Composite digital acoustic flow control chip, preparation method and multi-dimensional processing method

Abstract

The application discloses a composite digital acoustic flow control chip, a preparation method and a multi-dimensional processing method. The chip comprises detachably connected upper and lower plates and a gap support assembly arranged between the upper and lower plates. The upper plate comprises a piezoelectric substrate, an acoustic surface wave interdigital electrode array arranged on the piezoelectric substrate, a first dielectric layer covering the interdigital electrode array, a conductive layer arranged on the first dielectric layer, and a first hydrophobic layer arranged on the conductive layer. By constructing the multi-dimensional acoustic wave control unit of the upper plate and the electrode array of the lower plate based on the dielectric wetting effect, the programmable and controllable movement of the droplet sample and the action of the acoustic surface wave in the droplet are realized, the digital control of the acoustic flow control technology is realized, and the capacity of the chip for sample enrichment, control, mixing and fixed-point heating is greatly improved through the design of multiple IDTs.

Description

Technical Field

[0001] This invention relates to the field of microfluidic chip technology, and in particular to a composite digital acoustic fluid control chip, its fabrication method, and a multi-dimensional processing method. Background Technology

[0002] Microfluidic chips, with their advantages of low sample consumption, high degree of automation, and strong functional integration, are widely used in biomedical detection, chemical analysis, and other fields. Among them, surface acoustic wave (SAW) acoustic fluidization technology based on lithium niobate utilizes the excellent piezoelectric properties of lithium niobate to excite directional surface acoustic waves. Through the interaction between sound waves and fluids, effects such as acoustic radiation force and acoustic flow are generated, which can efficiently realize operations such as droplet mixing, particle sorting, and target enrichment. It is an important branch of the microfluidics field.

[0003] Based on lithium niobate substrates, the technology of exciting surface acoustic waves through the piezoelectric effect has led to the cutting-edge field of acoustic fluid control. This technology enables diverse sample processing capabilities for droplets and biological particles through non-contact, high-precision acoustic field manipulation. Functionally, its acoustic field can drive droplets to move, fuse, split, and mix rapidly, and can also utilize acoustic radiation force to sort, enrich, and lyse cells, etc. Simultaneously, the accompanying targeted and controllable thermal effect can synergize with the aforementioned mechanical operations to further enhance mixing and mass transfer efficiency, significantly accelerating biochemical reactions such as nucleic acid amplification. In terms of applications, this technology has formed a multifunctional operating platform that can support various core scenarios, from integrated nucleic acid detection (fully automated process) to organoid drug screening (non-invasive manipulation), as well as environmental monitoring and high-throughput chemical analysis, demonstrating powerful potential for sample processing and workflow integration.

[0004] However, traditional acoustic fluid control chips have technical pain points that are difficult to overcome. Most acoustic fluid control devices still need to be used in conjunction with microfluidic chips, rely on fluid-driven execution functions, require additional fluid control equipment, such as micropumps, and are difficult to automate sample processing. Secondly, current acoustic fluid control devices are designed for specific functions, and the movement path of the sample cannot be changed, resulting in limited functionality.

[0005] To address these challenges, digital microfluidics (DMF) technology, which transforms continuous flow into discrete droplet units and utilizes electrowetting-driven motion, promises to offer new solutions. The core characteristics of DMF technology lie in its high flexibility and reconfigurability; it allows for precise control of droplet trajectory on an electrode array through programming, enabling the precise setting of droplet generation, movement, merging, and segmentation. However, integrating SAW devices onto a digital microfluidic platform to achieve sample processing within the droplet units remains a challenging problem and has received limited research attention.

[0006] Although the patent "Digital Microfluidic Device for High-Throughput Particle Analysis Using Surface Acoustic Wave Technology" (application number: 201811407247) achieves particle separation by fabricating electrowetting electrodes and interdigitated surface acoustic wave (IDTs) on a lithium niobate substrate with an ITO glass top cover, generating traveling waves within the droplet, this method suffers from several drawbacks. The electrowetting electrodes and IDTs are located on the same side and cannot be separated. This restricts the positional relationship and function of the IDTs and electrowetting electrodes, significantly limiting flexibility and the number of electrodes that can be fabricated. Furthermore, this patent only provides one IDT design and a separation function based on it, failing to meet the needs of multi-dimensional sample processing. Summary of the Invention

[0007] In view of this, the purpose of this invention is to propose a composite digital acoustic fluid control chip, its fabrication method, and a multi-dimensional processing method. By constructing a multi-dimensional acoustic wave manipulation unit on the upper plate and an electrode array based on the dielectric wetting effect (Electrowetting on Dielectrics, EWOD) on the lower plate, programmable and controllable movement of droplet samples and the effect of surface acoustic waves in droplets are realized, achieving digital control of acoustic fluid control technology. At the same time, through the design of various IDTs, the chip's ability to enrich, manipulate, mix, and heat samples at specific points is greatly improved.

[0008] According to one aspect of the present invention, a composite digital acoustic flow control chip is provided, comprising: A detachable upper electrode plate and a lower electrode plate, and a gap support assembly disposed between the upper electrode plate and the lower electrode plate; The upper electrode plate includes a piezoelectric substrate, a surface acoustic wave interdigitated electrode array disposed on the piezoelectric substrate, a first dielectric layer covering the interdigitated electrode array, a conductive layer disposed on the first dielectric layer, and a first hydrophobic layer disposed on the conductive layer; the surface acoustic wave interdigitated electrode array is used to excite surface acoustic waves in the droplet to achieve multi-dimensional acoustic field manipulation of the sample in the droplet. The lower electrode plate includes a substrate, a driving electrode array disposed on the substrate, a second dielectric layer covering the driving electrode array, and a second hydrophobic layer disposed on the second dielectric layer; the driving electrode array is used to perform programmable generation, movement, segmentation, and merging operations on droplets based on the dielectric wetting effect; A cavity for filling the oil phase medium is formed between the upper electrode plate and the lower electrode plate; The driving electrode array of the lower electrode plate is configured to be connected to the DMF control board, and the surface acoustic wave interdigitated electrode array of the upper electrode plate is configured to be connected to the surface acoustic wave signal generator. The DMF control board and the signal generator are configured to be connected to a host computer. The driving electrode array and the surface acoustic wave interdigitated electrode array are configured to be started and stopped in coordination by the host computer in order to jointly perform droplet transport and acoustic field processing functions.

[0009] The above technical solution describes a hardware architecture for a composite digital acoustic fluid control chip. Its core lies in integrating a surface acoustic wave (SAW) manipulation unit and a dielectric wetting drive unit onto detachable upper and lower electrodes, respectively, and achieving collaborative operation between the two through an external control interface. Specifically, the upper electrode, using a piezoelectric substrate as a carrier, integrates a SAW interdigital electrode array to excite SAW waves within the droplet, enabling multi-dimensional acoustic field manipulation. The lower electrode, using a substrate as a carrier, integrates a drive electrode array for programmable generation, movement, segmentation, and merging of the droplet based on the dielectric wetting effect. A cavity filled with an oil-phase medium is formed between the upper and lower electrodes, each possessing a dielectric layer and a hydrophobic layer to ensure electrical isolation and droplet response sensitivity. At the control level, the lower electrode's drive electrode array is configured to connect to a DMF control board, and the upper electrode's SAW interdigital electrode array is configured to connect to a SAW signal generator. Both are further connected to the same host computer, thereby achieving coordinated control of start / stop and the linked execution of droplet transport and acoustic field processing functions.

[0010] Unlike traditional acoustic fluid control chips that integrate acoustic wave manipulation and fluid drive structures on the same substrate, rely on external micro-pumps to drive droplets, and have a single function, the essential feature of this technology lies in achieving functional separation in physical structure and synergistic linkage in control architecture.

[0011] Firstly, by placing the surface acoustic wave (SAW) manipulation unit and the dielectric wetting drive unit on detachable upper and lower electrodes respectively, a separate structure is formed with "sound wave function on top and droplet drive on the bottom." This structural arrangement allows the two functional units to be physically independent, avoiding the wiring conflicts, signal crosstalk, and electrode density limitations caused by the sharing of the same substrate between the acoustic wave electrode and the electrowetting electrode in traditional solutions. Simultaneously, the detachable connection method, combined with the gap support assembly, allows the upper and lower electrodes to be independently fabricated, maintained separately, and replaced as needed, providing a structural basis for chip reusability and functional reconfiguration.

[0012] Secondly, in terms of control architecture, the driving electrode array and the surface acoustic wave interdigitated electrode array are respectively connected to the DMF control board and the signal generator, and are coordinated through the same host computer. This architecture logically decouples the "motion control" and "processing control" of the droplet, but coordinates them in terms of timing: the driving electrode array is responsible for the spatial transport of the droplet on the chip, the surface acoustic wave electrode array is responsible for the acoustic field processing function inside the droplet, and the host computer coordinates the start-up and shutdown and execution sequence of the two types of electrodes according to the preset process.

[0013] Furthermore, the surface acoustic wave interdigitated electrode array integrated on the upper electrode plate can be used to achieve multi-dimensional acoustic field manipulation (such as particle alignment, mixing, enrichment, heating, etc.), while the driving electrode array integrated on the lower electrode plate supports programmable droplet generation, movement, segmentation, and merging. The two complement each other functionally: the former provides high-precision acoustic field intervention capabilities within the droplets, while the latter provides flexible path planning capabilities for the droplets on the chip. The synergistic execution of both enables sample processing procedures that originally required multiple devices and multiple steps of manual intervention (such as heating, mixing, and particle detection in nucleic acid amplification) to be integrated into a single chip, thereby significantly improving the integration of sample processing.

[0014] This chip employs an architecture design of "functional separation, independent control, and collaborative linkage" to construct a composite chip structure that combines the programmability of digital microfluidics with the multi-dimensional processing capabilities of acoustic fluid control. At the physical level, it decouples the acoustic wave manipulation unit from the droplet driving unit, improving the chip's layout flexibility, maintainability, and functional scalability. At the control level, it establishes a timing-based collaborative mechanism, providing the hardware foundation for the collaborative execution of complex sample processing flows.

[0015] In some embodiments, the surface acoustic wave interdigitated electrode array includes at least two functional types of interdigitated electrodes, the functional types including: standard rectangular interdigitated electrodes for particle alignment or manipulation, focused interdigitated electrodes for sample mixing, circular focused interdigitated electrodes for sample aggregation, trapezoidal interdigitated electrodes for sample enrichment, chirped interdigitated electrodes for particle sorting and mixing, and narrow rectangular interdigitated electrodes for point heating.

[0016] In the aforementioned technical solution, this technical feature further defines the surface acoustic wave interdigital electrode array in the aforementioned composite digital acoustic fluid control chip, clarifying that it includes at least two functional types of interdigital electrodes, and specifically listing six electrode types with different structures and functions: standard rectangular interdigital electrodes for particle alignment or manipulation, focusing interdigital electrodes for sample mixing, circular focusing interdigital electrodes for sample aggregation, trapezoidal interdigital electrodes for sample enrichment, chirped interdigital electrodes for particle sorting and mixing, and narrow rectangular interdigital electrodes for point heating. This feature, on a single piezoelectric substrate such as the upper electrode plate, integrates multiple acoustic field manipulation functions into the same chip unit through differentiated electrode structure design, providing a selectable and combinable functional carrier for multi-dimensional processing of samples within droplets.

[0017] Unlike traditional acoustic fluid control chips that integrate only a single type of interdigital electrode and can only achieve a single function (such as particle separation or mixing), the essential feature of this technology is that it integrates multiple types of interdigital electrodes on a single piezoelectric substrate, and each type of electrode has a clear functional division.

[0018] Specifically, the standard rectangular interdigitated electrode forms a standing wave field through orthogonally distributed traveling wave electric fields, utilizing acoustic radiation force to achieve patterned arrangement and manipulation of particles; the focusing interdigitated electrode adopts a concentric arc structure, forming vortex flow within microscale droplets through the synergistic effect of electroosmotic flow and dielectric force, achieving rapid sample mixing; the circular focusing interdigitated electrode constructs a centrally focused dielectric force field through a concentric circular radial electric field, directionally pulling the target object to the central region, achieving spatial aggregation of the sample; the trapezoidal interdigitated electrode uses a gradient electric field formed by gradually varying electrode spacing, constructing an "electric field funnel" pointing towards the center, reducing edge escape and improving enrichment efficiency and uniformity; the chirped interdigitated electrode achieves particle sorting and mixing through broadband acoustic wave excitation and multi-frequency synergy; and the narrow rectangular interdigitated electrode achieves rapid, localized heating of droplets through the Joule heating effect generated by high-frequency acoustic wave vibration.

[0019] The aforementioned electrode structures complement each other functionally: mixing, enrichment, and aggregation provide diverse methods for sample pretreatment; particle arrangement provides an ordered sample distribution for the detection process; and point heating provides precise temperature control for temperature-sensitive biochemical reactions (such as nucleic acid amplification). The integration of multiple functions onto the same upper electrode plate allows the chip to sequentially or selectively perform a series of operations such as mixing, enrichment, heating, and arrangement on a single platform without the need to replace the chip or transfer samples.

[0020] Compared to existing acoustic fluid control devices described in the background art, which are "designed for specific functions, with no change in the sample's movement path and limited functionality," this feature transforms the chip from a "single-function device" into a "multi-functional integrated platform" through the diversified integration of functional electrodes. This integration method not only reduces sample transfer losses and contamination risks between different devices, but also enables complex multi-step sample processing procedures (such as "sample enrichment → mixing → amplification heating → particle alignment detection") to be completed on the same chip, significantly improving the integration and efficiency of sample processing.

[0021] In some embodiments, the driving electrode array is arranged in an orthogonal array.

[0022] In the above technical solution, this technical feature defines the spatial arrangement of the lower electrode driving electrode array, namely, an orthogonal array arrangement. In this arrangement, the driving electrodes are arranged in a grid structure with the row and column directions perpendicular to each other, and each electrode corresponds to an independent unit in the grid. This orthogonal array constitutes the spatial basis for the programmable motion of the droplet, physically separated from the surface acoustic wave manipulation unit of the upper electrode, and together they support the coordinated execution of droplet transport and acoustic field processing functions.

[0023] Unlike traditional solutions that integrate dielectric wetting electrodes and surface acoustic wave electrodes on the same substrate, the essential feature of this technology is that the driving electrode array is arranged in an orthogonal grid pattern, and the array is located on an independent lower electrode plate, which is completely spatially separated from the surface acoustic wave electrodes on the upper electrode plate.

[0024] This structural arrangement frees the design and layout of the orthogonal array from the constraints of the surface acoustic wave (SAW) electrodes, enabling high-density electrode arrangement and full coverage on a two-dimensional plane. Specifically, each electrode in the orthogonal array can be addressed independently. By controlling the on / off timing of adjacent electrodes, an electric field gradient in any direction can be generated in the two-dimensional plane, thereby driving the droplet to move horizontally, vertically, and even diagonally. Compared to linear arrays that can only achieve one-dimensional movement, the orthogonal array gives the droplet completely free path planning capabilities on the chip plane, providing spatial flexibility for multi-region, multi-step transport in complex sample processing workflows.

[0025] The spatial separation of the orthogonal array from the upper plate surface acoustic wave electrode further eliminates electrical interference between the two types of electrodes. In traditional integrated schemes, the dielectric wetting electrode and the interdigital electrode share the same substrate, and their signal wiring is intertwined, which limits the increase in electrode density and increases the risk of signal crosstalk. This technology, by independently setting the driving electrode array on the lower plate, physically isolates the signal paths of droplet motion control and acoustic field processing control, providing a clean electrical environment for high-frequency, high-precision independent control of the two functions.

[0026] In some embodiments, the gap support assembly includes a support member with a preset thickness disposed along the edge of the lower electrode plate, and the surface of the support assembly is coated with a flexible adhesive to fill the gap between the support member and the upper and lower electrode plates, forming a flexible adhesive layer.

[0027] In the above technical solution, this technical feature defines the specific implementation method of the gap support assembly between the upper and lower electrode plates. This structure forms the basis for the detachable connection between the upper and lower electrode plates and the cavity sealing: the support member forms a gap of fixed thickness between the upper and lower electrode plates, defining the space for droplet manipulation and oil phase filling; after the flexible adhesive cures, it forms a flexible adhesive layer, which not only ensures the sealing of the cavity, but also gives the connection reversibility, so that the upper and lower electrode plates can be separated for cleaning, maintenance or functional reconfiguration when needed.

[0028] Unlike traditional acoustic fluid control chips or digital microfluidic chips that use integrated packaging or permanent bonding, the essential feature of this technology lies in the use of a support component and a flexible adhesive to jointly construct a gap support structure that combines positioning, sealing, and detachability.

[0029] Specifically, the support component serves a dual function in this structure: firstly, its thickness directly determines the vertical spacing between the upper and lower electrodes. This spacing needs to be precisely controlled to ensure that the droplet can move freely within the cavity without excessive deformation, while also providing a stable propagation distance for the effective coupling of surface acoustic waves from the piezoelectric substrate to the droplet; secondly, the support component is continuously arranged along the edge of the lower electrode to form a circumferential dam around the cavity, providing a physical boundary for subsequent oil phase filling and sealing.

[0030] A flexible adhesive is applied to the surface of the spacer tape and cured to form a flexible adhesive layer. Compared to rigid bonding or mechanical pressing, the flexible adhesive layer has the following characteristics: Firstly, during the curing process, it can adaptively fill the microscopic unevenness of the contact surface between the upper and lower electrodes, forming a uniform, bubble-free sealing interface, effectively preventing silicone oil leakage and droplet evaporation; secondly, the elasticity of PDMS allows it to undergo reversible deformation when a moderate external force is applied, thereby achieving the separation of the upper and lower electrodes without damaging the electrode structure and the dielectric hydrophobic layer, and maintaining sealing performance when re-attached after separation.

[0031] From the perspective of maintainability and reusability, this structure overcomes the limitations of traditional integrated chips that are "single-use and unrepairable." In practical use, if the surface acoustic wave electrode area of ​​the upper plate or the driving electrode area of ​​the lower plate fails due to sample contamination, electrode aging, or dielectric layer damage, the upper and lower plates can be separated for cleaning, replacement, or functional upgrades. Damaged plates can be handled individually, while undamaged plates can continue to be used. This feature significantly reduces the cost of chip use, making it particularly suitable for scenarios involving frequent changes in sample types or multiple rounds of experiments.

[0032] From a functional synergy perspective, this structure provides a reliable assembly basis for the aforementioned "acoustic wave function on top, droplet drive on the bottom" split architecture. The support component ensures the parallelism and gap consistency between the upper and lower plates, enabling surface acoustic waves to act on the droplet with stable coupling efficiency; the sealing performance of the flexible adhesive ensures the integrity of the oil-filled cavity, providing a stable fluid environment for dielectric wetting effect and acoustic wave propagation. Together, they ensure that the upper and lower plates can still achieve functional synergy even under physical separation.

[0033] This technical feature utilizes a combination of spacer tape and PDMS prepolymer to create a gap support solution that satisfies both sealing requirements and detachability. This solution ensures acoustic coupling stability and cavity sealing integrity while providing the chip with the ability to be cleaned, maintained, and reconfigured, solving the technical problems of traditional integrated chips being difficult to maintain and having poor reusability. This feature, combined with the functional separation of the upper and lower electrode plates, gives the chip physical structural flexibility for being both detachable and reconfigurable, and functionally achieves precise positioning and reliable sealing.

[0034] According to another aspect of the present invention, a method for fabricating a composite digital acoustic flow control chip is provided, the method comprising the following steps: Fabrication of the lower electrode: A driving electrode array based on the dielectric wetting effect is fabricated on the substrate, and a second dielectric layer and a second hydrophobic layer are deposited sequentially; Fabrication of the upper electrode plate: A surface acoustic wave interdigitated electrode array is fabricated on a piezoelectric substrate by photolithography and deposition processes. The interdigitated electrode array includes at least two functional types of interdigitated electrodes. A first dielectric layer, a conductive layer and a first hydrophobic layer are sequentially deposited on the interdigitated electrode array. Chip assembly: The upper electrode and the lower electrode are detachably connected by a gap support assembly to form a cavity, which is then filled with an oil phase medium.

[0035] The above technical solution describes a method for fabricating a composite digital acoustic fluid control chip, which consists of three core stages: lower electrode fabrication, upper electrode fabrication, and chip assembly. In the lower electrode fabrication, a driving electrode array based on the dielectric wetting effect is formed on a substrate, followed by the sequential deposition of a dielectric layer and a hydrophobic layer. In the upper electrode fabrication, a surface acoustic wave electrode array containing at least two functional types of interdigitated electrodes is formed on a piezoelectric substrate using photolithography and deposition processes, followed by the sequential deposition of a dielectric layer, a conductive layer, and a hydrophobic layer. In the chip assembly stage, the upper and lower electrodes are detachably connected using gap support components to form a cavity filled with an oil-phase medium. This fabrication method, based on the premise of independently fabricating functionally separated electrodes and culminating in detachable assembly, completely constructs the aforementioned chip structure.

[0036] Unlike traditional fabrication methods that integrate dielectric wetting electrodes and surface acoustic wave electrodes on the same substrate and employ integrated packaging or permanent bonding processes, the essential feature of this technology lies in its "functionally separated fabrication and detachable assembly" process. The acoustic wave manipulation unit and the droplet driving unit are constructed on separate electrode plates, and the system is finally integrated in a detachable manner.

[0037] Specifically, this fabrication method decouples the two functional units at the process level. The fabrication of the lower electrode focuses on the dielectric wetting-driven electrode array, and its process path (electrode patterning—dielectric layer deposition—hydrophobic layer coating) is compatible with conventional digital microfluidic chip fabrication processes and can be completed independently on PCB boards or glass substrates. The fabrication of the upper electrode focuses on the surface acoustic wave interdigitated electrode array, and its process path (piezoelectric substrate cleaning—photolithography patterning—metal deposition and lift-off—dielectric layer deposition—conductive layer deposition—hydrophobic layer coating) is executed independently on piezoelectric single-crystal substrates such as lithium niobate. The fabrication processes of the two types of electrodes do not interfere with each other in terms of equipment, materials, and process parameters, avoiding the problem of mutual constraints between the two electrode fabrication processes in traditional single-substrate integration schemes. For example, the electrode coating process may affect the acoustic excitation efficiency of the interdigitated electrodes.

[0038] This fabrication method achieves a "divide and conquer" effect in terms of integration. In the fabrication of the upper electrode, multiple functional electrodes can be patterned within a single photolithography mask design, and a multifunctional electrode array can be obtained through a single photolithography and deposition process. Compared to methods that fabricate different functional electrodes in stages or fabricate them separately on different substrates and then stitch them together, this method maintains both functional diversity and the simplicity of the fabrication process and the precision of the relative positions between the electrodes.

[0039] In the assembly stage, the use of gap support components to achieve detachable connections is another key feature of this fabrication method. Compared to irreversible anodic bonding or adhesive encapsulation, detachable connections allow the upper and lower electrodes to be separated even after fabrication. This characteristic brings two advantages at the process level: firstly, after the electrodes are fabricated independently, they can be subjected to quality inspection and performance testing separately, and only those that pass the test can be assembled, improving the yield rate; secondly, after use, the electrodes can be separated for cleaning or replacement, extending the overall lifespan of the chip and reducing the cost per use.

[0040] From the overall process flow perspective, the chip structure produced by this fabrication method has a completely physical separation between the driving electrode array of the lower electrode plate and the surface acoustic wave electrode array of the upper electrode plate, providing a hardware foundation for the independent access and collaborative operation of subsequent control signals. The lead interfaces reserved during the fabrication process of the two types of electrodes are connected to the DMF control board and the surface acoustic wave signal generator respectively after assembly, and finally, collaborative control is achieved through the host computer.

[0041] This technical feature establishes a manufacturing path for the aforementioned composite digital acoustic fluid control chip through a process flow of "functionally separated fabrication and detachable assembly." This fabrication method resolves the spatial conflicts and process compatibility issues faced by integrating two types of functional units onto a single substrate at the process level; achieves maintainability and reusability through detachable connections at the structural level; and supports the collaborative control functions of the acoustic wave manipulation unit and the droplet driving unit at the product level. This fabrication method and product structural features complement each other, together forming a complete manufacturing foundation for realizing the "digital acoustic fluid control" technical solution.

[0042] In some embodiments, the upper electrode plate and the lower electrode plate are detachably connected by the following method: a support member with a preset thickness is provided at the edge of the lower electrode plate, a flexible adhesive is coated on the surface of the support member, and the upper electrode plate and the lower electrode plate are aligned and bonded together and then cured into a flexible adhesive layer to form a detachable sealed cavity.

[0043] In the above technical solution, this step, through the combined application of a support component and a flexible adhesive, simultaneously achieves precise positioning of the cavity gap, integrity of the circumferential seal, and reversibility of the connection method. Unlike traditional microfluidic chip fabrication processes that employ permanent bonding (such as anodic bonding or thermoforming bonding) or one-time adhesive encapsulation, the essential characteristic of this technology lies in utilizing a support component and a flexible adhesive to construct a composite connection structure that integrates gap positioning, sealing adhesion, and reversible disassembly.

[0044] Specifically, the support component serves a dual function in this process. First, the thickness of the support component itself determines the vertical spacing between the upper and lower electrode plates after assembly. Compared to solutions that rely on external clamps or shims to control the gap, defining the gap directly through the tape thickness is simpler and more repeatable. Second, the tape is continuously arranged along the edge of the lower electrode plate, forming the circumferential physical boundary of the cavity, providing a prefabricated dike for subsequent oil phase filling and preventing liquid overflow.

[0045] A flexible adhesive is applied to the surface of the spacer tape, and its curing process forms a flexible adhesive layer. This material characteristic gives the process the following advantages: First, the flexible adhesive is fluid before curing, which can fill the microscopic unevenness of the contact surface between the upper and lower electrodes. After curing, it forms a uniform, bubble-free sealing interface, ensuring that the oil phase medium does not leak during long-term use. Second, the flexible adhesive is elastic after curing, and its bonding strength is between "separable" and "self-detachable"—sufficient to maintain the cavity seal and the relative position of the electrodes under normal use conditions, and able to separate the upper and lower electrodes without damaging the electrode structure, dielectric layer, or hydrophobic layer when a moderate external force is applied. Third, the adhesive layer remaining after the flexible adhesive is separated can be removed by mechanical peeling or solvent cleaning, and can be re-coated and reassembled, realizing the reuse of the electrodes.

[0046] From a process operability perspective, this scheme is relatively lenient in its requirements for electrode surface flatness. Permanent bonding processes typically require extremely high flatness and cleanliness of the electrode surface; otherwise, bonding defects are prone to occur. However, the fluidity of the flexible adhesive can adaptively compensate for a certain degree of surface undulation, reducing the stringency of the electrode preparation process and contributing to improved yield.

[0047] From a functional synergy perspective, this connection technology directly supports the practical application of the aforementioned "acoustic wave function on top, droplet drive on the bottom" structural design. After the upper and lower plates are connected in this way, on the one hand, the parallelism and gap consistency between the upper and lower plates are ensured, providing a stable propagation distance for surface acoustic waves; on the other hand, the detachable feature allows the upper plate to be replaced separately while retaining the lower plate and its driving electrode array if the performance of the multifunctional interdigitated electrode array on the upper plate degrades after long-term use, and vice versa. This ability to perform local maintenance reduces chip usage costs and also allows the chip to flexibly replace the upper plate with different functional configurations (such as adding or removing specific functional electrodes) according to sample processing needs, expanding the chip's application scenarios.

[0048] This technology achieves precise control of the gap between the upper and lower electrodes, reliable cavity sealing, and reversible disassembly in one step. While ensuring acoustic coupling stability and oil phase filling integrity, this process endows the chip with the capabilities of being removable, maintainable, reusable, and functionally reconfigurable.

[0049] In some embodiments, the surface acoustic wave interdigitated electrode array integrates at least two functional types of interdigitated electrodes through photolithography and deposition processes, with each functional type of interdigitated electrode having independent leads for separate control.

[0050] In the aforementioned technical solution, this technical feature defines the integration process and control configuration of the surface acoustic wave interdigital electrode array on the upper electrode plate in the fabrication method of the composite digital acoustic fluid control chip. Specifically, it integrates at least two functional types of interdigital electrodes on the same piezoelectric substrate through photolithography and deposition processes, and assigns independent leads to each functional type of electrode to achieve separate control. This feature is located in the core step of upper electrode plate fabrication, clarifying the physical integration method of the multifunctional electrodes and its electrical control architecture. It is the concrete realization of the aforementioned "multi-dimensional acoustic field manipulation" function at the fabrication process and hardware configuration level.

[0051] Unlike traditional acoustic fluid control chip fabrication methods that integrate only a single type of interdigital electrode or integrate multiple electrodes but share leads leading to functional coupling, the essential feature of this technology is that it integrates multiple functional types of interdigital electrodes on a single piezoelectric substrate through a single photolithography and deposition process, and gives each type of electrode an independent electrical path.

[0052] From a process integration perspective, the combined use of photolithography and deposition processes allows for the simultaneous fabrication of interdigitated electrodes with various functional types using different pattern areas of the same photomask. Compared to fabricating different functional electrodes in stages (requiring multiple photolithography and alignment steps) or fabricating them separately on different substrates and then splicing them together, this process path significantly reduces fabrication steps and alignment times while ensuring the relative positional accuracy between electrodes. This also reduces the cumulative errors and contamination risks introduced by multiple processes. The simplification of process steps directly translates into improved fabrication efficiency and yield.

[0053] From a functional decoupling perspective, providing independent leads for each type of interdigital electrode and configuring them for separate control during subsequent use is another core innovation of this feature. In traditional integrated solutions, if multiple electrodes share leads or signal channels, different functional electrodes cannot be independently started / stopped or have their frequency and amplitude adjusted independently. This results in the chip having multiple electrode structures but being unable to achieve true functional switching and combination. This feature, through its independent lead design, allows each functional electrode (such as a focusing interdigital electrode for mixing, a narrow rectangular interdigital electrode for heating, and a standard rectangular interdigital electrode for particle alignment) to be connected to an independent channel of the surface acoustic wave signal generator, thereby achieving independent adjustment of its frequency, amplitude, and phase. This configuration enables the chip to flexibly call upon the required functional electrodes in different processing stages or application scenarios without requiring any physical modifications to the hardware.

[0054] From the perspective of chip functional scalability, users can configure different combinations of functional electrodes in the same mask design (such as combinations emphasizing mixing and enrichment, or combinations emphasizing heating and particle alignment) according to actual application needs, without changing the fabrication process. This modularity and configurability in design enables the chip to adapt to the differentiated sample processing needs of different fields such as biomedical detection, chemical analysis, and environmental monitoring.

[0055] According to another aspect of the present invention, a multi-dimensional sample processing method is provided, the method being based on the aforementioned composite digital acoustic flow control chip, the method comprising: The drive electrode array of the lower electrode plate and the surface acoustic wave interdigital electrode array of the upper electrode plate are controlled in a coordinated manner by the host computer. According to the preset sample processing procedure, at least one processing step is executed, and each processing step includes: The droplets are transported to the corresponding functional electrode region in the surface acoustic wave interdigitated electrode array via the driving electrode array; When the droplet reaches the functional electrode area, the host computer controls the corresponding surface acoustic wave interdigitated electrode to activate and perform corresponding type of acoustic field manipulation on the sample in the droplet. After all processing steps are completed, the droplets are transported to the collection area via the driving electrode array.

[0056] In the above technical solution, this technical feature describes a multi-dimensional sample processing method based on the aforementioned composite digital acoustic fluid control chip. Its core lies in establishing a collaborative control relationship between the lower electrode driving electrode array and the upper electrode surface acoustic wave interdigital electrode array via a host computer, and executing one or more processing steps according to a preset process. Each processing step follows a logical chain of "transfer—arrival—trigger—execution": the driving electrode array transfers the droplet to the target functional electrode region; upon arrival, the host computer controls the corresponding surface acoustic wave interdigital electrode to activate, performing corresponding type of acoustic field manipulation on the sample within the droplet. After all steps are completed, the driving electrode array transfers the droplet to the collection area.

[0057] Unlike traditional acoustic fluid control chips that rely on external micropumps to drive droplets and require manual intervention to switch processing functions, or existing technologies that can only realize droplet movement but lack the ability to finely manipulate the inside of droplets, the essential feature of this technology lies in the construction of a collaborative control mechanism that organizes the multi-step processing flow into a programmable loop unit of "transfer-trigger-execution".

[0058] Firstly, this feature establishes a collaborative logic between the driving electrode array and the surface acoustic wave (SAW) electrode array at the control level. In traditional solutions, droplet motion control and acoustic field processing control are usually independent systems with no temporal correlation—either all droplet transfer is completed before the acoustic field processing is manually started, or the acoustic field processing operates continuously throughout the droplet motion and cannot be started or stopped as needed. This feature achieves unified scheduling of both through a host computer, enabling precise timing matching between the transfer task of the driving electrode array and the processing task of the SAW electrode array. This collaborative control ensures that acoustic field energy is applied only when the droplet is in the target functional electrode region, avoiding energy waste and unnecessary heat accumulation caused by prolonged acoustic field operation, and preventing interference from the acoustic field to droplets in non-target areas or the surrounding medium.

[0059] Secondly, this feature organizes multi-dimensional sample processing into a programmable sequence of processing steps. Each processing step can independently define two elements: "transfer target area" and "acoustic field manipulation type," and different steps can be chained together through preset procedures. For example, the first step can be set to transfer to the heating electrode area and perform fixed-point heating, the second step can be set to transfer to the mixing electrode area and perform rapid mixing, and the third step can be set to transfer to the particle alignment electrode area and perform standing wave field alignment. This process organization method breaks through the limitations of the traditional chip's "one step, one operation" approach, enabling complex multi-step biochemical detection processes (such as heating, mixing, and pre-detection alignment in nucleic acid amplification) to be completed on a single chip, and the order, repetition count, and conditional branches between steps can all be flexibly adjusted by modifying the preset procedures.

[0060] Third, this method forms a tight functional coupling with the aforementioned chip structure. The orthogonal arrangement of the driving electrode array provides two-dimensional arbitrary path movement capability for "transferring to the corresponding functional electrode area", enabling the droplet to be accurately delivered to the projection area of ​​different functional electrodes on the chip plane of the upper plate; the multi-functional interdigitated electrodes and independent lead design integrated on the upper plate provide an optional function library and independent control hardware foundation for "performing corresponding types of sound field manipulation"; the detachable connection of the upper and lower plates and the oil phase filling cavity provide a stable and low-loss working environment for droplet movement and sound wave propagation.

[0061] This technology leverages a "host computer collaborative control, programmable process execution" architecture to transform the structural advantages of the aforementioned chip into practical sample processing capabilities. This method achieves precise temporal coupling between droplet spatial transport and internal acoustic field processing, supporting automated continuous execution of multi-step, multi-functional processing flows. It resolves the technical problems of traditional solutions, such as the disconnect between droplet movement and sample processing, limited functionality, and frequent manual intervention. In some embodiments, the host computer controls the activation of the corresponding surface acoustic wave interdigitated electrode in the following manner: The host computer drives the electrode array according to the programmed control to transport the droplet along a predetermined path to the target functional electrode area; when the programmed control is executed to the corresponding step, the host computer triggers the surface acoustic wave interdigitated electrode to start.

[0062] In the above technical solution, this technical feature further defines the specific implementation method of controlling the activation of the surface acoustic wave interdigitated electrodes by the host computer in the multi-dimensional sample processing method. From the perspective of triggering logic, this feature is based on programmable control, which can estimate the arrival time based on the droplet movement distance and preset speed, and set a delay trigger accordingly. This method strengthens the timing coupling between the driving electrode array and the surface acoustic wave electrode array.

[0063] In some embodiments, the multi-dimensional sample processing method includes multiple processing steps executed sequentially, with different functional electrode regions corresponding to different processing steps, and the type of acoustic field manipulation in each processing step is selected from at least one of particle arrangement, sample mixing, sample aggregation, sample enrichment, or fixed-point heating.

[0064] In the above technical solution, this technical feature further defines the organization and functional configuration of the processing steps in the multi-dimensional sample processing method. Specifically, the method includes multiple processing steps executed sequentially, with different processing steps corresponding to different types of functional electrode regions. Furthermore, the acoustic field manipulation type performed in each step is selected from at least one of particle arrangement, sample mixing, sample aggregation, sample enrichment, or point heating. Based on the aforementioned single-step "transfer-trigger-execution" process, this feature extends the method to a multi-step, multi-functional sequential processing architecture, clarifying the specific configuration requirements for the number of steps, step order, functional region correspondence, and acoustic field manipulation type combinations in the sample processing flow.

[0065] Unlike traditional sample processing methods that involve single-function execution or multiple steps that are independent of each other and lack a process-oriented organization, the essential feature of this technology is that it organizes multi-dimensional sample processing into a serialized process of "sequential execution, region correspondence, and function combination," enabling the chip to complete complex sample processing tasks in a programmable manner.

[0066] First, this feature constructs a streamlined architecture for sample processing through "multiple sequentially executed processing steps." In traditional acoustic fluidic chips or digital microfluidic chips, multi-step operations typically require manual intervention or manual sample transfer, making it impossible to complete continuously and automatically on the same chip. This feature decomposes the sample processing flow into multiple sequentially executed processing steps, with each step triggering the next. This allows complex processes that originally required multiple devices and stages (such as "sample enrichment—mixing—heating—particle alignment") to be integrated into a single chip and executed continuously in a pipeline manner. This streamlined organization significantly reduces the number of times samples are transferred between different devices, lowering the risk of cross-contamination and sample loss.

[0067] Secondly, this feature establishes a mapping relationship between steps and spatial locations by defining different functional electrode regions corresponding to different processing steps. The various functional interdigitated electrodes integrated on the upper plate are physically distributed across different regions. Each processing step transfers the droplet to the corresponding functional electrode region, ensuring that the acoustic field manipulation required for that step is executed by the appropriate electrode. This one-to-one correspondence between "steps" and "regions" allows the chip to solve the function reuse problem through spatial separation: different functional electrodes can work independently without interference, and can perform different operations in parallel or sequentially on the same chip. Compared to achieving different functions by switching signals in a single region, spatial separation avoids residual interference during function switching and also makes it possible to process multiple droplets simultaneously.

[0068] Third, this feature clarifies the multi-dimensional attributes of the method by stating that "the type of sound field manipulation in each processing step is selected from at least one of...". Specifically, the five types of sound field manipulation correspond to different physical effects and application scenarios. By selecting at least one of the above types and executing them sequentially, this method can achieve multi-step, multi-functional cascaded processing on the same chip, such as "enrichment followed by mixing and then heating" or "mixing followed by aggregation and then arrangement," thereby adapting to the diverse operational needs of complex sample processing workflows.

[0069] Fourth, this feature forms a tight functional coupling with the aforementioned chip structure and control mechanism. The upper electrode plate integrates multiple functional types of interdigitated electrodes, each with independent leads, providing a selectable library of acoustic field manipulation types for the method; the lower electrode plate drives the orthogonal arrangement and programmable control of the electrode array, providing the method with the path planning capability to sequentially transfer droplets to different functional regions; and the upper computer collaborative control provides the method with automated support for the timing scheduling of multi-step processes and the connection between steps. The structural features, control features, and method features form a complete closed loop, transforming the "sequential execution of multiple processing steps" from a method-level description into an implementable hardware operation sequence.

[0070] Fifth, this feature, through programmability, enables the method to flexibly adapt to different application scenarios. Users can preset the number and order of processing steps, as well as the corresponding sound field control type for each step, based on sample type and processing objectives, without changing the chip hardware configuration. For example, in nucleic acid detection, a three-step process of "mixing-heating-particle arrangement" can be set; in cell analysis, a two-step process of "enrichment-arrangement" can be set; and in drug screening, a multi-step process of "mixing-aggregation-pre-detection arrangement" can be set. This configurability allows the same chip to be applied to sample processing needs in multiple fields such as biomedical detection, chemical analysis, and environmental monitoring, enhancing the chip's versatility and application value.

[0071] This technical feature extends the aforementioned single-step "transfer-trigger-execution" mechanism into a programmable multi-step processing flow through a serialized processing architecture of "sequential execution, region correspondence, and function combination." This feature enables the chip to continuously complete various sound field manipulation tasks in an automated, pipelined manner, achieving chip-level integration of complex sample processing flows. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 This is a cross-sectional structural schematic diagram of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 3 This is a schematic diagram of a surface acoustic wave interdigital electrode array according to an embodiment of the composite digital acoustic fluid control chip of the present invention. Figure 4 This is a schematic diagram of a standard rectangular interdigital electrode of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 5 This is a schematic diagram of the focusing interdigital electrode of an embodiment of the composite digital acoustic fluid control chip of the present invention; Figure 6 This is a schematic diagram of the circular focusing interdigital electrode of an embodiment of the composite digital acoustic fluid control chip of the present invention; Figure 7 This is a schematic diagram of the trapezoidal interdigital electrode of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 8 This is a schematic diagram of a narrow rectangular interdigital electrode of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 9 This is a schematic diagram of the chirped interdigital electrodes of an embodiment of the composite digital acoustic flow control chip of the present invention; Figure 10 This is a schematic flowchart of an embodiment of the fabrication method of the composite digital acoustic fluid control chip of the present invention; Figure 11 This is a flowchart illustrating an embodiment of the multi-dimensional sample processing method of the present invention. Detailed Implementation

[0074] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] This invention discloses a composite digital acoustic fluid control chip, its fabrication method, and a multi-dimensional sample processing technology. By constructing a multi-dimensional acoustic wave manipulation unit on the upper plate and an electrode array based on the dielectric wetting effect (EWOD) on the lower plate, programmable and controllable movement of droplet samples and the effect of surface acoustic waves in droplets are realized, achieving digital control of acoustic fluid control technology. At the same time, through the design of various IDTs, the chip's ability to enrich, manipulate, mix, and heat samples at specific points is greatly improved.

[0076] Example 1 Please see Figure 1 , Figure 2 A composite digital acoustic flow control chip includes: a detachably connected upper electrode plate and a lower electrode plate, and a gap support component disposed between the upper electrode plate and the lower electrode plate (it should be noted that in this application, the terms upper and lower electrode plates are used to better understand the overall structure, but reversing the upper and lower electrodes does not affect the function). The upper electrode plate includes a piezoelectric substrate 1 and a surface acoustic wave interdigitated electrode array 2 disposed on the piezoelectric substrate 1. (It should be noted that...) Figure 1 , Figure 2 To better illustrate the overall architecture, the surface acoustic wave interdigitated electrode array shown in the figure only uses standard rectangular interdigitated electrodes for illustrative purposes. Other electrode types will be introduced later. Figure 1 , Figure 2 (Without going into too much detail), a first dielectric layer 3 covering the interdigitated electrode array 2, a conductive layer 4 disposed on the first dielectric layer 3, and a first hydrophobic layer 5 disposed on the conductive layer 4; the surface acoustic wave interdigitated electrode array 2 is used to excite surface acoustic waves in the droplet 6 to achieve multi-dimensional acoustic field manipulation of the sample in the droplet 6. The lower electrode plate includes a substrate 10, a driving electrode array 9 disposed on the substrate, a second dielectric layer 8 covering the driving electrode array 9, and a second hydrophobic layer 7 disposed on the second dielectric layer; the driving electrode array 9 is used to perform programmable generation, movement, segmentation and merging operations on the droplets 6 based on the dielectric wetting effect; A cavity X for filling the oil phase medium is formed between the upper electrode plate and the lower electrode plate; The driving electrode array of the lower electrode plate is configured to be connected to the DMF control board, and the surface acoustic wave interdigitated electrode array of the upper electrode plate is configured to be connected to the surface acoustic wave signal generator. The DMF control board and the signal generator are configured to be connected to a host computer; (this part is not shown in the figure) The driving electrode array and the surface acoustic wave interdigitated electrode array are configured to be started and stopped in coordination by the host computer in order to jointly perform droplet transport and acoustic field processing functions.

[0077] In this embodiment, the surface acoustic wave interdigitated electrode array 2 includes at least two functional types of interdigitated electrodes, including: a standard rectangular interdigitated electrode for particle alignment or manipulation, a focusing interdigitated electrode for sample mixing, a circular focusing interdigitated electrode for sample aggregation, a trapezoidal interdigitated electrode for sample enrichment, a chirped interdigitated electrode for particle sorting and mixing, and a narrow rectangular interdigitated electrode for point heating.

[0078] In this embodiment, the present invention provides a method for multi-dimensional sample processing based on the chip, and designs six IDTs to achieve different functions, specifically including the following: To adapt to the differentiated needs of different sample processing scenarios, the present invention specifically designs six functionally differentiated surface acoustic wave interdigitated electrodes on the upper electrode plate. Each electrode has a unique structural design and dedicated functional positioning. Please refer to [link to relevant documentation]. Figure 3 The specific compatibility is as follows: Please see Figure 4 The standard rectangular interdigitated electrode 27 has an interdigitation width of 75 μm and is used for particle alignment or manipulation. It achieves precise particle alignment by applying a low-frequency electrical signal to form a standing wave field. The principle is as follows: To manipulate cells or particles in a droplet sample, four orthogonally distributed interdigitated electrodes are designed, each with a width and spacing equal to 1 / 4 of the acoustic wavelength (λ). Surface waves are generated by applying a radio frequency signal with a frequency of f = c / λ to both ends of the electrodes, where c is the sound velocity of the lithium niobate substrate. The orthogonal traveling surface waves generate a standing wave field in the central region. The standing wave field exhibits a periodic arrangement of a square lattice. Particles are concentrated at the nodes by acoustic radiation forces, and their movement can be controlled by adjusting the signal phase.

[0079] Please see Figure 5 The focused interdigitated electrodes 25, with a concentric arc distribution, are used for sample mixing. They generate electroosmotic flow and dielectric force by applying a high-frequency electrical signal, achieving rapid and uniform mixing of samples within droplets. The principle is as follows: To achieve rapid and efficient mixing of micro-droplet samples within the microfluidic chip, while precisely limiting the mixing area to a designated micro-region of the chip to avoid sample diffusion loss, a concentric arc-shaped interdigitated electrode structure is designed. The width and spacing of the interdigitated electrodes are both 1 / 4 of the acoustic wavelength (λ). During operation, a high-frequency AC signal is applied, exciting an alternating electric field between the electrodes, inducing periodic electroosmotic flow (EOF) and dielectric force in the surrounding medium. The electroosmotic flow forms a vortex-like microscale flow, while the dielectric force drives sample particles to perform radial oscillation and rotational motion. This dual action tears apart laminar flow and promotes component collision and fusion. The signal is precisely controlled by a function generator (frequency matches particle relaxation time, amplitude controls perturbation intensity), adaptable to samples of different viscosities or components (such as cell suspensions and reagent mixtures). Compared to static mixing structures, this electrode achieves rapid and uniform mixing within a small microfluidic volume through active perturbation by a dynamic electric field, providing crucial support for downstream applications requiring uniform samples, such as biochemical reactions and immunoassays.

[0080] Please see Figure 6The circular focusing interdigital electrodes 24 are arranged in concentric circles and are used for sample aggregation. They guide the target object to the central region through the dielectrophoresis effect. The principle is as follows: To achieve efficient enrichment and detection of the target object in the sample, the circular focusing interdigital electrodes achieve this function by precisely controlling the local electric field distribution. Its core structure consists of concentrically arranged interdigital electrode pairs, with adjacent electrode strips alternately distributed on the inner and outer circles of the arc, forming a radial electric field layout with central focusing. During operation, when a high-frequency AC voltage is applied, a non-uniform electric field is generated between the electrodes. Utilizing the dielectrophoresis effect (DEP)—the target object, due to differences in dielectric properties, is subjected to an electric field force and is guided to the central region with the highest electric field strength—spatial focusing of the sample is achieved, solving the enrichment problem of traditionally dispersed electrode distribution. This process is driven by a controllable electrical signal (such as a sine wave / square wave with adjustable frequency and amplitude) output from a function generator. By adjusting the signal parameters, it can be adapted to target particles of different sizes and electrical properties.

[0081] Please see Figure 7 Trapezoidal interdigitated electrodes 23: Arranged in a trapezoidal contour, these electrodes are used for sample enrichment. They form an "electric field funnel" through a gradient electric field, improving enrichment efficiency. The principle is as follows: To achieve efficient enrichment of target analytes in samples, the trapezoidal interdigitated electrodes improve capture efficiency by optimizing the electric field gradient distribution. Their structure is characterized by a trapezoidal contour: the electrode fingers are arranged in a symmetrical trapezoidal pattern, with shorter inner sides and longer outer sides (or vice versa), forming an electric field space that gradually decreases from the edge to the center. This geometric design causes the electric field strength to decrease gradually with increasing distance from the center, constructing an "electric field funnel" pointing towards the center. During operation, an electrical signal is applied, and the target analytes, driven by dielectric forces due to differences in dielectric properties, migrate and accumulate along the trapezoidal edge towards the central region where the electric field is strongest. The signal is output by a function generator, and its frequency and amplitude can be adjusted to suit particles of different sizes or electrical properties (such as cells and nanoparticles). Compared to traditional rectangular interdigitated electrodes, the trapezoidal gradient electric field better matches the force characteristics of the target object, reduces edge escape, and significantly enhances enrichment efficiency and uniformity, laying a solid foundation for subsequent high-sensitivity detection.

[0082] Please see Figure 8 Narrow rectangular interdigitated electrode 22: The interdigitated width is 40μm, used for point heating, and the droplet is rapidly heated by Joule heating generated by high-frequency acoustic vibration. The principle is as follows: With the adaptation design of narrow interdigitated structure and high-frequency electrical signal, compared with standard rectangular electrode, its spatial resolution is significantly improved, which can realize finer particle arrangement. At the same time, it has exclusive high-frequency vibration heating and oscillation dispersion functions, which can meet the needs of precise control and accelerated biochemical reaction. Please see Figure 9The chirped interdigitated electrode 26 is used for particle sorting and mixing. The principle is as follows: with a unique design featuring a finger width that gradually changes along the direction of sound wave propagation, it can achieve broadband sound wave excitation. Its core advantage lies in its ability to adapt to the differentiated separation requirements of particles with different sizes. At the same time, it can enhance the mixing effect through multi-frequency synergy, making it a multifunctional unit that takes into account both separation and mixing.

[0083] In this embodiment, please refer to Figure 2 The driving electrode array is arranged in an orthogonal array.

[0084] In this embodiment, the gap support assembly includes a spacer tape disposed along the edge of the lower electrode plate, the surface of which is coated with PDMS prepolymer. (This part is not shown in the figure; PDMS serves as a sealing adhesive in this embodiment, but UV adhesive or other suitable colloids can also be used.) The gap range can be set from 20 micrometers to 500 micrometers.

[0085] For example, this example provides a composite digital acoustic flow control chip, such as Figure 1 , Figure 2 As shown, it adopts a detachable bipolar plate structure, mainly composed of an upper plate, a lower plate and a gap support assembly, which is suitable for programmable manipulation of droplet samples and multi-dimensional sound field processing.

[0086] I. Overall Structure The chip employs a separate upper and lower electrode design, with a gap support component enabling detachable connection. The upper electrode integrates a surface acoustic wave (SAW) manipulation unit to excite SAW waves within the droplet, achieving multi-dimensional acoustic field manipulation of the sample within the droplet. The lower electrode integrates a driving electrode array based on the dielectric wetting effect, used for programmable generation, movement, segmentation, and merging of the droplet. A sealed cavity is formed between the upper and lower electrodes, filled with silicone oil as a continuous phase, ensuring the stability of electrical manipulation while preventing droplet evaporation and cross-contamination.

[0087] II. Lower electrode structure The lower electrode plate, serving as a programmable droplet transport unit, has the following structure from bottom to top: Substrate 10: A 60mm × 70mm PCB board is selected for large-scale circuit integration. A driving electrode array 9 is fabricated on the substrate surface. The electrode material is a chromium-gold composite metal thin film (5nm chromium transition layer, 80nm gold functional layer), which has excellent conductivity and oxidation resistance. The driving electrode array 9 is arranged in an orthogonal array, with each electrode measuring 3mm × 3mm, arranged in a 9 × 10 rectangular array, with an electrode spacing of 0.15mm, for a total of 96 driving electrodes.

[0088] The second dielectric layer 8 covers the surface of the driving electrode array 9. It is formed by spin coating, exposure and curing of SU-8 photoresist to form a dense insulating layer with uniform thickness. This achieves electrical isolation between the driving electrode array 9 and the droplet 6 above it, avoiding corrosion and leakage caused by the droplet 6 contacting the electrode, while ensuring the stable generation of the dielectric wetting effect.

[0089] The second hydrophobic layer 7 is coated on the surface of the second dielectric layer 8. It is formed by spin coating and heat treatment using Teflon material, and has a uniform thickness. It is used to reduce the adhesion between the droplet and the substrate and improve the electric field response sensitivity of the droplet.

[0090] III. Upper Electrode Structure The upper electrode plate, as a multi-dimensional acoustic wave manipulation unit, has the following structure from bottom to top: Piezoelectric substrate 1: A 3-inch 128° YX-cut lithium niobate single crystal wafer is selected, which has excellent piezoelectric properties and provides a basis for the efficient excitation of surface acoustic waves.

[0091] Surface acoustic wave interdigitated electrode array 2: Integrated onto the surface of a piezoelectric substrate using photolithography and thermal evaporation processes, employing a chromium-gold composite electrode (5nm chromium, 80nm gold). Please refer to [link / reference]. Figure 3 The array includes six functional types of interdigitated electrodes, specifically: Standard rectangular interdigitated electrode: interdigitated width 75μm, used for particle alignment or manipulation, forming a standing wave field by applying a low-frequency electrical signal to achieve precise alignment of particles; Focused interdigitated electrodes: concentric arc-shaped distribution, used for sample mixing, generating electroosmotic flow and dielectric force by applying high-frequency electrical signals to achieve rapid and uniform mixing of samples within droplets; Circular focusing interdigitated electrodes: arranged in concentric circles, used for sample aggregation, and guided to the central region of the circle through the dielectrophoretic effect; Trapezoidal interdigitated electrodes: arranged in a trapezoidal outline, used for sample enrichment, forming an "electric field funnel" through a gradient electric field to improve enrichment efficiency; Narrow rectangular interdigitated electrode: The interdigitated width is 40μm, which is used for fixed-point heating. The droplet is rapidly heated by Joule heating generated by high-frequency acoustic vibration.

[0092] Chirped interdigitated electrodes: used for particle sorting and mixing, they can adapt to the differentiated separation needs of particles of different sizes, and can enhance the mixing effect through multi-frequency synergy, making them a multifunctional unit that combines separation and mixing.

[0093] Each type of interdigitated electrode has an independent lead, which is connected to a different channel of the surface acoustic wave signal generator to control its frequency, amplitude and phase respectively.

[0094] The first dielectric layer 3 covers the surface of the interdigital electrode array 2 and is formed using the same SU-8 spin coating process as the lower electrode plate. This achieves electrical isolation between the interdigital electrodes and the upper transparent conductive layer 4, protects the interdigital electrode structure from damage by subsequent processes, and maintains the stability of acoustic excitation.

[0095] Transparent conductive layer 4: deposited on the surface of the first dielectric layer 3, indium tin oxide (ITO) layer is formed by magnetron sputtering process, with sheet resistance of 60Ω / □ and light transmittance ≥85%, serving as the dielectric wetting upper electrode (ground electrode), and cooperating with the lower electrode driving electrode array 9 to form an electric field loop.

[0096] First hydrophobic layer 5: Coated on transparent conductive layer 4, formed by spin coating and heat treatment of Teflon material, working in conjunction with second hydrophobic layer 7 of lower electrode to reduce droplet movement resistance.

[0097] IV. Gap Support Components and Cavity (not shown in the component diagram) The gap support assembly uses 70μm thick spacer tape, which is applied around the edge of the lower electrode (1mm from the edge) to form a semi-closed cavity frame. The surface of the spacer tape is coated with PDMS prepolymer. After the upper and lower electrodes are aligned and bonded, they are cured to form a detachable connection, which facilitates the cleaning, replacement and maintenance of the functional layer.

[0098] A sealed cavity X is formed between the upper and lower electrodes, filled with silicone oil as a continuous phase. Silicone oil possesses both excellent insulation and biocompatibility, ensuring the stability of the chip's electrical control, preventing damage to biological samples, and effectively reducing droplet evaporation to avoid cross-contamination between different droplets.

[0099] V. Control Connection The driving electrode array 9 of the lower electrode plate is connected to the DMF control board via a lead interface. Each electrode independently corresponds to an I / O port on the control board. By programming and configuring the timing and voltage of the I / O ports, the path planning and precise transport of the droplets can be achieved. The surface acoustic wave interdigitated electrode array 2 of the upper electrode plate is connected to the surface acoustic wave signal generator via an independent lead interface. The signal generator supports multi-channel independent control, and the frequency (1–50MHz), amplitude (0–20Vpp), and phase (0–360°) of each electrode can be adjusted separately. The DMF control board and the signal generator are both connected to the same host computer. The host computer software coordinates the start and stop of both, realizing the automated linkage of "droplet transport - electrode triggering - function execution".

[0100] The composite digital acoustic flow control chip of this invention adopts a detachable bipolar plate core structure, such as... Figure 1As shown, the chip mainly consists of an upper electrode plate, a lower electrode plate, and a gap support assembly. The structural design combines practicality and ease of maintenance. The gap support assembly uses spacer tape to isolate and connect the upper and lower electrode plates. This detachable design allows for convenient cleaning, replacement, and maintenance of the functional layers, significantly improving chip reusability and reducing operating costs. The chip cavity is filled with an oil-phase medium that possesses both good insulation and biocompatibility: insulation ensures the stability of the chip's electrical control and prevents interference such as leakage; biocompatibility prevents damage to biological samples (such as cells and nucleic acids); and the oil phase effectively reduces droplet evaporation, avoiding cross-contamination between different droplets and providing a stable environment for precise droplet control.

[0101] The chip's core functions rely on two key technological principles, which respectively ensure the basic manipulation of droplets and the advanced sample processing requirements: Firstly, the basic movement, separation, and merging of droplets are achieved based on the principle of dielectric wetting (EWOD). The core principle is to control the contact angle between the solid surface and the droplet by changing the electric field distribution on the electrode surface: when a voltage is applied to the electrode in a specific area, the contact angle between the droplet and the electrode surface changes, generating a surface tension gradient. Under the driving force of this gradient, the droplet moves in the direction where the contact angle decreases. By precisely controlling the on / off timing and voltage parameters of the electrodes in different areas, directional migration of droplets, on-demand separation (dividing large droplets into multiple smaller droplets), and precise merging (merging multiple small droplets into one large droplet) can be achieved, providing a fundamental guarantee for the streamlined and automated processing of subsequent samples.

[0102] Secondly, advanced sample processing functions are achieved based on the surface acoustic wave (SAW) coupling and modulation principle. The excitation of SAW originates from the piezoelectric effect of lithium niobate material. By applying an alternating voltage to the interdigital transducer on the piezoelectric substrate, SAW propagates along the substrate surface. To achieve efficient transfer of acoustic energy to the droplet, the chip constructs an acoustic propagation channel through a dielectric layer (e.g., SU8). The SAW propagates directionally through the SU8 dielectric layer and effectively couples with the droplet in the cavity. After the specifically modulated acoustic field acts on the droplet, it can produce a variety of controllable effects: first, it forms a standing wave field, using the acoustic radiation force of the standing wave field to achieve precise sorting, enrichment, and patterned arrangement of biological particles; second, it constructs a focused acoustic field, concentrating acoustic energy in a specific area to achieve point-to-point manipulation of the droplet; third, the acoustic energy is concentrated and dissipated inside the droplet, generating local heat through energy conversion to achieve point-to-point heating of the droplet, meeting the precise temperature control requirements of temperature-sensitive biochemical reactions (such as enzyme amplification).

[0103] Example 2 Please see Figure 10 A method for fabricating a composite digital acoustic flow control chip, the method comprising the following steps: A1. Fabrication of the lower electrode: A driving electrode array based on dielectric wetting effect is fabricated on the substrate, and a second dielectric layer and a second hydrophobic layer are deposited sequentially. A2. Fabrication of the upper electrode plate: A surface acoustic wave interdigitated electrode array is fabricated on a piezoelectric substrate by photolithography and deposition processes. The interdigitated electrode array includes at least two functional types of interdigitated electrodes. A first dielectric layer, a conductive layer and a first hydrophobic layer are sequentially deposited on the interdigitated electrode array. A3. Chip assembly: The upper electrode plate and the lower electrode plate are detachably connected by a gap support assembly to form a cavity, which is then filled with an oil phase medium.

[0104] In this embodiment, the upper electrode plate and the lower electrode plate are detachably connected in the following manner: a spacer tape is provided on the edge of the lower electrode plate, PDMS prepolymer is coated on the surface of the spacer tape, the upper electrode plate and the lower electrode plate are aligned and bonded together and then cured to form a detachable sealed cavity.

[0105] In this embodiment, the surface acoustic wave interdigitated electrode array integrates at least two functional types of interdigitated electrodes through photolithography and deposition processes. Each functional type of interdigitated electrode has independent leads for separate control.

[0106] In this embodiment, preferably, the lower electrode plate serves as a programmable droplet transport unit. Based on the dielectric wetting principle, the droplet's movement path is flexibly planned through electrode timing programming. Its structure, from bottom to top, is as follows: the substrate is either a PCB board or borosilicate glass (PCB boards are suitable for large-scale circuit integration, while borosilicate glass is suitable for optical observation scenarios); a driving electrode array is fabricated on the substrate surface, using a metal thin film with excellent conductivity and strong oxidation resistance; a dielectric layer is coated on the electrode array surface to achieve electrical isolation between the driving electrodes and the droplet above, preventing corrosion and leakage caused by the droplet contacting the electrodes, while ensuring the stable generation of the dielectric wetting effect. A hydrophobic layer is then coated on the dielectric layer to reduce the adhesion between the droplet and the substrate, improving the droplet's electric field response sensitivity.

[0107] In this embodiment, preferably, the lithium niobate single-crystal substrate is first subjected to a fine cleaning process, using acetone, anhydrous ethanol, and deionized water in sequence for ultrasonic cleaning to remove surface oil and impurities. After cleaning, it is dried with nitrogen and then baked for later use. Subsequently, a photolithography process is performed, where photoresist is uniformly coated onto the cleaned lithium niobate substrate surface. After pre-baking, exposure, development, and post-baking, a photoresist pattern matching the surface acoustic wave interdigitated electrode (IDT) array is obtained. Next, a thermal evaporation process is used to deposit a metal electrode layer on the lithium niobate substrate surface with the photoresist pattern, ensuring uniform electrode layer thickness and tight adhesion to the substrate. After metal deposition, a stripping process is performed to remove residual photoresist, resulting in a complete surface acoustic wave interdigitated electrode (IDT) array. Then, a dielectric layer is deposited. For the preparation of the dielectric layer, a spin-coating process is used to coat the surface of the interdigital electrode array with a dielectric layer, forming a dense insulating dielectric layer. This layer serves two purposes: firstly, it provides electrical isolation between the surface acoustic wave interdigital electrodes and the upper ITO conductive layer and droplets, preventing electrode corrosion and leakage caused by short circuits between the electrodes and the ITO layer or contact with droplets, thus ensuring the independence of electric and acoustic field manipulation; secondly, it protects the interdigital electrode structure from damage caused by subsequent ITO sputtering and hydrophobic layer coating processes, maintaining the stability of acoustic wave excitation. After the dielectric layer is prepared, an ITO transparent conductive layer is deposited on its surface using magnetron sputtering of indium tin oxide, serving as the dielectric wetting upper electrode (ground electrode). Finally, a hydrophobic material is coated on the surface of the ITO layer using a spin-coating process, followed by curing to form a uniform hydrophobic layer, completing the preparation of the upper electrode plate.

[0108] In this embodiment, preferably, the overall chip assembly adopts the following steps: 1. Plate cleaning: The prepared upper and lower plates are blown off with nitrogen to remove surface dust, and then placed in a clean bench and dried with a heating table at 65°C. After being removed, they are cooled to room temperature for later use. 2. Gap and sealing setup: A 70 μm thick spacer tape is used and applied around the edge of the lower electrode (1 mm from the edge), with vent holes reserved at the edge to form a semi-closed cavity frame; a layer of PDMS prepolymer is evenly coated on the surface of the tape to improve subsequent connection performance; 3. Alignment and Fixing of Electrodes: Align the upper electrode with the lower electrode precisely using an optical alignment stage, and slowly press down the upper electrode to make the two electrodes fit together; use a clamp to gently press and fix the two electrodes, and place them in an 80℃ oven to heat for 30 minutes to allow the PDMS to cure and complete the connection. 4. Silicone oil filling: Place the connected chip horizontally, and slowly inject silicone oil into the inlet at an appropriate tilt angle using a micro-syringe until the silicone oil surface is flush with the tape surface. During the process, you can gently tap the side wall of the upper electrode to remove air bubbles. 5. Interface reservation: Reserve openings at the corresponding positions on the spacer tape (at the lower electrode lead and the upper electrode lead) for subsequent signal connection.

[0109] In this embodiment, the signal wiring and control logic preferably adopt the following scheme: 1. Lower electrode plate signal connection: Connect the driving electrode array leads of the lower electrode plate to the DMF control board through pin connectors. Each electrode corresponds to an I / O port of the control board. By programming and configuring the timing and voltage of the I / O port, the path planning and precise transport of the droplets can be realized. 2. Upper electrode plate signal connection: Connect the independent leads of the various functional electrodes of the upper electrode plate to the surface acoustic wave signal generator through a high-frequency coaxial cable. The signal generator supports multi-channel independent control, and the frequency (1-50MHz), amplitude (0-20Vpp), and phase (0-360°) of each electrode can be adjusted separately. 3. Collaborative control: The host computer software synchronously controls the DMF control board and signal generator to achieve automated linkage of "droplet transfer - electrode triggering - function execution": When the droplet reaches the target area, the host computer triggers the signal output of the corresponding functional electrode, completes the processing, and then controls the droplet to transfer to the next area.

[0110] For example, this example provides a specific fabrication method for the composite digital acoustic fluid control chip based on one of the embodiments, particularly the implementation of integrating multiple functional types of interdigitated electrodes on the upper electrode plate and the detachable assembly of the upper and lower electrode plates. Please refer to... Figure 1 , Figure 2 Understand the following process: I. Preparation of the lower electrode plate (1) Substrate selection and electrode design A 60mm×70mm PCB board was selected as the substrate 10. A sawtooth square driving electrode was used, with each electrode measuring 3mm×3mm and arranged in a 9×10 rectangular array with an electrode spacing of 0.15mm. An inlet, an outlet, and a waste liquid tank were set above the array, with a total of 96 driving electrodes designed.

[0111] (2) Substrate 10 cleaning The glass was ultrasonically cleaned for 30 minutes with glass cleaning fluid, 15 minutes with anhydrous ethanol, and then twice with deionized water for 15 minutes each time. After being dried with nitrogen, it was placed in a 120°C oven for 30 minutes and then cooled to room temperature for later use.

[0112] (3) Fabrication of the second dielectric layer 8 SU-8 dielectric layer was deposited using a spin coating process: SU-8 2015 photoresist was spin coated at a speed of 3500 r / min, with a pre-baking temperature of 65℃ for 10 min and a pre-baking temperature of 95℃ for 15 min; after cooling, it was exposed to ultraviolet light (power 7.22 mW / cm², exposure time 21 s); the post-baking temperature was 65℃ for 15 min and the post-baking temperature was 95℃ for 20 min; finally, it was cured in a 165℃ oven for 2 h.

[0113] (4) Preparation of the second hydrophobic layer 7 The lower electrode plate with the dielectric layer was activated in a plasma cleaner; a 1% Teflon solution (solvent being electronic fluorinated liquid F-40) was prepared and dropped onto the surface of the lower electrode plate, and then spin-coated at 1500 rpm for 60 s; after standing for 5 min, it was heated in an oven at 165℃ for 15 min to complete the preparation of the hydrophobic layer.

[0114] II. Preparation of the Upper Electrode (1) Selection and cleaning of piezoelectric substrate 1 A 3-inch 128° YX-cut lithium niobate single crystal wafer was selected as the piezoelectric substrate. It was ultrasonically cleaned with acetone for 15 min, anhydrous ethanol for 15 min, and deionized water for 15 min twice. After being dried with nitrogen, it was dried on a hot plate at 65°C and cooled to room temperature for later use.

[0115] (2) Fabrication of multifunctional interdigital electrode array 2 Customized photolithography processes were used to integrate and fabricate multifunctional surface acoustic wave interdigitated electrode arrays on the substrate surface. Spin-coat Shipley S1813 photoresist at 3200 rpm for 50 seconds; pre-baking at 65°C for 2 minutes and 95°C for 2 minutes.

[0116] UV exposure was performed using a custom photomask (power 7.22mW / cm², exposure 36s), with patterned areas for six functional electrodes designed on the photomask.

[0117] After drying, bake at 65°C for 2 minutes and at 95°C for 2 minutes; soak in developer for 30 seconds and shake for 30 seconds; rinse thoroughly with pure water; blow dry with nitrogen and then dry on a hot plate at 65°C.

[0118] A chromium transition layer (5 nm) and a gold functional layer (80 nm) were sequentially deposited using a thermal evaporation process to form an interdigitated electrode array.

[0119] The photoresist is stripped by immersion in acetone to obtain a complete interdigitated electrode array, including: a standard rectangular interdigitated electrode (75 μm interdigitated width) for particle alignment or manipulation; a focusing interdigitated electrode (concentric arc distribution) for sample mixing; a circular focusing interdigitated electrode for sample aggregation; a trapezoidal interdigitated electrode for sample enrichment; a chirped interdigitated electrode for particle sorting and mixing; and a narrow rectangular interdigitated electrode (40 μm interdigitated width) for point heating. Each functional type of interdigitated electrode has independent leads, each connected to a different channel of the surface acoustic wave (SAW) signal generator for individual control. (The electrode types are not specifically indicated in the figure, but those skilled in the art can prepare the corresponding electrodes according to actual needs based on this step; further details are omitted here.) (3) Fabrication of the first dielectric layer 3 Using the same spin-coating SU-8 process as the lower electrode plate, a dense dielectric layer is deposited on the surface of the interdigital electrode array to achieve electrical isolation between the interdigital electrodes and the subsequent ITO layer.

[0120] (4) Preparation of transparent conductive layer 4 ITO layers were deposited using magnetron sputtering: ITO target purity 99.99%, sputtering power 100W, argon flow rate 60sccm, sputtering time 5min50s, sheet resistance 60Ω / □, and transmittance ≥85%, which served as the dielectric wetting top electrode (ground electrode).

[0121] (5) Preparation of the first hydrophobic layer 5 Using the same Teflon spin coating process as the lower electrode, a uniform hydrophobic layer is formed on the surface of the ITO layer.

[0122] This electrode plate achieves an integrated innovation of acoustic wave manipulation, dielectric wetting assistance, and optical observation compatibility through the design of "multifunctional electrode integration + piezoelectric substrate adaptation + multi-layer structure synergy", which greatly improves the functional integration and application compatibility of the chip.

[0123] III. Chip Assembly (1) Plate cleaning The prepared upper and lower plates were blown off with nitrogen to remove surface dust, placed on a 65°C heating platform to dry the moisture, and then cooled to room temperature.

[0124] (2) Gap and sealing settings A 70μm thick spacer tape is applied around the edge of the lower electrode (1mm from the edge), with vent holes left at the edge to form a semi-closed cavity frame; a layer of PDMS prepolymer is evenly coated on the surface of the tape.

[0125] (3) Alignment and fixing of electrode plates The upper electrode plate is precisely aligned with the lower electrode plate using an optical alignment stage, and then slowly pressed down to make the two electrodes fit together. It is then lightly pressed and fixed with a clamp, and placed in an 80°C oven for 30 minutes to cure the PDMS and form a detachable and sealed cavity.

[0126] (4) Oil phase filling Place the connected chip horizontally, and slowly inject silicone oil into the inlet at an appropriate tilt angle using a micro-syringe until the silicone oil level is flush with the tape surface. Gently tap the side wall of the upper electrode to expel air bubbles, thus completing chip fabrication.

[0127] Example 3 Please see Figure 11 A multi-dimensional sample processing method, characterized in that the method is based on the composite digital acoustic flow control chip described in one of the embodiments, the method comprising: B1. The drive electrode array of the lower electrode plate and the surface acoustic wave interdigitated electrode array of the upper electrode plate are controlled by the host computer. B2. According to the preset sample processing flow, perform at least one processing step, each processing step including: (1) The droplet is transported to the corresponding functional electrode region in the surface acoustic wave interdigitated electrode array through the driving electrode array; (2) When the droplet reaches the functional electrode area, the host computer controls the corresponding surface acoustic wave interdigitated electrode to start, and performs corresponding type of acoustic field manipulation on the sample in the droplet; B3. After all processing steps are completed, the droplets are transferred to the collection area through the driving electrode array.

[0128] In this embodiment, the host computer controls the corresponding surface acoustic wave interdigitated electrode to start in the following way: The host computer drives the electrode array according to the programmed control to transport the droplet along a predetermined path to the target functional electrode area; when the programmed control is executed to the corresponding step, the host computer triggers the surface acoustic wave interdigitated electrode to start.

[0129] In this embodiment, the multi-dimensional sample processing method includes multiple processing steps executed sequentially. The functional electrode regions corresponding to different processing steps are different, and the type of acoustic field manipulation in each processing step is selected from at least one of particle arrangement, sample mixing, sample aggregation, sample enrichment, or fixed-point heating.

[0130] For example, this example uses a chip prepared according to Embodiment 2. Through coordinated control of the lower electrode array and the upper electrode array with a host computer, it sequentially achieves rapid, targeted heating of the sample and precise particle alignment, verifying the chip's multi-dimensional sample processing capabilities. This example provides an application instance of targeted heating using a composite digital acoustic fluid control chip prepared according to the method in Embodiment 2. It leverages the synergistic effect of two core functional electrodes on the upper electrode (narrow 40μm interdigital electrodes and standard 75μm interdigital electrodes) to sequentially achieve rapid, targeted heating of the sample and precise particle alignment, verifying the chip's adaptability to multiple scenarios. The specific operating procedures are as follows: I. Experimental Preparation (1) Chip assembly Take the upper and lower electrode plates prepared in Example 2, and use a spacer tape of a preset thickness to wrap around and adhere to the edge of the lower electrode plate to achieve gap positioning and preliminary sealing of the upper and lower electrode plates; slowly fill the cavity formed by the two electrode plates with silicone oil as a continuous phase, and gently tap the chip during the filling process to remove air bubbles, ensuring that the cavity is completely filled and there are no air bubbles left. Finally, press and fix the spacer tape to complete the chip assembly.

[0131] (2) Basic temperature setup Place the assembled chip stably on a 50°C constant-temperature hot plate and let it stand for 5 minutes to allow the overall chip temperature to stabilize at the baseline temperature of 50°C. This step provides a temperature reference for the denaturation and annealing steps of ultrafast PCR, preventing damage to the sample and chip due to sudden temperature changes.

[0132] (3) Sample loading The sample to be heated (PCR reaction solution containing fluorescently labeled microparticles) is precisely loaded into the initial transport area of ​​the lower electrode using a pipette, ensuring that the droplet shape is intact and does not contact the sidewall of the cavity.

[0133] II. Multi-step processing flow (1) Droplet transport to the heating zone By timing the programmable drive electrode array of the lower electrode plate, an electrical signal is applied to control the droplet to move precisely along a preset path to the working area corresponding to the narrow rectangular interdigital electrode.

[0134] (2) Fixed-point heating Upon reaching the target area, the narrow rectangular interdigitated electrode is controlled by the host computer according to the timing program or manually: a high-frequency sinusoidal electrical signal with a frequency of 22MHz and an amplitude of 15Vpp is applied, and the Joule heat generated by the high-frequency sound wave vibration is used to rapidly raise the temperature of the target area from 50℃ to 92–95℃ in ≤60s, thus completing the rapid temperature rise of the sample at a fixed point.

[0135] (3) Droplet transport to the particle alignment region After heating is complete, the narrow rectangular interdigitated electrode stops outputting according to the timing program or manually, and the lower electrode driving electrode array is restarted to transfer the droplet to the corresponding action area of ​​the standard rectangular interdigitated electrode (75μm interdigitated width). Once the droplet arrives, the droplet transfer is stopped by the driving electrode array via the host computer, either according to the timing program or manually.

[0136] (4) Particle arrangement According to a timing program or manually, the standard rectangular interdigitated electrodes are controlled by a host computer: a low-frequency sinusoidal electrical signal with a frequency of 12MHz and an amplitude of 10Vpp is applied to form a stable standing wave field within the droplet. Under the action of acoustic radiation, the fluorescently labeled microparticles aggregate at the nodes, forming a uniform linear array. The arrangement effect is observed in real time using a microscope during the process.

[0137] (5) Product collection After the particles are aligned, the host computer controls the standard rectangular interdigitated electrode to stop outputting and drives the electrode array through the lower electrode plate to transfer the processed droplets to the product collection area, thus completing the entire multi-dimensional sample processing process.

[0138] III. Experimental Results In this example, the chip, through coordinated control of the lower electrode array and the upper multifunctional interdigital electrode array via a host computer, achieves automated linkage of "droplet transport → acoustic field processing → re-transport". First, narrow rectangular interdigital electrodes are used to achieve rapid, targeted heating to meet the temperature requirements of PCR amplification; then, standard rectangular interdigital electrodes are used to form a standing wave field, achieving gentle and precise alignment of the particles. The two functional electrodes work collaboratively on the same chip, fully validating the chip's core capability of "multi-dimensional sample processing".

[0139] The beneficial effects of this invention are as follows: 1. Integrating a SAW chip into a digital acoustic fluid control chip enables additional analytical capabilities beyond the functions of droplet sample movement, separation, and fusion. This includes coupling an acoustic field within the droplet and leveraging various effects of the acoustic field to achieve particle manipulation, sample enrichment, liquid mixing, and heating. This addresses the challenges of traditional acoustic fluid control technologies, which require micropumps for sample delivery and suffer from limitations in automated operation and digital analysis due to their simplistic chip structures. Furthermore, compared to traditional digital microfluidics, the integration of the acoustic field significantly enhances the manipulation and analysis capabilities of the droplets.

[0140] 2. The composite bipolar plate structure overcomes the design limitations and space waste caused by the traditional digital acoustic fluid control chip integrating EWOD electrodes and IDTs on a single substrate. This increases the density of both electrodes, facilitating the integration of more functions and simplifying wire design. Furthermore, the separate control of the EWOD and IDT electrodes on the two plates resolves the issue of mutual interference between their control signals.

[0141] 3. The composite bipolar plate design allows for flexible disassembly and reassembly, solving the problems of difficult maintenance and poor reusability of traditional integrated chips, and reducing usage costs.

[0142] 4. Compared to traditional digital acoustic fluid control chips, this chip offers a variety of IDTs designs and corresponding sample analysis methods, expanding its functionality. It boasts high functional integration, adaptable to complex sample processing needs in multiple fields such as biomedical detection and chemical analysis, and has broad application prospects.

[0143] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification and drawings, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A composite digital acoustic flow control chip, characterized in that, include: A detachable upper electrode plate and a lower electrode plate, and a gap support assembly disposed between the upper electrode plate and the lower electrode plate; The upper electrode plate includes a piezoelectric substrate, a surface acoustic wave interdigitated electrode array disposed on the piezoelectric substrate, a first dielectric layer covering the interdigitated electrode array, a conductive layer disposed on the first dielectric layer, and a first hydrophobic layer disposed on the conductive layer; the surface acoustic wave interdigitated electrode array is used to excite surface acoustic waves in the droplet to achieve multi-dimensional acoustic field manipulation of the sample in the droplet. The lower electrode plate includes a substrate, a driving electrode array disposed on the substrate, a second dielectric layer covering the driving electrode array, and a second hydrophobic layer disposed on the second dielectric layer; the driving electrode array is used to perform programmable generation, movement, segmentation, and merging operations on droplets based on the dielectric wetting effect; A cavity for filling the oil phase medium is formed between the upper electrode plate and the lower electrode plate; The driving electrode array of the lower electrode plate is configured to be connected to the DMF control board, and the surface acoustic wave interdigitated electrode array of the upper electrode plate is configured to be connected to the surface acoustic wave signal generator. The DMF control board and the signal generator are configured to be connected to a host computer. The driving electrode array and the surface acoustic wave interdigitated electrode array are configured to be started and stopped in coordination by the host computer in order to jointly perform droplet transport and acoustic field processing functions.

2. The composite digital acoustic flow control chip according to claim 1, characterized in that, The surface acoustic wave interdigitated electrode array includes at least two functional types of interdigitated electrodes, namely: a standard rectangular interdigitated electrode for particle alignment or manipulation, a focusing interdigitated electrode for sample mixing, a circular focusing interdigitated electrode for sample aggregation, a trapezoidal interdigitated electrode for sample enrichment, and a narrow rectangular interdigitated electrode for point heating.

3. The composite digital acoustic flow control chip according to claim 1, characterized in that, The driving electrode array is arranged in an orthogonal array.

4. The composite digital acoustic flow control chip according to claim 1, characterized in that, The gap support assembly includes a support component with a preset thickness disposed along the edge of the lower electrode plate. The surface of the support component is coated with a flexible adhesive, which is used to fill the gap between the support component and the upper and lower electrode plates, and is cured to form a flexible adhesive layer.

5. A method for fabricating a composite digital acoustic fluid control chip, characterized in that, The method includes the following steps: Fabrication of the lower electrode: A driving electrode array based on the dielectric wetting effect is fabricated on the substrate, and a second dielectric layer and a second hydrophobic layer are deposited sequentially; Fabrication of the upper electrode plate: A surface acoustic wave interdigitated electrode array is fabricated on a piezoelectric substrate by photolithography and deposition processes. The interdigitated electrode array includes at least two functional types of interdigitated electrodes. A first dielectric layer, a conductive layer and a first hydrophobic layer are sequentially deposited on the interdigitated electrode array. Chip assembly: The upper electrode and the lower electrode are detachably connected by a gap support assembly to form a cavity, which is then filled with an oil phase medium.

6. The method for fabricating a composite digital acoustic fluid control chip according to claim 5, characterized in that, The upper electrode plate and the lower electrode plate are detachably connected by a gap support assembly: a support member with a preset thickness is provided at the edge of the lower electrode plate, a flexible adhesive is coated on the surface of the support member, and after the upper electrode plate and the lower electrode plate are aligned and attached, the flexible adhesive is cured into a flexible bonding layer to form a detachable sealed cavity.

7. The method for fabricating a composite digital acoustic flow control chip according to claim 5, characterized in that, The surface acoustic wave interdigitated electrode array integrates at least two functional types of interdigitated electrodes through photolithography and deposition processes. Each functional type of interdigitated electrode has independent leads for separate control.

8. A multi-dimensional sample processing method, characterized in that, The method is based on the composite digital acoustic flow control chip according to any one of claims 1 to 4, and the method includes: The drive electrode array of the lower electrode plate and the surface acoustic wave interdigital electrode array of the upper electrode plate are controlled in a coordinated manner by the host computer. According to the preset sample processing procedure, at least one processing step is executed, and each processing step includes: The droplets are transported to the corresponding functional electrode region in the surface acoustic wave interdigitated electrode array via the driving electrode array; When the droplet reaches the functional electrode area, the host computer controls the corresponding surface acoustic wave interdigitated electrode to activate and perform corresponding type of acoustic field manipulation on the sample in the droplet. After all processing steps are completed, the droplets are transported to the collection area via the driving electrode array.

9. A multi-dimensional sample processing method according to claim 8, characterized in that, The host computer controls the activation of the corresponding surface acoustic wave interdigitated electrode in the following manner: The host computer drives the electrode array according to the programmed control to transport the droplet along a predetermined path to the target functional electrode area; when the programmed control is executed to the corresponding step, the host computer triggers the surface acoustic wave interdigitated electrode to start.

10. A multi-dimensional sample processing method according to claim 8, characterized in that, The multi-dimensional sample processing method includes multiple processing steps executed sequentially. The functional electrode regions corresponding to different processing steps are different, and the type of acoustic field manipulation in each processing step is selected from at least one of particle arrangement, sample mixing, sample aggregation, sample enrichment, or fixed-point heating.

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