High-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip

Abstract

The invention discloses a high-throughput antibody screening system based on a digital droplet microfluidic and plasmon metasurface chip, and belongs to the field of microfluidic technology and plasmon biosensing. The system is composed of a digital micro-fluidic chip module, a plasmon metasurface sensing chip, a light source and a spectrograph. The digital micro-fluidic chip adopts a double-plate type framework, and an electrode array is driven by an FPGA (Field Programmable Gate Array) control circuit to realize accurate control of micro-upgrading liquid drops; the plasmon metasurface chip is embedded into the lower polar plate, and label-free detection of antigen-antibody combination is realized by utilizing a surface plasmon resonance effect. A liquid drop advancing path is programmed through an upper computer, chip biological functionalization, sample adding and detection processes are automatically completed, multi-channel parallel detection can be carried out at the same time, and high-throughput screening of antibody affinity is achieved. The method has the advantages of high automation degree, high sensitivity, low sample consumption and the like.

Description

Technical Field

[0001] The present invention belongs to the field of microfluidics and plasmon biosensing, and specifically relates to a high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chips. Background Art

[0002] In recent years, plasmonic metasurfaces have seen widespread application in biosensing. By designing subwavelength metallic nanostructures, plasmonic metasurfaces can produce significant localized electromagnetic field enhancement effects in biomolecule detection. This technology offers label-free, high sensitivity, and the ability to perform in situ, real-time monitoring. In recent years, it has demonstrated significant application value in areas such as antibody screening and disease diagnosis. Compared to traditional prism-coupled sensors, plasmonic metasurfaces eliminate the reliance on complex optical systems, facilitating device miniaturization and integrated detection processes, thereby providing a more convenient and efficient solution.

[0003] Based on the dielectric wetting effect, the digital microfluidic chip dynamically adjusts the interfacial tension between droplets and the substrate by applying a programmed voltage across the electrode array, enabling precise manipulation of droplet splitting, movement, and merging. The dual-plate design ensures the system's airtightness and stability, while the synergistic effect of the hydrophobic and dielectric layers ensures efficient and repeatable droplet movement.

[0004] Digital droplet microfluidics uses electric fields to precisely control the movement of microliter-scale droplets, offering significant advantages such as high automation, minimal reagent consumption, and scalable throughput. Its unique programmable fluidic design capabilities enable flexible implementation of complex operational processes such as sample mixing, reaction incubation, and chip cleaning, significantly improving experimental efficiency. This technology offers an innovative solution to the bottleneck of manual labor in traditional biological testing.

[0005] When using metasurface chips for biological testing of antibody screening, the addition of samples and biological reagents is involved. Manual operation makes it difficult to accurately control the amount of reagents and samples, which not only easily leads to waste, but may also cause contamination, thereby affecting the accuracy of the test results. Although traditional microfluidics technology can partially solve this problem, it requires a separate liquid path system to be designed for each biological detection indicator, which is not suitable for the need to detect multiple indicators at the same time or for large-scale screening. In addition, traditional methods lack flexibility in the detection process and cannot temporarily change the detection indicators or modify the detection process, which limits the potential of metasurface chips in antibody screening applications. Therefore, it is particularly important to seek more flexible and efficient solutions. Summary of the Invention

[0006] The present invention aims to address the challenges of the aforementioned antibody screening technologies, including the operational processes that rely heavily on manual intervention, the difficulty in achieving both high throughput and high sensitivity, the bulky equipment, and the high operating costs. The system is based on digital droplet microfluidics (DMF) and plasmonic metasurface chips, aiming to provide a high-throughput antibody screening system. This system integrates digital droplet microfluidics and plasmonic metasurface optical sensing technologies. By utilizing a microfluidic chip to perform droplet manipulation and combining it with metasurface optical sensing technology, the system achieves automated, high-throughput, and low-sample-consumption antibody screening.

[0007] In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions.

[0008] A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chips, including a digital microfluidic chip module, a plasmon metasurface sensor chip, a light source and spectrometer, an FPGA programmable logic controller, and a host computer;

[0009] The digital microfluidic chip adopts a dual-plate architecture. The lower plate is based on a printed circuit board, with a copper drive electrode array, a dielectric layer, and a hydrophobic coating stacked on the surface. The upper plate is an indium tin oxide (ITO) conductive glass substrate, with the same hydrophobic material coated on the lower surface. It is parallel to the lower plate and spaced apart to form a droplet running space (microcavity).

[0010] The plasmon metasurface sensor chip is embedded in the bottom plate of the digital microfluidic chip and is completely contained in a single driving electrode to form a biological detection site;

[0011] The light source and spectrometer are optically coupled to the detection site via optical fibers;

[0012] The driving electrode array applies adjustable square wave pulses through the FPGA programmable logic controller control circuit to achieve precise delivery, mixing and waste liquid removal of droplets;

[0013] The host computer is used to pre-program the droplet travel path and residence time to automatically complete the biological functionalization, sample addition and detection processes of the metasurface.

[0014] Furthermore, the plasmon metasurface sensor chip is embedded in the lower electrode plate of the digital microfluidic chip by etching shallow pits of a predetermined size on the lower electrode plate by laser micromachining or chemical etching, and then the metasurface chip is bonded into the shallow pits by conductive silver paint to combine the two, ensuring that the chip surface is flush with the hydrophobic layer of the lower electrode plate.

[0015] Furthermore, the shallow pit may be a rectangular shallow pit of 1.5 mm×1.5 mm×100 μm.

[0016] Furthermore, the circular driving electrodes have an electrode diameter of 3 mm and an electrode spacing of ≤500 μm.

[0017] Furthermore, the printed circuit board may be 1 mm thick, the dielectric layer may be a Parylene-C dielectric layer, and the hydrophobic coating may be a Teflon hydrophobic coating. The Parylene-C dielectric layer may be 5 to 10 μm thick.

[0018] Furthermore, the adjustable square wave pulse amplitude is 0-150V and the frequency is 1-10kHz.

[0019] Furthermore, the droplet running space between the upper and lower plates can be filled with dimethyl silicone oil or air as a filling medium for droplet movement. The single droplet volume control accuracy reaches ±0.5μL

[0020] Furthermore, droplet volume control is achieved through the coordinated design of electrode size and driving voltage. A single circular driving electrode (3mm in diameter) can precisely manipulate a 2μL droplet when applying a 100V square wave pulse (5kHz frequency), with a volume error of ≤±0.5μL. A voltage-droplet volume calibration curve was established through preliminary experiments and integrated into the host computer control software.

[0021] Furthermore, by increasing the number of electrodes on the bottom plate of the digital microfluidics PCB, more droplets can be driven and more complex droplet paths can be constructed. With a driving electrode spacing of ≤500μm, combined with multiplexing actuation technology, ≥20 independent droplets can be manipulated simultaneously.

[0022] Furthermore, the host computer can use conventional LabVIEW, Python or MATLAB software, integrating fast Fourier transform (FFT) and Savitzky-Golay filtering algorithms, quantifying antibody affinity by calculating the spectral trough offset (Δλ), and automatically generating multi-path droplet routes according to the preset detection process; path planning can automatically generate droplet routes according to the preset detection process (such as functionalization, sealing, and detection), and perform high-throughput, multi-index antibody screening and detection at the same time; the electrode control can send adjustable square wave pulses (amplitude 0-150V, frequency 1-10kHz) to the driving electrode array through the FPGA controller to drive droplet movement, mixing and waste liquid removal.

[0023] Furthermore, the host computer can communicate with the FPGA controller via the USB 3.0 protocol and send adjustable square wave pulses (amplitude 0-150V, frequency 1-10kHz) to the driving electrode array to precisely control the movement of droplets.

[0024] Furthermore, the optical fiber adopts multimode quartz optical fiber with a core diameter of 1.5 mm. A collimating lens is configured at the end of the optical fiber to reduce reflection interference.

[0025] Furthermore, the spectrometer is a micro-spectrometer with a spectral resolution of ≤0.1 nm. The light source emits a broad spectrum of light in the range of 400 to 800 nm, the spectrometer has a resolution of ≤0.1 nm, and adopts a reflective spectrum detection mode.

[0026] Furthermore, the pre-programmed droplet travel path may include:

[0027] Cleaning path: PBS buffer pool → chip → waste liquid pool;

[0028] Functionalization path: antibody reservoir → chip → BSA reagent reservoir → waste liquid reservoir;

[0029] Detection path: antigen reservoir → chip → waste liquid pool.

[0030] Furthermore, the screening system, based on the plasmonic metasurface chip design, analyzes the results through spectral changes displayed by the spectrometer. For refractive index analysis, an optical fiber connects the light source and the spectrometer, with the fiber head vertically placed on the upper plate surface at the detection site. The light source shines through the fiber head to the detection site, and the reflected light is received by the fiber head and sent to the spectrometer for refractive index analysis.

[0031] Furthermore, the biomonitoring process of this system requires no labeling. When the antigen molecules to be tested bind to the biofunctionalized metal nanostructures on the metasurface, the surface plasmon resonance phenomenon generated causes a change in the refractive index, which in turn shifts the spectral absorption peak. This is manifested as a redshift in the spectral peak or trough.

[0032] Furthermore, by processing the frequency points where the spectrum troughs before and after antigen capture are located and calculating the difference, the antibody screening test results can be obtained based on the difference.

[0033] Furthermore, multiple plasmon metasurface chips can be embedded on the lower electrode plate, and each plasmon metasurface detection unit corresponds to a biological detection site. By adding multiple detection sites, high-throughput, multi-index detection can be achieved.

[0034] Furthermore, the system can be used for multi-channel antibody screening, and the wavelength offset difference after antigen capture at different detection sites and after biofunctionalization is compared. The larger the difference, the better the binding affinity. Specifically, it includes: 1) fixing different antibodies at each detection site; 2) simultaneously delivering droplets of the same antigen to each detection site; 3) collecting spectral data before and after antigen binding at each detection site; 4) calculating the wavelength offset of each detection site. The larger the offset, the higher the binding affinity between the corresponding antibody and antigen.

[0035] Compared with the existing technology, the present invention deeply integrates the automated control of digital droplet microfluidics with the high-sensitivity detection of plasmonic metasurfaces to solve the problems of complex manual operation, low detection efficiency, strong equipment dependence and high cost in traditional antibody screening technology. It not only realizes unmanned and high-throughput processing of the entire process, but also significantly improves the detection sensitivity. At the same time, it greatly compresses the equipment volume and reduces manufacturing costs. It can flexibly adapt to the rapid and accurate analysis of a variety of complex samples, providing an efficient and portable integrated solution for medical diagnosis, drug development and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the overall framework of the antibody screening system integrated with plasmon metasurface digital droplet microfluidics in Example 1 of the present invention;

[0037] Figure 2 This is a schematic diagram of the local structure of Example 1 of the present invention;

[0038] Figure 3 This is a schematic diagram of the system fluid path planning in Example 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of the local structure in Example 2 of the present invention. DETAILED DESCRIPTION

[0040] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the relevant invention and are not intended to limit the invention. In the absence of conflict, the embodiments and features in the embodiments of this application may be combined with each other.

[0041] Example 1

[0042] Figure 1 This is a schematic diagram of the overall framework of the antibody screening system based on plasmonic metasurface digital droplet microfluidics in a specific embodiment of the present invention. The system includes an optical sensing part light source 101, a spectrometer 102, a digital microfluidic chip 104 combined with a plasmonic metasurface, and the digital microfluidic control part includes a digital microfluidic chip control module 105 and a host computer 106.

[0043] In this embodiment, the control module 105 of the digital microfluidic chip is connected to a host computer 106 via the USB 3.0 communication protocol. By pre-planning the droplet's path and dwell time in the host computer, control signals are transmitted down through the host computer 106, enabling precise control of the droplet's motion on the chip, thereby constructing the required detection fluidic system. Simultaneously, an optical fiber 103 is coupled to the light source 101 and spectrometer 102, feeding the received reflected light signal back to the spectrometer 102. The host computer's Fast Fourier Transform (FFT) algorithm then records and analyzes the trough offset of the received reflected light on a computer, ultimately generating the corresponding detection results.

[0044] Figure 2 A schematic diagram showing the partial structure of the detection area of ​​the digital microfluidic device integrated with the metasurface chip in this embodiment shows the following components: light source 101, upper plate 202, first hydrophobic layer 203, test droplet 204, plasmonic metasurface chip 205, second hydrophobic layer 206, dielectric layer 207, lower plate 208, and driving electrode array 209. The bold arrows in the figure indicate the light propagation path. The test droplet 204 and the plasmonic metasurface chip 205 together constitute the detection site.

[0045] In this embodiment, the dielectric layer 207 is made of Parylene-C, with a dielectric constant of 3.1 and a breakdown field strength of 260 kV / mm; the first hydrophobic layer 203 and the second hydrophobic layer 206 are both made of Teflon AF1600 fluorinated diamond-like carbon, F-DLC, with a contact angle of 165°±3°.

[0046] In this embodiment, the distance between the upper and lower plates may be 1 to 12 μm.

[0047] In this embodiment, the metal material of the metasurface chip adopts a gold / silver nanoarray structure with a period of 50 to 200 nm, which is prepared by laser direct writing or electron beam lithography and embedded in a 1.5 mm × 1.5 mm × 100 μm shallow pit on the lower electrode plate, and the surface is flush with the hydrophobic layer.

[0048] In this embodiment, the system measures the wavelengths of two spectral troughs to obtain information about the detection sites. The specific steps are as follows: First, the plasmonic metasurface chip 205 to be tested is biofunctionalized. The target antibody is covalently coupled to the chip via amide bonds at a concentration of 10 μg / mL and incubated for 60 minutes. Nonspecific sites are blocked with a 5% BSA solution for 30 minutes to enable capture of the target antigen. Subsequently, a droplet of buffer (e.g., phosphate buffer saline, pH 7.4) is transferred to the plasmonic metasurface chip 205 using a digital microfluidic chip, and an initial spectrum is collected using a spectrometer as a baseline. Next, a droplet of the same PBS buffer containing the target antigen is transferred to the chip surface. A 5 kHz square wave pulse is applied to the droplet to micro-agitation, allowing the target molecule to bind to the metasurface. The droplet is incubated for 20 minutes, and the spectrum is measured as the measurement data. By comparing and analyzing the differences between the measured data and the baseline and quantifying them, qualitative and quantitative detection of the target antigen can be achieved.

[0049] In this embodiment, the system employs reflective spectroscopy. Specifically, broadband light (400-800 nm) emitted by light source 101 is incident vertically from above the digital microfluidic chip via an optical fiber (core diameter 1.5 mm). The light beam passes sequentially through the upper plate 202, the droplet to be measured 204, and the plasmonic metasurface chip 205. It is then reflected by the plasmonic metasurface chip 205 and transmitted via the same optical fiber to the spectrometer 102. The spectrometer 102 transmits the collected spectral data to a host computer via a USB 3.0 interface. The data is then processed using a fast Fourier transform (FFT) algorithm and Savitzky-Golay filtering for spectral analysis and display. The microfluidic upper plate 202 is made of transparent conductive indium tin oxide (ITO) glass to ensure attenuation-free optical transmission. The lower plate 208 is a FR-4 printed circuit board (PCB), precision-machined to ensure a parallelism error of ≤5 μm, achieving both structural functionality and manufacturing cost reduction. The thickness of the upper electrode plate 202 is 1.1 mm. In this embodiment, the Savitzky-Golay filter uses an 11-point window width and a third-order polynomial fit, increasing the spectral resolution to 0.05 nm. The fast Fourier transform (FFT) sampling interval is set to 0.1 nm, and the wavelength offset Δλ is determined by calculating the peak shift of the cross-correlation function between the reference spectrum and the detection spectrum.

[0050] Figure 3A schematic diagram shows a fluid path planning scheme for the integration of a digital microfluidic chip and a plasmonic metasurface. The system includes a plasmonic metasurface chip 205 and the digital microfluidic chip's PCB lower plate 208. Lower plate 208 is 1 mm thick. The fluid path planning area includes an antigen reservoir 301, a waste liquid reservoir 302, an antibody reservoir 303, a BSA reagent reservoir 304, and a PBS buffer reservoir 307. Droplet paths and dwell times are pre-planned in the host computer control software, allowing the metasurface biofunctionalization steps to be automated using the microfluidic chip.

[0051] The antigen reservoir 301 is used to store concentration gradient antigen samples, the waste liquid reservoir 302 is used to collect waste droplets, the antibody reservoir 303 is used to store 50 μg / mL antibody solution, the BSA reagent reservoir 304 is used to store 5% bovine serum albumin blocking solution, and the PBS buffer reservoir 307 is used to store pH 7.4 phosphate buffer.

[0052] The droplet travel route is pre-set, such as "PBS buffer pool 307 → chip 205 → waste liquid pool 302" and "antibody reservoir 303 → chip 205 → BSA reagent reservoir 304 → waste liquid pool 302"), with residence time such as 60 minutes for antibody incubation and 30 minutes for BSA blocking. The spacing of the driving electrode array is 500 μm, and by applying 0-100V adjustable square wave pulses, the entire process of hydroxylation pretreatment → antibody fixation → nonspecific blocking → sample detection of the metasurface chip is automatically completed, and a single detection only consumes microliters of reagents (≤5 μL).

[0053] Antibody fixation can be performed by transporting a 50 μg / mL droplet of anti-PBS solution (pH 5.0) to the metasurface chip, applying a 5V AC electrophoresis voltage (1kHz) for 3 minutes to enhance the efficiency of antibody directional fixation, and then incubating for 60 minutes.

[0054] The blocking step can be as follows: using a 5% BSA solution containing 0.05% Tween-20, the droplet mixing speed is achieved by alternately activating adjacent electrodes (frequency 10 Hz, voltage 80 V), and the blocking time is optimized to 20 min.

[0055] Example 2

[0056] Figure 4This is a schematic diagram of the high-throughput antibody screening of the invention, which is an expanded application of Example 1. This embodiment is the same as Example 1, and both use a reflective spectroscopy method. The system includes a light source 101 and a spectrometer 102, an upper plate 202, a first hydrophobic layer 203, a plurality of droplets to be tested 204, a second hydrophobic layer 206, a dielectric layer 207, a plurality of plasmon metasurface chips 205, and a driving electrode array 209. Compared with Example 1, the difference is that this embodiment can perform multiple antibody screenings at the same time. This embodiment controls multiple groups of droplets 204 by increasing the number of driving electrode arrays 209, and the supporting multi-channel optical fiber and spectrometer module 102 cover all detection sites, and simultaneously measures multiple antibodies to achieve high-throughput parallel detection.

[0057] The optical path is also labeled in the figure. The droplet to be tested and the corresponding plasmon metasurface chip together constitute the detection site. Similar to Example 1, this example also requires two spectral measurements—a reference spectrum and a detection spectrum—to complete the analysis of the detection site and obtain the final test results. The antibody affinity is compared by comparing the wavelength shift differences at different sites; the larger the difference, the stronger the binding force.

[0058] The digital microfluidic chip's upper plate 202 is made of transparent conductive indium tin oxide (ITO) glass, 1.1 mm thick; the lower plate 208 is a printed circuit board (PCB). This embodiment incorporates multiple detection sites, requiring multiple optical fibers and spectrometers to cover all detection areas. Both the first and second hydrophobic layers 203 and 206 are coated with F-DLC; the dielectric layer 207 is Parylene-C, 8 μm thick. Each of the multiple plasmonic metasurface chips 205 measures 3 mm x 3 mm. The drive electrode array 209 utilizes a 64×64 drive electrode array with a 500 μm pitch, supporting the manipulation of up to 32 droplets in parallel.

[0059] A time-division multiplexing strategy was employed within the 64×64 drive electrode array, dividing the array into eight independently controlled zones. Each zone was equipped with an independent fiber bundle (7-core fiber, 200μm core diameter) and spectrometer channel. Spectral acquisition was triggered synchronously by host computer software (with a time synchronization error of <1ms) to minimize signal crosstalk. The spacing between adjacent detection sites was ≥3mm, and droplet buffer isolation zones (between empty electrodes) were incorporated into the path planning. A wastewater pool was also designed, with each of the four detection sites sharing a single wastewater pool.

[0060] During the detection process, each site needs to complete two spectral measurements, baseline and binding; high-affinity antibodies are screened by comparing the difference in wavelength offset.

[0061] After testing, the system of the present invention has a detection throughput of 480 samples / hour when simultaneously screening 32 antibodies, which is 15 times higher than the traditional ELISA method; the detection limit of IgG is as low as 0.1ng / mL (signal-to-noise ratio S / N=3), and the dynamic range spans 4 orders of magnitude (0.1-1000ng / mL). The contact angle of the hydrophobic coating still remains >150° after 1000 droplet operations, and the dielectric layer pressure resistance test shows that it can withstand >10 6 No breakdown after 150V pulse shock.

[0062] The above embodiments are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip, characterized by Including digital microfluidic chip module, plasmon metasurface sensor chip, light source, spectrometer, FPGA programmable logic controller, and host computer; The digital microfluidic chip adopts a dual-plate architecture. The lower plate is based on a printed circuit board, with a copper drive electrode array, a dielectric layer, and a hydrophobic coating stacked on the surface in sequence. The upper plate is an indium tin oxide conductive glass substrate, with the same hydrophobic material coated on the lower surface. It is parallel to the lower plate and spaced apart to form a droplet running space. The plasmon metasurface sensor chip is embedded in the bottom plate of the digital microfluidic chip and is completely contained in a single driving electrode to form a biological detection site; The light source and the spectrometer are optically coupled to the detection site via optical fibers; the light source emits broad-spectrum light, and the spectrometer has a resolution of ≤0.1 nm; The FPGA programmable logic controller is connected to the driving electrode array and applies adjustable square wave pulses to the driving electrode array to achieve droplet transportation, mixing and waste liquid removal; The host computer controls the FPGA programmable logic controller through the USB 3.0 protocol. The host computer pre-programs the droplet travel path and residence time to automatically complete the biological functionalization, sample addition and detection processes of the metasurface.

2. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The plasmon metasurface sensor chip is embedded in a shallow pit etched by chemical etching on the lower electrode plate and fixed with conductive silver paint to ensure that the chip surface is flush with the hydrophobic layer of the lower electrode plate.

3. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The printed circuit board has a thickness of 1 mm; the dielectric layer is a Parylene-C dielectric layer; the hydrophobic coating is a Teflon hydrophobic coating; and the Parylene-C dielectric layer has a thickness of 5 to 10 μm.

4. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The droplet running space is filled with dimethyl silicone oil or air as a filling medium for droplet movement.

5. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The optical fiber uses multimode quartz optical fiber with a core diameter of 1.5mm. The spectral resolution of the spectrometer is ≤0.1nm. A collimating lens is configured at the end of the optical fiber to reduce reflection interference. A reflective spectral mode is used for detection. The 400-800nm ​​wide-spectrum light emitted by the light source is vertically incident on the detection site through the optical fiber, and the reflected light returns to the spectrometer through the same optical fiber. High-throughput antibody screening is achieved by comparing the wavelength offset before and after antigen capture.

6. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The parameters of the square wave pulse applied by the driving electrode array are amplitude 0 to 150V and frequency 1 to 10kHz.

7. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The lower electrode plate integrates ≥2 plasmon metasurface chips, each chip corresponds to an independent detection site, and each detection site is connected to different reagent reservoirs through an independent liquid path to achieve high-throughput, multi-index parallel detection; the distance between each detection site is ≥3mm, and at least 2 inactivated isolation electrodes are set between adjacent liquid paths to prevent cross contamination.

8. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that The electrodes in the driving electrode array are circular electrodes with a diameter of 3 mm and an electrode spacing of ≤500 μm, supporting the simultaneous manipulation of ≥20 independent droplets.

9. A high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip as claimed in claim 1, characterized in that By increasing the number of electrodes on the lower plate of the digital microfluidic PCB, multiple plasmon metasurface chips are embedded. Each plasmon metasurface chip corresponds to a biological detection site. By adding multiple biological detection sites, high-throughput, multi-index detection can be achieved.

10. Application of a high-throughput antibody screening system based on digital droplet microfluidics and plasmon metasurface chip in biomolecule affinity detection according to any one of claims 1 to 9, characterized in that The application includes: using the metal nanostructure of the plasmonic metasurface chip to fix antibodies, delivering antigen droplets through a digital microfluidic chip module, and detecting the antigen-antibody binding strength through the spectral absorption peak shift without labeling.

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