Microfluidic sorting chip and sorting device based on surface acoustic waves

Abstract

The invention provides a micro-fluidic sorting chip based on surface acoustic waves and a sorting device. The micro-fluidic sorting chip comprises a piezoelectric substrate; the particle inlet is used for inputting particles to be sorted; the sorting unit is communicated with the particle inlet and is used for guiding the particles to be sorted; the detection point is used for detecting the type of flowing particles; the sorting unit comprises a sorting pipeline, a collecting pipeline and a surface sound wave generator which are arranged on the piezoelectric substrate, and the surface sound wave generator is used for generating surface sound waves when the target particles reach the area where the sorting pipeline communicates with the collecting pipeline so as to convey the target particles to the collecting pipeline from the sorting pipeline; and the waste liquid outlet is communicated with the tail end of the sorting pipeline. Compared with the prior art, the target particles are sorted through surface acoustic waves, adverse effects of a high-voltage electric field and high temperature on the activity of the target particles are avoided, and the activity of the target particles can be kept to the maximum extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological microparticle sorting, in particular to a microfluidic sorting chip based on surface acoustic waves and a sorting device. BACKGROUND

[0002] The existing microfluidic sorting chip is mainly a dielectrophoresis sorting chip, the core of which is to use a non-uniform electric field to sort neutral biological microparticles (such as cells, bacteria, exosomes, droplets, etc.) without contact. When the neutral biological microparticles are in the non-uniform electric field, they will be polarized and induce a dipole moment, and the interaction between the electric field and the dipole moment generates a dielectrophoresis force. The size and direction of the dielectrophoresis force depend on the characteristics of the biological microparticles themselves, such as membrane capacitance, cytoplasm conductivity, size and shape, etc. Therefore, biological microparticles of different characteristics will produce different deflections under the action of dielectrophoresis force, thereby separating biological microparticles of different characteristics.

[0003] The dielectrophoresis sorting chip of the prior art includes three core modules. First, the sample inlet module is designed as a multi-inlet, which is divided into a sample inlet, a buffer focusing inlet or a spacer oil inlet, which can realize fluid focusing or ordered spacing of the sample, facilitating subsequent sorting operation; second, the sorting module refers to the metal electrode structure used to generate a non-uniform electric field, and different electrode arrangement designs will also have different sorting performance; finally, the collection module generally includes two flow channels leading to two outlets, one is a waste liquid channel, which has smaller flow resistance, and the particles will flow to the waste liquid channel with smaller flow resistance when there is no non-uniform electric field, and the other is a collection channel, and when a non-uniform electric field is applied, the target particles will be attracted to the collection channel under the action of dielectrophoresis force to realize sorting.

[0004] However, the dielectrophoresis chip of the prior art has the following disadvantages: (1) When the dielectrophoresis sorting chip is working, the electrodes need to be connected to several hundred volts or even thousands of volts, and the high voltage will generate Joule heat to raise the temperature of the chip, thereby affecting the cell activity.

[0005] (2) Many current dielectrophoresis sorting chips have single function and only one sorting flow channel, and usually can only sort one kind of target microparticle, which is not suitable for some sorting scenarios of mixed multiple target microparticles.

[0006] (3) The existing sorting chip needs to generate droplets of biological microparticles in a droplet generation chip first, and then the droplets are introduced into the sorting chip for sorting. In the process of generating droplets, a large number of empty package droplets and a small number of multiple package droplets will be generated due to Poisson distribution, and the middle droplets may be broken or merged during transfer, thereby causing unnecessary sample waste. SUMMARY

[0007] In order to solve the above technical problems, the application provides a microfluidic sorting chip based on surface acoustic waves, comprising: a piezoelectric substrate; a microparticle inlet for inputting microparticles to be sorted; a sorting unit, an input end of the sorting unit being in communication with the microparticle inlet, the sorting unit being used for guiding microparticles to be sorted; a detection point for detecting the type of microparticles flowing therethrough; a sorting unit, comprising a sorting pipeline, a collection pipeline and a surface acoustic wave generator arranged on the piezoelectric substrate, a first end of the sorting pipeline being in communication with an output end of the sorting unit through the detection point, the collection pipeline being in communication with the sorting pipeline through a side wall of the sorting pipeline, the surface acoustic wave generator being arranged correspondingly at a position in communication with the sorting pipeline and the collection pipeline, the surface acoustic wave generator being used for generating surface acoustic waves when target microparticles reach a region in communication with the sorting pipeline and the collection pipeline, so as to transport the target microparticles from the sorting pipeline to the collection pipeline; a waste liquid outlet in communication with a tail end of the sorting pipeline.

[0008] Further, the sorting unit comprises a spiral sorting pipeline, an input end of the sorting pipeline being in communication with the microparticle inlet, and an output end of the sorting pipeline being in communication with the first end of the sorting pipeline through the detection point.

[0009] Further, the sorting unit comprises a sorting pipeline and an interdigital electrode pair arranged on the piezoelectric substrate, the interdigital electrode pair being used for generating a surface standing wave on the sorting pipeline.

[0010] Further, the surface acoustic wave generator comprises an interdigital electrode arranged on the piezoelectric substrate, and the interdigital electrode is located on a side of the sorting pipeline away from the collection pipeline.

[0011] Further, an air chamber is arranged on a side of the sorting pipeline away from the collection pipeline, and the interdigital electrode is located in the air chamber.

[0012] Further, the collection pipeline comprises a collection channel and a transport channel, one end of the collection channel being in communication with the sorting pipeline through a side wall of the sorting pipeline, and the other end of the collection channel being in communication with the transport channel through a side wall of the transport channel.

[0013] Further, the sorting pipeline is a straight pipeline.

[0014] Further, the sorting unit comprises a plurality of sorting units, and the plurality of sorting units are arranged on the piezoelectric substrate in sequence. The end of the sorting pipe of each sorting unit is connected to the beginning of the sorting pipe of the downstream sorting unit. The beginning of the sorting pipe of the upstream sorting unit is connected to the output end of the sorting unit through the detection point. The end of the sorting pipe of the downstream sorting unit is connected to the waste liquid outlet.

[0015] On the other hand, this application also provides a microfluidic sorting device based on surface acoustic waves, comprising: piezoelectric substrate; The particle inlet is used to input the particles to be sorted. A sorting unit, the input end of which is connected to the particle inlet, is used to guide the particles to sort. Detection points are used to detect the type of particles flowing through them; The first sorting unit includes a first sorting pipe, a first collection pipe, and a first surface acoustic wave generator disposed on the piezoelectric substrate. The first end of the first sorting pipe is connected to the output end of the sorting unit through the detection point. The first collection pipe is connected to the first sorting pipe through the side wall of the first sorting pipe. The first surface acoustic wave generator is disposed in a corresponding area to the area where the first sorting pipe and the first collection pipe are connected. A detection unit is used to detect the type of particles flowing through the detection point; The control unit is electrically connected to the detection unit and the first surface acoustic wave generator. The control unit is used to control the first surface acoustic wave generator to generate surface acoustic waves when the time difference between the time when the detection unit detects the first target particle and the current time reaches a preset first time delay, so as to transport the first target particle from the first sorting pipeline to the first collection pipeline.

[0016] Furthermore, it also includes a second sorting unit, which includes a second sorting pipe, a second collection pipe, and a second surface acoustic wave generator disposed on the piezoelectric substrate. The first end of the second sorting pipe is connected to the end of the first sorting pipe, and the second collection pipe is connected to the second sorting pipe through the side wall of the second sorting pipe. The second surface acoustic wave generator is disposed in a corresponding manner with the areas where the second sorting pipe and the second collection pipe are connected. The control unit is also electrically connected to the second surface acoustic wave generator. The control unit is also used to control the second surface acoustic wave generator to generate surface acoustic waves when the time difference between the time when the detection unit detects the second target particle and the current time reaches a preset second time delay, so as to transport the second target particle from the second sorting pipeline to the second collection pipeline.

[0017] Furthermore, it also includes a third sorting unit, which includes a third sorting pipe, a third collection pipe, and a third surface acoustic wave generator disposed on the piezoelectric substrate. The first end of the third sorting pipe is connected to the end of the second sorting pipe, and the third collection pipe is connected to the third sorting pipe through the side wall of the third sorting pipe. The third surface acoustic wave generator is disposed in a corresponding manner to the area where the third sorting pipe and the third collection pipe are connected. The control unit is also electrically connected to the third surface acoustic wave generator. The control unit is also used to control the third surface acoustic wave generator to generate surface acoustic waves when the time difference between the time when the detection unit detects the third target particle and the current time reaches a preset third time delay, so as to transport the third target particle from the third sorting pipeline to the third collection pipeline.

[0018] Compared with the prior art, the technical solution of this application has the following advantages: (1) The target particles are sorted by surface acoustic waves, which is a mechanical sorting method. It does not generate a high voltage electric field or a high temperature, thus avoiding the adverse effects of the high voltage electric field and high temperature on the activity of the target particles and maximizing the activity of the target particles.

[0019] (2) Multiple sorting units are set up. Different sorting units can be used to sort different target particles, so that multiple target particles can be sorted in one experiment.

[0020] (3) The collection pipeline includes a collection channel and a delivery channel. One end of the collection channel is connected to the sorting pipeline through the side wall of the sorting pipeline, and the other end of the collection channel is connected to the delivery channel through the side wall of the delivery channel. When it is necessary to encapsulate the target particles into droplets to form a separate reaction system, an oil phase is introduced into the delivery channel. When the target particles are "pushed" into the delivery channel by the sound wave through the collection channel, the oil phase with a higher flow rate cuts the water phase with a lower flow rate containing the target particles, so that the target particles are encapsulated in the droplets. This breaks through the Poisson distribution and accurately encapsulates a single target particle into the droplet to form a single encapsulated droplet, avoiding the formation of multiple encapsulated droplets and empty encapsulated droplets, thereby avoiding sample waste.

[0021] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the microfluidic sorting chip according to Embodiment 1 of this application; Figure 2 This is a partial enlarged view of the sorting unit area of ​​the microfluidic sorting chip in Embodiment 1 of this application; Figure 3This is a schematic diagram of the overall structure of another microfluidic sorting chip according to Embodiment 1 of this application; Figure 4 This is a schematic diagram of the overall structure of the sorting chip in the microfluidic sorting device of Embodiment 2 of this application; Figure 5 This is a schematic diagram of the circuit connection structure of the microfluidic sorting device according to Embodiment 2 of this application.

[0023] In the picture: 10. Piezoelectric substrate; 20. Particle inlet; 30. Sorting unit; 31. Sorting pipeline; 32. Interdigitated electrode pair; 40. Detection point; 50. Sorting unit; 51. Sorting pipeline; 52. Collection pipeline; 521. Collection channel; 522. Conveying channel; 523. Current-carrying inlet; 524. Target particle outlet; 53. Surface acoustic wave generator; 531. Interdigitated electrode; 532. Air chamber; 50a. First sorting unit; 51a. First sorting Piping; 52a, First sorting piping; 53a, First surface acoustic wave generator; 50b, Second sorting unit; 51b, Second sorting piping; 52b, Second sorting piping; 53b, Second surface acoustic wave generator; 50c, Third sorting unit; 51c, Third sorting piping; 52c, Third sorting piping; 53c, Third surface acoustic wave generator; 60, Waste liquid outlet; 100, Microfluidic sorting chip; 200, Detection unit; 300, Control unit. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0025] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, and not all of them.

[0027] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship 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 limitations on this invention.

[0028] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0029] The following are several specific embodiments to illustrate the technical solutions of this application in detail. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0030] Example 1 This embodiment provides a microfluidic sorting chip 100 based on surface acoustic waves, such as... Figure 1 As shown, it includes a piezoelectric substrate 10 and a particle inlet 20, a sorting unit 30, a detection point 40, a sorting unit 50, and a waste liquid outlet 60 arranged sequentially along the flow direction.

[0031] The microparticle inlet 20 is used to input biological microparticles to be sorted, such as cells, bacteria, exosomes, and droplets. The biological microparticles to be sorted can be input into the microparticle inlet 20 in the form of a cell suspension, which includes liquid culture medium and the biological microparticles to be sorted.

[0032] The input end of the sorting unit 30 is connected to the particle inlet 20. The particle inlet 20 transports the biological particles to be sorted to the sorting unit 30. The sorting unit 30 is used to guide the biological particles to sort, so that the biological particles are arranged to form a linear queue.

[0033] The detection point 40 is connected to the output end of the sorting unit 30 and is used to detect the type of each biological particle output after sorting by the sorting unit 30.

[0034] like Figure 1 and Figure 2As shown, the sorting unit 50 includes a sorting pipe 51, a collection pipe 52, and a surface acoustic wave generator 53 disposed on the piezoelectric substrate 10. The first end of the sorting pipe 51 is connected to the output end of the sorting unit 30 through the detection point 40. The sorted biological particles output by the sorting unit 30 are transported to the sorting pipe 51 after passing through the detection point 40. The collection pipe 52 is connected to the sorting pipe 51 through the side wall of the sorting pipe 51. The surface acoustic wave generator 53 is disposed at a position corresponding to the area where the sorting pipe 51 and the collection pipe 52 are connected. The surface acoustic wave generator 53 is used to generate surface acoustic waves when the target particles reach the area where the sorting pipe 51 and the collection pipe 52 are connected, so as to transport the target particles from the sorting pipe 51 to the collection pipe 52 through the surface acoustic waves. The collection pipe 52 is used to collect the target particles.

[0035] like Figure 1 As shown, the waste liquid outlet 60 is connected to the end of the sorting pipeline 51 and is used to collect the waste liquid after the target particles are sorted out.

[0036] Compared with the prior art, the microfluidic sorting chip 100 of this embodiment sorts target particles by surface acoustic waves, which is a mechanical force sorting method. It does not generate a high voltage electric field or a high temperature, thereby avoiding the adverse effects of high voltage electric field and high temperature on the activity of target particles and maximizing the activity of target particles.

[0037] To improve the accuracy of detecting and sorting biological particles, in this embodiment, such as Figure 1As shown, the sorting unit 30 includes a spiral sorting conduit 31, whose input end is connected to the particle inlet 20, and whose output end is connected to the beginning of the sorting conduit 51 via a detection point 40. The orderly arrangement of the biological particles to be sorted in the spiral conduit is the result of a balance of several forces. First is inertial lift, which is the force perpendicular to the flow direction experienced by the biological particles in the fluid. In laminar flow, the flow velocity is fastest at the center of the channel and slowest near the wall. This velocity difference causes a shear field that causes the cells to rotate, thus experiencing a force pointing towards the sidewall of the channel. In a straight channel, this force causes the cells to focus at an equilibrium position at a specific distance from the center of the channel. The curvature of the spiral channel introduces Dean's flow, because the fluid velocity and inertia are high at the center of the channel, causing it to move towards the outer wall; while the fluid velocity is slow near the wall, causing it to move inward along the wall, thus forming a pair of vortices rotating in opposite directions on the cross-section of the channel. The cells experience Dean's force in these vortices. Ultimately, the focusing position of the cells depends on the balance between inertial lift and Dean's force. For larger biological particles, inertial lift dominates, causing them to focus more stably on the inner side of the channel. For smaller biological particles, Dean's force has a more significant effect, carrying them towards the outer side of the channel. In practical applications, when the size differences between the various biological particles to be sorted are not significant, they may be simultaneously focused on either the inner or outer side of the channel under the influence of the fluid, thus arranging them in an orderly manner as they move forward.

[0038] Because the biological particles to be sorted are sorted by the sorting unit 30, at any given time, at most one biological particle passes through the detection point 40. This makes the detection of the type of biological particles more accurate and avoids interference from multiple biological particles arriving at the detection point 40 simultaneously. At any given time, at most one biological particle reaches the area where the sorting pipe 51 and the collection pipe 52 are connected. When the target particle reaches the area where the sorting pipe 51 and the collection pipe 52 are connected, no other biological particles have reached that area. At this time, the surface acoustic wave generator 53 generates surface acoustic waves to transport the target particle into the collection pipe 51. No other particles are transported into the collection pipe 51 at the same time, thus making the sorting of the target particle more accurate.

[0039] Besides using spiral tubing to sort the biological particles, surface standing waves can also be used to sort them. For example... Figure 3As shown, in another optional embodiment, the sorting unit 30 may also include a sorting conduit 31 and an interdigitated electrode pair 32 disposed on the piezoelectric substrate 10. The interdigitated electrode pair 32 is used to generate surface standing waves on the sorting conduit 31. Specifically, the interdigitated electrode pair 32 includes a pair of identical interdigitated electrodes, which are symmetrically disposed on both sides of the sorting conduit 31. When the same radio frequency signal is applied to the two interdigitated electrodes, they will excite two columns of surface acoustic waves with the same amplitude and frequency but opposite propagation directions on the surface of the piezoelectric substrate 10. When these two columns of sound waves meet in space, they will interfere and superimpose, resulting in some positions on the waveform where the amplitude is always at its maximum, called antinodes, and other positions where the amplitude is always zero, called nodes. The positions of the antinodes and nodes remain fixed in space. Through a specific design, a single standing surface acoustic wave node is positioned parallel to the middle of the sorting conduit 31. The cell sample will move towards this sound wave node under the action of acoustic radiation force, thereby achieving sorting and focusing.

[0040] In this embodiment, fluorescence detection is used to detect the type of biological particles flowing through detection point 40. Before the biological particles to be sorted are introduced into the microfluidic sorting chip 100 through particle inlet 20, the target particles are fluorescently labeled to facilitate identification in subsequent processes. For example, when the target particles are cells, methods for fluorescent labeling cells include: immunofluorescence labeling, which involves the binding of antigens with specific antibodies, resulting in fluorescence under specific wavelength laser irradiation; fluorescent protein labeling, which involves linking a fluorescent protein gene with a target gene and transferring it into the cell to induce expression and luminescence; synthetic fluorescent dye or probe labeling, which involves small molecule dyes directly and specifically binding to cell structures or ions, resulting in fluorescence under specific wavelength laser irradiation; and bioluminescent labeling, which involves the expression of a luciferase gene in living cells, catalyzing the oxidation of a luciferin substrate to induce luminescence. When there are multiple target particles, different labeling methods can be used to enable different target particles to produce different fluorescence, thus distinguishing the different target particles.

[0041] In order to detect the type of biological particles flowing through the detection point 40, a fluorescence detection optical path needs to be built outside the microfluidic sorting chip 100 in this embodiment to guide a laser of a specific wavelength to irradiate the detection point 40. When the marked biological particles flow through the detection point, they will be excited by the laser to produce fluorescence of a specific wavelength. Under the guidance of the optical path, the fluorescence signal is received by the photomultiplier tube and converted into an electrical signal, which is then transmitted to the subsequent system for signal processing and threshold discrimination, thereby realizing the detection of the type of biological particles.

[0042] After the target particle is detected at detection point 40, it continues to flow downstream. When the target particle reaches the area where the sorting pipe 51 and the collection pipe 52 are connected, the surface acoustic wave generator 53 generates surface acoustic waves to transport the target particle from the sorting pipe 51 to the collection pipe 52. To determine whether the target particle has reached the area where the sorting pipe 51 and the collection pipe 52 are connected, a corresponding time delay can be preset, with the start of timing being when the target particle is detected at detection point 40. When the preset time delay is reached, it is determined that the target particle has reached the area where the sorting pipe 51 and the collection pipe 52 are connected. At this time, the surface acoustic wave generator 53 generates surface acoustic waves to transport the target particle into the collection pipe 52. Preferably, a control unit can be provided to execute the above detection, judgment, and control process. The preset time delay is the time difference between when the target particle arrives at the detection point 40 and when it arrives at the area where the sorting pipe 51 and the collection pipe 52 are connected. This time difference is related to factors such as the distance between the detection point 40 and the area where the sorting pipe 51 and the collection pipe 52 are connected, and the flow rate of the target particle. The preset time delay can be obtained through calculation or experiment.

[0043] In this embodiment, as Figure 2 As shown, the surface acoustic wave generator 53 includes interdigitated electrodes 531 disposed on the piezoelectric substrate 10. The interdigitated electrodes 531 are located on the side of the sorting pipe 51 away from the collecting pipe 52. The interdigitated electrodes 531 generate surface acoustic waves through the inverse piezoelectric effect. When a high-frequency alternating current is applied to the interdigitated electrodes 531, a periodically distributed electrostatic field is generated on the surface of the piezoelectric substrate 10. Under the action of the periodic electrostatic field, the corresponding area on the surface of the piezoelectric substrate 10 will periodically expand and compress, thereby generating surface acoustic waves on the surface of the piezoelectric substrate 10. Preferably, the piezoelectric substrate 10 is a lithium niobate substrate; in other optional embodiments, the piezoelectric substrate 10 may also be a quartz substrate, a lithium tantalate substrate, or a lithium tetraborate substrate.

[0044] In this embodiment, the microfluidic sorting chip 100 has a three-layer structure: the bottom layer is a piezoelectric substrate 10, the middle layer is an electrode layer, and the top layer is a flow channel layer. Interdigitated electrodes 531 are disposed on the electrode layer and formed on the surface of the piezoelectric substrate 10. The flow channel layer is made of PDMS (polydimethylsiloxane). The sorting conduit 31, detection point 40, sorting conduit 51, and collection conduit 52 are all disposed on the PDMS flow channel layer, which is bonded to the side surface of the piezoelectric substrate 10 where the interdigitated electrodes 531 are located. If the PDMS material flow channel layer directly contacts and presses against the interdigital electrode 531, it may affect the normal operation of the interdigital electrode 531. Specifically, this is reflected in: (1) PDMS is an elastic material that absorbs and consumes acoustic energy, causing acoustic energy attenuation, frequency shift and other negative effects; (2) If the bonding process of the flow channel layer is improper (such as introducing bubbles, impurities or causing electrode damage), it may cause the resistance of the interdigital electrode 531 to change or even cause a short circuit; (3) The non-uniformity of PDMS material has a significant impact on applications that require precise acoustic field distribution, such as the application of sorting biological microparticles in this application. The non-uniformity of PDMS material will change the energy distribution of the surface acoustic wave field and reduce the screening accuracy.

[0045] To solve the above technical problems, such as Figure 2 As shown, the microfluidic chip 100 of this embodiment also includes an air chamber 532 disposed on the side of the sorting channel 51 away from the collection channel 52. The interdigital electrode 531 is located inside the air chamber 532, and the height of the air chamber 532 is greater than the thickness of the interdigital electrode 531 to avoid contact between the interdigital electrode 531 and the PDMS material. Preferably, the air chamber 532 is a groove structure formed on the surface of the flow channel layer facing the piezoelectric substrate 10. Similarly, the structure of the air chamber 532 can also be provided on the interdigital electrode pair 32 of the sorting unit 30.

[0046] In this embodiment, as Figure 2 As shown, the collection pipeline 52 includes a collection channel 521 and a conveying channel 522. One end of the collection channel 521 is connected to the sorting pipeline 51 through the side wall of the sorting pipeline 51, and the other end of the collection channel 521 is connected to the conveying channel 522 through the side wall of the conveying channel 522. When the target particle reaches the area where the sorting pipeline 51 and the collection channel 521 are connected, the surface acoustic wave generator 51 generates surface acoustic waves to convey the target particle through the collection channel 521 to the conveying channel 522.

[0047] The two ends of the collection channel 522 are connected to the flow inlet 523 and the target particle outlet 524, respectively. The flow inlet 523 is used to input the fluid medium carrying the target particles, and the target particle outlet 524 is used to connect to the next-level equipment that needs to acquire the target particles.

[0048] When it is necessary to encapsulate target particles into droplets to form a separate reaction system, the flow inlet 523 is filled with an oil phase. When the target particles are "pushed" into the collection channel 522 by the sound waves, the higher-velocity oil phase cuts through the lower-velocity aqueous phase containing the target particles, causing the target particles to be encapsulated in droplets. This breaks through the Poisson distribution, precisely encapsulating individual target particles into droplets to form single-encapsulated droplets, avoiding the formation of multiple encapsulated droplets and empty encapsulated droplets, thus avoiding sample waste. Furthermore, in this embodiment, the target particles are sorted out before being formed into droplets, eliminating the need to set up a droplet generation chip before the microfluidic sorting chip 100.

[0049] When there is no need to encapsulate the target microparticles, but only to enrich and purify a certain target microparticle, the flow inlet 523 is filled with the same culture medium solution as the cell suspension. Finally, the target microparticles are sorted and collected to obtain the purified and enriched sample.

[0050] To prevent non-target particles from entering the collection pipe 52, in a preferred embodiment, such as Figure 2 As shown, the sorting pipe 51 is a straight pipe, and the collection pipe 52 is connected to the sorting pipe 51 through the side wall of the sorting pipe 51. This results in lower flow resistance in the sorting pipe 51 and higher flow resistance towards the collection pipe 52. When non-target particles flow into the area where the sorting pipe 51 and the collection pipe 52 are connected, the surface acoustic wave generator 53 does not generate surface acoustic waves. The non-target particles continue to flow downstream along the sorting pipe 51 instead of flowing towards the more resistant collection pipe 52, thus preventing non-target particles from entering the collection pipe 52 and achieving more accurate sorting. More preferably, the extension direction of the collection channel 521 of the collection pipe 52 is perpendicular to the sorting pipe 51 to further increase the flow resistance towards the collection pipe 52.

[0051] In order to be able to sort multiple target particles, in this embodiment, such as Figure 1 As shown, the sorting unit 50 includes multiple units, which are arranged sequentially on the piezoelectric substrate 10. The end of the sorting pipe 51 of each sorting unit 50 is connected to the beginning of the sorting pipe 51 of the downstream sorting unit 50. The beginning of the sorting pipe 51 of the upstream sorting unit 50 is connected to the output of the sorting unit 30 through the detection point 40, and the end of the sorting pipe 51 of the downstream sorting unit 50 is connected to the waste liquid outlet 60. Thus, different sorting units 50 can be used to sort different target particles, and the microfluidic sorting chip 100 of this application can sort multiple target particles in one experiment.

[0052] Example 2 This embodiment provides a microfluidic sorting device based on surface acoustic waves, including a detection unit 200, a control unit 300, and the microfluidic sorting chip 100 described in Embodiment 1. The microfluidic sorting chip 100 includes multiple sorting units 50. The structures of each sorting unit 50 can be the same or different, and the structure of each sorting unit 50 can be adjusted according to the properties of the target particles. In this embodiment, the microfluidic sorting chip 100 includes three sorting units 50 as an example for illustration. However, the number of sorting units 50 is not limited to three; it can also be one, two, or more than three, depending on the number of types of target particles to be sorted. For ease of description, the three sorting units 50 in this embodiment are referred to as the first sorting unit 50a, the second sorting unit 50b, and the third sorting unit 50c, respectively.

[0053] Specifically, such as Figure 4 As shown, the microfluidic sorting chip 100 includes: Piezoelectric substrate 10; Microparticle inlet 20 is used to input biological microparticles to be sorted; The sorting unit 30 has its input end connected to the particle inlet 20. The particle inlet 20 transports the biological particles to be sorted to the sorting unit 30. The sorting unit 30 is used to guide the biological particles to sort, so that the biological particles are arranged to form a linear queue. Detection point 40 is connected to the output end of sorting unit 30 and is used to detect the type of each biological particle output after sorting by sorting unit 30. The first sorting unit 50a includes a first sorting pipe 51a, a first collection pipe 52a and a first surface acoustic wave generator 53a disposed on the piezoelectric substrate 10. The first end of the first sorting pipe 51a is connected to the output end of the sorting unit 30 through the detection point 40. The first collection pipe 52a is connected to the first sorting pipe 51a through the side wall of the first sorting pipe 51a. The first surface acoustic wave generator 53a is disposed in a corresponding manner to the areas connected to the first sorting pipe 51a and the first collection pipe 52a. The second sorting unit 50b includes a second sorting pipe 51b, a second collection pipe 52b, and a second surface acoustic wave generator 53b disposed on the piezoelectric substrate 10. The first end of the second sorting pipe 51b is connected to the end of the first sorting pipe 51a. The second collection pipe 52b is connected to the second sorting pipe 51b through the side wall of the second sorting pipe 51b. The second surface acoustic wave generator 53b is disposed in a corresponding manner with the areas where the second sorting pipe 51b and the second collection pipe 52b are connected. The third sorting unit 50c includes a third sorting pipe 51c, a third collection pipe 52c and a third surface acoustic wave generator 53c disposed on the piezoelectric substrate 10. The first end of the third sorting pipe 51c is connected to the end of the second sorting pipe 51b. The third collection pipe 52c is connected to the third sorting pipe 51c through the side wall of the third sorting pipe 51c. The third surface acoustic wave generator 53c is disposed in a corresponding manner with the areas connected to the third sorting pipe 51c and the third collection pipe 52c. Waste liquid outlet 60 is connected to the end of the third sorting pipeline 51c.

[0054] like Figure 5 As shown, the control unit 300 is electrically connected to the detection unit 200, the first surface acoustic wave generator 53a, the second surface acoustic wave generator 53b, and the third surface acoustic wave generator 53c, respectively. The detection unit 200 is used to detect the type of biological particles flowing through the detection point 40. The control unit 300 is used to acquire the detection results of the detection unit 200. The control unit 300 is also used to: (1) when the time difference between the time when the detection unit 200 detects the first target particle and the current time reaches a preset first time delay, control the first surface acoustic wave generator 53a to generate surface acoustic waves to displace the first target particle from the first sorting pipe 51. (1) The second target particle is transported to the first collection pipe 52a; (2) When the time difference between the detection unit 200 detecting the second target particle and the current time reaches a preset second time delay, the second surface acoustic wave generator 53b is controlled to generate surface acoustic waves to transport the second target particle from the second sorting pipe 51b to the second collection pipe 52b; and (3) When the time difference between the detection unit 200 detecting the third target particle and the current time reaches a preset third time delay, the third surface acoustic wave generator 53c is controlled to generate surface acoustic waves to transport the third target particle from the third sorting pipe 51c to the third collection pipe 52c.

[0055] In this embodiment, the methods for determining the first time delay, the second time delay, and the third time delay can refer to the method for determining the time delay in the first embodiment. The specific structures of the first sorting pipe 51a, the second sorting pipe 51b, and the third sorting pipe 51c in this embodiment can refer to the sorting pipe 51 in the first embodiment. The specific structures of the first collection pipe 52a, the second collection pipe 52b, and the third collection pipe 52c in this embodiment can refer to the collection pipe 52 in the first embodiment. The specific structures of the first surface acoustic wave generator 53a, the second surface acoustic wave generator 53b, and the third surface acoustic wave generator 53c in this embodiment can refer to the surface acoustic wave generator 53 in the first embodiment.

[0056] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A microfluidic sorting chip based on surface acoustic waves, characterized in that, include: Piezoelectric substrate (10); Particle inlet (20) is used to input particles to be sorted; The sorting unit (30) has its input end connected to the particle inlet (20) and is used to guide the particles to sort. Detection point (40) is used to detect the type of particles flowing through it; The sorting unit (50) includes a sorting pipe (51), a collection pipe (52), and a surface acoustic wave generator (53) disposed on the piezoelectric substrate (10). The first end of the sorting pipe (51) is connected to the output end of the sorting unit (30) through the detection point (40). The collection pipe (52) is connected to the sorting pipe (51) through the side wall of the sorting pipe (51). The surface acoustic wave generator (53) is disposed corresponding to the area connected to the sorting pipe (51) and the collection pipe (52). The surface acoustic wave generator (53) is used to generate surface acoustic waves when the target particle arrives at the area connected to the sorting pipe (51) and the collection pipe (52) to transport the target particle from the sorting pipe (51) to the collection pipe (52). Waste liquid outlet (60) is connected to the end of the sorting pipeline (51).

2. The microfluidic sorting chip based on surface acoustic waves according to claim 1, characterized in that, The sorting unit (30) includes a spiral sorting pipeline (31), the input end of which is connected to the particle inlet (20), and the output end of which is connected to the head end of the sorting pipeline (51) through the detection point (40).

3. The microfluidic sorting chip based on surface acoustic waves according to claim 1, characterized in that, The sorting unit (30) includes a sorting conduit (31) and an interdigitated electrode pair (32) disposed on the piezoelectric substrate (10), the interdigitated electrode pair (32) being used to generate surface standing waves on the sorting conduit (31).

4. The microfluidic sorting chip based on surface acoustic waves according to claim 1, characterized in that, The surface acoustic wave generator (53) includes an interdigitated electrode (531) disposed on the piezoelectric substrate (10), and the interdigitated electrode (531) is located outside the sorting pipeline (51) on the side away from the collection pipeline (52); the surface acoustic wave generator (53) also includes an air chamber (532) disposed outside the sorting pipeline (51) on the side away from the collection pipeline (52), and the interdigitated electrode (531) is located inside the air chamber (532).

5. The microfluidic sorting chip based on surface acoustic waves according to claim 1, characterized in that, The collection pipeline (52) includes a collection channel (521) and a conveying channel (522). One end of the collection channel (521) is connected to the sorting pipeline (51) through the side wall of the sorting pipeline (51), and the other end of the collection channel (521) is connected to the conveying channel (522) through the side wall of the conveying channel (522).

6. The microfluidic sorting chip based on surface acoustic waves according to claim 1, characterized in that, The sorting pipeline (51) is a straight pipe.

7. The microfluidic sorting chip based on surface acoustic waves according to any one of claims 1 to 6, characterized in that, The sorting unit (50) includes a plurality of sorting units (50), which are arranged sequentially on the piezoelectric substrate (10); The end of the sorting pipe (51) of each sorting unit (50) is connected to the beginning of the sorting pipe (51) of the downstream sorting unit (50). The beginning of the sorting pipe (51) of the upstream sorting unit (50) is connected to the output end of the sorting unit (30) through the detection point (40). The end of the sorting pipe (51) of the downstream sorting unit (50) is connected to the waste liquid outlet (60).

8. A microfluidic sorting device based on surface acoustic waves, characterized in that, include: Piezoelectric substrate (10); Particle inlet (20) is used to input particles to be sorted; The sorting unit (30) has its input end connected to the particle inlet (20) and is used to guide the particles to sort. Detection point (40) is used to detect the type of particles flowing through it; The first sorting unit (50a) includes a first sorting pipe (51a), a first collection pipe (52a), and a first surface acoustic wave generator (53a) disposed on the piezoelectric substrate (10). The first end of the first sorting pipe (51a) is connected to the output end of the sorting unit (30) through the detection point (40). The first collection pipe (52a) is connected to the first sorting pipe (51a) through the side wall of the first sorting pipe (51a). The first surface acoustic wave generator (53a) is disposed in a corresponding manner to the area connected to the first sorting pipe (51a) and the first collection pipe (52a). The detection unit (200) is used to detect the type of particles flowing through the detection point (40); The control unit (300) is electrically connected to the detection unit (200) and the first surface acoustic wave generator (53a); the control unit (300) is used to control the first surface acoustic wave generator (53a) to generate surface acoustic waves when the time difference between the time when the detection unit (200) detects the first target particle and the current time reaches a preset first time delay, so as to transport the first target particle from the first sorting pipeline (51a) to the first collection pipeline (52a).

9. The microfluidic sorting device based on surface acoustic waves according to claim 8, characterized in that, It also includes a second sorting unit (50b), which includes a second sorting pipe (51b), a second collection pipe (52b), and a second surface acoustic wave generator (53b) disposed on the piezoelectric substrate (10). The first end of the second sorting pipe (51b) is connected to the end of the first sorting pipe (51a). The second collection pipe (52b) is connected to the second sorting pipe (51b) through the side wall of the second sorting pipe (51b). The second surface acoustic wave generator (53b) is disposed in a corresponding manner to the area where the second sorting pipe (51b) and the second collection pipe (52b) are connected. The control unit (300) is also electrically connected to the second surface acoustic wave generator (53b). The control unit (300) is also used to control the second surface acoustic wave generator (53b) to generate surface acoustic waves when the time difference between the time when the detection unit (200) detects the second target particle and the current time reaches a preset second time delay, so as to transport the second target particle from the second sorting pipeline (51b) to the second collection pipeline (52b).

10. The microfluidic sorting device based on surface acoustic waves according to claim 9, characterized in that, It also includes a third sorting unit (50c), which includes a third sorting pipe (51c), a third collection pipe (52c), and a third surface acoustic wave generator (53c) disposed on the piezoelectric substrate (10). The first end of the third sorting pipe (51c) is connected to the end of the second sorting pipe (51b). The third collection pipe (52c) is connected to the third sorting pipe (51c) through the side wall of the third sorting pipe (51c). The third surface acoustic wave generator (53c) is disposed in a corresponding manner to the area where the third sorting pipe (51c) and the third collection pipe (52c) are connected. The control unit (300) is also electrically connected to the third surface acoustic wave generator (53c). The control unit (300) is also used to control the third surface acoustic wave generator (53c) to generate surface acoustic waves when the time difference between the time when the detection unit (200) detects the third target particle and the current time reaches a preset third time delay, so as to transport the third target particle from the third sorting pipeline (51c) to the third collection pipeline (52c).

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