Particle sorting device and method

Abstract

The application relates to a particle sorting device and method, which comprises a microfluidic channel, a bulk acoustic wave device, two first surface acoustic wave resonators located outside the microfluidic channel for generating a standing wave with two nodes in the microfluidic channel, the two nodes being located at the same positions as the acoustic fluid tunnels of the two side edges of the bulk acoustic wave device to enhance the effect of the acoustic fluid tunnels of the two side edges on capturing particles; two second surface acoustic wave resonators located outside the microfluidic channel downstream of the bulk acoustic wave device for generating a standing wave with one node in the microfluidic channel to move part of the particles released at the end of the bulk acoustic wave device to the node position; the particles released at the end of the bulk acoustic wave device and not moved to the node position generated by the two second surface acoustic wave resonators flow to a first sub-channel, and the particles released at the end of the bulk acoustic wave device and moved to the node position generated by the two second surface acoustic wave resonators flow to a second sub-channel. The application can improve the sorting performance of particles.

Description

Technical Field

[0001] This application relates to the fields of micro-electro-mechanical systems (MEMS) technology and microfluidics technology, and in particular to a particle sorting device and method. Background Technology

[0002] In the process of detecting biological cells and other particles in fluids based on microfluidic systems, in order to enhance the detection performance (such as detecting cells, proteins and other particles), the particles are usually enriched first, and then the enriched particles or the sorted target particles are detected.

[0003] The microfluidic system is based on a microfluidic control chip, supplemented by an external driving physical field and a detection system. It aims to build a miniaturized on-chip biochemical laboratory, that is, to integrate the basic operation processes involved in the fields of biology and chemistry, such as sample preparation, reaction, detection, separation, cell culture, screening, and lysis, into a micron-level microchannel network, so as to realize the various functions of the biochemical laboratory more efficiently at a lower cost.

[0004] Microfluidics includes liquid particle capture technology, a crucial branch of microfluidics. After capturing particles, they can be further sorted, released at specific points, and detected. In particle capture and release techniques, the jet effect of a bulk acoustic wave (BAW) device generates microvortices in the liquid, creating an acoustic-fluid tunnel effect at the edge of the BAW device. This traps particles within the tunnel, allowing them to queue and move downstream to a specific location (e.g., an end point of the BAW device) for release, thus achieving sorting. This acoustic-based approach offers advantages such as low power consumption, minimal cell damage, and high versatility.

[0005] Generally speaking, for integrated acoustic wave devices, their ability to capture particles can be controlled by adjusting the driving power. For example, the stronger the power, the stronger the particle capture ability of the bulk acoustic wave device. This can be reflected in the fact that the particles captured through microvortices or acoustic fluid tunnels are smaller in size, or the trajectory of the captured particles is closer to the inner orbit of the microvortex or acoustic fluid tunnel (see [reference]). Figure 1a The diagram on the right illustrates the trajectory of the microparticles. Since microchannels are bounded spaces (such as top constraints), when the power of the bulk acoustic wave device exceeds a certain threshold, the jet generated within the limited space becomes too strong, causing a chaotic flow effect in the fluid. This increases the instability of microvortices or acoustic-fluid tunnels within the microchannel, making it impossible to form stable microvortices or acoustic-fluid tunnels, thus reducing the ability to capture and manipulate particles.

[0006] How to improve the ability to capture particles and thus enhance sorting and detection capabilities is a technical problem that needs to be solved. Summary of the Invention

[0007] In view of the above-mentioned problems of the prior art, this application provides a particle sorting device and method to improve the ability to sort and detect particles.

[0008] The first aspect of this application provides a particle sorting device, comprising:

[0009] Microchannels contain liquids containing microparticles;

[0010] A bulk acoustic wave device is located at the bottom of a microchannel. The bulk acoustic wave device is leaf-shaped, with two sides of the leaf shape extending parallel to each other along the direction of the microchannel. The upstream and downstream ends of the leaf shape are angled, forming the head and tail of the bulk acoustic wave device. When the bulk acoustic wave device is in operation, it is used to generate an acoustic tunnel corresponding to the edge of the bulk acoustic wave device in the microchannel to capture particles in the liquid in the microchannel and release them at its tail.

[0011] Two first surface acoustic wave resonators are located outside the microchannel and on both sides of the bulk acoustic wave device to generate standing waves in the microchannel. The standing waves have two nodes, and the positions of the two nodes are the same as the positions of the acoustic fluid tunnels on both sides of the bulk acoustic wave device, so as to enhance the effect of the acoustic fluid tunnels on both sides capturing particles.

[0012] Two second surface acoustic wave resonators are arranged on both sides of the microchannel downstream of the bulk acoustic wave device to generate a standing wave in the microchannel, and the standing wave has a node to move some of the particles released at the end of the bulk acoustic wave device to the node position.

[0013] At least two sub-channels are located at the downstream end of the main flow channel. The at least two sub-channels include a first sub-channel and a second sub-channel. The inlet position of the first sub-channel corresponds to the end position of the bulk acoustic wave device, and the inlet position of the second sub-channel corresponds to the node position generated by the two second surface acoustic wave resonators. This is used to allow particles released at the end of the bulk acoustic wave device that are not moved to the node position generated by the two second surface acoustic wave resonators to flow to the first sub-channel, and particles released at the end of the bulk acoustic wave device that are moved to the node position generated by the two second surface acoustic wave resonators to flow to the second sub-channel.

[0014] Optionally, a portion of the surface acoustic wave resonator extends upstream of the microchannel relative to the side of the bulk acoustic wave device.

[0015] Optionally, the effect of the enhanced side acoustic fluid tunnel in capturing particles includes at least one of the following: the captured particles include smaller particles compared to particles captured using only a bulk acoustic device; and the captured particles are more concentrated towards the center of the acoustic fluid tunnel compared to particles captured using only a bulk acoustic device.

[0016] Optionally, it also includes: a particle enrichment device disposed in at least one sub-channel; and a detection device for detecting the particles enriched by the particle enrichment device.

[0017] Optionally, the first and second surface acoustic wave resonators are disposed on the same substrate as the microchannel, and the first and second surface acoustic wave resonators propagate surface waves to the microchannel through the substrate.

[0018] A second aspect of this application provides a particle sorting method using any of the particle sorting devices described above, the method comprising:

[0019] Based on the bulk acoustic wave device, an acoustic flow tunnel is generated at the edge position of the bulk acoustic wave device in the microchannel to capture particles in the liquid in the microchannel and release them at the end of the bulk acoustic wave device.

[0020] Based on two first surface acoustic wave resonators, a standing wave with two nodes is generated in the microchannel, which enhances the effect of the acoustic fluid tunnels on both sides of the bulk acoustic wave device in capturing particles.

[0021] Two second surface acoustic wave resonators are used to generate a standing wave with a node in the microchannel, so as to move some of the particles released at the end of the bulk acoustic wave device to the node position.

[0022] Particles released at the end of the bulk acoustic wave device that are not moved to the node positions generated by the two second surface acoustic wave resonators flow to the first sub-channel, while particles released at the end of the bulk acoustic wave device that are moved to the node positions generated by the two second surface acoustic wave resonators flow to the second sub-channel.

[0023] Optionally, it further includes: capturing and enriching particles flowing into at least one sub-channel using a particle enrichment device, and detecting them using a detection device.

[0024] Optionally, it also includes: turning off or reducing the power of the surface acoustic wave resonator to reduce the effect of the acoustic fluid tunnel trapping particles, thereby releasing some of the trapped particles.

[0025] Optionally, it may also include: reducing the power of the bulk acoustic device to reduce the effect of the acoustic fluid tunnel trapping particles, thereby releasing some of the trapped particles.

[0026] Optionally, it also includes: adjusting the flow rate of the fluid within the microchannel to adjust the effect of the acoustic fluid tunnel in capturing particles.

[0027] The particle sorting scheme provided in this application improves the particle capture capability during the particle sorting process. For example, it can capture particles with smaller diameters and make particles gather more towards the center of the acoustic fluid tunnel, thereby improving the enrichment or aggregation capability. Furthermore, it also brings the ability of particles to queue more focusedly along the acoustic fluid tunnel and the focusing capability of release at a fixed point (such as the end of the bulk acoustic wave device), thereby improving the sorting performance (such as the release position of the downstream sorting channel is more accurate due to the focusing of the release point). Attached Figure Description

[0028] Figure 1a This is a schematic diagram of the jet phenomenon and secondary flow phenomenon generated by the bulk acoustic wave device provided in the embodiments of this application;

[0029] Figure 1b This is a schematic diagram of the acoustic-fluid tunnel provided in an embodiment of this application;

[0030] Figure 2a This is a schematic diagram of the particle sorting device provided in the first embodiment of this application;

[0031] Figure 2b This is a schematic diagram of the standing waves of the first SAW and the second SAW.

[0032] Figure 3a This is a top view schematic diagram of a specific embodiment of the particle sorting device provided in this application;

[0033] Figure 3b yes Figure 3a A schematic diagram of its side view;

[0034] Figure 4 This is a simulation diagram of the BAW and the first SAW capturing particles provided in the embodiments of this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1-Sample inlet tube, 2-Substrate, 3-First surface acoustic wave resonator, 4-Second surface acoustic wave resonator, 5-Sample outlet tube, 6-Particle enrichment device, 7-Bulk acoustic wave device.

[0037] It should be understood that the dimensions and shapes of the blocks in the above structural diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of the present invention. The relative positions and inclusion relationships between the blocks presented in the structural diagrams are only schematic representations of the structural relationships between the blocks, and are not intended to limit the physical connection methods of the embodiments of the present invention. Detailed Implementation

[0038] The technical solutions provided in this application will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the system architecture and business scenarios provided in the embodiments of this application are mainly for illustrating possible implementations of the technical solutions of this application and should not be construed as the sole limitation on the technical solutions of this application. Those skilled in the art will recognize that the technical solutions provided in this application are equally applicable to similar technical problems as system architectures evolve and new business scenarios emerge.

[0039] It should be understood that the particle sorting schemes provided in the embodiments of this application include particle sorting devices and methods. Since these technical solutions solve problems based on the same or similar principles, some repetitive details may not be repeated in the following descriptions of specific embodiments. However, it should be considered that these specific embodiments have mutual references and can be combined with each other.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application. To accurately describe the technical content of this application and to accurately understand the invention, the following explanations or definitions of the terms used in this specification are provided before describing specific embodiments:

[0041] 1) Bulk Acoustic Wave Device: A high-frequency resonator, which can be a device that generates mechanical vibration by applying voltage based on the piezoelectric effect. In a liquid, it can generate volume force based on bulk acoustic waves to push the liquid to form a jet and induce micro-vortices in the fluid. In this application, a piezoelectric resonator that generates at least 0.5 GHz (gigahertz is equivalent to GHz) during operation is used. Preferably, it is a piezoelectric resonator that generates at least 1 GHz and no more than 30 GHz during operation, for example, a piezoelectric resonator of 2 GHz to 2.5 GHz.

[0042] Among them, bulk acoustic wave devices can include thin-film bulk acoustic wave devices (FBAR) and solid-state assembled resonators (SMR).

[0043] 2) Jet phenomenon: This is a phenomenon that occurs when the sound waves from a bulk acoustic wave device act on a liquid. The regional vibration generated at the working interface of the bulk acoustic wave device can form a traveling wave in the liquid and exert a continuous thrust on the local liquid in the liquid environment, causing at least a portion of the liquid to move in a straight line along the direction of sound wave propagation. This phenomenon of straight-line movement is called jet phenomenon.

[0044] Secondary flow phenomena, including eddies and thermal recirculation, are another phenomenon generated when a bulk acoustic wave device acts on a liquid. They include eddies (or micro vortices) caused by the local circulation of the liquid driven by the jet, and thermal recirculation generated by the heat generated by the bulk acoustic wave device.

[0045] The jet phenomenon and secondary flow phenomenon can be found in [reference needed]. Figure 1a The images and diagrams shown. Figure 1a The diagram shows a schematic of using eddies (i.e., microvortices) to capture particles.

[0046] 3) Acoustic-Fluid Tunnel: Under the excitation of an input signal, a bulk acoustic wave device generates ultra-high frequency vibrations and emits bulk acoustic waves. These waves propagate through the fluid, inducing directional fluid motion (jet phenomenon), further forming fluid micro-vortices. One such phenomenon is the generation of numerous tiny fluid micro-vortices (e.g., at the chip edge of the bulk acoustic wave device) within the fluid. Figure 1a As shown in the diagram, these fluid microvortices can trap particles in the liquid. Combined with the positional distribution of these fluid microvortices, they exhibit the phenomenon of particles in the liquid being distributed along the chip edge of a bulk acoustic wave device. Since the particles in the fluid flow through these fluid microvortices distributed along the chip edge, the paths formed by these fluid microvortices that allow particles to flow (such as...) Figure 1b As shown in the figure, this application refers to it as an acoustic fluid tunnel.

[0047] 4) Surface Acoustic Wave (SAW) Resonator: Typically formed by interdigitated electrodes, the sound wave propagates directionally along the surface of the substrate containing the interdigitated electrodes. When applied to a liquid, it can generate a standing wave, which includes antinodes and nodes. When used to manipulate particles in microchannels, the SAW resonator can move the particles to the nodes.

[0048] 5) Particles: refers to geometric bodies with a specific shape within a certain size range. For example, microscopic particles that are located in a liquid environment and can be distinguished from the liquid environment (i.e., insoluble) and can be moved in the liquid environment can all be regarded as particles as described in this application.

[0049] In some embodiments, the particle diameter can range from the nanoscale to the millimeter scale, and the particles can include: cells, molecules, molecular polymers, long-chain molecules, DNA nucleic acids, inorganic particles, metal particles, composite particles, magnetic particles, quantum dots, microbeads (or microspheres, used for functional modification, such as modifying proteins, specific substances, etc.), etc. In some embodiments, the particles can also be non-solid, for example, they can be in the form of droplets, such as in the form of droplets in another immiscible liquid medium, such as water droplets (or water beads) in the oil phase of a microfluidic channel, or oil droplets (or oil beads) in the aqueous phase, etc.

[0050] 6) Reasonable range of parameters, and positive and negative correlations between parameters: A reasonable range refers to the range of parameters that conform to the scheme of this application, such as particle size within a reasonable range, power control within a reasonable range, etc. These ranges can be obtained experimentally. Positive correlation between parameters means that one parameter increases as another parameter increases, and negative correlation means that one parameter increases as another parameter decreases. The parameters mentioned in this application cannot be infinitely small or infinitely large. Therefore, unless otherwise specified, the parameter values ​​mentioned in this application refer to values ​​within a reasonable range. For example, when describing a positive correlation between parameter A and parameter B, it means that within a certain range, parameter A and parameter B are positively correlated, and it can be predicted that beyond this range, parameter B will no longer be positively correlated with parameter A (after parameter A increases to a certain value, B reaches a saturation state, and then parameter B will no longer increase with the increase of parameter A). This range of values ​​is the reasonable range of values.

[0051] This application provides an improved particle sorting scheme. By combining bulk acoustic wave devices and SAW devices, the capture capability of particles can be improved, and particles with smaller diameters can be captured. Alternatively, the trajectory of the captured particles can be made closer to the inner orbit of micro vortices or acoustic fluid tunnels, resulting in a stronger aggregation effect and thus improving the subsequent particle sorting performance.

[0052] The solutions provided in this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] The first embodiment of this application provides a particle manipulation device, referring to... Figure 2a , Figure 2b , Figure 3a , Figure 3b As shown, the control device includes:

[0054] Microchannels contain liquids containing microparticles;

[0055] The bulk acoustic wave device 7 is located at the bottom of the microchannel, and the bulk acoustic wave device 7 is leaf-shaped (the leaf shape in this application is as follows). Figure 2b As shown, it is approximately spindle-shaped. The two sides forming the leaf shape extend along the direction of the microchannel and are arranged in parallel. The upstream and downstream ends forming the leaf shape are angled and are the head and tail ends of the bulk acoustic wave device 7. When the bulk acoustic wave device 7 is in working state, it is used to generate an acoustic flow tunnel in the microchannel corresponding to the edge of the bulk acoustic wave device 7 to capture the particles in the liquid in the microchannel and release them at its tail.

[0056] Two first surface acoustic wave resonators 3 (hereinafter referred to as SAW) are located outside the microchannel and on both sides of the bulk acoustic wave device 7. They are used to generate standing waves in the microchannel, and the standing waves have two nodes. The positions of the two nodes are the same as the positions of the acoustic fluid tunnels on both sides of the bulk acoustic wave device 7, so as to enhance the effect of the acoustic fluid tunnels on both sides capturing particles.

[0057] Two second surface acoustic wave resonators 4 are arranged on both sides of the microchannel downstream of the bulk acoustic wave device 7 to generate a standing wave in the microchannel, and the standing wave has a node to move some of the particles released at the end of the bulk acoustic wave device 7 to the node position.

[0058] At least two sub-channels are located at the downstream end of the main flow channel. The at least two sub-channels include a first sub-channel and a second sub-channel. The inlet position of the first sub-channel corresponds to the end position of the bulk acoustic wave device 7, and the inlet position of the second sub-channel corresponds to the node position generated by the two second SAWs. The sub-channels are used to allow particles released at the end of the bulk acoustic wave device 7 that are not moved to the node position generated by the two second SAWs to flow to the first sub-channel, and particles released at the end of the bulk acoustic wave device 7 that are moved to the node position generated by the two second SAWs to flow to the second sub-channel.

[0059] The particle size of the particles that are moved to the node positions generated by the two second SAWs is larger than that of the particles released at the end of the bulk acoustic wave device 7 that are not moved to the node positions generated by the two second SAWs. This is because the larger particles are more affected by the force of the standing waves generated by the two second SAWs and are more easily moved to the node positions.

[0060] In some embodiments, at least one sub-channel includes a particle enrichment device 6 and a detection device. The particle enrichment device 6 may be implemented as a regular pentagonal bulk acoustic wave device located at the bottom of the corresponding sub-channel, which captures and enriches particles through micro-vortices on its sides. The detection device may be an optical device, such as a fluorescence detection device, facing the particle enrichment device 6, used to detect the enriched particles (the particles may be pre-fluorescently modified). The detection device may also be an electron microscope, etc.

[0061] The surface wave propagation directions of the two first SAWs and two second SWAs located outside the microchannel are all towards the microchannel. The first SAWs, second SAWs and the microchannel can be disposed on the same substrate 2, and the surface waves propagate to the microchannel through the substrate 2.

[0062] In some embodiments, enhancing the effect of the acoustic fluid tunnel in capturing particles includes including smaller particles among the captured particles compared to particles captured using only the bulk acoustic device 7. This allows for the application of manipulation techniques for smaller particles.

[0063] In some embodiments, enhancing the effect of acoustic-fluid tunneling in trapping particles includes causing the trapped particles to concentrate more towards the center of the acoustic-fluid tunnel, an effect that can be seen in [reference needed]. Figure 4 The simulation diagram of c in the figure shows that further aggregation of the captured particles can be achieved, which can facilitate enrichment detection (such as checking the intensity of modified fluorescence; the higher the aggregation degree, the stronger the fluorescence intensity) or manipulation of the movement trajectory (the movement trajectory is more focused).

[0064] In some embodiments, the width of the two first SAWs (the width direction refers to the direction parallel to the interdigitation of the SAWs) can be matched with the length of the two sides of the bulk acoustic wave device 7, for example, the same size.

[0065] In other embodiments, the width of the two first SAW devices can be longer than the length of the two sides of the bulk acoustic wave device 7, and the extended portion extends upstream relative to the two sides of the bulk acoustic wave device 7. Thus, before the particles in the fluid within the microchannel reach the bulk acoustic wave device 7, some particles can be migrated to the two nodes of the standing wave formed by the two first SAW devices, and then enter the acoustic-fluid tunnels on both sides of the bulk acoustic wave device 7. That is, preliminary particle aggregation is formed through the two first SAW devices.

[0066] like Figure 3a and Figure 3b The figure shows a specific embodiment of a particle sorting device. In this figure, the upstream of the microchannel is connected to a sample inlet tube 1, and the downstream of the microchannel has three subchannels, which are respectively connected to the sample outlet tube 5. The particle enrichment device 6 adopts a pentagonal BAW device.

[0067] The second embodiment of this application also provides a particle sorting method, which uses the particle sorting device described in the first embodiment or any optional embodiment to manipulate particles. The method includes:

[0068] The bulk acoustic wave device 7 is put into operation to generate an acoustic flow tunnel corresponding to the edge of the bulk acoustic wave device 7 in the microchannel, so as to capture particles in the liquid in the microchannel and release them at its end.

[0069] The two first SAWs are put into operation to generate a standing wave with two nodes in the microchannel, which enhances the effect of the acoustic fluid tunnels on both sides of the bulk acoustic wave device 7 in capturing particles.

[0070] The two second SAWs are put into operation to generate a standing wave with a node in the microchannel, so that some of the particles released at the end of the bulk acoustic wave device 7 are moved to the node position.

[0071] Particles released at the end of the bulk acoustic wave device 7 that are not moved to the node positions generated by the two second SAWs flow to the first sub-channel, while particles released at the end of the bulk acoustic wave device 7 that are moved to the node positions generated by the two second SAWs flow to the second sub-channel.

[0072] In some embodiments, the method further includes: capturing and enriching particles flowing into at least one subchannel using a particle enrichment device 6, and detecting them using a detection device.

[0073] In some embodiments, the method further includes: turning off or reducing the first SAW power to reduce the effect of the acoustic fluid tunnel in trapping particles, thereby releasing some of the trapped particles. The released particles are smaller in size than the unreleased particles.

[0074] In some embodiments, the method further includes reducing the power of the bulk acoustic device 7 to reduce the effect of the acoustic fluid tunnel trapping particles, thereby releasing some of the trapped particles. The released particles are smaller in size than the unreleased particles.

[0075] In some embodiments, the method further includes adjusting the flow rate of the fluid within the microchannel to adjust the effect of the acoustic-fluid tunnel in capturing particles. The faster the flow rate, the shorter the residence time of the particles within the microchannel, and the weaker the capture effect.

[0076] The following further explains why this application can improve particle manipulation capabilities based on the combination of a bulk acoustic wave (BAW) device and two first SAWs. Specifically, the microchannel is designed with a height of 50 μm, the particles are 1 μm in size, and a BAW is used as the bulk acoustic wave device. Simulations were then performed by individually starting the two first SAWs and the BAW, and simultaneously starting the BAW and the two first SAWs. Figure 4 The simulation diagram is shown.

[0077] See Figure 4 Figure a in the diagram is a simulation of the flow field velocity distribution in the microchannel when only the first SAW is activated. The right figure represents the simulation of the enrichment of 1μm diameter particles in the microchannel. It can be seen that due to the attenuation of acoustic radiation force, the enrichment effect of only activating the first SAW on 1μm particles is weak. In the right figure, the arrows near the bottom point to the enriched particles, and the arrows near the top point to the unenriched particles.

[0078] In this process, the acoustic radiation force of the two first SAW devices forms a standing wave in the microchannel, which migrates the nanoparticles in the microchannel to the vicinity of the wave node, forming a focusing of the particles, thereby confining the randomly dispersed nanoparticles in the microchannel to a certain position (i.e., the wave node position). Figure 4 In point a, the point above the highest velocity point at the bottom of the microchannel is the lowest velocity point, also known as the wave node.

[0079] See Figure 4 Figure b in the figure is a simulation diagram of the flow field velocity distribution in the microchannel when only the BAW is activated. As shown in the flow field diagram on the left, the maximum velocity of the flow field can reach 0.176 m / s. The figure on the right represents the simulation of the distribution of 1 μm particles in the microchannel after the BAW is activated. Most particles are distributed in the outer orbit of the micro vortex (generated by BAW) corresponding to the acoustic fluid tunnel, as shown by the arrow in the figure.

[0080] In this process, the acoustic radiation force of the BAW device pushes the nanoparticles to the central region of the acoustic flow microvortex. The nanoparticles then follow a spiral trajectory within the acoustic flow microvortex, gradually reaching an equilibrium position and distributing along its orbit. Figure 4 The simulation diagram in Figure b shows the capture capability of 1μm particles at a higher power achieved by continuously increasing the power of the BAW to improve its capture capability. When the power is further increased, the capture capability of 1μm particles will decrease. It is speculated that this is due to the excessively strong jet combined with the limitation of the microchannel, which makes it difficult for the fluid to generate stable microvortices.

[0081] See Figure 4 Figure c in the diagram is a simulation of the flow field velocity distribution superimposed after the two first SAWs and BAW are simultaneously activated. The standing wave nodes formed by the two first SAWs are located at the microvortices (acoustic-fluid tunnels) corresponding to the two edges of the BAW. When both devices are operating simultaneously, as shown in the flow field diagram on the left, the maximum flow field velocity can reach 0.22 m / s (meaning stronger trapping capability). On the other hand, the 1 μm particles in the microchannel, due to the simultaneous influence of acoustic radiation forces from both the first SAW and BAW, move closer to the center of the acoustic-fluid microvortex, as indicated by the arrows in the particle enrichment diagram on the right.

[0082] As can be seen above, under the influence of the two primary SAW and BAW acoustic radiation forces, the motion trajectory is closer to the center of the acoustofluid microvortex, which means a stronger aggregation effect. Since the simulation uses 1μm particles, this means that particles smaller than 1μm can be captured on the outer orbit of the microvortex.

[0083] The simulation diagram above shows the velocity field. It can be seen that the velocity field formed when the two first SAWs and BAWs are turned on simultaneously is still a relatively stable velocity field. The reason for this is that one is the flow field formed by the jet generated by the BAW and the other is the flow field formed by the standing wave generated by the first SAW. The superposition of these two flow fields (in reality, the flow fields formed by the simultaneous opening of the first SAW and BAW will have mutual influence, but for the sake of simplifying the analysis, we simply consider it as superposition) does not enhance the jet field like increasing the BAW, but is the superposition of different flow fields, so it still maintains a relatively stable velocity field.

[0084] Next, we will further analyze the mechanical aspects, temporarily disregarding the gravity of the particles and the viscous forces in the liquid. Within the microchannel, the particles are subjected to both the drag force of the fluid (causing them to move downstream) and the drag force of the microvortices formed by the BAW acoustic radiation (keeping the particles moving along microvortex tracks). The larger the particle size, the greater the acoustic force. Therefore, when only BAW is used to capture particles in the microchannel, the particles captured by the microvortices are in microvortex tracks. Larger particles are closer to the inner track of the microvortex, while smaller particles are closer to the outer track. Very small particles experience insufficient acoustic force to be captured. However, when two first SAWs are activated simultaneously, the first SAWs acting on the particles in the fluid push the particles towards the standing wave nodes, which can be understood as providing the particles with a force towards the nodes. In this embodiment, the position of the standing wave node corresponds to the position of the BAW edge acoustic fluid tunnel (i.e., micro vortex). That is, by activating the two first SAWs, each particle is given a force toward the micro vortex. Based on this force, the particles are more likely to enter the micro vortex or enter the inner orbit of the micro vortex, thereby improving the control performance of particle capture, aggregation, etc.

[0085] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods are not limited to the above embodiments and can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0086] Furthermore, the terms "first, second, third, etc." or similar terms such as module A, module B, and module C used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that, where permissible, a specific order or sequence may be interchanged so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0087] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0088] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this application. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0089] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, all of which fall within the scope of protection of this application.

Claims

1. A particle sorting device, characterized in that, include: Microchannels contain liquids containing microparticles; A bulk acoustic wave device is located at the bottom of a microchannel. The bulk acoustic wave device is leaf-shaped, with two sides of the leaf shape extending parallel to each other along the direction of the microchannel. The upstream and downstream ends of the leaf shape are angled, forming the head and tail of the bulk acoustic wave device. When the bulk acoustic wave device is in operation, it is used to generate an acoustic tunnel corresponding to the edge of the bulk acoustic wave device in the microchannel to capture particles in the liquid in the microchannel and release them at its tail. Two first surface acoustic wave resonators are located outside the microchannel and on both sides of the bulk acoustic wave device to generate standing waves in the microchannel. The standing waves have two nodes, and the positions of the two nodes are the same as the positions of the acoustic fluid tunnels on both sides of the bulk acoustic wave device, so as to enhance the effect of the acoustic fluid tunnels on both sides capturing particles. Two second surface acoustic wave resonators are arranged on both sides of the microchannel downstream of the bulk acoustic wave device to generate a standing wave in the microchannel, and the standing wave has a node to move some of the particles released at the end of the bulk acoustic wave device to the node position. At least two sub-channels are located at the downstream end of the main flow channel. The at least two sub-channels include a first sub-channel and a second sub-channel. The inlet position of the first sub-channel corresponds to the end position of the bulk acoustic wave device, and the inlet position of the second sub-channel corresponds to the node position generated by the two second surface acoustic wave resonators. This is used to allow particles released at the end of the bulk acoustic wave device that are not moved to the node position generated by the two second surface acoustic wave resonators to flow to the first sub-channel, and particles released at the end of the bulk acoustic wave device that are moved to the node position generated by the two second surface acoustic wave resonators to flow to the second sub-channel.

2. The apparatus according to claim 1, characterized in that, The surface acoustic wave resonator extends a certain distance upstream of the microchannel relative to the side of the bulk acoustic wave device.

3. The apparatus according to claim 1, characterized in that, The effect of enhancing the acoustic-fluid tunnels on both sides to trap particles includes at least one of the following: The captured particles include smaller particles compared to those captured using only bulk acoustic devices; This causes the captured particles to concentrate more towards the center of the acoustic fluid tunnel compared to particles captured using only bulk acoustic devices.

4. The apparatus according to claim 1, characterized in that, Also includes: A particle enrichment device is installed in at least one sub-channel; A detection device for detecting the particles enriched by the particle enrichment device.

5. The apparatus according to claim 1, characterized in that, The first and second surface acoustic wave resonators are disposed on the same substrate as the microchannel, and the first and second surface acoustic wave resonators propagate surface waves to the microchannel through the substrate.

6. A particle sorting method, using the particle sorting apparatus according to any one of claims 1-5, characterized in that, include: Based on the bulk acoustic wave device, an acoustic flow tunnel is generated at the edge position of the bulk acoustic wave device in the microchannel to capture particles in the liquid in the microchannel and release them at the end of the bulk acoustic wave device. Based on two first surface acoustic wave resonators, a standing wave with two nodes is generated in the microchannel, which enhances the effect of the acoustic fluid tunnels on both sides of the bulk acoustic wave device in capturing particles. Two second surface acoustic wave resonators are used to generate a standing wave with a node in the microchannel, so as to move some of the particles released at the end of the bulk acoustic wave device to the node position. Particles released at the end of the bulk acoustic wave device that are not moved to the node positions generated by the two second surface acoustic wave resonators flow to the first sub-channel, while particles released at the end of the bulk acoustic wave device that are moved to the node positions generated by the two second surface acoustic wave resonators flow to the second sub-channel.

7. The method according to claim 6, characterized in that, Also includes: In at least one sub-channel, particles flowing into the sub-channel are captured and enriched by a particle enrichment device and detected by a detection device.

8. The method according to claim 6, characterized in that, Also includes: Turning off or reducing the power of the surface acoustic wave resonator reduces the effect of the acoustic fluid tunnel trapping particles, thereby releasing some of the trapped particles.

9. The method according to claim 6, characterized in that, Also includes: The power of the bulk acoustic wave device is reduced to decrease the effect of the acoustic fluid tunnel trapping particles, thereby releasing some of the trapped particles.

10. The method according to claim 6, characterized in that, Also includes: Adjusting the flow rate of the fluid within the microchannel adjusts the effect of the acoustic fluid tunnel in trapping particles.

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