid in the second flow channel can flow out through the paired flow channel and the second waste liquid flow channel.

[0028] In other embodiments of the present invention, the microfluidic system further includes a second flow channel, an oil flow channel, and a paired flow channel, wherein the paired flow channel is connected to the oil flow channel, and both the first flow channel and the second flow channel are connected to the paired flow channel;

[0029] The microfluidic system further includes a pairing microvalve corresponding to the paired flow channel and a second microvalve corresponding to the second flow channel. The pairing microvalve is used to control the opening and closing of the paired flow channel, and the second microvalve is used to control the opening and closing of the second flow channel.

[0030] When a single first target object from the first flow channel and a single second target object from the second flow channel are present in the paired flow channel, the first microvalve, the second microvalve, the first waste liquid microvalve, and the cleaning microvalve are all in a closed state, and the paired microvalve and the first buffer solution microvalve are in an open state, so that the buffer solution in the first buffer solution microvalve delivers the single first target object and the single second target object in the paired flow channel into the oil in the oil flow channel to form droplets.

[0031] In other embodiments of the present invention, the second target is a detection microsphere, the detection microsphere comprising a marker core and a magnetic coating layer covering the marker core; wherein, the marker core comprises a polymer core and a detection marker located on the surface of the polymer core; and primer chains are bonded to the surface of the magnetic coating layer.

[0032] In other embodiments of the present invention, the surface of the magnetic coating layer is modified with streptavidin, and the primer chain is modified with biotin, wherein the primer chain binds to the streptavidin on the surface of the magnetic coating layer via biotin.

[0033] In other embodiments of the present invention, the number of primer chains bound to the surface of the magnetic coating layer is 5×10⁷ to 2×10⁸.

[0034] In other embodiments of the invention, the polymer comprises a copolymer or homopolymer formed from at least one monomer selected from styrene, acrylic acid, acrylate, and methacrylate.

[0035] In other embodiments of the present invention, the magnetic coating layer includes at least one of iron(II,III) oxide, iron(III) oxide, and ferrite materials.

[0036] In other embodiments of the invention, the detection marker includes a fluorescent detection marker.

[0037] In other embodiments of the present invention, the fluorescent detection marker includes at least one of APC, Coomassie Brilliant Blue, and Nell Blue Chloride.

[0038] In other embodiments of the present invention, the diameter of the detection microspheres is 10–20 μm.

[0039] The aforementioned microfluidic systems are used in single-cell sequencing, cell screening, cell interaction detection, cell omics analysis, proteomics analysis, and the preparation of cell therapy products or cell drugs.

[0040] The microfluidic system according to a second embodiment of the present invention includes:

[0041] The aforementioned microfluidic chip;

[0042] Detection module;

[0043] The first flow channel has a first identification position, and the detection module is configured to identify the single first target object at the first identification position. When the detection module identifies the single first target object, both the first micro valve and the first waste liquid micro valve are switched to the closed state so that the single first target object is located in the first area.

[0044] In other embodiments of the present invention, when the detection module does not identify a single first target object, both the first microvalve and the first waste liquid microvalve remain in the open state, and the first buffer microvalve and the cleaning microvalve remain in the closed state, so that the liquid in the first flow channel can flow out through the first waste liquid flow channel.

[0045] In other embodiments of the present invention, the detection module includes a camera and a controller, the controller being configured to control the camera to capture an image of the first identification position, and the controller being further configured to identify the single first target object based on the first image.

[0046] In other embodiments of the present invention, the detection module includes a first light source, a first light detection device, and a controller. The controller is configured to control the first light source to emit a first detection light toward the first identification position. The first detection light can excite a first fluorescence after irradiating the single first target object, and the detection device identifies the single first target object when the first light detection device detects the first fluorescence.

[0047] In other embodiments of the present invention, the detection module further includes a first light-conducting device and a second light-conducting device. The first light-conducting device is configured to receive the first detection light from the first light source and conduct the first detection light to the first identification position. The second light-conducting device is configured to receive the first fluorescence and conduct the first fluorescence to the first light detection device.

[0048] In other embodiments of the present invention, the first flow channel includes a first flow channel segment and a second flow channel segment arranged sequentially along the flow direction. The first buffer solution flow channel, the first waste liquid flow channel, and the cleaning flow channel group are all connected to the second flow channel segment. The axes of the first flow channel segment and the second flow channel segment intersect. The first identification position is disposed in the second flow channel segment. The first light-conducting device is disposed on the side of the first flow channel segment away from the second flow channel segment and points towards the second flow channel segment. The second light-conducting device is disposed in the second flow channel segment corresponding to the first identification position. The axes of the first light-conducting device and the second light-conducting device intersect.

[0049] In other embodiments of the present invention, the first flow channel segment is perpendicular to the axis of the second flow channel segment, the first light-conducting device is perpendicular to the axis of the second light-conducting device, and the second light-conducting device is disposed on the side of the second flow channel segment away from the first flow channel segment and points towards the first flow channel segment.

[0050] In other embodiments of the present invention, the first light-conducting device and the second light-conducting device are respectively disposed on opposite sides of the first flow channel, and the first light-conducting device and the second light-conducting device are coaxially disposed.

[0051] In other embodiments of the present invention, the detection module includes a first detection electrode and a controller. The first detection electrode is disposed at the first identification position and extends into the first flow channel. The controller is configured to identify the single first target object based on the signal detected by the first detection electrode.

[0052] In other embodiments of the invention, the first identification site is located upstream of the first buffer channel along the flow direction.

[0053] The microfluidic system according to a third embodiment of the present invention includes:

[0054] The aforementioned microfluidic chip;

[0055] Detection module;

[0056] The first channel between the cleaning channel group and the paired channel has a second identification position. The detection module is configured to identify the single first target object at the second identification position. When the detection module identifies the single first target object, both the first micro valve and the paired micro valve are in a closed state to keep the single first target object in the paired channel.

[0057] And / or, the second flow channel has a third identification position, and the detection module is configured to identify a single second target object at the third identification position, wherein when the detection module identifies a single second target object, both the second microvalve and the paired microvalve are in a closed state to keep the single second target object within the paired flow channel.

[0058] In other embodiments of the present invention, the first flow channel has a first identification position, and the detection module is configured to identify the single first target object at the first identification position, wherein when the detection module identifies the single first target object, both the first microvalve and the paired microvalve are switched to the closed state so that the single first target object is located in the first area;

[0059] The microfluidic system also includes a platform for carrying the microfluidic chip and is movable between a first position and a second position.

[0060] Wherein, when the loading platform is located at the first position, the detection module is configured to identify the single first target object at the first identification position; when the loading platform is located at the second position, the detection module is configured to identify the single first target object at the second identification position, and / or, the detection module is configured to identify the single second target object at the third identification position.

[0061] According to the processing method of the fourth embodiment of the present invention, it is applied to the screening of a first target object in a microfluidic system. The microfluidic system includes a microfluidic chip, the microfluidic chip includes a first channel and a cleaning channel group connected to the first channel, the cleaning channel group includes at least two cleaning channels, the at least two cleaning channels are arranged sequentially along the flow direction of the first carrier liquid in the first channel, and the diameter of the inlet of the cleaning channel is smaller than the diameter of the first target object.

[0062] The screening method includes the following steps:

[0063] Along the flow direction, a single first target object is identified from the first carrier liquid upstream of the cleaning channel assembly;

[0064] After identifying the single first target object, the first flow channel is shut off by closing the first stop position upstream of the single first target object and the second stop position downstream of the cleaning flow channel group along the flow direction.

[0065] A first buffer solution is introduced into the first channel between the first stop position and the second stop position and upstream of the first target object. The first buffer solution transports the single first target object to the inlet of one of the cleaning channels and stops at the inlet, and the first buffer solution flows out through the other cleaning channels.

[0066] The cleaning channel is shut off, and the first channel at the second stop position is reopened to allow the single first target object to continue to be transported through the first buffer solution.

[0067] In other embodiments of the present invention, the step of continuing to transport the single first target object through the first buffer solution includes: after transporting the single first target object to the target area through the first buffer solution, stopping the input of the first buffer solution so that the single first target object stops in the target area.

[0068] In other embodiments of the present invention, the microfluidic chip further includes a second flow channel;

[0069] The processing method further includes the following steps:

[0070] Identify a single second target object from the second carrier liquid within the second flow channel;

[0071] After identifying the single second target object, the third stop position upstream of the single second target object is closed along the flow direction of the second carrier liquid in the second flow channel, thereby shutting off the second flow channel and causing the single second target object to stop in the target area.

[0072] After both the single first target object and the single second target object stop in the target area, a second buffer solution is directly introduced into the target area. The single first target object and the single second target object in the target area are then fed into the oil to form droplets through the second buffer solution. Alternatively, a first buffer solution is introduced into the first flow channel between the first stop position and the second stop position. The single first target object and the single second target object in the target area are then fed into the oil to form droplets through the first buffer solution.

[0073] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0074] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0075] Figure 1 is a schematic diagram of the microfluidic chip in the first embodiment of the present invention;

[0076] Figure 2 is an enlarged schematic diagram of region F in Figure 1;

[0077] Figure 3 is an enlarged schematic diagram showing the paired flow channels in Figure 2;

[0078] Figure 4 is a schematic diagram of the process of pairing the first target object with the second target object by the microfluidic system in the first embodiment of the present invention;

[0079] Figure 5 is an exploded view of the microfluidic chip in the first embodiment of the present invention;

[0080] Figure 6 is a schematic diagram of a microfluidic chip in another embodiment of the present invention using a photoconductive device;

[0081] Figure 7 is a schematic diagram of the microfluidic system in the second embodiment of the present invention;

[0082] Figure 8 is a schematic diagram of the microvalve of the microfluidic system in the embodiment of the present invention in the open and closed states.

[0083] Reference numerals: Microfluidic chip 100, base layer 110, control layer 120, first microvalve 121, diaphragm 1211, second microvalve 122, first buffer solution microvalve 123, first waste liquid microvalve 124, cleaning microvalve 125, oil microvalve 126, second buffer solution microvalve 127, paired microvalve 128, second waste liquid microvalve 129, flow channel layer 130, first flow channel 131, first region 1311, second region 1312, first flow channel segment 1313, second flow channel segment 1314, second flow channel 132, first buffer solution flow channel 133, first waste liquid flow channel 134, cleaning flow channel 135, first cleaning segment 1351, second cleaning segment 1352, oil flow channel 136, second buffer solution flow channel 137, paired flow channel 138, second waste liquid flow channel 139, connecting flow channel 1310; Detection module 200; first optical transmission device 210; second optical transmission device 220; first target object A; second target object B; first identification bit C; second identification bit D; third identification bit E; droplet G Detailed Implementation

[0084] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0085] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0086] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0087] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0088] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0089] The first embodiment of this invention proposes a microfluidic system. Referring to Figures 1 and 2, the microfluidic system includes a first channel 131 and a first buffer solution channel 133, a first waste liquid channel 134, and a cleaning channel assembly respectively connected to the first channel 131. The cleaning channel assembly includes at least two cleaning channels 135. The first channel 131 is used for a first carrier liquid containing a first target A to flow through. The first buffer solution channel 133 is used for a buffer solution to flow through. The cleaning channel 135 and the first waste liquid channel 134 are both used for waste liquid to flow through. It should be noted that the waste liquid referred to here refers to the first carrier liquid that does not contain or substantially does not contain the first target A, or a mixture of the first carrier liquid and the buffer solution. It should be noted that in this embodiment, the first target is a cell, such as a tumor cell.

[0090] Along the flow direction of the liquid in the first flow channel 131, the first waste liquid flow channel 134 and the cleaning flow channel group are both located downstream of the first buffer solution flow channel 133. That is, the first carrier liquid will first reach the first buffer solution flow channel 133, and then reach the first waste liquid flow channel 134 and the cleaning flow channel group. For example, in the direction from top to bottom in Figure 1, the first waste liquid flow channel 134 and the cleaning flow channel group are both located below the first buffer solution flow channel 133. It should be noted that the order of the first waste liquid flow channel 134 and the cleaning flow channel group is not limited in this invention. In the embodiment shown in Figure 1, the cleaning flow channel group is located downstream of the first waste liquid flow channel 134. In other embodiments, the first waste liquid flow channel 134 is located downstream of the cleaning flow channel group.

[0091] Referring to Figure 2, along the flow direction of the liquid in the first flow channel 131, the cleaning channel group includes at least two cleaning channels 135 arranged sequentially along the flow direction. The diameter of the inlet of the cleaning channel 135 is smaller than the diameter of the first target A, so that the first target A cannot be discharged from the cleaning channel 135. In addition, when the first carrier fluid also contains non-target objects, such as red blood cells, white blood cells, etc., the diameter of the inlet of the cleaning channel 135 is larger than the diameter of these non-target objects, so that the non-target objects can be discharged from the cleaning channel 135. One of the cleaning channels 135 is used to intercept the first target A, and the other cleaning channels 135 are used for waste liquid to pass through. In the embodiment shown in Figure 2, there are two cleaning channels 135. The cleaning channel 135 on the right is used to intercept the first target A, and the cleaning channel 135 on the left is used for waste liquid to pass through. It should be noted that, as shown in Figure 2, each cleaning channel 135 can have its front section (the part near the first channel 131) separated and its rear section (the part away from the first channel 131) merged into one channel. In other words, Figure 2 can be regarded as a block set in the front section of a larger channel, which separates the front section of the larger channel into at least two independent channels. In other embodiments, two completely independent cleaning channels 135 can also be set directly.

[0092] Referring again to Figure 1, the microfluidic system of this embodiment further includes multiple microvalves, specifically including a first microvalves 121 corresponding to the first flow channel 131, a first buffer solution microvalves 123 corresponding to the first buffer solution flow channel 133, a first waste liquid microvalves 124 corresponding to the first waste liquid flow channel 134, and cleaning microvalves 125 corresponding to each cleaning flow channel 135. The first microvalves 121 control the opening and closing of the first flow channel 131, the first buffer solution microvalves 123 control the opening and closing of the first buffer solution flow channel 133, and the first waste liquid microvalves 124 control the opening and closing of the first waste liquid flow channel 135. The on / off state of 134, the cleaning micro-valve 125 is used to control the on / off state of each cleaning channel 135. Taking the first channel 131 and the first micro-valve 121 as an example, the control of the on / off state of the first channel 131 by the first micro-valve 121 means that the first micro-valve 121 has an open state and a closed state. When the first micro-valve 121 is in the open state, the first channel 131 is in the unobstructed state, and the first carrier liquid can flow in the first channel 131. When the first micro-valve 121 is in the closed state, the first channel 131 is in the closed state, and the first carrier liquid cannot flow in the first channel 131.

[0093] In some specific embodiments, referring to FIG8, the microvalve includes a diaphragm. Taking the first microvalve 121 as an example, the diaphragm 1211 is disposed between the first flow channel 131 and the first microvalve control flow channel corresponding to the first flow channel 131. When the first microvalve 121 is in the open state, the diaphragm is in a horizontal state, and the first carrier liquid can flow in the first flow channel 131. When the diaphragm is driven to protrude into the first flow channel 131 to be in the closed state, the diaphragm is close to the inner wall of the first flow channel 131 to block the first flow channel 131, and the first carrier liquid cannot flow in the first flow channel 131. For example, the inner wall of the first flow channel 131 is an arc-shaped inner wall, which facilitates the contact with the diaphragm 1211 protruding into the first flow channel 131, thereby ensuring the blocking effect. It should be noted that the power to drive the diaphragm to bulge can be air pressure. In this embodiment, the first microvalve controls the flow channel to be filled with liquid. An external air source drives the first microvalve to control the flow of liquid in the flow channel, thereby pushing the diaphragm to bulge or reset. Compared with the method of driving directly by air pressure, since liquid is difficult to compress, this method can achieve a rapid response of the diaphragm, thus adapting to high-speed pairing.

[0094] This embodiment can screen out a single first target A from a first carrier liquid containing a first target A and non-target objects. It mainly includes two steps: the first step is to screen out a single first target A, and the second step is to separate the single first target A from the non-target objects. Specifically, the first flow channel 131 between the first buffer solution flow channel 133 and the cleaning flow channel group is defined as the first region 1311 (for ease of understanding, the range of the first region 1311 is roughly marked by dashed lines in Figure 1). First, the first micro valve 121 and the first waste liquid micro valve 124 are in the open state. At this time, the first carrier liquid containing the first target A and non-target objects will continuously flow from the first flow channel 131 to the first waste liquid flow channel 134. When a single first target A is detected (the specific detection scheme will be described later) flowing to the first region 1311 with the first carrier liquid, the first micro valve 121 and the first waste liquid micro valve 124 are switched to the closed state. At this time, the first carrier liquid A no longer flows, and the single first target A will remain in the first region 1311, thus completing the first step. Then, the first buffer solution microvalve 123 and the cleaning microvalve 125 are opened. Driven by the buffer solution, the single first target object A remaining in the first region continues to flow into the cleaning channel group, eventually stopping at the inlet of one of the cleaning channels 135 due to its large diameter. At this point, the cleaning channel 135 is blocked by the first target object A. Therefore, the buffer solution and residual first carrier liquid continue to be discharged from the other cleaning channels 135, thereby carrying away the non-target objects in the first region 1311. After being rinsed with the buffer solution, the first region 1311 contains only or almost only the first target object A, thus completing the second step. It should be noted that during the process of completing the first step, the first buffer solution microvalve 123 and the cleaning microvalve 125 can be in either the closed or open state.

[0095] As mentioned above, the microfluidic chip 100 of this embodiment sets up corresponding flow channels and valves, and filters out a single first target A from the first carrier liquid containing the first target A and non-target objects by switching the valves, thereby reducing the contamination of non-target objects and improving the accuracy of subsequent detection.

[0096] Based on the first embodiment, in some embodiments of the present invention, referring to FIG1, the first waste liquid channel 134 and the cleaning channel 135 are independent channels, and the diameter of the first waste liquid channel 134 is larger than that of the cleaning channel 135. Typically, the quantity of the first target A in the first carrier liquid is small; therefore, rapid drainage can be achieved through the larger diameter first waste liquid channel 134 during the first step, thereby improving the screening speed of the microfluidic chip 100.

[0097] When the first waste liquid channel 134 and the cleaning channel 135 are independent channels, in some specific embodiments, referring to FIG1, the first buffer solution channel 133, the first waste liquid channel 134 and the cleaning channel group are arranged sequentially along the flow direction of the first carrier fluid. That is, when the first micro valve 121 is opened, the first carrier liquid will sequentially reach the first buffer solution channel 133, the first waste liquid channel 134 and the cleaning channel group.

[0098] In this embodiment, the first channel 131 between the first buffer solution channel 133 and the first waste liquid channel 134 is defined as the second region 1312, and the second region 1312 is a part of the first region 1311. Based on the above structure, the aforementioned "when the first microvalve 121 and the first waste liquid microvalve 124 are in the open state, and a single first target A flows to the first region 1311, the first microvalve 121 and the first waste liquid microvalve 124 switch to the closed state, and the first buffer solution microvalve 123 and the cleaning microvalve 125 are in the open state" specifically means that: in the initial test state, the first buffer solution microvalve 123 and the cleaning microvalve 125 are in the closed state; when the first microvalve 121 and the first waste liquid microvalve 124 are in the open state, and a single first target A flows to the second region 1312, the first microvalve 121 and the first waste liquid microvalve 124 switch to the closed state, and the first buffer solution microvalve 123 and the cleaning microvalve 125 switch to the open state, thereby allowing the single first target A to flow to the inlet of one of the cleaning channels 135.

[0099] Since the cleaning channel assembly is located downstream of the first waste liquid channel 134, the entire first region 1311 can be rinsed when non-target substances are rinsed with buffer solution, thereby minimizing the residue of non-target substances.

[0100] Based on the first embodiment, in some embodiments of the present invention, at least one cleaning channel 135 is a first waste liquid channel 134, and the cleaning microvalve 125 is a first waste liquid microvalve 124. In other words, this embodiment does not provide a separate first waste liquid channel 134, but uses at least one cleaning channel 135 in the cleaning channel group as the first waste liquid channel 134. Correspondingly, the cleaning microvalve 125 thereon is also used as the first waste liquid microvalve 124, which simplifies the structure of the microfluidic chip 100.

[0101] Based on the first embodiment, in some embodiments of the present invention, referring to FIG2, the cleaning channel 135 includes a first cleaning section 1351 communicating with the first channel 131. It should be noted that the communication here includes both direct communication with the first channel 131 and indirect communication through, for example, a subsequent connecting channel 1310. The first cleaning section 1351 has an inlet at one end facing the first channel 131. Along the flow direction of the liquid in the cleaning channel 135, for example, from bottom to top in FIG2, the cross-sectional area of ​​the first cleaning section 1351 gradually increases from the end with the inlet. That is, the cross-sectional area at the inlet of the first cleaning section 1351 is the smallest, thereby achieving the purpose of intercepting a single first target A. At the same time, the gradual increase in the cross-sectional area of ​​the first cleaning section 1351 can increase the throughput of the cleaning channel 135, thereby helping to improve the screening speed of the microfluidic chip 100. For example, when each cleaning channel 135 is an independent channel, the opposite sides of the first cleaning section 1351 are both set as inclined or curved surfaces to achieve the purpose of gradually increasing the cross-sectional area, which can reduce the flow resistance of the fluid. When each cleaning channel 135 is as shown in Figure 2, and its first cleaning section 1351 is separated from each other by baffles and the later sections are merged into an integral channel, the first cleaning section 1351 can also have one side set as an inclined or curved surface to achieve the purpose of gradually increasing the cross-sectional area.

[0102] When the cleaning channel 135 includes a first cleaning section 1351 connected to the first channel 131, in some specific embodiments, referring to FIG2, along the flow direction of the liquid in the cleaning channel 135, the cleaning channel 135 also includes a second cleaning section 1352 connected to the first cleaning section 1351. When each cleaning channel 135 is an independent channel, the cross-sectional area of ​​the second cleaning section 1352 can be equal to the maximum cross-sectional area of ​​the first cleaning section 1351. When each cleaning channel 135, as shown in FIG2, has its first cleaning section 1351 separated by baffles and is independent of each other, and its subsequent sections are merged into a single channel, the cross-sectional area of ​​the second cleaning section 1352 can be greater than the maximum cross-sectional area of ​​the first cleaning section 1351. By setting a second cleaning section 1352 with a larger cross-sectional area, the throughput of the cleaning channel 135 can be increased, thereby helping to improve the screening speed of the microfluidic chip 100.

[0103] Based on the first embodiment, in some embodiments of the present invention, the diameter of the inlet of the first waste liquid flow channel 134 is 5 micrometers to 10 micrometers, thereby adapting to the interception of common tumor cells. For example, the diameter of the inlet of the first waste liquid flow channel 134 is 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, etc.

[0104] Based on the first embodiment, in some embodiments of the present invention, referring to FIG2, the microfluidic chip 100 further includes a connecting channel 1310. One end of the connecting channel 1310 is connected to the first channel 131, and the other end is connected to each cleaning channel 135. That is, each cleaning channel 135 is indirectly connected to the first channel 131 through the connecting channel 1310. Along the flow direction of the liquid in the connecting channel 1310, such as the up and down direction in FIG2, the length of the connecting channel 1310 is 3 micrometers to 8 micrometers. Thus, when a single first target A stops at the inlet of a cleaning channel 135, due to the blocking and limiting effect of the channel wall of the connecting channel 1310, it can prevent the buffer from continuing to clean non-target objects and causing the first target A to deviate from the stop position. At the same time, by limiting the length of the connecting channel 1310 (which can also be understood as the recessed depth of the connecting channel 1310), it can also avoid excessive limiting and affecting the subsequent flow of the buffer to drive the single first target A along the first channel 131 to the paired channel 138.

[0105] Based on the first embodiment, in some embodiments of the present invention, referring to Figures 1 and 3, the microfluidic chip 100 further includes a second flow channel 132, an oil flow channel 136, a second buffer flow channel 137, and a pairing flow channel 138. The second flow channel 132 is used for the passage of a second carrier liquid containing the second target substance B; the second buffer flow channel 137 is used for the passage of a buffer solution; the oil flow channel 136 is used for the passage of an oil solution that is immiscible with the first carrier liquid, the second carrier liquid, and the buffer solution; and the pairing flow channel 138 is used for the residence of a single first target substance A and a single second target substance B. The pairing flow channel 138 is connected to the oil flow channel 136, and the first flow channel 131, the second flow channel 132, and the second buffer flow channel 137 are all connected to the pairing flow channel 138. In this embodiment, the first target substance A is described as a cell, and the second target substance B is described as a detection microsphere. Those skilled in the art will understand that the first target substance A can be a cell, and the second target substance B can also be a cell.

[0106] Correspondingly, the microfluidic chip 100 also includes a pairing microvalve 128 corresponding to the pairing channel 138, a second microvalve 122 corresponding to the second channel 132, and a second buffer microvalve 127 corresponding to the second buffer channel 137. The pairing microvalve 128 is used to control the opening and closing of the pairing channel 138, the second microvalve 122 is used to control the opening and closing of the second channel 132, and the second buffer microvalve 127 is used to control the opening and closing of the second buffer channel 137.

[0107] In this embodiment, referring to steps (c) to (d) in FIG4, when there is a single first target A and a single second target B in the paired flow channel 138, the first microvalve 121 and the second microvalve 122 are in the closed state (the microvalve in FIG4 is filled with black to indicate that it is in the closed state), and the paired microvalve 128 and the second buffer microvalve 127 are in the open state (the microvalve in FIG4 is filled with gray to indicate that it is in the open state). At this time, the buffer in the second buffer flow channel 137 can send the single first target A and the single second target B in the paired flow channel 138 into the oil in the oil flow channel 136 to form droplets G.

[0108] As described above, this embodiment has a separate pairing channel 138 for temporarily storing a single first target A and a single second target B, and a separate second buffer solution channel 137. The buffer solution pushes the single first target A and the single second target B into the oil, eliminating the need for the first and second carrier liquids to push them. Therefore, the first channel 131 and the second channel 132 can remain in a closed state during the encapsulation process, thereby completely preventing other first targets and / or other second targets from entering the droplet G. This improves the success rate of encapsulation and reduces cell loss caused by multiple encapsulations.

[0109] When the microfluidic chip 100 further includes the aforementioned second flow channel 132, oil flow channel 136, second buffer flow channel 137, and paired flow channel 138, in some embodiments, referring to Figures 1 to 4, the microfluidic system further includes a second waste liquid flow channel 139. The second waste liquid flow channel 139 is used to discharge a first carrier liquid that does not contain or substantially does not contain the first target A, and a second carrier liquid that does not contain or substantially does not contain the second target B. The second waste liquid flow channel 139 is connected to the paired flow channel 138. In addition, the microfluidic system also includes a second waste liquid microvalve 129 corresponding to the second waste liquid flow channel 139. The second waste liquid microvalve 129 is used to control the opening and closing of the second waste liquid flow channel 139.

[0110] Based on the above structure, when a single first target object A stops at the inlet of one of the cleaning channels 135, and the buffer solution in the first buffer microvalve 123 has completed the cleaning of non-target objects (refer to step (a) in Figure 4), the first microvalve 121, the first waste liquid microvalve 124, the cleaning microvalve 125, the second buffer solution microvalve 127, and the paired microvalve 128 are all in the closed state, while the first buffer solution microvalve 123 and the second waste liquid microvalve 129 are in the open state. At this time, the buffer solution in the first buffer solution microvalve 123 will flow from the first channel 131 through the paired channel 138 and into the second waste liquid channel 139, thereby driving the single first target object A that stops at the inlet of the cleaning channel 135 to flow into the paired channel 138 (refer to step (b) in Figure 4). When the single first target object A is located in the paired channel 138, the first buffer solution microvalve 123 switches to the closed state, and the single first target object A will remain in the paired channel 138.

[0111] When the microfluidic chip 100 also includes the aforementioned second waste liquid channel 139, in some embodiments, the microfluidic chip 100 is further configured such that: when a single first target A stops at the inlet of one of the cleaning channels 135, and the first buffer microvalve 123 and the cleaning microvalve 125 remain in the open state for a set time, the cleaning microvalve 125 switches to the closed state, and the second waste liquid microvalve 129 switches to the open state, so that the single first target A enters the paired channel 138 from the first channel 131. In this way, this embodiment can ensure that the buffer solution has sufficient cleaning time for the single first target A, thereby reducing the residue of non-target objects. It should be noted that the aforementioned "set time" can be set and adjusted according to the data obtained in the actual application process. For example, by changing different time lengths, the residual rate of non-target objects after cleaning can be detected, thereby finally obtaining a cleaning time that meets the requirements.

[0112] When the microfluidic chip 100 further includes the aforementioned second flow channel 132, oil flow channel 136, second buffer flow channel 137 and paired flow channel 138, in some embodiments, referring to Figures 1 to 4, the microfluidic system further includes a second waste liquid flow channel 139 and a second waste liquid microvalve 129 corresponding to the second waste liquid flow channel 139. The second waste liquid flow channel 139 and the second waste liquid microvalve 129 can be understood with reference to the aforementioned embodiments.

[0113] When the first microvalve 121, the first waste liquid microvalve 124, the cleaning microvalve 125 and the paired microvalve 128 are all in the closed state, and the first buffer microvalve 123 and the second waste liquid microvalve 129 are in the open state, the liquid in the first flow channel 131 can flow out through the paired flow channel 138 and the second waste liquid flow channel 139, thereby enabling the flow of a single first target A to the paired flow channel 138.

[0114] Furthermore, when the paired microvalve 128 is in the closed state and the second microvalve 122 and the second waste liquid microvalve 129 are in the open state, the liquid in the second flow channel 132 can flow out through the paired flow channel 138 and the second waste liquid flow channel 139, thereby enabling the flow of a single second target object B into the paired flow channel 138.

[0115] Based on the above, and referring to Figures 1 and 4, a complete pairing process in one embodiment is described, which includes the following steps:

[0116] Screening of the first target A: Initially, the first microvalve 121, the first buffer solution microvalve 123, the first waste liquid microvalve 124, the cleaning microvalve 125, the second buffer solution microvalve 127, the second waste liquid microvalve 129, and the paired microvalve 128 are all in the closed state. Then, the first microvalve 121 and the first waste liquid microvalve 124 open, and the first carrier liquid containing the first target A flows through the first flow channel 131 to the first waste liquid flow channel 134. When a single first target A appears in the first region 1311, the first microvalve 121 and the first waste liquid microvalve 124 switch to the closed state, and the first buffer solution microvalve 125 and the first waste liquid microvalve 126 switch to the closed state. The cleaning microvalve 125 is switched to the open state, and the buffer solution carries a single first target A into the cleaning channel 135 and stops at the inlet of one of the cleaning channels 135. After the single first target A stops, the buffer solution continues to rinse for a set time. Then the cleaning microvalve 125 is switched to the closed state, and the second waste liquid microvalve 129 is switched to the open state. The buffer solution carries the cleaned single first target A into the pairing channel 137. After the single first target A enters the pairing channel 137, the first buffer solution microvalve 123 is switched to the closed state. At this time, the single first target A will remain in the pairing channel 137.

[0117] Screening of the second target B: In the initial state, the second micro valve 122, the second waste liquid micro valve 129 and the paired micro valve 128 are all in the closed state. Then, the second micro valve 122 and the second waste liquid micro valve 129 are opened, and the second carrier liquid containing the second target A flows through the second flow channel 132 to the second waste liquid flow channel 139. When a single second target B appears in the paired flow channel 138, the second micro valve 122 switches to the closed state. At this time, the single second target B will stay in the paired flow channel 137.

[0118] Pairing of targets: When a single first target A and a single second target B are both in the pairing channel 137, the second buffer microvalve 127 and the pairing microvalve 128 are switched to the open state. The buffer carries the single first target A and the single second target B in the pairing channel 137 into the oil channel 136 to be encapsulated into droplets.

[0119] The foregoing embodiments propose a scheme using independently configured first buffer channel 133 and second buffer channel 137. In other embodiments, the second buffer channel 137 can be omitted, and the function of the second buffer channel 137 can be replaced by the first buffer channel 133. Specifically, the microfluidic system also includes a second channel 132, an oil channel 136, and a paired channel 138. The paired channel 138 is connected to the oil channel 136, and both the first channel 131 and the second channel 132 are connected to the paired channel 138. The microfluidic system also includes a paired microvalve 128 corresponding to the paired channel 138 and a second microvalve 122 corresponding to the second channel 132. The paired microvalve 128 is used to control the opening and closing of the paired channel 138, and the second microvalve 122 is used to control the opening and closing of the second channel 132. These channels and microvalve can be understood with reference to the foregoing embodiments.

[0120] When a single first target A from the first flow channel 131 and a single second target B from the second flow channel 132 are present in the paired flow channel 138, the first microvalve 121, the second microvalve 122, the first waste liquid microvalve 124, the second waste liquid microvalve 129 and the cleaning microvalve 125 are all in the closed state, and the paired microvalve 128 and the first buffer solution microvalve 123 are in the open state, so that the buffer solution in the first buffer solution microvalve 123 can send the single first target A and the single second target B in the paired flow channel 138 into the oil in the oil flow channel 136 to form droplets, thereby achieving the pairing of target objects.

[0121] When the microfluidic chip also includes a second flow channel 132 and associated microvalves, in some embodiments, the second target A includes a detection microsphere. The structure of the detection microsphere includes a marker core and a magnetic coating layer covering the marker core. The marker core includes a polymer core (e.g., polystyrene) and a detection marker (e.g., fluorescent dyes APC, Coomassie Brilliant Blue, and Nell Blue chloride) modified on the surface of the polymer core. The shell is a magnetic coating layer made of ferromagnetic materials such as iron(III) oxide. The aforementioned detection microsphere forms a "sandwich" structure consisting of a polymer core, a marker layer, and a coating layer. On the outermost layer, the surface of the coating layer is also modified with streptavidin (SA) groups to bind a primer chain (the primer chain is modified with biotin, which can bind to streptavidin on the surface of the magnetic coating layer).

[0122] In some implementations, the primer strand includes an amplification primer (PCR Handle) serving as the starting point for PCR and sequencing, a barcode sequence for labeling cell identity, a molecular tag sequence (UMI) for excluding PCR bias interference, and a probe capture sequence (polydtVN). Additionally, the 5' end of the primer strand is modified with biotin.

[0123] In sequencing, existing fluorescent magnetic microspheres use coupling to connect fluorescent dyes. This method results in lower fluorescence intensity and uniformity, and reduces the number of linkers on the microsphere surface, thus affecting subsequent biological reactions. In this invention, the detection microspheres embed the detection label within a magnetic shell, allowing for the inclusion of more labels and more uniform label distribution. Furthermore, the connection between the detection microspheres and primer chains in this invention utilizes the SA group modified on the surface of the microsphere coating to connect to the 5' end of the primer chain via a streptavidin-biotin affinity reaction, forming a disulfide bond. This tighter binding allows the detection microspheres to carry more primer chains (e.g., 5 × 10⁻⁶). 7 Up to 2×10 8 (Strips), thereby capturing more mRNA released after lysis and improving sequencing efficiency. At the same time, a reducing agent can be used to separate the primer strands and detection microspheres, which is simple and convenient.

[0124] In some implementations, the detection microspheres are 10–20 μm in size, preferably 15 μm, suitable for fluorescence-based single-cell sequencing pairing systems.

[0125] Building upon the first embodiment, in some embodiments, the microfluidic system further includes a power element such as a pump to drive the flow of the buffer solution. In some specific embodiments, the microfluidic system includes a high-speed pump capable of achieving high-speed flow and stoppage of the buffer solution, thereby adapting to high-speed pairing.

[0126] Based on the first embodiment, in some embodiments, referring to FIG1, along the extending direction of the paired flow channel 138, the second waste liquid flow channel 139 is located between the first flow channel 131 and the second flow channel 132. In this way, when the first carrier liquid is discharged, it will not drive the already stationary single second target object B. Similarly, when the second carrier liquid is discharged, it will not drive the already stationary single second target object A. The discharge of the first carrier liquid and the second carrier liquid can be carried out synchronously.

[0127] Based on the first embodiment, in some embodiments, referring to FIG1, the first flow channel 131 and the second flow channel 132 are located on the same side of the paired flow channel 138, and the second waste liquid flow channel 139 is located on the other side of the paired flow channel 138. Specifically, in the embodiment shown in FIG1, the first flow channel 131 and the second flow channel 132 are located on the upper side of the paired flow channel 138, and the second waste liquid flow channel 139 is located on the lower side of the paired flow channel 138. In this way, the first carrier liquid and the second carrier liquid can flow in approximately the same direction, which facilitates the discharge of waste liquid.

[0128] Based on the first embodiment, in some embodiments, referring to FIG1, a first portion of the first flow channel 131 that is at least connected to the paired flow channel 138 is intersected with the paired flow channel 138. Specifically, in the embodiment shown in FIG1, the first portion is perpendicular to the paired flow channel 138.

[0129] Based on the first embodiment, in some embodiments, referring to FIG1, the second portion of the second flow channel 132 that is at least connected to the paired flow channel 138 is intersected with the paired flow channel 138. Specifically, in the embodiment shown in FIG1, the second portion is perpendicular to the paired flow channel 138.

[0130] Based on the first embodiment, in some embodiments, referring to FIG1, the third part of the second waste liquid flow channel 139, which is at least connected to the paired flow channel 138, is arranged to intersect with the paired flow channel 138. Specifically, in the embodiment shown in FIG1, the third part is perpendicular to the paired flow channel 138.

[0131] Based on the first embodiment, in some embodiments, referring to Figure 1, at least the fourth portion of the second buffer solution channel 137 that communicates with the paired channel 138 is coaxially arranged with the paired channel 138. Thus, the buffer solution can enter the paired channel 138 in the same direction and carry a single first target A and a single second target B into the oil. It should be noted that in this embodiment, the second buffer solution channel 137 and the paired channel 138 can be two parts of a single channel. Taking Figure 1 as an example, the left side of the vertical channel is the paired channel 138, and the right side is the second buffer solution channel 137. For ease of reading, the range of the paired channel 138 is roughly marked by a dashed box in the figure; however, the dashed box should not be construed as a specific limitation on the shape or length of the paired channel 138.

[0132] It is understood that the above embodiments can be combined, that is, the first part, the second part and the third part are all arranged to intersect with the mating flow channel, while the fourth part is arranged coaxially with the mating flow channel 138.

[0133] The microfluidic chips mentioned in the foregoing embodiments can be applied to single-cell sequencing, cell screening, cell interaction detection, cell omics analysis, proteomics analysis, and the preparation of cell therapy products or cell drugs.

[0134] Based on the first embodiment, in some embodiments of the present invention, referring to FIG5, the microfluidic chip 100 includes a base layer 110, a control layer 120 and a flow channel layer 130 stacked sequentially. The base layer 110 may be made of glass, and the control layer 120 and the flow channel layer 130 may be made of polydimethylsiloxane (PDMS).

[0135] The flow channel layer 130 includes the aforementioned first flow channel 131, second flow channel 132, first buffer solution flow channel 133, first waste liquid flow channel 134, cleaning flow channel 135, oil flow channel 136, second buffer solution flow channel 137, paired flow channel 138, second waste liquid flow channel 139, and connecting flow channel 1310. The control layer 120 includes the aforementioned first microvalve 121, second microvalve 122, first buffer solution microvalve 123, first waste liquid microvalve 124, cleaning microvalve 125, oil microvalve 126, second buffer solution microvalve 127, paired microvalve 128, second waste liquid microvalve 129, and microvalve control flow channels corresponding to each microvalve.

[0136] Based on the first embodiment, referring to FIG5, in some embodiments of the present invention, the microfluidic system includes a microfluidic chip 100, the microfluidic chip 100 including a base layer 110, a control layer 120 and a flow channel layer 130 stacked sequentially, the base layer 110 may be made of glass, and the control layer 120 and the flow channel layer 130 may be made of polydimethylsiloxane (PDMS).

[0137] The flow channel layer 130 includes the aforementioned first flow channel 131, second flow channel 132, oil flow channel 136, second buffer flow channel 137, second waste liquid flow channel 139, and paired flow channel 138. The control layer 120 includes the aforementioned paired microvalve 128, first microvalve 121, second microvalve 122, and second buffer microvalve 127, as well as microvalve control flow channels corresponding to each microvalve.

[0138] Based on the first embodiment, in some embodiments of the present invention, the first target A is a cell, and the second target B is a microsphere. In some embodiments, the microspheres can be further configured as magnetic microspheres, so that the RNA released after cell lysis can be adsorbed onto the surface of the microspheres, and the microspheres can be collected subsequently by a magnetic component, thereby collecting the RNA. In some embodiments, the microspheres can be further configured as fluorescent magnetic microspheres so that they emit fluorescence when excited by external light.

[0139] Based on the first embodiment, in some embodiments of the present invention, the first target A is a first cell and the second target B is a second cell, used to study the interaction effects between cells.

[0140] The second embodiment of the present invention proposes a microfluidic system, which includes a detection module 200 and a microfluidic chip 100 of the aforementioned embodiments. Referring to FIG1, the first flow channel 131 has a first identification position C. The detection module 200 is configured to identify a single first target A at the first identification position C. When the detection module 200 identifies a single first target A, the first microvalve 121 and the first waste liquid microvalve 124 are both switched to the closed state so that the single first target A is located in the first region 1311.

[0141] Based on the second embodiment, in some embodiments, when the detection module 200 does not identify a single first target A, the first microvalve 121 and the first waste liquid microvalve 124 are both kept in the open state, and the first buffer microvalve 123 and the cleaning microvalve 125 are kept in the closed state, so that the liquid in the first flow channel 131 can flow out through the first waste liquid flow channel 134.

[0142] Correspondingly, in some embodiments, the detection module 200 can also identify a single second target object B. When the detection module 200 does not identify a single second target object A, both the second micro valve 122 and the second waste liquid micro valve 129 remain in the open state so that the liquid in the second flow channel 132 can flow out through the second waste liquid flow channel 139.

[0143] In some embodiments of the present invention, when a single first target object A is identified by the detection module, the detection module is specifically a visual detection module, which includes a camera and a controller. The controller is configured to control the camera to capture images. In this embodiment, the image captured by the camera includes at least a first image of the first flow channel 131. After the camera captures the image, the controller is further configured to identify the single first target object A based on the first image.

[0144] Correspondingly, in some embodiments, the detection module 200 can also identify a single second target object B, the image captured by the camera also includes a second image of the second flow channel 132, and the controller is also configured to identify a single second target object B based on the second image.

[0145] In the above process, after the image captured by the camera is transmitted to the controller, the controller detects the target in the detection area (e.g., an area with a length and width of 200 pixels), classifies the cropped target image through a model trained by a convolutional neural network, and makes a judgment based on the classification output and controls the corresponding micro valve.

[0146] When the detection module identifies a single first target A through an image, in some embodiments of the present invention, the image captured by the camera also includes at least a third image of the pairing channel 138. The controller is configured to identify whether a single first target A exists in the pairing channel 138 based on the third image. In other words, in this embodiment, the image captured by the camera can also be used to verify whether a single first target A has entered the pairing channel 138.

[0147] Correspondingly, in some embodiments, the detection module 200 can also identify a single second target object B. The image captured by the camera also includes at least a third image of the pairing channel 138. The controller is configured to identify whether a single second target object B exists in the pairing channel 138 based on the third image. In other words, in this embodiment, the image captured by the camera can also be used to verify whether a single second target object B has entered the pairing channel 138.

[0148] It should be noted that the above embodiments can be combined. For example, the images captured by the camera include the aforementioned first image, second image, and third image. In this way, the controller can perform combined operations through the same image. For example, it can simultaneously identify a single first target A and a single first target B, or identify a single first target A and determine whether a single second target B has reached the pairing channel 138, or identify a single first target B and determine whether a single first target A has reached the pairing channel 138, or determine whether a single first target A and a single second target B have reached the pairing channel 138.

[0149] When a single first target object A is identified by the detection module, in some embodiments of the present invention, the detection module is specifically a fluorescence detection module, which includes a first light source, a first light detection device, and a controller. The controller is configured to control the first light source to emit a first detection light into the first flow channel 131. The first detection light can excite a first fluorescence after irradiating the single first target object A. The first light detection device can receive the first fluorescence excited by the single first target object A. For example, the first light source is a laser, and the first light detection device is a photomultiplier tube. After receiving the first fluorescence emitted by the single first target object A, the photomultiplier tube can convert the light signal into an electrical signal and transmit it to the controller.

[0150] For example, referring to FIG1, the first light source projects the first detection light onto the first identification position C of the first flow channel 131. When no cell reaches the first identification position C, the first light detection device will not receive the light signal. When a cell reaches the first identification position C, the cell is excited by the first detection light and generates fluorescence. When the first light detection device detects the first fluorescence, the detection device identifies a single first target A.

[0151] Correspondingly, in some embodiments, the detection module 200 can also identify a single second target object B. In some embodiments of the present invention, the detection module is specifically a fluorescence detection module, which includes a second light source, a second light detection device and a controller. The controller is configured to control the second light source to emit a second detection light into the second flow channel 132. The second detection light can excite a second fluorescence after irradiating a single second target object B. When the second light detection device detects the second fluorescence, the controller identifies a single second target object B.

[0152] For example, referring to FIG1, the second light source projects a second detection light onto the third recognition position E of the second flow channel 132. When no cell reaches the third recognition position E, the second light detection device will not receive a light signal. When a cell reaches the third recognition position E, the cell is excited by the second detection light and produces fluorescence. When the second light detection device detects the second fluorescence, the detection device identifies a single second target A.

[0153] It should be noted that the first light source and the second light source can be lasers of different wavelengths.

[0154] When the detection module is a fluorescence detection module, in some embodiments of the present invention, referring to FIG1, the detection module 200 further includes a first light transmission device 210 and a second light transmission device 220. The first light transmission device 210 is configured to receive the first detection light from the first light source and transmit the first detection light to the first identification position C. The second light transmission device 220 is configured to receive the first fluorescence and transmit the first fluorescence to the first light detection device. For example, both the first light transmission device 210 and the second light transmission device 220 are optical fibers inserted into the microfluidic chip, with one end facing the first identification position C.

[0155] When the detection module 200 further includes a first light-conducting device 210 and a second light-conducting device 220, in some embodiments of the present invention, referring to FIG1, the first flow channel 131 includes a first flow channel segment 1313 and a second flow channel segment 1314 arranged sequentially along the flow direction. The first buffer solution flow channel 133, the first waste liquid flow channel 134, and the cleaning flow channel group are all connected to the second flow channel segment 1314. The axes of the first flow channel segment 1313 and the second flow channel segment 1314 intersect. For example, both the first flow channel segment 1313 and the second flow channel segment 1314 are straight segments. A first identification position C is disposed in the second flow channel segment 1314. For example, the first identification position C is disposed at the end of the second flow channel segment 1314 near the first flow channel segment 1313.

[0156] In this embodiment, the axes of the first optical transmission device 210 and the second optical transmission device 220 intersect. Specifically, the first optical transmission device 210 is disposed on the side of the first flow channel segment 1313 away from the second flow channel segment 1314 and points towards the second flow channel segment 1314. For example, in Figure 1, the second flow channel segment 1314 is located below the first flow channel segment 1313, so the first optical transmission device 210 is disposed above the first flow channel segment 1313. The second optical transmission device 220 is disposed on the second flow channel segment 1314 corresponding to the first identification position C. For example, the second optical transmission device 220 is flush with or approximately flush with the first identification position C.

[0157] Based on the above, the first light-conducting device 210 and the second light-conducting device 220 are staggered, thereby enabling the setting of multiple recognition positions to adapt to the recognition of different first target objects. For example, along the flow direction of the first carrier liquid, multiple first recognition positions C are sequentially arranged on the second flow channel section 1314, and multiple second light-conducting devices 220 are arranged corresponding to each first recognition position C. The first carrier liquid contains multiple first target objects A, and different target objects A emit different fluorescence, for example, different wavelengths of fluorescence. When the first detection light emitted by the first light-conducting device 210 irradiates different first target objects A, it can excite fluorescence of different wavelengths. The different fluorescence is received by the first light detection device, thereby enabling the recognition of different first target objects A. That is, this embodiment facilitates the expansion of recognition points, and multiple fluorescence recognition can be achieved using one first light detection device, which helps to simplify the structure and reduce costs. It should be noted that, in order to avoid interference between fluorescence, a filter device can be set on the light transmission path of the corresponding second light-conducting device 220 to filter out fluorescence of other wavelength ranges.

[0158] In some specific embodiments, the axes of the first flow channel segment 1313 and the second flow channel segment 1314 are perpendicular, the axes of the first light-conducting device 210 and the second light-conducting device 220 are perpendicular, and the second light-conducting device 220 is disposed on the side of the second flow channel segment 1314 away from the first flow channel segment 1313 and points towards the first flow channel segment 1313. For example, in FIG1, the first flow channel segment 1313 is disposed on the left side of the second flow channel segment 1314, and the second light-conducting device 220 is disposed on the right side of the second flow channel segment 1314.

[0159] In some specific embodiments, referring to FIG1, along the flow direction of the first carrier liquid in the first flow channel 131, the first identification position C is located upstream of the first buffer flow channel 133. Typically, the microvalve controlling the opening and closing of the flow channel has a certain response time. By setting the first identification position C upstream of the first buffer flow channel 133, the first target A can be identified in advance, thereby facilitating the first identification position C to stay in the first region 1311. For example, the first identification position C is located on the upper side of the first buffer flow channel 133.

[0160] In other embodiments, referring to FIG6, the first light-conducting device 210 and the second light-conducting device 220 may also be respectively disposed on opposite sides of the first flow channel 131, and the first light-conducting device 210 and the second light-conducting device 220 are coaxially disposed. This is more conducive to the conduction of excited fluorescence by the second light-conducting device 220. It should be noted that, in order to avoid interference from the first detection light, a filter device can be disposed on the light transmission path of the second light-conducting device 220 to filter out the first detection light.

[0161] In some embodiments, the detection module 200 can also identify a single second target object B, which can also use the aforementioned light transmission device to transmit light, which will not be described in detail here.

[0162] In some embodiments of the present invention, when a single first target object A is identified by the detection module, the detection module is specifically an electrode detection module, which includes a first detection electrode and a controller. The first detection electrode extends into the first flow channel 131. When a single first target object A passes through the first detection electrode, the first detection electrode generates a corresponding signal. The controller is configured to identify the single first target object A based on the signal detected by the first detection electrode. Specifically, the first detection electrode includes a positive electrode and a negative electrode, which are arranged side by side. For example, the first detection electrode can be a metal layer disposed between the control layer 120 and the flow channel layer 130 of the microfluidic chip 100. Furthermore, in this embodiment, the signal detected by the first detection electrode can be a change in amplitude and phase difference. It should be noted that the microspheres in this embodiment can be magnetic microspheres, which can be adsorbed by magnetic components for recycling.

[0163] Accordingly, in some embodiments, the detection module 200 can also identify a single second target object B. In some embodiments of the present invention, the detection module is specifically an electrode detection module, which includes a second detection electrode and a controller. The second detection electrode extends into the second flow channel 132, and the controller is configured to identify a single second target object B based on the signal detected by the second detection electrode. The second detection electrode can be understood with reference to the first detection electrode.

[0164] In some embodiments of the present invention, when a single first target object A is identified by the detection module, after the detection module identifies the single first target object A, the first microvalve 121 switches from an open state to a closed state after a set delay, so that the single first target object A stays in the first region 1311. Referring to Figure 1, the first identification position C of the single first target object A is at a certain distance from the first region 1311. This embodiment uses the method of delaying the closing of the first microvalve 121 to ensure that the single first target object A can enter the first region 1311. It should be noted that the set delay time can be determined according to the distance between the identification position and the first region 1311 and the flow rate of the first carrier liquid.

[0165] Correspondingly, in some embodiments, the detection module 200 can also identify a single second target object B. In some embodiments of the present invention, after the detection module identifies a single second target object B, the second microvalve 122 switches from the open state to the closed state after a set delay, so that the single second target object B can enter the pairing flow channel 138 from the second flow channel 132. Referring to Figure 1, the third identification position E of identifying the single second target object B is at a certain distance from the pairing flow channel 138. In this embodiment, the second microvalve 122 is closed with a delay to ensure that the single second target object B can enter the pairing flow channel 138. It should be noted that the set delay time can be determined according to the distance between the identification position and the pairing flow channel 138 and the flow rate of the second carrier liquid.

[0166] The third embodiment of the present invention proposes a microfluidic system, which includes a detection module 200 and the microfluidic chip 100 of the aforementioned embodiments. Referring to FIG7, the first channel 131 between the cleaning channel group and the pairing channel 138 has a second identification bit D. The detection module 200 is configured to identify a single first target object A at the second identification bit D. When the detection module 200 identifies a single first target object A, both the first microvalve 121 and the pairing microvalve 128 are in a closed state to keep the single first target object A within the pairing channel 138. That is, this embodiment is used to further identify the single first target object A after the single first target object A has stopped at the inlet of the cleaning channel 135 and completed cleaning, so as to ensure that the single first target object A can remain within the pairing channel 138.

[0167] In other embodiments, the second flow channel 132 has a third identification position E, and the detection module 200 is configured to identify a single second target object B at the third identification position E. When the detection module 200 identifies a single second target object B, both the second microvalve 122 and the paired microvalve 128 are in a closed state to keep the single second target object B within the paired flow channel 138.

[0168] It should be noted that the detection module in the foregoing embodiments may be the visual detection module, fluorescence detection module, or electrode detection module mentioned in the second embodiment.

[0169] Based on the third embodiment, in some embodiments of the present invention, referring to FIG7, the first flow channel 131 has a first identification position C, and the detection module 200 is configured to identify a single first target object A at the first identification position C. When the detection module 200 identifies a single first target object A, both the first microvalve 121 and the paired microvalve 128 are switched to the closed state so that the single first target object A is located within the first region 1311. The first identification position C can be understood with reference to the aforementioned second embodiment.

[0170] The microfluidic system of this embodiment also includes a platform for carrying the microfluidic chip 100 and capable of moving between a first position and a second position. In some specific embodiments, the platform can move horizontally to switch between the first and second positions. Further, the platform can move linearly horizontally to switch between the first and second positions. Exemplarily, the platform is connected to a drive mechanism, which includes a drive seat capable of moving linearly in a horizontal plane and a power mechanism for driving the drive seat. The platform is connected to the drive seat.

[0171] In this embodiment, the detection module can be the aforementioned visual detection module or fluorescence detection module. When the platform is in the first position, the detection module 200 is configured to identify a single first target object A at the first identification position C. When the platform is in the second position, the detection module 200 is configured to identify a single first target object A at the second identification position D. In other embodiments, the detection module 200 is configured to identify a single second target object B at the third identification position E. In other embodiments, the detection module 200 is configured to simultaneously identify a single first target object A at the second identification position D and a single second target object B at the third identification position E. Thus, a single first target object A can be identified twice, and / or, a single first target object A and a single second target object B can be identified, using a visual camera or a photoelectric sensor.

[0172] The fourth embodiment of the present invention proposes a processing method for screening a first target A within a microfluidic system. The microfluidic system includes a microfluidic chip, which includes a first channel 131 and a cleaning channel group connected to the first channel 131. The cleaning channel group includes at least two cleaning channels 135, which are sequentially arranged along the flow direction of the first carrier liquid within the first channel 131. The diameter of the inlet of the cleaning channel 135 is smaller than the diameter of the first target A. The microfluidic system can be understood with reference to the microfluidic systems in the aforementioned second and third embodiments, but is not limited thereto. The processing method includes the following steps:

[0173] Step 1: Along the flow direction of the first carrier liquid, identify a single first target object A from the first carrier liquid upstream of the cleaning channel assembly. Identification can be performed using methods such as image recognition, fluorescence recognition, or electrode recognition as described in the preceding embodiments. For example, the identification location can be understood with reference to the aforementioned first identification position C.

[0174] Step Two: After identifying a single first target object A, the first flow channel 131 is shut off by closing the first stop position upstream of the single first target object A and the second stop position downstream of the cleaning flow channel group along the flow direction. The first stop position can be understood as referring to the location of the first micro-valve 121 in the previous embodiment, and the second stop position can be understood as referring to the second waste liquid micro-valve 129 in the previous embodiment. It should be noted that closing the stop positions here includes: switching the stop position from an open state to a closed state, for example, switching the first micro-valve 121 from an open state to a closed state, and keeping the stop position in a closed state, for example, keeping the second waste liquid micro-valve 129 in a closed state. It should also be noted that when, in Step One, liquid is drained through, for example, the aforementioned first waste liquid flow channel 134 to allow the single first target object A to continue flowing, this step also includes the step of switching the first waste liquid flow channel 134 to a closed state.

[0175] Step 3: A first buffer solution is introduced into the first flow channel 131 upstream of the first target object A between the first stop position and the second stop position. The first buffer solution transports the single first target object A to the inlet of one of the cleaning channels 135 and stops it at the inlet, while the first buffer solution flows out through the other cleaning channels 135. The first buffer solution can be provided, for example, through the aforementioned first buffer solution channel 133. In some specific embodiments, after the single first target object A stops at the inlet, the first buffer solution continues to rinse for a set time to remove non-target objects near the first target object A.

[0176] Step 4: Shut down the cleaning channel 135 and restore the flow of the first channel 131 at the second stop position, then continue to transport the single first target A through the first buffer solution. In this way, the single first target can be screened and non-target objects can be removed, avoiding contamination from non-target objects.

[0177] Based on the fourth embodiment, in some embodiments of the present invention, the phrase "continue to transport the single first target A through the first buffer solution" mentioned in step four specifically refers to: after transporting the single first target A to the target area through the first buffer solution, stopping the input of the first buffer solution so that the single first target A stops in the target area. The target area can be understood with reference to the pairing channel 138 in the aforementioned embodiment, meaning that this embodiment can be applied to the pairing of target objects.

[0178] In some specific embodiments, the microfluidic chip further includes a second flow channel 132, which can be understood as described in the foregoing embodiments, and is used to allow a second carrier liquid containing the second target object B to flow through.

[0179] Based on the above solution, the processing method also includes the following steps:

[0180] Step 5: Identify a single second target object B from the second carrier liquid within the second flow channel 132. This identification can be performed using image recognition, fluorescence recognition, or electrode recognition methods as described in the previous embodiments. For example, the identification location can be understood with reference to the aforementioned third identification position E.

[0181] Step Six: After identifying a single second target object B, the second flow channel 132 is shut off by closing the third stop position upstream of the single second target object B along the flow direction of the second carrier liquid within the second flow channel 132, thereby stopping the single second target object B in the target area. The third stop position can be understood with reference to the location of the second micro-valve 122 in the aforementioned embodiment. It should be noted that, as mentioned here, closing the stop position includes: switching the stop position from an open state to a closed state, for example, switching the second micro-valve 122 from an open state to a closed state.

[0182] Step 7: Once both the individual first target A and the individual second target B have stopped in the target area, a second buffer solution is directly introduced into the target area. The second buffer solution then carries the individual first target A and the individual second target B into the oil to form droplets. The second buffer solution can be provided, for example, through the aforementioned second buffer solution channel 137.

[0183] In other embodiments, after both the individual first target A and the individual second target B stop in the target area, a first buffer solution is introduced into the first flow channel 131 between the first stop position and the second stop position. The individual first target A and the individual second target B in the target area are sent into the oil to form droplets through the first buffer solution. That is, the same first buffer solution is used to send the individual first target A and the individual second target B into the oil.

[0184] It should be noted that steps five and six can be performed before step two or after step three.

[0185] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A microfluidic chip for screening of a first target, characterized in that, The microfluidic chip includes a first flow channel and a first buffer solution flow channel, a first waste liquid flow channel, and a cleaning flow channel group respectively connected to the first flow channel. The first flow channel is used for the liquid containing the first target to flow through. Along the flow direction of the liquid in the first flow channel, the first waste liquid flow channel and the cleaning flow channel group are both located downstream of the first buffer solution flow channel. The cleaning flow channel group includes at least two cleaning channels arranged sequentially along the flow direction. The diameter of the inlet of the cleaning channel is smaller than the diameter of the first target. The microfluidic system further includes a first microvalve corresponding to the first flow channel, a first buffer microvalve corresponding to the first buffer solution flow channel, a first waste liquid microvalve corresponding to the first waste liquid flow channel, and a cleaning microvalve corresponding to each of the cleaning flow channels. The first microvalve is used to control the opening and closing of the first flow channel, the first buffer solution microvalve is used to control the opening and closing of the first buffer solution flow channel, the first waste liquid microvalve is used to control the opening and closing of the first waste liquid flow channel, and the cleaning microvalve is used to control the opening and closing of each of the cleaning flow channels. Wherein, the first channel between the first buffer solution channel and the cleaning channel group is defined as the first region, and the microfluidic chip is configured to: when the first microvalve and the first waste liquid microvalve are in the open state to allow a single first target object to flow into the first region, the first microvalve and the first waste liquid microvalve switch to the closed state, and the first buffer solution microvalve and the cleaning microvalve are in the open state to allow the single first target object to flow to the inlet of one of the cleaning channels and stop at the inlet, and to allow the liquid in the first region to flow out through the other cleaning channels.

2. The microfluidic chip of claim 1, wherein, The first waste liquid channel and the cleaning channel are independent channels, and the diameter of the first waste liquid channel is larger than the diameter of the cleaning channel.

3. The microfluidic chip of claim 2, wherein, Along the flow direction, the first buffer solution channel, the first waste liquid channel, and the cleaning channel group are arranged sequentially; Wherein, the first flow channel between the first buffer solution flow channel and the first waste liquid flow channel is defined as the second region. The step of switching the first microvalve and the first waste liquid microvalve to the closed state and the first buffer solution microvalve and the cleaning microvalve to the open state after the first microvalve and the first waste liquid microvalve are in the open state and a single first target object flows into the second region, and the first microvalve and the first waste liquid microvalve to the closed state and the first buffer solution microvalve and the cleaning microvalve to the open state.

4. The microfluidic chip of claim 1, wherein, At least one of the cleaning channels is the first waste liquid channel, and the cleaning micro-valve is the first waste liquid micro-valve.

5. The microfluidic chip of claim 1, wherein, The cleaning channel includes a first cleaning section communicating with the first channel. The first cleaning section has an inlet at one end facing the first channel. Along the flow direction of the liquid in the cleaning channel, the cross-sectional area of ​​the first cleaning section gradually increases from the end with the inlet.

6. The microfluidic chip of claim 4, wherein, Along the flow direction of the liquid in the cleaning channel, the cleaning channel also includes a second cleaning section connected to the first cleaning section, and the cross-sectional area of ​​the second cleaning section is greater than or equal to the maximum cross-sectional area of ​​the first cleaning section.

7. The microfluidic chip of claim 1, wherein, The diameter of the inlet of the first waste liquid channel is 5 micrometers to 10 micrometers.

8. The microfluidic chip of claim 1, wherein, The microfluidic chip also includes a connecting channel, one end of which is connected to the first channel and the other end of which is connected to each cleaning channel. The length of the connecting channel is 3 micrometers to 8 micrometers along the flow direction of the liquid in the connecting channel.

9. The microfluidic chip of claim 1, wherein, The microfluidic chip further includes a second channel, an oil channel, a second buffer channel, and a paired channel. The paired channel is connected to the oil channel. The first channel, the second channel, and the second buffer channel are all connected to the paired channel. The second channel is used to allow liquid containing the second target to flow through. The microfluidic chip further includes a pairing microvalve corresponding to the paired flow channel, a second microvalve corresponding to the second flow channel, an oil microvalve corresponding to the oil flow channel, and a second buffer microvalve corresponding to the second buffer flow channel. The pairing microvalve is used to control the opening and closing of the paired flow channel, the second microvalve is used to control the opening and closing of the second flow channel, the oil microvalve is used to control the opening and closing of the oil flow channel, and the second buffer microvalve is used to control the opening and closing of the second buffer flow channel. When a single first target object from the first flow channel and a single second target object from the second flow channel are present in the paired flow channel, the first microvalve, the second microvalve, the first buffer microvalve, the first waste liquid microvalve, and the cleaning microvalve are all in a closed state, and the paired microvalve and the second buffer microvalve are in an open state, so as to send the single first target object and the single second target object in the paired flow channel into the oil in the oil flow channel to form droplets.

10. The microfluidic chip of claim 9, wherein, The microfluidic system further includes a second waste liquid channel and a second waste liquid microvalve corresponding to the second waste liquid channel. The second waste liquid channel is connected to the paired channel. The second waste liquid microvalve is used to control the opening and closing of the second waste liquid channel. The microfluidic chip is also configured such that when the single first target object stops at the inlet of one of the cleaning channels, the first microvalve, the first waste liquid microvalve, the cleaning microvalve, the second buffer channel, and the paired microvalve are all in a closed state, and the first buffer microvalve and the second waste liquid microvalve are in an open state, the liquid in the first channel can flow out through the paired channel and the second waste liquid channel, so that the single first target object enters the paired channel from the first channel.

11. The microfluidic chip of claim 10, wherein, The microfluidic chip is further configured such that when the single first target object stops at the inlet of one of the cleaning channels, and after the first buffer microvalve and the cleaning microvalve remain in the open state for a set time, the cleaning microvalve switches to the closed state, and the second waste liquid microvalve switches to the open state, so that the single first target object enters the paired channel from the first channel.

12. The microfluidic chip of claim 9, wherein, The microfluidic system further includes a second waste liquid channel and a second waste liquid microvalve corresponding to the second waste liquid channel. The second waste liquid channel is connected to the paired channel, and the second waste liquid microvalve is used to control the opening and closing of the second waste liquid channel. When the first microvalve, the first waste liquid microvalve, the cleaning microvalve, and the paired microvalve are all in the closed state, and the first buffer microvalve and the second waste liquid microvalve are in the open state, the liquid in the first flow channel can flow out through the paired flow channel and the second waste liquid flow channel. And / or, when the paired microvalve is in the closed state and the second microvalve and the second waste liquid microvalve are in the open state, the liquid in the second flow channel can flow out through the paired flow channel and the second waste liquid flow channel.

13. The microfluidic system of claim 1, wherein, The microfluidic system further includes a second flow channel, an oil flow channel, and a paired flow channel, wherein the paired flow channel is connected to the oil flow channel, and both the first flow channel and the second flow channel are connected to the paired flow channel; The microfluidic system further includes a pairing microvalve corresponding to the paired flow channel and a second microvalve corresponding to the second flow channel. The pairing microvalve is used to control the opening and closing of the paired flow channel, and the second microvalve is used to control the opening and closing of the second flow channel. When a single first target object from the first flow channel and a single second target object from the second flow channel are present in the paired flow channel, the first microvalve, the second microvalve, the first waste liquid microvalve, and the cleaning microvalve are all in a closed state, and the paired microvalve and the first buffer solution microvalve are in an open state, so that the buffer solution in the first buffer solution microvalve delivers the single first target object and the single second target object in the paired flow channel into the oil in the oil flow channel to form droplets.

14. The microfluidic chip of any one of claims 9 to 13, wherein, The second target is a detection microsphere, which includes a marker core and a magnetic coating layer covering the marker core; wherein, the marker core includes a polymer core and a detection marker located on the surface of the polymer core; and primer chains are attached to the surface of the magnetic coating layer.

15. The microfluidic chip of claim 14, wherein, The magnetic coating layer is modified with streptavidin, and the primer chain is modified with biotin. The primer chain binds to the streptavidin on the surface of the magnetic coating layer via biotin.

16. The microfluidic chip of claim 14, wherein, The number of primer strands bound to the surface of the magnetic coating layer is 5 x 10 7 ~ 2 x 10 8 pieces.

17. The microfluidic chip of claim 14, wherein, The polymer includes copolymers or homopolymers formed from at least one monomer selected from styrene, acrylic acid, acrylate, and methacrylate.

18. The microfluidic chip of claim 14, wherein, The magnetic coating layer includes at least one of iron(II,III) oxide, iron(III) oxide, and ferrite materials.

19. The microfluidic chip of claim 14, wherein, The detection markers include fluorescent detection markers.

20. The microfluidic chip of claim 19, wherein, The fluorescent detection markers include at least one of APC, Coomassie Brilliant Blue, and Nell Blue Chloride.

21. The microfluidic chip of claim 14, wherein, The diameter of the detection microspheres is 10–20 μm.

22. The use of the microfluidic system as described in any one of claims 1 to 21 in single-cell sequencing, cell screening, cell interaction detection, cytomic analysis, proteomics analysis, and preparation of cell therapy products or cell drugs.

23. Microfluidic systems, including: The microfluidic chip according to any one of claims 1 to 21; Detection module; The first flow channel has a first identification position, and the detection module is configured to identify the single first target object at the first identification position. When the detection module identifies the single first target object, both the first micro valve and the first waste liquid micro valve are switched to the closed state so that the single first target object is located in the first area.

24. The microfluidic system of claim 23, wherein, When the detection module does not identify a single first target object, both the first microvalve and the first waste liquid microvalve remain in the open state, and the first buffer microvalve and the cleaning microvalve remain in the closed state, so that the liquid in the first flow channel can flow out through the first waste liquid flow channel.

25. The microfluidic system of claim 23, wherein, The detection module includes a camera and a controller. The controller is configured to control the camera to capture an image of the first identification position. The controller is also configured to identify the single first target object based on the first image.

26. The microfluidic system of claim 23, wherein, The detection module includes a first light source, a first light detection device, and a controller. The controller is configured to control the first light source to emit a first detection light toward the first identification position. The first detection light can excite a first fluorescence after illuminating the single first target object. When the first light detection device detects the first fluorescence, the detection device identifies the single first target object.

27. The microfluidic system of claim 26, wherein, The detection module further includes a first light-conducting device and a second light-conducting device. The first light-conducting device is configured to receive the first detection light from the first light source and conduct the first detection light to the first identification position. The second light-conducting device is configured to receive the first fluorescence and conduct the first fluorescence to the first light detection device.

28. The microfluidic system of claim 27, wherein, The first flow channel includes a first flow channel segment and a second flow channel segment arranged sequentially along the flow direction. The first buffer solution flow channel, the first waste liquid flow channel, and the cleaning flow channel group are all connected to the second flow channel segment. The axes of the first flow channel segment and the second flow channel segment intersect. The first identification position is disposed in the second flow channel segment. The first light-conducting device is disposed on the side of the first flow channel segment away from the second flow channel segment and points towards the second flow channel segment. The second light-conducting device is disposed in the second flow channel segment corresponding to the first identification position. The axes of the first light-conducting device and the second light-conducting device intersect.

29. The microfluidic system of claim 28, wherein, The first flow channel segment is perpendicular to the axis of the second flow channel segment, the first optical transmission device is perpendicular to the axis of the second optical transmission device, and the second optical transmission device is disposed on the side of the second flow channel segment away from the first flow channel segment and points towards the first flow channel segment.

30. The microfluidic system of claim 27, wherein, The first optical transmission device and the second optical transmission device are respectively disposed on opposite sides of the first flow channel, and the first optical transmission device and the second optical transmission device are coaxially disposed.

31. The microfluidic system of claim 23, wherein, The detection module includes a first detection electrode and a controller. The first detection electrode is disposed at the first identification position and extends into the first flow channel. The controller is configured to identify the single first target object based on the signal detected by the first detection electrode.

32. The microfluidic system of any one of claims 23-31, wherein, Along the flow direction, the first identification position is located upstream of the first buffer solution channel.

33. A microfluidic system, including: The microfluidic chip according to any one of claims 9 to 21; Detection module; The first flow channel between the cleaning flow channel group and the paired flow channel has a second identification position. The detection module is configured to identify the single first target object at the second identification position. When the detection module identifies the single first target object, both the first microvalve and the paired microvalve are in a closed state to keep the single first target object safe. Hold within the paired flow channel; And / or, the second flow channel has a third identification position, and the detection module is configured to identify a single second target object at the third identification position, wherein when the detection module identifies a single second target object, both the second microvalve and the paired microvalve are in a closed state to keep the single second target object within the paired flow channel.

34. The microfluidic system of claim 33, wherein, The first flow channel has a first identification position, and the detection module is configured to identify the single first target object at the first identification position. When the detection module identifies the single first target object, both the first micro valve and the paired micro valve are switched to the closed state so that the single first target object is located in the first area. The microfluidic system also includes a platform for carrying the microfluidic chip and is movable between a first position and a second position. Wherein, when the loading platform is located at the first position, the detection module is configured to identify the single first target object at the first identification position; when the loading platform is located at the second position, the detection module is configured to identify the single first target object at the second identification position, and / or, the detection module is configured to identify the single second target object at the third identification position.

35. A method of treatment characterised by, The method is applied to the screening of a first target in a microfluidic system. The microfluidic system includes a microfluidic chip, the microfluidic chip includes a first channel and a cleaning channel group connected to the first channel. The cleaning channel group includes at least two cleaning channels, and the at least two cleaning channels are arranged sequentially along the flow direction of the first carrier liquid in the first channel. The diameter of the inlet of the cleaning channel is smaller than the diameter of the first target. The screening method includes the following steps: Along the flow direction, a single first target object is identified from the first carrier liquid upstream of the cleaning channel assembly; After identifying the single first target object, the first flow channel is shut off by closing the first stop position upstream of the single first target object and the second stop position downstream of the cleaning flow channel group along the flow direction. A first buffer solution is introduced into the first channel between the first stop position and the second stop position and upstream of the first target object. The first buffer solution transports the single first target object to the inlet of one of the cleaning channels and stops at the inlet, and the first buffer solution flows out through the other cleaning channels. The cleaning channel is shut off, and the first channel at the second stop position is reopened to allow the single first target object to continue to be transported through the first buffer solution.

36. The treatment method of claim 35, wherein, The step of continuing to transport the single first target object through the first buffer solution includes: after transporting the single first target object to the target area through the first buffer solution, stopping the input of the first buffer solution so that the single first target object stops in the target area.

37. The treatment method of claim 36, wherein, The microfluidic chip also includes a second flow channel; The processing method also Includes the following steps: Identify a single second target object from the second carrier liquid within the second flow channel; After identifying the single second target object, the third stop position upstream of the single second target object is closed along the flow direction of the second carrier liquid in the second flow channel, thereby shutting off the second flow channel and causing the single second target object to stop in the target area. After both the single first target object and the single second target object stop in the target area, a second buffer solution is directly introduced into the target area. The single first target object and the single second target object in the target area are then fed into the oil to form droplets through the second buffer solution. Alternatively, a first buffer solution is introduced into the first flow channel between the first stop position and the second stop position. The single first target object and the single second target object in the target area are then fed into the oil to form droplets through the first buffer solution.

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