An integrated surface acoustic wave device, system and method for digital microfluidic sessile droplet rotation and centrifugation manipulation

Abstract

This invention relates to an integrated surface acoustic wave (SAW) device, system, and method for digital microfluidic control of droplet rotation and centrifugal manipulation. The device includes a digital microfluidic region, a SAW processing region, and a droplet transition interface region located between the two. A droplet residence area is provided within the SAW processing region. After sample introduction, transport, splitting, fusion, or temporary storage within the digital microfluidic region, the droplet enters the droplet residence area via the droplet transition interface region, where it forms a rotating flow, a circulating flow, and local enrichment under the influence of an asymmetric acoustic field. After enrichment or mixing, bright-field, dark-field, or fluorescence detection can be performed using an in-situ optical detection module. After processing, the droplet returns to the digital microfluidic region for continued transport, collection, or disposal. This solution improves the continuity, automation, and on-chip integration of droplet cross-region manipulation.

Description

Technical Field

[0001] This invention relates to the field of microfluidics and biomedical detection technology, specifically to a device, system, and method for droplet cross-regional introduction, in-situ rotation, mixing, enrichment, detection, and return for the coordinated manipulation of digital microfluidics and surface acoustic waves.

[0002] More specifically, the present invention relates to an interface-based structural scheme that couples a dielectric electrowetting droplet transport unit and a surface acoustic wave processing unit on the same platform, which is suitable for on-chip sample preprocessing, nanoparticle or vesicle enrichment, in-situ optical detection and automated droplet scheduling. Background Technology

[0003] Digital microfluidics technology, based on the principle of dielectric electrowetting, can control the injection, transport, splitting, fusion, and residence of micro-discrete droplets on open or closed planes. It features programmability, low sample consumption, and ease of automation, and has been widely used in scenarios such as nucleic acid detection, immunoassay, single-cell manipulation, and on-chip experiments.

[0004] The advantages of existing digital microfluidic platforms are mainly reflected in planar path planning and basic droplet manipulation. However, after a droplet enters a certain processing site, there is still a lack of stable, compact solutions suitable for chip integration to achieve rapid in-situ mixing, rotational flow-driven enrichment, and reconnection to the main array after processing without disrupting the original scheduling capabilities.

[0005] Surface acoustic wave (SAW) technology can couple with droplets through high-frequency mechanical vibrations, inducing acoustic flow, pressure gradients, and local interface deformation within the droplets, thereby achieving mixing, disturbance, particle manipulation, and local enrichment. Although there are existing combined SAW and digital microfluidics schemes, these schemes mostly focus on parallel integration or single-processing, often lacking a systematic structural design for stable droplet introduction across boundaries, de-evolution during the residence processing stage, and reliable post-processing return.

[0006] On the other hand, when the droplet is located in the acoustic processing area, if its bottom continues to participate in the digital microfluidic stepping drive, it is easy to cause wetting boundary disturbance, droplet drift or coupling interference between the acoustic field and the electric field, thereby reducing the consistency and enrichment effect of the rotating flow establishment; if it relies entirely on external limiting walls, microwells or three-dimensional constraint structures, it will increase the processing complexity, sample residual area and cross-contamination risk.

[0007] For targets with small particle sizes or low concentrations, such as exosomes, microvesicles, protein aggregates, and nanoparticles, on-chip enrichment efficiency and post-enrichment detectability are particularly critical. Current technologies lack a unified structure between the digital microfluidic platform and the surface acoustic wave (SAW) processing unit that balances cross-regional introduction, stable residence, asymmetric acoustic field processing, and feedback rescheduling. This leaves room for improvement in the continuity, automation, and detection integration of droplet manipulation processes. Summary of the Invention

[0008] The purpose of this invention is to provide a surface acoustic wave device, system, and method for rotating and centrifugally manipulating fixed droplets in digital microfluidics, in order to solve problems such as unstable connection between the digital microfluidic region and the surface acoustic wave processing region, insufficient reliability of droplet cross-region entry and post-processing return, susceptibility to stepper drive interference during the dwell processing stage, and unstable droplet in-situ rotation and enrichment effects in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a droplet transition interface region is set between the digital microfluidic region and the surface acoustic wave (SAW) processing region. The droplet transition interface region is composed of a transition driving electrode set at the boundary of the region and an adjacent driving electrode that cooperates with it. The droplet dwelling region is set within the SAW processing region and is located within the acoustic field range. After the droplet is transported from the digital microfluidic region to the adjacent driving electrode, it crosses the boundary and enters the droplet dwelling region under the action of the asymmetric wetting driving force formed by the adjacent driving electrode and the transition driving electrode. During the processing stage, the droplet dwelling region does not participate in the digital microfluidic stepping drive and is within the asymmetric acoustic field range to establish a rotating flow, a circulating flow, and / or a locally enriched flow field. After processing, the droplet is guided back to the digital microfluidic region by the coordinated action of the transition driving electrode and the adjacent driving electrode.

[0010] Preferably, the transition driving electrode adopts a trapezoidal structure that is wider at the front and narrower at the back along the droplet entry direction, so as to form a wetting potential gradient pointing towards the droplet residence region when the droplet crosses the region, and to provide a reverse traction basis during the return phase. Preferably, the bottom of the droplet residence region does not have an active digital microfluidic electrode participating in the stepping drive, or it is set in an electrode structure that is in a closed or suspended state during the processing phase, so as to reduce the disturbance caused by electrowetting during the acoustic field action.

[0011] Preferably, the surface acoustic wave processing area includes two interdigital transducers that are relatively offset, misaligned, or not directly opposite each other to form an asymmetric sound field in the droplet residence area; by selecting different frequencies, different powers, and single or simultaneous loading operating modes, different processing objectives such as droplet reception, initial disturbance, spreading, rotation, enhanced mixing, and local enrichment can be achieved.

[0012] Preferably, the device can adopt a single-substrate integrated architecture or a multi-substrate combination architecture formed by splicing glass digital microfluidic substrate and piezoelectric substrate, in order to adapt to different manufacturing processes and cost requirements.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects: First, by setting an interface-based transition structure between the digital microfluidic region and the surface acoustic wave processing region, stable cross-regional introduction, residence processing, and return and reconnection of droplets are realized; Second, by designing that the residence region does not participate in the stepping drive during the processing stage, the residence stability of droplets and the consistency of rotating flow under the action of asymmetric acoustic field are improved; Third, through the coordinated control of transition drive electrodes, asymmetric acoustic field and multi-frequency working mode, droplets can complete preprocessing, enrichment, detection and rescheduling on the same platform, which is conducive to improving the level of automation and on-chip integration. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall top view structure of the device in one embodiment of the present invention, wherein A is a schematic diagram of local enrichment of droplets, and B is a schematic diagram of droplet top / side view detection;

[0015] Figure 2 This is a schematic cross-sectional view of a single-substrate integrated structure in one embodiment of the present invention;

[0016] Figure 3 This is a schematic cross-sectional view of a multi-base splicing in one embodiment of the present invention;

[0017] Figure 4 This is a partial enlarged view of the droplet transition interface region in one embodiment of the present invention;

[0018] Figure 5 This is an asymmetric layout diagram of a bifid transducer in one embodiment of the present invention;

[0019] Figure 6 This is a flowchart of a droplet manipulation method in one embodiment of the present invention;

[0020] Figure 7 This is a schematic diagram of the rotating flow and equivalent centrifugal enrichment mechanism in one embodiment of the present invention;

[0021] Figure 8 This is a block diagram of a droplet cooperative manipulation system in one embodiment of the present invention.

[0022] 1-Digital microfluidic region; 2-Surface acoustic wave processing region; 3-Droplet transition interface region; 4-Interdigital transducer; 5-Piezoelectric substrate; 6-Driving electrode array; 7-Glass substrate; 8-Dielectric insulating layer; 9-Hydrophobic layer; 10-Transition driving electrode; 11-Droplet dwelling region; 12-Droplet; 13-Boundary transition seam; 14-High voltage driving module; 15-RF signal source; 16-Power amplifier; 17-Control unit; 18-Image sensor; 19-In-situ optical detection module; 20-Host computer; 21-Sample inlet / outlet; 22-Adjacent driving electrode; 23-Acoustic propagation direction; 24-Enrichment region; 25-Rotating flow; 26-Stabbing interface. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are used to explain the present invention, and not to limit the scope of protection of the present invention. Equivalent substitutions, combinations, or improvements made by those skilled in the art based on the present invention without departing from the concept of the present invention should all fall within the scope of protection of the present invention.

[0024] Example 1: Overall Device Structure. See also... Figure 1 This embodiment provides a surface acoustic wave (SAW) device for digital microfluidic fixed droplet rotation and centrifugal manipulation. The device includes a digital microfluidic region 1, a SAW processing region 2, and a droplet transition interface region 3 disposed between the two. The digital microfluidic region 1 is used for droplet introduction, transport, splitting, fusion, temporary storage, and path scheduling; the SAW processing region 2 is used for droplet in-situ rotation, mixing, and enrichment, and includes a droplet residence area 11; the droplet transition interface region 3 is used to achieve stable cross-regional introduction and processing of droplets between the digital microfluidic region 1 and the SAW processing region 2, and subsequent return. Figure 1 In the diagram, A shows the state in which a droplet forms a local enrichment region 24 under the action of a rotating flow; B shows a schematic diagram of the top and side views of the droplet acquired by the image sensor assembly.

[0025] The digital microfluidic region 1 includes a substrate, a driving electrode array 6, a dielectric insulating layer 8, and a hydrophobic layer 9. The driving electrode array 6 can be a regular square array to facilitate two-dimensional path planning. Preferably, a coplanar grounding network is provided around the driving electrode array 6 or between arrays to improve the driving electric field distribution, reduce crosstalk, and enhance droplet transport stability. The dielectric insulating layer 8 can be made of Parylene, SU-8, or other insulating materials suitable for digital microfluidic actuation. The hydrophobic layer 9 can be made of Teflon, CYTOP, PDMS, or other hydrophobic materials. By controlling the conduction sequence of adjacent driving electrodes, the droplet 12 can migrate sequentially within the array.

[0026] A droplet transition interface region 3 is located at the boundary between the digital microfluidic region 1 and the surface acoustic wave (SAW) processing region 2. The droplet transition interface region 3 consists of an adjacent driving electrode 22 located at the edge of the digital microfluidic region and a transition driving electrode 10 spanning the region boundary. A droplet residence region 11 is located within the SAW processing region 2 and behind the transition driving electrode 10. The transition driving electrode 10 is preferably a trapezoidal electrode, wider at the front and narrower at the rear. Under the coordinated drive of the adjacent driving electrode 22 and the transition driving electrode 10, the droplet crosses the region boundary and enters the droplet residence region 11, thereby obtaining a progressively stronger traction effect along the entry direction and improving the success rate of cross-boundary transfer. During the return phase, through the timing coordination of the transition driving electrode 10 and the adjacent driving electrode 22, the processed droplet can be pulled back into the digital microfluidic region 1.

[0027] See Figure 4 The length L of the transition drive electrode 10 is preferably 1.0 to 2.2 times the pitch p, the inlet width W1 is preferably 0.8 to 1.6 times the pitch p, and the outlet width W2 is preferably 0.25 to 0.80 times the pitch p. If the transition electrode length is too short, it is not conducive to droplet stretching and insertion across the boundary; if the outlet is too wide, the droplet is prone to over-spreading at the boundary; if the outlet is too narrow, it may reduce the re-entry stability during the return stage. The above parameter ranges are used to form an interface structure that balances both inlet and return stability. Figure 4 The mating relationship and geometric parameters between the adjacent driving electrode 22 and the transition driving electrode 10 are shown.

[0028] The droplet dwelling region 11 is located within the acoustic action range of the surface acoustic wave processing region 2. Unlike ordinary digital microfluidic stepping points, the droplet dwelling region 11 does not undertake the function of droplet cell-by-cell migration during the processing stage. Preferably, no active stepping electrode is provided at its bottom, or it is provided in an electrode structure that is in a closed or suspended state during the processing stage, so as to reduce the interference of electrowetting drive on the establishment process of acoustic swirling flow. By not participating in the stepping drive during the processing stage, the stability of the droplet dwelling position can be improved, and the accidental displacement of the droplet under high-frequency excitation can be reduced.

[0029] Example 2: Single-substrate and multi-substrate structures. See also Figure 2 In the single-substrate integrated implementation, the piezoelectric substrate 5 serves as a common substrate for both the surface acoustic wave region and the digital microfluidic region. A driving electrode array 6 and an interdigital transducer 4 are formed on the same or coplanar layers, and a dielectric insulating layer 8 and a hydrophobic layer 9 are selectively covered above the digital microfluidic region 1. This approach facilitates overall thickness control and printing. Figure 1 bodyization.

[0030] See Figure 3In the multi-substrate combination implementation, the digital microfluidic region 1 uses a glass substrate 7, and the surface acoustic wave (SAW) treatment region 2 uses a piezoelectric substrate 5. The two are spliced ​​together to form a continuous droplet pathway. Using a multi-substrate structure allows piezoelectric materials to be used only in the localized areas requiring SAW excitation, reducing material costs and broadening the range of process options for the digital microfluidic region. Preferably, the boundary height difference between the digital microfluidic region and the SAW treatment region is no greater than 80 μm, and the boundary transition seam 13 is 50 μm to 900 μm, balancing manufacturing feasibility and droplet stability across regions. Preferably, the surface of the SAW treatment region 2 is provided with a hydrophobic layer, which can be a PDMS thin film.

[0031] Example 3: Asymmetric sound field layout. See also Figure 5 Two interdigital transducers 4 can be installed in the surface acoustic wave processing region 2. The two interdigital transducers 4 are arranged with relative offset, staggered offset, or non-directly opposite arrangement relative to the droplet residence region 11. Compared with symmetrical excitation, asymmetrical arrangement more easily establishes directional rotating and circulating flow within the droplet, thereby driving particles, vesicles, or other target components to migrate to a predetermined location and form a local enrichment region 24. The offset amount e is preferably the equivalent diameter of the droplet residence region. The frequency of the interdigital transducer 4 can be 0.15 to 0.80 times that of the droplet. The operating frequency of the interdigital transducer 4 can be from 20 MHz to 50 MHz. As a preferred embodiment, the first transducer operates at approximately 32 MHz for droplet reception, initial perturbation, spreading, or gentle cycling; the second transducer operates at approximately 40 MHz for enhanced mixing, enhanced rotation, or local enrichment. Both transducers operate independently and controllably, and can be loaded individually or simultaneously according to processing requirements, allowing for staged control or synergistic enhancement of the processing effect based on the droplet state. For a piezoelectric substrate with a surface sound velocity of v, the transducer is designed with a specific wavelength. satisfy .

[0032] Example 4: Parameter Matching and Mechanism. See also Figure 7 Under the influence of an asymmetric acoustic field, a rotating flow 25 and an accompanying pressure gradient are formed inside the droplet. The target particle or vesicle migrates towards the enrichment region 24 under the combined effects of the flow field and inertial effects. The term "centrifugal manipulation" in this specification refers to a centrifugal-like enrichment effect exhibited by the droplet under the drive of a rotating flow, rather than a macroscopic centrifugal process driven by a mechanical shaft. For ease of parameter estimation, an equivalent droplet diameter can be introduced. and equivalent eccentricity coefficient , where V is the droplet volume, ω is the droplet angular velocity, r is the target enrichment radius, and g is the gravitational acceleration.

[0033] Under a set of preferred parameters, when the droplet volume is 0.2 μL to 1 μL, the displacement amplitude can be 1 nm to 5 nm; when the droplet volume is 1 μL to 5 μL, the displacement amplitude can be 3 nm to 12 nm; and when the droplet volume is 5 μL to 20 μL, the displacement amplitude can be 8 nm to 25 nm. Correspondingly, when the droplet volume is 0.5 μL to 2 μL, the RF power can be 18 dBm to 25 dBm; when the droplet volume is 2 μL to 10 μL, the RF power can be 24 dBm to 31 dBm; and when the droplet volume is 10 μL to 20 μL, the RF power can be 28 dBm to 34 dBm. These parameters are used for engineering selection and mode switching and can be further modified according to droplet viscosity, surface tension, and target material properties.

[0034] Example 5: Droplet manipulation method. See also Figure 6 The droplet manipulation process includes the following steps: First, droplet introduction, transport, splitting, fusion, and / or temporary storage are completed in the digital microfluidic region 1; then, the droplet is transported to the adjacent driving electrode 22, and crosses the boundary into the droplet residence region 11 under the synergistic action of the adjacent driving electrode 22 and the transition driving electrode 10; then, according to the processing requirements, the surface acoustic wave (SAW) working mode is selected to receive, disturb, rotate, mix, or enrich the droplet; the SAW working mode can be a 32MHz mode, a 40MHz mode, or a mode with both simultaneously applied; when the processing time, angular velocity change rate, target area position stability, or detection signal reaches the preset conditions, the SAW excitation is turned off; finally, the transition driving electrode 10 is controlled to work synergistically with the adjacent driving electrode 22 to make the droplet return to the digital microfluidic region 1 and continue to be sent to the detection area, collection area, or waste liquid area.

[0035] Preferably, the preset processing state includes at least one of the following conditions: reaching a preset processing time threshold; the droplet angular velocity change rate is lower than a preset threshold; the position or area of ​​the target region obtained by image recognition tends to stabilize; and the output signal of the in-situ optical detection module 19 reaches a preset intensity threshold. If the droplet does not reach the preset processing state, the current acoustic mode can be maintained, or it can be switched to another working mode and processed again.

[0036] Example 6: System Structure. See also... Figure 8The present invention also provides a droplet cooperative manipulation system, including a surface acoustic wave device body, and electrically connected to it a high-voltage drive module 14, a radio frequency signal source 15, a power amplifier 16, a control unit 17, an image sensor 18, an in-situ optical detection module 19, and a host computer 20. The high-voltage drive module 14 is used to drive the relevant electrodes in the digital microfluidic region 1 and the droplet transition interface region 3; the radio frequency signal source 15 and the power amplifier 16 are used to drive the interdigital transducer 4; the control unit 17 is responsible for the timing coordination between the modules and controls the 32MHz and 40MHz transducers to work individually or simultaneously; the image sensor 18 and the in-situ optical detection module 19 are used to acquire droplet morphology, position, and enrichment signals; and the host computer 20 is used to display the status, input commands, and record detection results.

[0037] In closed-loop control mode, the image sensor 18 can acquire the spatial position, contact line changes, and rotation state of the droplet in the droplet residence area 11 in real time. The control unit 17 dynamically adjusts the high-voltage drive timing, radio frequency excitation timing, and operating mode switching timing based on the above image feedback. As a result, more stable processing results can be obtained under different droplet volumes, different sample types, and different enrichment targets.

[0038] Example 7: In-situ Detection Method. A sample droplet carrying the target and labeled reagent is transported to the droplet residence area 11. Under the influence of an asymmetric acoustic field, the sample droplet is mixed and / or enriched. After turning off or reducing the surface acoustic wave excitation, bright-field, dark-field, or fluorescence images are acquired using the in-situ optical detection module 19. The location, area, grayscale value, or fluorescence intensity of the enriched region is extracted through image analysis, and the quantitative results of the sample are output based on a pre-established calibration relationship. This method is suitable for on-chip detection of proteins, nucleic acids, extracellular vesicles, nanoparticles, and other trace targets.

[0039] Example 8: Parallel Processing. The surface acoustic wave processing area 2 can be equipped with multiple processing units distributed around the periphery of the digital microfluidic main array. Different droplets first complete queuing, buffering, fusion or splitting within the central digital microfluidic array, and then are scheduled to different acoustic processing units for customized processing. After processing, they return to the main array for unified detection, collection or waste liquid treatment, thereby improving the system's parallel capability and throughput.

[0040] The above embodiments are merely preferred embodiments of the present invention. Those skilled in the art can combine, substitute, or adjust the parameters of the embodiments without departing from the spirit and substance of the present invention, and such changes should fall within the protection scope of the present invention.

Claims

1. A surface acoustic wave device for digital microfluidic pinned droplet rotation and centrifugation manipulation, characterized in that, The system includes a digital microfluidic region, a surface acoustic wave (SAW) processing region, and a droplet transition interface region disposed between the digital microfluidic region and the SAW processing region. The digital microfluidic region includes a substrate, a driving electrode array disposed on the substrate, and a dielectric insulating layer and a hydrophobic layer covering the driving electrode array, used for droplet introduction, transport, splitting, fusion, temporary storage, and retention based on the dielectric electrowetting principle. The SAW processing region includes a piezoelectric substrate and at least one interdigital transducer disposed on the piezoelectric substrate, with a droplet retention area provided within the acoustic range of the interdigital transducer. The droplet transition interface region is formed by a layer disposed on the substrate... The system comprises a transition driving electrode at the boundary of the region and an adjacent driving electrode that cooperates with it. Under the synergistic action of the adjacent driving electrode and the transition driving electrode, the droplet crosses the boundary from the digital microfluidic region into the droplet residence region. The bottom of the droplet residence region is not provided with an active digital microfluidic electrode that participates in the droplet stepping drive, or it is provided with an electrode structure that is in a closed, suspended, or non-participating stepping drive state during the processing stage. The droplet is excited by surface acoustic waves in the droplet residence region to form a rotating flow, a circulating flow, and / or a locally enriched flow field. After processing, the droplet returns to the digital microfluidic region by the synergistic action of the transition driving electrode and the adjacent driving electrode.

2. The surface acoustic wave device according to claim 1, characterized in that, The transition driving electrode is a trapezoidal electrode that is wider at the front and narrower at the back along the droplet entry direction. Its length is 1.0 to 2.2 times the pitch p of the adjacent digital microfluidic driving electrode, its width on the side near the digital microfluidic region is 0.8 to 1.6 times the pitch p, and its width on the side near the droplet residence region is 0.25 to 0.80 times the pitch p.

3. The surface acoustic wave device according to claim 1 or 2, characterized in that, The height difference between the digital microfluidic region and the surface acoustic wave processing region is no greater than 80 μm, and the width of the boundary transition gap is 50 μm to 900 μm.

4. The surface acoustic wave device according to claim 1, characterized in that, The driving electrode array of the digital microfluidic region is a regular square array and is provided with a coplanar grounding network; the pitch p of the driving electrode array is 0.4 mm to 2.5 mm, the thickness of the dielectric insulating layer is 0.5 μm to 5 μm, and the thickness of the hydrophobic layer is 20 nm to 300 nm.

5. The surface acoustic wave device according to claim 1, characterized in that, The surface acoustic wave device adopts a single-substrate integrated architecture, with a piezoelectric substrate as the common substrate, and the driving electrode array and the interdigital transducer are formed on the same or coplanar level, and the dielectric insulating layer and hydrophobic layer are selectively covered in the digital microfluidic region.

6. The surface acoustic wave device according to claim 1, characterized in that, The surface acoustic wave device adopts a multi-substrate combination architecture. The digital microfluidic region adopts a glass substrate, and the surface acoustic wave processing region adopts a piezoelectric substrate. The two are spliced ​​together to form a continuous droplet path. Preferably, the surface of the surface acoustic wave processing region is provided with a hydrophobic layer, which is a PDMS thin film.

7. The surface acoustic wave device according to claim 1, characterized in that, The piezoelectric substrate is 128°YX-cut lithium niobate, 41°YX-cut lithium niobate, piezoelectric quartz, or other piezoelectric materials suitable for forming surface acoustic waves; the interdigital transducer operates at a frequency of 20MHz to 50MHz, and the designed wavelength λ satisfies... , where v is the sound velocity on the surface of the piezoelectric substrate and f is the operating frequency.

8. The surface acoustic wave device according to claim 1, characterized in that, The surface acoustic wave (SAW) processing region includes two interdigital transducers, which are arranged with relative offset, staggered offset, or non-directly facing each other to form an asymmetric sound field. The offset e of the two interdigital transducers relative to the center of the droplet dwelling region is the equivalent diameter of the droplet dwelling region. 0.15 to 0.80 times.

9. The surface acoustic wave device according to claim 8, characterized in that, The two interdigital transducers operate in an independent and controllable mode. The first operating frequency is lower than the second operating frequency. The lower frequency is used for droplet reception, initial perturbation, spreading, or gentle cycling, while the higher frequency is used for enhanced mixing, enhanced rotation, or local enrichment. Preferably, the first operating frequency is 32MHz and the second operating frequency is 40MHz. The two interdigital transducers can be loaded individually or simultaneously.

10. The surface acoustic wave device according to claim 1, characterized in that, The surface acoustic wave (SAW) processing area is provided with multiple SAW processing units arranged along the edge or periphery of the digital microfluidic area. Each SAW processing unit includes at least one interdigital transducer and its corresponding droplet dwell area, forming a parallel processing architecture that combines the central digital microfluidic main array with multiple peripheral acoustic processing units.

11. A droplet cooperative manipulation system, characterized in that, The device includes the surface acoustic wave (SAW) device according to any one of claims 1 to 10, and a high-voltage drive module, a radio frequency (RF) signal source, a power amplifier, and a control unit electrically connected to the SAW device. The control unit controls the digital microfluidic region to perform droplet introduction, transport, splitting, fusion, temporary storage, and return; controls the droplet to enter the droplet residence region via the droplet transition interface region; and controls the RF signal source and power amplifier to apply power to the interdigital transducer when the droplet is in the droplet residence region. Radio frequency excitation is applied to enable droplets to undergo rotation, mixing, and / or enrichment processes.

12. The droplet cooperative manipulation system according to claim 11, characterized in that, It also includes an image sensor assembly disposed above and / or to the side of the surface acoustic wave processing area. The image sensor assembly is used to acquire top view images, side view images and global position images of the droplet, and to provide the control unit with feedback on the droplet position, deformation and rotation status.

13. The droplet cooperative manipulation system according to claim 11 or 12, characterized in that, It also includes an in-situ optical detection module, which includes a microscopic imaging module, an image sensor, an excitation / emission filter unit, and an image analysis unit. This module is used to acquire bright-field, dark-field, or fluorescence images after the droplet has completed enrichment, and to output the location, area, gray value, fluorescence intensity, and / or enrichment kinetic parameters of the enriched region.

14. The droplet cooperative manipulation system according to claim 11, characterized in that, The control unit sets the radio frequency excitation parameters according to the droplet volume V, the preset target rotation speed, or the target enrichment radius r, and the droplet equivalent diameter. satisfy Equivalent eccentricity coefficient satisfy , where ω is the angular velocity of the droplet and g is the gravitational acceleration.

15. A droplet manipulation method based on the droplet cooperative manipulation system according to any one of claims 11 to 14, characterized in that, Includes the following steps: S1, the droplets to be processed are loaded into the digital microfluidic region, and the digital microfluidic region completes the sample introduction, transport, splitting, fusion and / or temporary storage; S2 controls the coordinated action of adjacent driving electrodes and transition driving electrodes, enabling the droplet to enter the droplet residence region through the droplet transition interface region; S3, activate at least one surface acoustic wave working mode according to processing requirements to make the droplets form a receiving, disturbing, rotating, mixing and / or enriching state; S4, after reaching the preset processing state, turn off the surface acoustic wave excitation; S5 controls the transition driving electrode to work in synergy with the adjacent driving electrode, causing the droplet to return to the digital microfluidic region and continue to be transported to the detection zone, collection zone and / or waste zone.

16. The droplet manipulation method according to claim 15, characterized in that, In step S3, two operating modes are used: 32MHz and 40MHz. The 32MHz mode is used for droplet reception, initial perturbation, spreading, or gentle cycling, while the 40MHz mode is used for enhanced mixing, enhanced rotation, or local enrichment. The two operating modes can be applied individually or simultaneously.

17. The droplet manipulation method according to claim 15, characterized in that, The preset processing state in step S4 includes at least one of the following: the processing time reaches a preset threshold; the droplet angular velocity change rate is lower than a preset threshold; the position or area of ​​the target region obtained by image recognition tends to stabilize; The output signal of the in-situ optical detection module reaches the preset intensity threshold.

18. An in-situ detection method, characterized in that, The droplet cooperative manipulation system according to any one of claims 11 to 14 includes the following steps: transporting a droplet carrying a target and labeled reagent to a droplet residence area; mixing and / or enriching the droplet under the action of an asymmetric acoustic field; after turning off the surface acoustic wave excitation, acquiring bright field, dark field, or fluorescence images of the droplet using an in-situ optical detection module; extracting the location, area, gray value, or fluorescence intensity of the enriched region through image analysis, and outputting the quantitative results of the sample to be tested in combination with a pre-established calibration relationship.

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