Microfluidic sorting chip, microfluidic sorting system and microfluidic sorting method

Abstract

The invention provides a micro-fluidic sorting chip, a micro-fluidic sorting system and a micro-fluidic sorting method. The micro-fluidic sorting chip comprises a cover plate, a substrate and an extrusion film, the cover plate and the substrate are covered to form a transmission channel, and the cover plate is provided with a sample inlet, a non-target particle outlet, at least one target particle outlet and at least one extrusion hole; one end of the transmission channel is communicated to the sample inlet, and the other end of the transmission channel is respectively communicated to the extrusion hole, the non-target particle outlet and the target particle outlet; the extrusion film and the extrusion hole form an extrusion cavity, the extrusion cavity has an extrusion state and a non-extrusion state, the solution is guided to the target particle outlet in the extrusion state, and the solution is guided to the non-target particle outlet in the non-extrusion state; and an electrode layer is arranged on the substrate and is used for being externally connected with an impedance detection module so as to detect the impedance of particles in the solution to control the piezoelectric actuator to switch the state of the extrusion cavity. The micro-fluidic sorting chip provided by the invention can simplify the sorting process, and is small in size and convenient to manufacture.

Description

Technical Field

[0001] The present disclosure generally relates to the field of microfluidic technology, and in particular to a microfluidic sorting chip, a microfluidic sorting system and a method. Background Art

[0002] Sorting target particles or cells according to a certain property or type from a heterogeneous mixture is an important step in many biomedical fields. Microfluidic sorting is widely used in the biomedical field as a particle or cell sorting technology, and microfluidic devices are usually called microfluidic chips.

[0003] Currently, conventional cell sorting relies on biochemical markers of cells and separation by applying external force fields. However, these methods usually require complex and time-consuming sample pretreatment operations, require operators to undergo professional training during sorting, and have high equipment costs. Summary of the invention

[0004] In view of the above defects or deficiencies in the prior art, it is desirable to provide a microfluidic sorting chip, a microfluidic sorting system and a method to solve the above problems.

[0005] In a first aspect, the present application provides a microfluidic sorting chip, comprising a cover plate, a substrate and an extruded film; The cover plate and the substrate are covered to form a transmission passage, and the cover plate is provided with an injection port, a non-target particle outlet, at least one target particle outlet and at least one extrusion hole; one end of the transmission passage is connected to the injection port, and the other end of the transmission passage is connected to the extrusion hole, the non-target particle outlet and the target particle outlet respectively; The extrusion film is arranged on a side of the cover plate away from the substrate, and forms an extrusion cavity with the extrusion hole, the extrusion cavity has an extrusion state and a non-extrusion state, when the extrusion cavity is in the extrusion state, the solution is guided to the target particle outlet, and when the extrusion cavity is in the non-extrusion state, the solution is guided to the non-target particle outlet; An electrode layer is provided on the substrate at a position corresponding to the transmission path. The electrode layer is used to be externally connected to an impedance detection module. The impedance detection module is used to detect the impedance of particles in the solution to control the switching state of the extrusion cavity.

[0006] According to the technical solution provided in the embodiment of the present application, the transmission passage includes a transmission part and an access part arranged at one end of the transmission part, the access part is connected to the injection port, the inner diameter of the access part is larger than the inner diameter of the transmission part, and the inner diameter of the transmission part satisfies the requirement for a single particle with the largest particle size in the solution to pass through.

[0007] According to the technical solution provided in the embodiment of the present application, the cover plate and the substrate are covered together to form a target particle passage and a non-target particle passage, the end of the transmission part away from the access part is connected to the target particle outlet through the target particle passage, and the end of the transmission part away from the access part is connected to the non-target particle outlet through the non-target particle passage; the extrusion cavity is connected to the interface between the transmission part and the target particle passage and the non-target particle passage.

[0008] According to the technical solution provided in the embodiment of the present application, the cover plate and the base plate are covered together to form an extrusion passage, the extrusion cavity and the transmission part are connected through the extrusion passage, and the inner diameter of one end of the extrusion passage connected to the transmission part is reduced.

[0009] According to the technical solution provided in the embodiment of the present application, the cover plate and the substrate are covered to form at least one external passage, one end of the external passage is connected to the extrusion chamber, and the other end is connected to the ambient atmosphere, and the length of the external passage is greater than the length of the target particle passage and the non-target particle passage.

[0010] According to the technical solution provided in the embodiment of the present application, the external path is configured to be serpentine.

[0011] According to the technical solution provided in the embodiment of the present application, the extrusion chamber, the target particle passage and the target particle outlet are respectively provided with two, the two extrusion chambers are respectively arranged on the opposite sides of the transmission passage, the two target particle passages and the two target particle outlets are respectively arranged on the opposite sides of the transmission passage, and the extrusion chamber on one side of the transmission passage is in the extrusion state, directing the solution to the target particle outlet on the other side.

[0012] A second aspect of the present application provides a microfluidic sorting system, comprising an impedance detection module, a data acquisition and processing module, a piezoelectric control module, a piezoelectric sorting module, and the microfluidic sorting chip as described above; The impedance detection module is electrically connected to the electrode layer and is used to detect the impedance of particles in the transmission path; The data acquisition and processing module is electrically connected to the impedance detection module, and is used to obtain the impedance of the particle and obtain a judgment result according to the impedance of the particle, wherein the judgment result includes whether the particle is a target particle or a non-target particle; The piezoelectric control module is used to generate a corresponding control signal according to the judgment result; The piezoelectric sorting module is used to perform an action according to the control signal to change the state of the extrusion cavity.

[0013] According to the technical solution provided in the embodiment of the present application, the piezoelectric sorting module includes a piezoelectric actuator, the top of the piezoelectric actuator is connected to a metal microcolumn, the metal microcolumn is arranged corresponding to the position of the extrusion hole, and the outer diameter of the top of the metal microcolumn is smaller than the inner diameter of the extrusion hole. A third aspect of the present application provides a microfluidic sorting method, based on the microfluidic sorting system as described above, the method comprising: The microfluidic sorting chip is manufactured according to the particle sizes of target particles and non-target particles; After the microfluidic sorting chip is manufactured, the impedance detection module and the electrode layer are electrically connected; Turning on the impedance detection module, the data acquisition and processing module, the piezoelectric control module and the piezoelectric sorting module, and adding the solution with particles from the injection port to start sorting; The solution containing target particles is collected at the target particle outlet, and the solution containing non-target particles is collected at the non-target particle outlet.

[0014] Compared with the prior art, the beneficial effects of the present application are as follows: through the transmission path, one end of the transmission path is connected to the injection port, and the other end is respectively connected to the non-target particle outlet and the target particle outlet, so that the solution with the target particles and the solution with the non-target particles can be respectively discharged; by arranging an extrusion hole on the cover plate and the extrusion hole and the extrusion film cooperate to form an extrusion cavity, and then by arranging an electrode at the position of the transmission path, the electrode is connected to the impedance detection module, when the solution passes through the electrode, the impedance detection module determines whether it is a target particle or a non-target particle according to the impedance of the detected particle, when the target particle is detected, the solution with the target particle can be guided to the target particle outlet by pressing the extrusion cavity, and when the extrusion cavity is not pressed, the solution with the non-target particles is guided to the non-target particle outlet, There is no need to pre-treat the particles during sorting, and sorting is achieved by using fluid to change the trajectory of particle movement, thus avoiding direct stimulation of the particles and achieving a fast response speed. The microfluidic sorting chip provided in the present application is composed of three parts: a cover plate, a substrate and an extrusion film. Since the thickness of the substrate and the extrusion film is constant, and since the extrusion cavity is squeezed by pressing the extrusion film to drive the fluid trajectory to change, rather than adjusting the pressure by directly pressing the cover plate, the problem of unclear pressure change due to excessive thickness of the cover plate will not occur. Therefore, the cover plate can be set thicker when the chip thickness is constant. A thicker cover plate is convenient for punching and can be better bonded to the substrate. There is no need to increase the size of the cover plate to bond with the substrate, thereby making the microfluidic sorting chip smaller and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 A schematic diagram of the structure of the microfluidic sorting chip provided in Example 1; Figure 2 for Figure 1 A schematic diagram of the structure of the bottom of the cover plate in the microfluidic sorting chip shown; Figure 3 for Figure 2 A schematic diagram of the enlarged structure at A in the middle; Figure 4 for Figure 2 A schematic diagram of the enlarged structure at B in the middle; Figure 5 for Figure 1 Schematic diagram of the structure of the electrode layer in the microfluidic sorting chip shown; Figure 6 for Figure 5 Schematic diagram of the enlarged structure at C in the middle; Figure 7 is a schematic diagram of the relative positions of the electrode layer and the transmission path; Figure 8 The schematic diagram of the structure of the microfluidic sorting chip that cooperates with the traditional and off-chip contact piezoelectric actuators; Fig. 9 A schematic diagram of the structure of the microfluidic sorting system provided in Example 2; Fig.10 This is a flow chart of the steps of the microfluidic sorting method provided in Example 3.

[0016] Figure numbers: 1. cover plate; 2. substrate; 3. extrusion film; 4. transmission path; 5. injection port; 6. target particle outlet; 7. non-target particle outlet; 8. extrusion hole; 9. extrusion cavity; 10. electrode layer; 11. transmission part; 12. access part; 13. target particle path; 14. non-target particle path; 15. extrusion path; 16. external path; 17. adapter block; 18. electrode; 100. impedance detection module; 200. data acquisition and processing module; 300. piezoelectric control module; 400. piezoelectric sorting module. DETAILED DESCRIPTION

[0017] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] Microfluidic sorting chips usually include three parts: sensors for identifying target particles and non-target particles, microchannel structures for sorting, and piezoelectric actuators for guiding particles or cells to specific outlets. There are two main types of piezoelectric actuators for microfluidic sorting chips, namely on-chip integrated and off-chip contact. The on-chip integrated piezoelectric actuators are complex to manufacture and because they are integrated on the chip, the chip size is large and the cost is high. The manufacture is complex. The off-chip contact piezoelectric actuator does not need to be integrated on the chip, which can greatly reduce the size of the chip and reduce costs. Therefore, this application improves the microfluidic sorting chip based on the off-chip contact piezoelectric actuator.

[0020] Example 1 Please refer to Figure 1-Figure 8 This embodiment provides a microfluidic sorting chip, including a cover plate 1, a substrate 2 and an extruded film 3: The cover plate 1 and the substrate 2 are covered to form a transmission passage 4, and the cover plate 1 is provided with an injection port 5, a non-target particle outlet 7, at least one target particle outlet 6 and at least one extrusion hole 8; one end of the transmission passage 4 is connected to the injection port 5, and the other end of the transmission passage 4 is respectively connected to the extrusion hole 8, the non-target particle outlet 7 and the target particle outlet 6; The extrusion film 3 is arranged on a side of the cover plate 1 away from the substrate 2, and forms an extrusion cavity 9 with the extrusion hole 8. The extrusion cavity 9 has an extrusion state and a non-extrusion state. When the extrusion cavity 9 is in the extrusion state, the solution is directed to the target particle outlet 6. When the extrusion cavity 9 is in the non-extrusion state, the solution is directed to the non-target particle outlet 7. An electrode layer 10 is provided on the substrate 2 at a position corresponding to the transmission path 4 . The electrode layer 10 is used to be externally connected to an impedance detection module 100 . The impedance detection module is used to detect the impedance of particles in the solution to control the switching state of the extrusion cavity 9 .

[0021] Specifically, the piezoelectric actuator of the microfluidic sorting chip provided in this embodiment is of off-chip contact type. The microfluidic sorting chip provided in this embodiment consists of three parts: a cover plate 1, a substrate 2 and an extruded film 3, wherein the cover plate 1 and the extruded film 3 are made of polydimethylsiloxane (PDMS), which is an elastic material, and the substrate 2 is made of glass.

[0022] like Figure 1As shown, an injection port 5, a non-target particle outlet 7 and a target particle outlet 6 are provided on the top surface of the cover plate 1, the injection port 5 is provided at one end of the top surface of the cover plate 1, the non-target particle outlet 7 is provided at the other end of the top surface of the cover plate 1, and the target particle outlet 6 is provided on one side of the non-target particle outlet 7; a microchannel groove is provided on the bottom surface of the cover plate 1, the depth of the microchannel groove is several tens of microns, the substrate 2 is bonded to the bottom surface of the cover plate 1, and after bonding, the substrate 2 and the microchannel groove cooperate to form a transmission path 4, one end of the transmission path 4 is connected to the injection port 5, and the other end is connected to the non-target particle outlet 7 and the target particle outlet 6 respectively. During the test, the solution to be sorted is added into the transmission path 4 from the injection port 5. The solution to be sorted includes at least a solvent, target particles and non-target particles. The target particles and non-target particles may also be selected as target cells and non-target cells. For the sake of convenience, target particles and non-target particles are used as examples in the following text, wherein non-target particles are particles other than target particles, and non-target particles may not be limited to one type. After the solution to be sorted is sorted in the transmission path 4, the solution containing target particles after sorting is discharged from the target particle outlet 6, while the solution containing non-target particles is discharged from the non-target particle outlet 7.

[0023] like Figure 1 and Figure 2 As shown, an extrusion hole 8 is also provided on the cover plate 1, which passes through the top and bottom surfaces of the cover plate 1. One end of the extrusion hole 8 passing through the bottom surface of the cover plate 1 is sealed by the substrate 2. An extrusion film 3 is correspondingly provided at the position where the extrusion hole 8 passes through one end of the top surface of the cover plate 1. The extrusion film 3 seals the end of the extrusion hole 8 passing through the top surface of the cover plate 1. The extrusion film 3 and the extrusion hole 8 cooperate to form an extrusion cavity 9 inside the extrusion hole 8. The extrusion cavity 9 is used to sort target particles and non-target particles. The extrusion cavity 9 and the transmission path 4 are connected to the positions where the target particle outlet 6 and the non-target particle outlet 7 are diverted respectively. It should be noted that the extrusion cavity 9 and the target particle outlet 6 are provided with at least one but not limited to one, and the extrusion cavity 9 and the target particle outlet 6 correspond one to one. Here, the extrusion cavity 9 and the target particle outlet 6 are provided with one for explanation: the non-target particle outlet 7 and the injection port 5 are arranged in a straight line. In the absence of lateral pressure interference, that is, when the extrusion film 3 is not pressed, the solution to be sorted added by the injection port 5 will be directly guided to the non-target particle outlet 7. The extrusion cavity 9 is on one side of the path between the injection port 5 and the non-target particle outlet 7, and the target particle outlet 6 is located on the other side of the path. By pressing the extrusion film 3, the pressure in the extrusion cavity 9 can be increased, and the solution is guided to one side of the target particle outlet 6, so as to achieve the sorting of target particles and non-target particles. By adjusting the pressure in the passage, the fluid is used to change the particle motion trajectory to achieve sorting, which avoids the direct stimulation of the particles by applying an external force field such as an electric field in the prior art. At the same time, the method has a fast response speed and high sorting accuracy. Optionally, in this embodiment, the diameter of the extrusion hole 8 is less than or equal to 1 mm.

[0024] like Figure 1 and Figure 5 As shown, an electrode layer 10 is provided on the side where the substrate 2 is bonded to the cover plate 1. The electrode layer 10 is arranged corresponding to the position of the transmission path 4. The electrode layer 10 is used to connect the microfluidic sorting chip with an external impedance detection module 100. The impedance of the particles when the solution flows in the transmission path 4 can be detected through the external impedance detection module 100. Since the impedances obtained by detecting different particles are different, it can be judged whether the passing particles are target particles. The judgment result can be used to indicate whether the piezoelectric actuator needs to extrude the extrusion film 3, thereby completing the sorting of the particles. The electrode layer 10 is equivalent to a sensor for distinguishing target particles from non-target particles. The method of detecting particle impedance for sorting particles does not require pre-treatment of the particles, so there is no need to require operators to undergo professional training, and it can also save related equipment for particle pre-treatment, simplify the sorting process and reduce equipment costs. The electrode layer 10 is the core component for microfluidic electrical impedance detection. The electrode layer 10 of this embodiment includes seven coplanar electrodes 18, such as Figure 6 As shown, through the double differential measurement composed of seven electrodes 18 arrays, the measured signal is fitted with a bipolar Gaussian template to obtain the physical parameters of the particle, and the calibrated electrical diameter of the particle can be obtained through calculation. The speed of the particle is calculated according to the time difference between the positive and negative peaks of the impedance signal to match the downstream voltage sorting; the specific content of the double differential measurement composed of seven electrodes 18 arrays belongs to the prior art and will not be described here. Optionally, in this embodiment, the electrode layer 10 is made of indium tin oxide (ITO). The ITO electrode has low resistivity, good conductivity, and excellent light transmittance. The production cost of the ITO electrode is lower than that of the gold electrode, which helps to reduce production costs.

[0025] In addition, the cover plate 1 in the conventional microfluidic sorting chip that cooperates with the off-chip contact piezoelectric actuator is usually relatively thin. The following is an example of the structure of the microfluidic sorting chip in this embodiment after being replaced by the conventional composition method: The conventional microfluidic sorting chip that cooperates with the off-chip contact piezoelectric actuator is as follows: Figure 8As shown, the chip includes a cover plate 1, a substrate 2 and a transfer block 17, and the extrusion cavity 9 is located in the cover plate 1. What is different from the present application is that the cover plate 1 on the microfluidic chip using the conventional off-chip contact piezoelectric actuator is thinner. The reason is that if the particles are to be sorted by pressing the extrusion cavity 9, the thickness of the cover plate 1 is too large to facilitate the volume change of the extrusion cavity 9, so the cover plate 1 is set to be thinner, but the thinner cover plate 1 is not convenient for adding solution to the injection port 5, so it is necessary to additionally set the transfer block 17 on the side of the cover plate 1 away from the substrate 2, and by connecting the corresponding injection port on the transfer block 17 5. Holes are made at the positions of the target particle outlet 6 and the non-target particle outlet 7. The figure shows the adapter block 17 only at the positions of the sample inlet 5, the target particle outlet 6 and the non-target particle outlet 7. The thickness of the cover plate 1 on the traditional microfluidic sorting chip is about 350μm, and the thickness of the adapter block 17 is about 3.5mm. Because the overall length of the cover plate 1 is long and the thickness is thin, it is difficult to check and punch the cover plate 1 and the adapter block 17 as a whole. At the same time, since the adapter block 17 needs a position of sufficient size when bonding, it will also increase the size of the microfluidic sorting chip. In the present application, since an extrusion film 3 is provided, there is no need to extrude the cover plate 1 when pressing the extrusion cavity 9. Only pressing the extrusion film 3 can cause the extrusion cavity 9 to deform. Therefore, the cover plate 1 can be set to a larger thickness to facilitate overall punching. When the total thickness of the microfluidic sorting chip is constant, the cover plate 1 can adopt a normal thickness of about 4mm.

[0026] Furthermore, the transmission passage 4 includes a transmission part 11 and an access part 12 arranged at one end of the transmission part 11, the access part 12 is connected to the injection port 5, the inner diameter of the access part 12 is larger than the inner diameter of the transmission part 11, and the inner diameter of the transmission part 11 satisfies the passage of a single particle with the largest particle size in the solution.

[0027] At present, conventional microchannel structures use focusing to form single-particle flow, that is, to maintain the particles in the center of the liquid flow in order and flow forward individually. A common focusing method is to use sheath flow to focus the fluid. The solution with particles flows together with the outflowing sheath liquid, so that the particles are surrounded by sheath liquid, thereby forming a single-particle flow. However, the focusing method using sheath flow increases the pressure required for sorting and the complexity of the sorting process, and the sheath flow-related structure will also increase the power consumption of the system when generating sheath flow, so an alternative to sheath flow is needed to simplify the sorting process.

[0028] Specifically, Figure 3As shown, the transmission passage 4 in this embodiment is composed of a transmission part 11 and an access part 12. The transmission part 11 and the access part 12 are different transmission sections interconnected on the transmission passage 4, wherein the transmission part 11 occupies most of the transmission passage 4 and serves as the main passage for solution transmission. One end of the transmission part 11 is connected to the injection port 5 through the access part 12, and the other end is connected to the target particle outlet 6 and the non-target particle outlet 7 respectively; the inner diameter of the transmission part 11 needs to be set according to the particle size of the largest particle in the solution to be sorted. Preferably, the inner diameter of the transmission part 11 is larger than the particle size of the largest particle in the solution to be sorted and is less than or equal to twice the particle size of the largest particle, so as to ensure that a single particle flow is formed in the transmission part 11 without using a sheath flow, thereby saving the pressure of the sheath flow sharing during the sorting process and the specific operation process. Since the inner diameter of the transmission part 11 is limited, in order to avoid the situation where the inner diameter of the transmission part 11 is too small and blocked, the inner diameter of the access part 12 is set to be larger than the inner diameter of the transmission part 11. Optionally, in this embodiment, the inner diameter of the transmission portion 11 is 30 μm, and the inner diameter of the access portion 12 is 50 μm.

[0029] Based on the above content, the microfluidic sorting chip provided in this embodiment can realize the single particle flow without the sheath flow related structure. In order to allow the particles to be discharged through the non-target particle outlet 7 without the influence of the lateral external force when there is no sheath flow related structure, the present application also makes the following settings: Furthermore, the cover plate 1 and the substrate 2 are covered to form a target particle passage 13 and a non-target particle passage 14; the end of the transmission part 11 away from the access part 12 is connected to the target particle outlet 6 through the target particle passage 13, and the end of the transmission part 11 away from the access part 12 is connected to the non-target particle outlet 7 through the non-target particle passage 14; the extrusion cavity 9 is connected to the interface between the transmission part 11 and the target particle passage 13 and the non-target particle passage 14.

[0030] Specifically, Figure 2As shown, in addition to forming the transmission path 4, the microchannel grooves on the cover plate 1 and the substrate 2 also form a target particle path 13 and a non-target particle path 14. The end of the transmission part 11 away from the access part 12 is connected to the target particle outlet 6 and the non-target particle outlet 7 through the target particle path 13 and the non-target particle path 14 respectively; in this embodiment, the non-target particle path 14 and the transmission part 11 are both straight paths and the two are collinear, the target particle path 13 is arranged on one side of the non-target particle path 14, and an extrusion cavity 9, a target particle path 13 and a target particle outlet 6 serve as a group of sorting units. The extrusion chamber 9 is connected to the interface of the transmission part 11, the target particle passage 13 and the non-target particle passage 14, and the extrusion chamber 9 is arranged on the side of the non-target particle passage 14 away from the target particle passage 13, so that when the solution to be sorted flows through the interface of the transmission part 11, the target particle passage 13 and the non-target particle passage 14, if the extrusion chamber 9 is not pressed, the solution will be guided to the non-target particle outlet 7 along the non-target particle passage 14, and if the extrusion chamber 9 is pressed, the solution will deflect the trajectory under the action of pressure, and then be guided to the target particle outlet 6 along the target particle passage 13. The length of the target particle passage 13 is set to be greater than the length of the non-target particle passage 14, so the non-target particle passage 14 has a smaller flow resistance than the target particle passage 13, further making it easier for particles to reach the non-target particle outlet 6 when the extrusion chamber 9 is not pressed. In order to ensure that all particles can enter the non-target particle passage 14 without being subjected to lateral external forces after removing the sheath flow related structure, it is also necessary to set the inner diameters of the target particle passage 13 and the non-target particle passage 14. Optionally, in this embodiment, the inner diameter of the target particle passage 13 is 30 μm, and the inner diameter of the non-target particle passage 14 is 80 μm.

[0031] The microfluidic sorting chip provided in this embodiment combines the restrictions on the position and size of the transmission part 11, the target particle passage 13, and the non-target particle passage 14, so that the particles can form a single particle flow during transmission, while ensuring that the particles can enter the non-target particle passage 14 without external force, thereby achieving effective sorting of target particles and non-target particles. At the same time, the overall voltage is reduced to below 10V, thereby reducing the power consumption of the sorting process.

[0032] Furthermore, the cover plate 1 and the base plate 2 are covered to form an extrusion passage 15, and the extrusion cavity 9 and the transmission part 11 are connected through the extrusion passage 15, and the inner diameter of one end of the extrusion passage 15 connected to the transmission part 11 is reduced.

[0033] Specifically, Figure 2As shown, in addition to forming the transmission passage 4, the microchannel grooves on the cover plate 1 and the substrate 2 also form an extrusion passage 15. The pressure generated by pressing the extrusion cavity 9 is guided to the interface of the transmission part 11, the target particle passage 13 and the non-target particle passage 14 through the extrusion passage 15, and the flow direction of the solution is changed by the pressure, thereby achieving particle sorting. In order to ensure that the pressure can be efficiently transmitted when the extrusion cavity 9 is pressed, the inner diameter of the extrusion passage 15 should be set as large as possible. At the same time, it is necessary to avoid particles entering the extrusion passage 15 due to the excessive inner diameter of the extrusion passage 15. Therefore, the position where the extrusion passage 15 is connected to the interface of the transmission part 11, the target particle passage 13 and the non-target particle passage 14 is designed as a contraction port structure, that is, the inner diameter size of the connection position is reduced, such as Figure 4 Optionally, in this embodiment, the inner diameter of the extrusion passage 15 is 80 μm, and the inner diameter of the position where the extrusion passage 15 communicates with the interface of the transmission part 11, the target particle passage 13 and the non-target particle passage 14 is 30 μm.

[0034] Furthermore, the cover plate 1 and the substrate 2 are combined to form at least one external passage 16, one end of the external passage 16 is connected to the extrusion chamber 9, and the other end is connected to the ambient atmosphere. The length of the external passage 16 is greater than the length of the target particle passage 13 and the non-target particle passage 14.

[0035] Specifically, Figure 2 As shown, in addition to forming the transmission path 4, the microchannel groove on the cover plate 1 and the substrate 2 also form an external path 16, which is used to further prevent particles from entering the extrusion path 15. One end of the external path 16 is connected to the side of the extrusion cavity 9 away from the extrusion path 15, and the other end passes through the cover plate 1 and is connected to the external environment atmosphere. The length of the external path 16 is set to be greater than the length of the target particle path 13 and the non-target particle path 14, in order to make the external path 16 have a greater flow resistance than the target particle path 13 and the non-target particle path 14. According to the principle of "minimum flow resistance path", the solution with particles after sorting will flow to the target particle path 13 or the non-target particle path 14, and will not enter the extrusion path 15.

[0036] Furthermore, the external passage 16 is configured to be serpentine.

[0037] Specifically, Figure 2 As shown, since the length of the external passage 16 is long, if the shape of the external passage 16 is not restricted, the length of the cover plate 1 needs to adapt to the longer setting of the external passage 16, which leads to an increase in the size of the microfluidic sorting chip. In this embodiment, the external passage 16 is set to be serpentine, which occupies a smaller area of ​​the cover plate 1 while ensuring that the external passage 16 has a greater flow resistance, thereby avoiding an increase in production costs due to an excessively large area of ​​the microfluidic chip.

[0038] Furthermore, the extrusion chamber 9, the target particle passage 13 and the target particle outlet 6 are respectively provided with two, the two extrusion chambers 9 are respectively provided on the opposite sides of the transmission passage 4, the two target particle passages 13 and the two target particle outlets 6 are respectively provided on the opposite sides of the transmission passage 4, and the extrusion chamber 9 on one side of the transmission passage 4 is in the extrusion state, directing the solution to the target particle outlet 6 on the other side.

[0039] Specifically, when there are two groups of sorting units, in order to facilitate the explanation of the positions of the two groups of sorting units, the two opposite sides of the non-target particle passage 14 are recorded as the first side and the second side. The extrusion chamber 9 of the first group of sorting units is arranged on the first side of the non-target particle passage 14, and the target particle passage 13 and the target particle outlet 6 of the first group of sorting units are arranged on the second side of the non-target particle passage 14. The extrusion chamber 9 of the second group of sorting units is symmetrically arranged with the extrusion chamber 9 of the first group of sorting units about the non-target particle passage 14, that is, the extrusion chamber 9 of the second group of sorting units is arranged on the second side of the non-target particle passage 14, and the target particle passage 13 and the target particle outlet 6 of the second group of sorting units are symmetrically arranged with the target particle passage 13 and the target particle outlet 6 of the first group of sorting units about the non-target particle passage 14, that is, the target particle passage 13 and the target particle outlet 6 of the second group of sorting units are arranged on the first side of the non-target particle passage 14. Since there are two groups of sorting units, the two groups of sorting units can be used to sort out the same target particles, and can also be used to sort out two different target particles; when the two groups of sorting units are used to sort out the same target particles, the two sorting units can be alternately operated by alternately pressing the extrusion cavities 9 of the two sorting units to improve the sorting efficiency; when the two groups of sorting units are used to sort out two different target particles, the two selected target particles are respectively discharged from the target particle outlets 6 of the two groups of sorting units.

[0040] Example 2 like Fig. 9 As shown, this embodiment provides a microfluidic sorting system, including an impedance detection module 100, a data acquisition and processing module 200, a piezoelectric control module 300, a piezoelectric sorting module 400 and the microfluidic sorting chip as described in Example 1; The impedance detection module 100 is electrically connected to the electrode layer 10 and is used to detect the impedance of particles in the transmission path 4; The data acquisition and processing module 200 is electrically connected to the impedance detection module 100, and is used to obtain the impedance of the particle and obtain a judgment result according to the impedance of the particle, wherein the judgment result includes whether the particle is a target particle or a non-target particle; The piezoelectric control module 300 is used to generate a corresponding control signal according to the judgment result; The piezoelectric sorting module 400 is used to perform an action according to the control signal to change the state of the extrusion cavity 9 .

[0041] Furthermore, the piezoelectric sorting module 400 includes a piezoelectric actuator, a metal microcolumn is connected to the top of the piezoelectric actuator, the metal microcolumn is arranged corresponding to the position of the extrusion hole 8, and the outer diameter of the top of the metal microcolumn is smaller than the inner diameter of the extrusion hole 8.

[0042] Specifically, in this embodiment, the piezoelectric actuator is of off-chip contact type, and a metal microcolumn is provided on the piezoelectric actuator. When the piezoelectric actuator is not powered on, the end of the metal microcolumn contacts the extrusion film 3 but does not squeeze it. When the piezoelectric actuator is powered on, the piezoelectric actuator drives the metal microcolumn downward to press the extrusion film 3 for particle sorting. The outer diameter of the end of the metal microcolumn in contact with the extrusion film 3 is smaller than the inner diameter of the extrusion hole 8.

[0043] Specifically, the impedance detection module 100 includes an impedance spectrometer, a current amplifier and related connecting cables. The impedance spectrometer is electrically connected to the electrode layer 10 on the substrate 2, and is used to detect the impedance of particles in the solution in the digital transmission path 4; the current amplifier is electrically connected to the impedance spectrometer, and is used to amplify the impedance signal detected by the impedance spectrometer, while eliminating noise interference. Optionally, the impedance spectrometer is an impedance spectrometer of model HF2IS produced by Zurich Instruments, and the current amplifier is a current amplifier of model HF2TA produced by Zurich Instruments. The system sampling rate is as high as 50MHz, and the differential current detection accuracy is as high as 2pA.

[0044] The data acquisition and processing module 200 includes a host computer, which is an operable computer. The host computer is electrically connected to the current amplifier. The host computer uses the written Python code to obtain the impedance signal in a specific time period in real time on the Pycharm platform. First, the measured impedance signal is filtered, and then two appropriate thresholds are set for the sorting of specific target particles, and the peak between the two thresholds is found. Then, a suitable time window is set to find the trough position corresponding to the peak (i.e., the time point of the positive and negative peaks) and its corresponding amplitude (and the voltage value of the positive and negative peaks). In order to achieve the sorting of specific target particles, the system will compare the real and imaginary peak voltage values ​​of the impedance signal with the preset values. When the voltage values ​​of the peaks are all within the preset value range, it means that the target particles have been successfully detected and the complete positive and negative peak waveforms are obtained. Then, the speed of the target particles can be determined by the obtained time difference between the positive and negative peaks and the electrode spacing on the electrode layer 10, and the delay time of the target particles reaching the interface position of the transmission part 11, the target particle transmission path 13 and the non-target particle path 14 can be estimated. The specific calculation method here belongs to the prior art, so it will not be described in detail.

[0045] The piezoelectric sorting control module includes a single-chip microcomputer, which is connected to the host computer through serial communication. The single-chip microcomputer sends a preset voltage value through the host computer control, thereby controlling the operation of the piezoelectric actuator. If the voltage required by the piezoelectric actuator during piezoelectric sorting is greater than the maximum voltage that the single-chip microcomputer can send, a signal amplification module can be connected to boost the voltage.

[0046] Example 3 like Fig.10 As shown, this embodiment provides a microfluidic sorting method, based on the microfluidic sorting system as described in Example 3, the method includes: S1: manufacturing the microfluidic sorting chip according to the particle sizes of target particles and non-target particles; S2: After the microfluidic sorting chip is manufactured, the impedance detection module 100 and the electrode layer 10 are electrically connected; S3: Turn on the impedance detection module 100, the data acquisition and processing module 200, the piezoelectric control module 300 and the piezoelectric sorting module 400, and add the solution with particles from the injection port 5 to start sorting; S4: collecting the solution containing target particles at the target particle outlet 6 , and collecting the solution containing non-target particles at the non-target particle outlet 7 .

[0047] Specifically, in step S1, the inner diameter of each passage on the microfluidic sorting chip is mainly set according to the particle size of the target particles and the non-target particles to ensure that each passage allows particles to pass through, especially to ensure that the particles in the transmission part 11 can all flow into the non-target particle outlet 7 when not affected by lateral external forces, and can successfully flow into the target particle outlet 6 when affected by lateral external forces. The specific method for making the microfluidic sorting chip in step S1 belongs to the prior art and will not be described here.

[0048] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A microfluidic sorting chip, characterized in that: It comprises a cover plate (1), a base plate (2) and an extruded film (3); The cover plate (1) and the base plate (2) are covered to form a transmission passage (4); the cover plate (1) is provided with an injection port (5), a non-target particle outlet (7), at least one target particle outlet (6) and at least one extrusion hole (8); one end of the transmission passage (4) is connected to the injection port (5), and the other end of the transmission passage (4) is respectively connected to the extrusion hole (8), the non-target particle outlet (7) and the target particle outlet (6); The extrusion film (3) is arranged on a side of the cover plate (1) away from the substrate (2), and forms an extrusion cavity (9) with the extrusion hole (8); the extrusion cavity (9) has an extrusion state and a non-extrusion state; when the extrusion cavity (9) is in the extrusion state, the solution is directed to the target particle outlet (6); when the extrusion cavity (9) is in the non-extrusion state, the solution is directed to the non-target particle outlet (7); An electrode layer (10) is provided on the substrate (2) at a position corresponding to the transmission path (4); the electrode layer (10) is used to be externally connected to an impedance detection module (100); the impedance detection module (100) is used to detect the impedance of particles in the solution to control the switching state of the extrusion cavity (9).

2. The microfluidic sorting chip according to claim 1, characterized in that: The transmission passage (4) comprises a transmission part (11) and an access part (12) arranged at one end of the transmission part (11), the access part (12) being connected to the injection port (5), the inner diameter of the access part (12) being larger than the inner diameter of the transmission part (11), and the inner diameter of the transmission part (11) being sufficient to allow a single particle with the largest particle size in the solution to pass through.

3. The microfluidic sorting chip according to claim 2, characterized in that: The cover plate (1) and the base plate (2) are covered to form a target particle passage (13) and a non-target particle passage (14); an end of the transmission part (11) away from the access part (12) is connected to the target particle outlet (6) through the target particle passage (13); an end of the transmission part (11) away from the access part (12) is connected to the non-target particle outlet (7) through the non-target particle passage (14); and the extrusion cavity (9) is connected to the interface between the transmission part (11) and the target particle passage (13) and the non-target particle passage (14).

4. The microfluidic sorting chip according to claim 3, characterized in that: The cover plate (1) and the base plate (2) are covered to form an extrusion passage (15), the extrusion cavity (9) and the transmission part (11) are connected via the extrusion passage (15), and the inner diameter of one end of the extrusion passage (15) connected to the transmission part (11) is reduced.

5. The microfluidic sorting chip according to claim 4, characterized in that: The cover plate (1) and the base plate (2) are covered to form at least one external passage (16), one end of the external passage (16) is connected to the extrusion chamber (9), and the other end is connected to the ambient atmosphere, and the length of the external passage (16) is greater than the length of the target particle passage (13) and the length of the non-target particle passage (14).

6. The microfluidic sorting chip according to claim 5, characterized in that: The external passage (16) is configured in a serpentine shape.

7. The microfluidic sorting chip according to claim 6, characterized in that: The extrusion chamber (9), the target particle passage (13) and the target particle outlet (6) are respectively provided with two, the two extrusion chambers (9) are respectively provided on two opposite sides of the transmission passage (4), the two target particle passages (13) and the two target particle outlets (6) are respectively provided on two opposite sides of the transmission passage (4), and the extrusion chamber (9) on one side of the transmission passage (4) guides the solution to the target particle outlet (6) on the other side when the extrusion chamber (9) is in the extrusion state.

8. A microfluidic sorting system, characterized in that: It comprises an impedance detection module (100), a data acquisition and processing module (200), a piezoelectric control module (300), a piezoelectric sorting module (400), and a microfluidic sorting chip as claimed in any one of claims 1 to 6; The impedance detection module (100) is electrically connected to the electrode layer (10) and is used to detect the impedance of particles in the transmission path (4); The data acquisition and processing module (200) is electrically connected to the impedance detection module (100) and is used to obtain the impedance of the particle and obtain a judgment result according to the impedance of the particle, wherein the judgment result includes whether the particle is a target particle or a non-target particle; The piezoelectric control module (300) is used to generate a corresponding control signal according to the judgment result; The piezoelectric sorting module (400) is used to perform an action according to the control signal to change the state of the extrusion cavity (9).

9. The microfluidic sorting system according to claim 8, characterized in that: The piezoelectric sorting module (400) comprises a piezoelectric actuator, the top end of the piezoelectric actuator is connected to a metal microcolumn, the metal microcolumn is arranged corresponding to the position of the extrusion hole (8), and the outer diameter of the top end of the metal microcolumn is smaller than the inner diameter of the extrusion hole (8).

10. A microfluidic sorting method, characterized in that: Based on the microfluidic sorting system according to any one of claims 8 or 9, the method comprises: The microfluidic sorting chip is manufactured according to the particle sizes of target particles and non-target particles; After the microfluidic sorting chip is manufactured, the impedance detection module (100) and the electrode layer (10) are electrically connected; The impedance detection module (100), the data acquisition and processing module (200), the piezoelectric control module (300) and the piezoelectric sorting module (400) are turned on, and a solution containing particles is added through the injection port (5) to start sorting; The solution containing target particles is collected at the target particle outlet (6), and the solution containing non-target particles is collected at the non-target particle outlet (7).

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