Micro-fluidic chip and single cell sorting method

Abstract

The invention provides a micro-fluidic chip and a single cell sorting method.The chip comprises a substrate, a plurality of obtaining units and a control circuit, a sample inlet, a main channel and a sample outlet which are sequentially communicated are formed in the substrate, the multiple obtaining units are distributed on at least one side of the main channel, each obtaining unit comprises an auxiliary channel, an impedance detection unit and a driving element, and the control circuit is connected with the auxiliary channel. The inlet of the auxiliary channel is communicated with the side wall of the main channel, the impedance detection unit is located at the inlet of the auxiliary channel to detect whether a single cell enters the auxiliary channel, the driving element is located at the outlet of the auxiliary channel to provide power for acquisition and export of the single cell, and the control circuit is electrically connected with the impedance detection unit and the driving element. And the single cells can be automatically obtained. When the micro-fluidic chip is used for single cell sorting, single cell sorting and planking can be efficiently and fully automatically completed, and the sorting requirements of high flux, high sorting purity and low cell damage are met.

Description

Technical Field

[0001] The invention belongs to the field of microfluidics and single cell sorting, and relates to a microfluidics chip and a single cell sorting method. Background Art

[0002] Cells are the basic units of life activities, and research based on the single-cell level can reveal the development laws of life activities at a deeper level. Single-cell sorting is the basis and key to single-cell research, and has important applications in the fields of monoclonal antibody preparation, cell line development, single B cell screening, etc. At present, single-cell sorting mainly includes microneedle aspiration, microdissection, limiting dilution, microwell array, and microfluidics-based sorting methods. The current methods face problems such as difficult operation, low efficiency, cell damage, and multi-cell acquisition, which is not conducive to subsequent analysis. Therefore, in single-cell research, there is an urgent need for an efficient sorting method with simple operation, less cell damage, and high single-cell rate. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a microfluidic chip and a single cell sorting method to solve the problems of single cell sorting in the prior art, such as high difficulty in operation, low efficiency, high cell loss and low single cell rate.

[0004] To achieve the above-mentioned object and other related objects, the present invention provides a microfluidic chip, comprising:

[0005] A substrate, wherein the substrate is provided with an injection port, a main channel and an outlet that are connected in sequence;

[0006] A plurality of acquisition units are distributed on at least one side of the main channel, the acquisition unit comprises a side channel, an impedance detection unit and a driving element, the entrance of the side channel is connected to the side wall of the main channel, the impedance detection unit is located at the entrance of the side channel to detect whether a single cell enters the side channel, and the driving element is located at the exit of the side channel to provide power for the acquisition and export of the single cell;

[0007] A control circuit is electrically connected to the impedance detection unit and the driving element.

[0008] Optionally, the extension direction of the secondary channel is perpendicular to the extension direction of the primary channel.

[0009] Optionally, in a direction perpendicular to the plane of the substrate, the height of the main channel is less than 50 microns; the length L1 of the main channel is greater than the length L2 of the secondary channel, the width W1 of the main channel is greater than the width W2 of the secondary channel, and the width W2 of the secondary channel is less than 200 microns.

[0010] Optionally, the driving element includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film microvalve.

[0011] Optionally, the impedance detection unit includes at least two detection electrodes disposed at intervals, the width and length of the detection electrodes are both less than 100 microns, and the interval between two adjacent detection electrodes is less than 100 microns.

[0012] Optionally, the microfluidic chip is connected to an external driving device, and the external driving device includes any one of a syringe pump, a peristaltic pump and a pneumatic pump.

[0013] Optionally, the sample outlet includes at least one fluid driving unit connected to the main channel.

[0014] Optionally, the fluid driving unit includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film microvalve.

[0015] Optionally, the substrate includes a silicon dioxide layer or a non-photosensitive dry film.

[0016] The present invention also provides a single cell sorting method, comprising the following steps:

[0017] Providing a microfluidic chip as described in any one of the above items, and introducing a cell suspension into the injection port;

[0018] Driving the cell suspension to flow toward the sample outlet through an external driving device connected to the sample inlet or a fluid driving unit connected to the sample outlet;

[0019] The driving element drives the cell suspension in the main channel to flow to the side channel. When the impedance detection unit detects that a single cell has entered the side channel, the control circuit stops the driving element in the corresponding side channel to complete the acquisition of the single cell in the corresponding side channel, and the driving elements in the remaining side channels continue to work.

[0020] When a preset number of the auxiliary channels have completed the acquisition of single cells, stopping all the driving elements;

[0021] injecting a buffer into the injection port to flush out the residual cells in the main channel;

[0022] The captured single cell is guided out via the driving element.

[0023] In summary, the present invention provides a microfluidic chip and a single cell sorting method, the chip includes a substrate, a plurality of acquisition units and a control circuit, wherein the substrate is provided with an inlet, a main channel and an outlet connected in sequence, a plurality of acquisition units are distributed on at least one side of the main channel, the acquisition unit includes a side channel, an impedance detection unit and a driving element, the entrance of the side channel is connected to the side wall of the main channel, the impedance detection unit is located at the entrance of the side channel to detect whether a single cell enters the side channel, the driving element is located at the exit of the side channel to provide power for the acquisition and export of single cells, the control circuit is electrically connected to the impedance detection unit and the driving element, and the acquisition of single cells can be automatically completed. The microfluidic chip of the present invention is used for single cell sorting, and single cell sorting and plating can be completed efficiently and automatically, meeting the sorting requirements of high throughput, high sorting purity and low cell damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. 4 is a schematic diagram of a top view of the microfluidic chip of the present invention in one embodiment.

[0025] Figure 2 FIG. 4 is a schematic top view of the structure of the microfluidic chip of the present invention in another embodiment.

[0026] Figure 3 Shown is a flow chart of the single cell sorting method of the present invention.

[0027] Description of Reference Numerals

[0028] 1 Microfluidic Chip

[0029] 2 Inlet

[0030] 3 Main Channel

[0031] 4 sample outlet

[0032] 5 Get Unit

[0033] 501 Secondary Channel

[0034] 502 Impedance Detection Unit

[0035] 503 drive element

[0036] 504 Heating film

[0037] 505 Detection Electrode

[0038] 506 Electrical Signal

[0039] 6 Single Cell

[0040] 7 Fluid drive unit

[0041] Steps S1 to S6 DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] See also Figures 1 to 3 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0044] Embodiment 1

[0045] This embodiment provides a microfluidic chip. Figure 1 , which is a schematic diagram of the top structure of the microfluidic chip, including: a substrate (not shown), a plurality of acquisition units 5 and a control circuit (not shown), wherein the substrate is provided with an inlet 2, a main channel 3 and a sample outlet 4 which are connected in sequence, and the plurality of acquisition units 5 are distributed on at least one side of the main channel 3, and the acquisition unit 5 includes a side channel 501, an impedance detection unit 502 and a driving element 503, the entrance of the side channel 501 is connected to the side wall of the main channel 3, the impedance detection unit 502 is located at the entrance of the side channel 501 to detect whether a single cell enters the side channel 501, the driving element 503 is located at the exit of the side channel 501 to provide power for the acquisition and export of single cells, and the control circuit is electrically connected to the impedance detection unit 502 and the driving element 503.

[0046] As an example, the substrate includes a silicon dioxide layer or a non-photosensitive dry film to avoid interference from the autofluorescence problem of the photosensitive dry film.

[0047] As an example, the sample inlet 2 is connected to the inlet of the main channel 3 to transport the cell suspension into the main channel 3 , and the sample outlet 4 is connected to the end of the main channel 3 .

[0048] As an example, the plurality of acquisition units 5 may be distributed only on one side of the main channel 3, or may be distributed on both sides of the main channel 3. The number of the acquisition units 5 on each side may be one or more. Preferably, in this embodiment, the plurality of acquisition units 5 are arranged in an array and distributed on both sides of the main channel 3.

[0049] As an example, the specific number of the acquisition units 5 integrated in the micro-control flow chip can be set according to the flux requirements, which is not limited here. By reasonably setting the number of the acquisition units 5, the integration can be improved to meet the needs of high-throughput single-cell acquisition.

[0050] As an example, the extension direction of the secondary channel 501 is perpendicular to the extension direction of the main channel 3 , which helps prevent subsequent cells from entering the secondary channel 501 where cells already exist, and also helps prevent cells already in the secondary channel 501 from being washed into the main channel 3 .

[0051] As an example, in the direction perpendicular to the plane of the substrate, the height of the main channel 3 is less than 50 microns; in the direction parallel to the plane of the substrate, the length L1 of the main channel 3 is greater than the length L2 of the secondary channel 501, the width W1 of the main channel 3 is greater than the width W2 of the secondary channel 501, and the width W2 of the secondary channel 501 is less than 200 microns.

[0052] As an example, the impedance detection unit 502 includes at least two detection electrodes 505 disposed at intervals, the width and length of the detection electrodes 505 are both less than 100 micrometers, and the interval between two adjacent detection electrodes 505 is less than 100 micrometers.

[0053] Specifically, the more the number of the detection electrodes 505 in the impedance detection unit 502 is, the more accurate the detection result is.

[0054] As an example, the driving element 503 includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film microvalve. In this embodiment, the driving element 503 preferably adopts a thermal bubble printing nozzle. The thermal bubble printing nozzle is made based on micro-nano processing technology, including a heating film 504 integrated at the top or bottom of the secondary channel 501, and the heating film 504 faces the outlet of the nozzle.

[0055] Specifically, the thermal bubble printing nozzle utilizes the instantaneous high temperature of the heating film 504 to gasify the liquid above the film, thereby generating bubbles to drive the liquid flow, realize the deflection of the cell flow direction, and complete the single cell sorting. In addition, the thermal bubble printing nozzle has the advantages of fast response, strong driving force, easy control, easy integration and miniaturization, which provides a guarantee for the rapid and high-throughput sorting of single cells.

[0056] Specifically, in this embodiment, when the liquid in the secondary channel 501 is ejected under the action of the heating film 504, the flow direction of the single cell 6 in the main channel 3 changes. The ejection of the thermal bubble printing nozzle provides power for the continuous flow of the liquid, so that the single cell 6 in the main channel 3 flows to the secondary channel 501 to replenish the liquid and realize the deflection of the flow direction of the single cell. In this embodiment, the control circuit determines whether to drive the thermal bubble printing nozzle to eject, so as to control the flow direction of the cells in the main channel 3.

[0057] As an example, the control circuit is integrated into the substrate, so as to monitor and process the electrical signal 506 of the impedance detection unit 502 in real time, and control the driving element 503 in real time.

[0058] Specifically, the control circuit detects whether a single cell enters the side channel 501 by real-time monitoring the change of the electrical signal 506 of the impedance detection unit 502. At the same time, the control circuit determines whether to stop driving the driving element 503 in the corresponding side channel 501 by analyzing the electrical signal 506 fed back by the impedance detection unit 502. This is because when a cell passes through the detection electrode 505, the impedance between the detection electrodes 505 will change, and the control circuit can achieve real-time control of the driving element 503 by capturing the change of the electrical signal 506 fed back by the impedance detection unit 502, and achieve accurate control of the single cell collection amount in the corresponding side channel 501.

[0059] In one embodiment, the microfluidic chip 1 is connected to an external driving device, and the external driving device includes any one of a syringe pump, a peristaltic pump, and a pneumatic pump. The external driving device drives the fluid to enter the sample inlet 2. After the fluid enters the sample inlet 2, it flows to the sample outlet 4 by itself through the main channel 3 or flows to the sample outlet 4 under the control of the external driving device. In this embodiment, the external driving device preferably adopts a syringe pump, which is a power unit for single cell injection and can control the flow speed and time of the fluid in the main channel 3.

[0060] In another embodiment, no external drive device may be used. Figure 2 , which is a schematic diagram of a top view of the structure of the microfluidic chip 1 in another embodiment, wherein the sample outlet 4 includes at least one fluid driving unit 7 connected to the main channel 3.

[0061] Specifically, the fluid driving unit 7 is used to drive the cell suspension to flow from the sample inlet 2 to the sample outlet 4. After the cell suspension is introduced into the sample inlet 2, the cell suspension in the main channel 3 flows to the sample outlet 4 by itself, or the cell suspension in the main channel 3 is driven to flow to the sample outlet 4 by the action of the fluid driving unit 7. The fluid driving unit 7 can avoid the introduction of the external driving device, making cell injection more convenient, reducing potential cross-contamination risks, and improving operability. It should be noted that the number of the fluid driving units 7 can be reasonably set according to the speed and flux requirements from the sample inlet 2 to the sample outlet 4, and is not limited here.

[0062] As an example, the fluid driving unit 7 includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film micro valve. Preferably, in this embodiment, the fluid driving unit 7 adopts a thermal bubble printing nozzle.

[0063] As an example, the fluid driving unit 7 is electrically connected to the control circuit to achieve real-time control of the fluid driving unit 7. The fluid driving unit 7 is turned on under the action of the control circuit to push the cell suspension in the main channel 3 to continuously flow toward the sample outlet 4, and the flow speed and time of the cell suspension in the main channel 3 are adjusted by the control circuit.

[0064] This embodiment realizes the fully automatic and accurate acquisition of single cells, improves cell flux, and reduces cell loss by controlling the impedance detection unit in real time, controlling the driving element in real time, and setting the position relationship of the flow channel of the microfluidic chip through the control circuit. At the same time, the microfluidic chip of the present invention uses the driving element as the power element for single cell acquisition and derivation, making the entire operation process more convenient and efficient.

[0065] Embodiment 2

[0066] This example provides a single cell sorting method. Figure 3 , shown as a flow chart of the method, comprising the following steps:

[0067] S1: providing the microfluidic chip as described in Example 1, and introducing the cell suspension into the injection port;

[0068] S2: driving the cell suspension to flow toward the sample outlet through an external driving device connected to the sample inlet or a fluid driving unit connected to the sample outlet;

[0069] S3: driving the cell suspension in the main channel to flow to the side channel by the driving element. When the impedance detection unit detects that a single cell has entered the side channel, the driving element in the corresponding side channel is stopped by the control circuit to complete the acquisition of the single cell in the corresponding side channel, and the driving elements in the remaining side channels continue to work.

[0070] S4: when a preset number of the auxiliary channels have completed the acquisition of single cells, stopping all the driving elements;

[0071] S5: injecting a buffer into the injection port to flush out the residual cells in the main channel;

[0072] S6: The acquired single cell is exported through the driving element.

[0073] As an example, the single cell guided out from the side channel 501 is received by a cell receiving device.

[0074] As an example, the cell receiving device includes a well plate, which includes a plurality of wells arranged according to a preset rule, each well being used to receive a single cell. The single cell derived from the side channel 501 can fall gently into the well plate, and the damage to the cell during the whole process can be ignored.

[0075] Combine the following Figure 1-Figure 2 The technical solutions of the present invention in specific embodiments are described in detail.

[0076] In one embodiment, single cell sorting is accomplished by using an external driving device, including the following steps:

[0077] (1) Provide Figure 1 The microfluidic chip 1 shown in the figure uses a syringe pump or other external driving device to introduce the cell suspension into the injection port 2.

[0078] (2) The cell suspension flows toward the sample outlet 4 in the main channel 3 by itself or flows toward the sample outlet 4 driven by a syringe pump or other external driving device connected to the sample inlet 2.

[0079] (3) During the flow of the cell suspension, the control circuit controls all the thermal bubble printing nozzles to spray, so that the cell flow direction is deflected, and the cell suspension in the main channel 3 flows to the side channel 501. At the same time, the control circuit monitors the changes of the impedance detection unit 502 in real time. When the single cell 6 in the main channel 3 enters the side channel 501, the electrical signal 506 of the impedance detection unit 502 changes. The control circuit captures this change and stops driving the thermal bubble printing nozzle in the corresponding side channel 501. At this time, the corresponding side channel 501 has completed the acquisition of the single cell 6, and the thermal bubble printing nozzles in the remaining side channels 501 continue to spray.

[0080] (4) When a preset number of the sub-channels 501 have completed the acquisition of single cells 6, the control circuit stops driving the corresponding thermal bubble printing nozzles.

[0081] (5) switching the syringe pump to inject buffer into the injection port 2 to flush out the residual cells in the main channel 3;

[0082] (6) driving all the thermal bubble printing nozzles to export the single cells 6 obtained from the thermal bubble printing nozzles.

[0083] (7) The exported single cells are received by the well plate. The single cells exported from the side channel 501 can fall gently into the well plate, and the damage to the cells during the whole process can be ignored.

[0084] In another embodiment, the single cell sorting is driven by the fluid driving unit of the microfluidic chip 1, which includes the following steps:

[0085] (1) Provide Figure 2 The microfluidic chip 1 shown introduces the cell suspension into the injection port 2 .

[0086] (2) The cell suspension flows toward the sample outlet 4 in the main channel 3 on its own or is driven by a thermal bubble printing nozzle or other fluid driving unit 7 connected to the sample outlet 4 and flows toward the sample outlet 4 .

[0087] (3) During the flow of the cell suspension, the control circuit controls the thermal bubble printing nozzles in all the acquisition units 5 to spray, so that the cell flow direction is deflected, and the cell suspension in the main channel 3 flows to the side channel 501. At the same time, the control circuit monitors the changes of the impedance detection unit 502 in real time. When the single cell 6 in the main channel 3 enters the side channel 501, the electrical signal 506 of the impedance detection unit 502 changes. The control circuit captures this change and stops driving the thermal bubble printing nozzle in the corresponding side channel 501. At this time, the corresponding side channel 501 has completed the acquisition of the single cell 6, and the thermal bubble printing nozzles in the remaining side channels 501 continue to spray.

[0088] (4) When a preset number of the sub-channels 501 have completed the acquisition of the single cell 6, the control circuit stops driving the corresponding thermal bubble printing nozzles in the acquisition unit 5.

[0089] (5) Injecting a buffer solution into the sample inlet 2, and at the same time driving the thermal bubble printing nozzle or the fluid driving unit 7 connected to the sample outlet 4 through the control circuit to drive the buffer solution to flow toward the sample outlet 4 to flush out the residual cells in the main channel 3.

[0090] (6) driving the thermal bubble printing nozzles in all acquisition units 5 to export the single cells 6 acquired in the thermal bubble printing nozzles.

[0091] (7) The exported single cells are received by the well plate. The single cells exported from the side channel 501 can fall gently into the well plate, and the damage to the cells during the whole process can be ignored.

[0092] It should be noted again that, in this embodiment, the main channel 3 and the auxiliary channel 501 are perpendicular to each other, so subsequent cells will not enter the auxiliary channel 501 containing existing cells, and the cells in the auxiliary channel 501 will not be flushed out, thereby further ensuring the accuracy of obtaining single cells.

[0093] The single cell sorting method in this example is simple and convenient to operate, and can quickly, efficiently and fully automatically complete single cell sorting and plating, reducing the potential risk of cross contamination. The cells obtained by the single cell sorting method in this example have the advantages of high throughput, high sorting purity and low cell damage.

[0094] Embodiment 3

[0095] This embodiment uses the microfluidic chip 1 in the first embodiment to sort Chinese hamster ovary (CHO) single cells. First, a CHO cell suspension is introduced into the injection port 2 of the microfluidic chip 1 by a syringe pump, and the injection port 2 is connected to the entrance of the main channel 3 to transport the CHO cell suspension to the main channel 3. The CHO cells flow to the sample outlet 4 in the main channel 3 by themselves or flow to the sample outlet 4 under the control of the syringe pump. During the flow of the CHO cell suspension, all the hot bubble printing nozzles are controlled by the control circuit to spray, and the spray of the hot bubble printing nozzle promotes the flow of liquid, so that the flow direction of the CHO cells in the main channel 3 is deflected, and the CHO single cells flow to the secondary channel 501 to supplement the liquid. At the same time, the control circuit monitors the changes of the impedance detection unit 502 in real time. When the CHO single cells in the main channel 3 enter the secondary channel 501, the electrical signal 506 of the impedance detection unit 502 changes. The control circuit captures this change and stops driving the thermal bubble printing nozzle in the corresponding sub-channel 501. At this time, the corresponding sub-channel 501 completes the acquisition of CHO single cells, while the thermal bubble printing nozzles in the remaining sub-channels 501 continue to spray. Specifically, in this embodiment, the impedance detection unit 502 includes three detection electrodes 505 arranged at intervals, wherein the length of the detection electrode 505 is 50 microns, the width of the detection electrode 505 is 25 microns, and the spacing between two adjacent detection electrodes 505 is 15 microns.

[0096] When a preset number of the sub-channels 501 have completed the acquisition of CHO single cells, the control circuit stops driving the corresponding thermal bubble printing nozzles. When the number of cells stored in the sub-channel 501 reaches the requirement, the injection pump is switched to inject buffer into the injection port 2 of the microfluidic chip 1 to rinse the residual cells in the main channel 3. Combined with motion control, the thermal bubble printing nozzles in all the acquisition units 5 are driven at the same time to export the CHO single cells in the thermal bubble printing nozzles into the well plate. The acquisition units 5 can be arranged in an array and can be controlled simultaneously, so that rapid and high-throughput sorting of CHO single cells can be achieved.

[0097] Of course, in other embodiments, the microfluidic chip 1 may also be used to sort other types of cells, and the protection scope of the present invention should not be overly limited here.

[0098] In summary, the present invention provides a microfluidic chip and a single cell sorting method, the chip includes a substrate, a plurality of acquisition units and a control circuit, wherein the substrate is provided with an inlet, a main channel and an outlet connected in sequence, and the plurality of acquisition units are distributed on at least one side of the main channel, the acquisition unit includes a side channel, an impedance detection unit and a driving element, the entrance of the side channel is connected to the side wall of the main channel, the impedance detection unit is located at the entrance of the side channel to detect whether a single cell enters the side channel, the driving element is located at the exit of the side channel to provide power for the acquisition and export of the single cell, the control circuit is electrically connected to the impedance detection unit and the driving element, and the acquisition of the single cell can be automatically completed. The microfluidic chip of the present invention is used for single cell sorting, and single cell sorting and plating can be completed efficiently and fully automatically, meeting the sorting requirements of high throughput, high sorting purity and low cell damage. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0099] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A microfluidic chip, characterized in that: include: A substrate, wherein the substrate is provided with an injection port, a main channel and an outlet that are connected in sequence; A plurality of acquisition units are distributed on at least one side of the main channel, the acquisition unit comprises a side channel, an impedance detection unit and a driving element, the entrance of the side channel is connected to the side wall of the main channel, the impedance detection unit is located at the entrance of the side channel to detect whether a single cell enters the side channel, and the driving element is located at the exit of the side channel to provide power for the acquisition and export of the single cell; A control circuit is electrically connected to the impedance detection unit and the driving element.

2. The microfluidic chip according to claim 1, characterized in that: An extension direction of the secondary channel is perpendicular to an extension direction of the primary channel.

3. The microfluidic chip according to claim 1, characterized in that: In a direction perpendicular to the plane of the substrate, the height of the main channel is less than 50 microns; the length L1 of the main channel is greater than the length L2 of the secondary channel, the width W1 of the main channel is greater than the width W2 of the secondary channel, and the width W2 of the secondary channel is less than 200 microns.

4. The microfluidic chip according to claim 1, characterized in that: The driving element includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film microvalve.

5. The microfluidic chip according to claim 1, characterized in that: The impedance detection unit includes at least two detection electrodes arranged at intervals, the width and length of the detection electrodes are both less than 100 microns, and the interval between two adjacent detection electrodes is less than 100 microns.

6. The microfluidic chip according to claim 1, characterized in that: The microfluidic chip is connected to an external driving device, and the external driving device includes any one of a syringe pump, a peristaltic pump and a pneumatic pump.

7. The microfluidic chip according to claim 1, characterized in that: The sample outlet includes at least one fluid driving unit communicated with the main channel.

8. The microfluidic chip according to claim 7, characterized in that: The fluid driving unit includes any one of a thermal bubble printing nozzle, a piezoelectric nozzle and a thin film microvalve.

9. The microfluidic chip according to claim 1, characterized in that: The substrate includes a silicon dioxide layer or a non-photosensitive dry film.

10. A single cell sorting method, characterized in that: The following steps are involved: Providing a microfluidic chip according to any one of claims 1 to 9, and introducing a cell suspension into the injection port; Driving the cell suspension to flow toward the sample outlet through an external driving device connected to the sample inlet or a fluid driving unit connected to the sample outlet; The driving element drives the cell suspension in the main channel to flow to the side channel. When the impedance detection unit detects that a single cell has entered the side channel, the control circuit stops the driving element in the corresponding side channel to complete the acquisition of the single cell in the corresponding side channel, and the driving elements in the remaining side channels continue to work. When a preset number of the auxiliary channels have completed the acquisition of single cells, stopping all the driving elements; injecting a buffer into the injection port to flush out the residual cells in the main channel; The captured single cell is guided out via the driving element.

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