Biochemical liquid drop sample preparation device and method regulated and controlled by sound field and electric field

Abstract

The invention discloses a device and a method for preparing a biochemical liquid drop sample regulated and controlled by a sound field and an electric field. The device comprises a sound focusing spray head, a three-axis motion platform and a digital micro-fluidic chip, acoustic waves generated by the Archimedes spiral interdigital transducer are adopted, the acoustic waves are focused at the nozzle when being transmitted to the tail end of the spray head, breakage and generation of liquid drops are promoted, and the size of the printing liquid drops is effectively controlled by adjusting sine alternating voltage parameter values and adjusting the printing speed of the liquid drops at the nozzle. The micro-electrodes integrated with the dielectrophoresis technology are adopted to generate dielectrophoretic force, directional movement of micro-droplets under the action of an electric field is achieved, by adjusting sine alternating voltage parameter values, the size of the moving droplets is adjustable, the droplets move to the mixing area, the mixing area vibrates under the resonant frequency of the piezoelectric plate, the droplets are promoted to be fully mixed, and the micro-droplets are fully mixed. The preparation of a biochemical liquid drop sample is realized; according to the invention, preparation of various biochemical liquid drop samples and fusion and mixing of various liquid drops can be realized, and a foundation is laid for further detection.

Description

Technical Field

[0001] The present invention relates to the field of biochemical droplet sample preparation, and in particular to a biochemical droplet sample preparation device and method regulated by an acoustic field and an electric field. Background Art

[0002] Biochemical testing provides early disease warning and personalized health management by analyzing biomarkers, helps evaluate treatment effects and promotes health intervention and scientific research. It is an important means to improve the effectiveness of big health management. Droplet microfluidics aims to construct discrete microdroplets through incompatible multiphase fluids. Because the independent nature of microdroplets can ensure that biochemical reactions are carried out in a microfluidic environment like a compartment, droplet microfluidics technology is also called "digital microfluidics technology". Microdroplets enable microfluidics technology to be digitalized and programmable, providing a platform for solving extremely challenging research problems in biochemical medicine. Discrete microdroplets can achieve precise control of the volume of biochemical test samples and improve the accuracy of analysis results. Therefore, biochemical droplet sample preparation is one of the important links in high-precision biochemical testing.

[0003] Methods for preparing droplet samples can be divided into two types: passive methods and active methods, depending on whether external energy is involved. Passive preparation methods rely on different microfluidic channel structures to prepare microdroplets through continuous shearing of the continuous phase on the dispersed phase, mainly including T-channel method, focusing channel method and capillary method. The passive method has a simple droplet structure, fast generation speed and low cost, but it is difficult to accurately control the parameters such as the size and generation speed of the generated single droplet in real time. Active droplet sample preparation controls the surface energy of microfluids by introducing external energy during the droplet generation process, mainly including acoustic field assisted method, electric field regulation method, thermal control method and mechanical control. Active droplet sample preparation can realize on-demand preparation of droplets and accurately control droplet parameters, but it also faces the challenges of increased energy consumption, high equipment complexity, stability and uniformity control.

[0004] Commonly used biochemical droplet samples are all prepared through microfluidic chips. The preparation process is complicated, the chip is expensive and cannot be reused, which affects the efficiency of the experiment. When performing biochemical tests on digital microfluidic chips, precise droplet supply is required. The commonly used pipettes in laboratories cannot meet this demand. The size of the droplets will affect the biochemical tests performed on digital microfluidic chips. Manufacturing precise monodisperse droplets has always been a huge manufacturing challenge. Current digital microfluidic chips are often used to control monodisperse droplets, but have specific requirements for the type of liquid materials or reagents used, which limits their scope of application. Summary of the invention

[0005] In order to solve the above problems and develop biochemical droplet sample preparation technology, the purpose of the present invention is to provide a biochemical droplet sample preparation device and method with on-demand regulation of acoustic field and electric field. By utilizing the focused acoustic field force of focused acoustic waves, the volume of biochemical droplet samples can be precisely controlled to achieve on-demand quantitative preparation of discrete droplets of biochemical reagents. Through the design of electric field-driven digital microfluidic chips, the fusion of droplets of different reagent types can be accurately completed, thereby achieving reagent mixing and biochemical reactions.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a biochemical droplet sample preparation device regulated by acoustic field and electric field, the device comprises a base, a first support is fixedly installed on the base, a first drive motor is fixedly installed on the first support, a first driving wheel is rotatably installed on the output end of the first drive motor, a first toothed belt is fixedly connected to the Y-axis moving platform, the first drive motor rotates, the first driving wheel drives the first toothed belt, so that the Y-axis moving platform realizes movement in the Y direction; a support arm is installed on both sides of the base, the top ends of the two support arms are connected by an upper support arm, a second drive motor is fixedly installed on the two support arms, a ball screw is rotatably installed on the output end of the second drive motor, and a Z-axis The mobile platform is connected to the ball screw through a screw nut, and the second drive motor rotates, and the Z-axis mobile platform can be driven by the ball screw to realize movement in the Z direction; a guide rail is fixedly installed on the front surface of the Z-axis mobile platform, and the third drive motor is fixedly installed on one side of the rear surface of the Z-axis mobile platform. The output end of the third drive motor passes through the Z-axis mobile platform and is rotatably installed with a second driving wheel, and the second toothed belt is installed on the second driving wheel. The nozzle fixture is fixedly connected to the second toothed belt, and the nozzle fixture is slidably connected to the guide rail through a slider. The third drive motor rotates, and the second toothed belt is driven to move through the second driving wheel, so that the nozzle fixture can realize movement in the X direction along the guide rail; an acoustic focusing nozzle assembly is fixedly installed on the nozzle fixture.

[0007] Furthermore, the acoustic focusing nozzle assembly comprises four nozzles, namely, a first nozzle, a second nozzle, a third nozzle and a fourth nozzle, the four nozzles have the same structure, each nozzle comprises an interdigital transducer and a conical nozzle, the conical nozzle is arranged on the lower surface of the interdigital transducer, the interdigital transducer comprises a piezoelectric substrate, a circular groove is provided on the upper surface of the piezoelectric substrate, a first spiral electrode and a second spiral electrode are fixedly installed in the groove. A vertical flow channel and a horizontal flow channel are provided inside the conical nozzle, the vertical flow channel and the horizontal flow channel are connected, wherein the other end of the horizontal flow channel is connected to the inlet on the conical surface of the conical nozzle, and the other end of the vertical flow channel is connected to the outlet at the tip of the conical nozzle.

[0008] Furthermore, the interdigital transducer is used to generate focused sound waves, the flow channel cross-section is circular, and the diameter of the circle is 100 microns; the material of the piezoelectric substrate is lithium niobate, the material of the first spiral electrode and the second spiral electrode are Cr-Au, and the conical nozzle is made on the piezoelectric substrate by 3D printing.

[0009] Furthermore, the chip fixture is fixedly installed on the Y-axis moving platform, which includes a second support, two clamping parts are symmetrically fixed on both sides of the upper surface of the second support, a groove is opened in the middle of the upper surface of the second support, and two L-shaped protrusions are arranged in the groove, and the two L-shaped protrusions are used to position the digital microfluidic chip.

[0010] Furthermore, the digital microfluidic chip includes a third support, on which a piezoelectric sheet, an electrode layer, a dielectric layer, a hydrophobic layer and a PDMS cavity are sequentially arranged. The piezoelectric sheet is a rectangular parallelepiped; the electrode layer includes a substrate, on the surface of which an electrode layer is printed by 3D printing, the electrode layer includes nine rows and nine columns, a total of 81 electrodes, each electrode is zigzag-shaped on all sides, the substrate is made of glass, and the electrode is made of Au; the dielectric layer is made of photoresist SU8, and the hydrophobic layer is made of perfluorodecyltrichlorosilane; the dielectric layer is 300nm thick; the hydrophobic layer is 50nm thick; Fig.12 As shown, the PDMS cavity consists of a fusion zone, a mixing zone and a storage zone. The fusion zone is provided with four openings, namely a first opening, a second opening, a third opening and a fourth opening.

[0011] Furthermore, the mixing area and the storage area are transitioned by an arc, ensuring that the mixed liquid droplets enter the storage area smoothly.

[0012] Further, the first electrode in the first row is electrode 1, the second electrode in the first row is electrode 2, ..., the ninth electrode in the ninth row is electrode 81; the fusion zone is located above electrodes 7-9, 16-18, and 25-27, the first opening on the fusion zone is located above electrode 7, the second opening is located above electrode 9, the third opening is located above electrode 25, and the fourth opening is located above electrode 27; the mixing zone is located above electrodes 10-14, 19-23, 28-32, 37-41, 46-50, 55-59, 64-68, and 73-77.

[0013] A method for preparing a biochemical droplet sample with acoustic and electric fields regulated on demand comprises the following steps:

[0014] S1: Install the digital microfluidic chip;

[0015] S2: Use a dropper to inject silicone oil into the PDMS cavity until the silicone oil fills the PDMS cavity;

[0016] S3: Connect the corresponding solution to the acoustic focusing nozzle assembly;

[0017] S4: control droplet generation;

[0018] S5: control the droplets to mix;

[0019] S6: preparing a plurality of mixed droplets.

[0020] Repeat S4-S5 to prepare multiple mixed droplets, which are finally stored in the storage area for use.

[0021] Furthermore, S1 is specifically:

[0022] The microfluidic chip is placed between the two L-shaped protrusions in the groove of the chip fixture and fixed by two clamps to prevent it from moving.

[0023] Furthermore, S2 is specifically:

[0024] The function of silicone oil is to suspend the mixed droplets in it. There is a difference in dielectric constant between the droplets and the silicone oil, so that the dielectrophoretic force can be used to manipulate the droplets in the silicone oil.

[0025] Furthermore, S3 is specifically:

[0026] Solution A is connected to the inlet on the conical surface of the conical nozzle of the first nozzle of the acoustic focusing nozzle assembly through injection pump A, solution B is connected to the inlet on the conical surface of the conical nozzle of the second nozzle of the acoustic focusing nozzle assembly through injection pump B, solution C is connected to the inlet on the conical surface of the conical nozzle of the third nozzle of the acoustic focusing nozzle assembly through injection pump C, and solution D is connected to the inlet on the conical surface of the conical nozzle of the fourth nozzle of the acoustic focusing nozzle assembly through injection pump D.

[0027] Furthermore, S5 is specifically:

[0028] Turn on syringe pumps A, B, C and D. Driven by the syringe pumps, the solution enters and fills the L-shaped three-dimensional flow channel. The first drive motor, the second drive motor and the third drive motor are controlled by the controller to align the outlets of the four conical nozzle tips of the acoustic focusing nozzle assembly with the four openings of the fusion zone. The positive electrode of the output signal of the surface acoustic wave signal generator is connected to the spiral electrode on the interdigital transducer, and the output signal of the signal generator is adjusted to be a sinusoidal continuous output. Press the "output" button of the surface acoustic wave signal generator, and set the corresponding sinusoidal AC voltage output value. The interdigital transducer folds the spherical acoustic vortex under the excitation of the AC voltage signal to generate sound waves. The sound waves converge at the outlet of the conical nozzle tip, squeeze the liquid in the L-shaped three-dimensional flow channel to generate liquid, wherein the first nozzle produces A droplets, the second nozzle produces B droplets, the third nozzle produces C droplets, and the fourth nozzle produces D droplets. Droplets A enter the first opening of the fusion zone, droplets B enter the second opening of the fusion zone, droplets C enter the third opening of the fusion zone, and droplets D enter the fourth opening of the fusion zone.

[0029] Furthermore, S1 is specifically:

[0030] The electrodes on the electrode layer are energized in sequence. The electric field generated by the adjacent electrodes causes an asymmetric change in the contact angle along the contour of the droplet, triggering the movement of the droplet. The 8th electrode is connected to the positive pole of the DC power supply, and the 7th and 9th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets A and B move to the position of the 8th electrode, contact and merge into droplet E; the 6th electrode is connected to the positive pole of the DC power supply, and the 25th and 27th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets C and droplet D move to the position of the 26th electrode, contact and merge into droplet F; the 17th electrode is connected to the positive pole of the DC power supply, and the 8th and 26th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets E and droplet F move to the position of the 17th electrode, contact and merge into droplet G; the 16th electrode is connected to the positive pole of the DC power supply, and the 8th and 26th electrodes are connected to the negative pole of the DC power supply. The first electrode is connected to the positive electrode of the DC power supply, and the 17th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 16th electrode; the 15th electrode is connected to the positive electrode of the DC power supply, and the 16th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 15th electrode; the 14th electrode is connected to the positive electrode of the DC power supply, and the 15th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 14th electrode; the 13th electrode is connected to the positive electrode of the DC power supply, and the 14th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 13th electrode; the 12th electrode is connected to the positive electrode of the DC power supply, The 13th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 12th electrode under the action of the dielectrophoretic force; the 21st electrode is connected to the positive pole of the DC power supply, and the 12th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 21st electrode under the action of the dielectrophoretic force; the 30th electrode is connected to the positive pole of the DC power supply, and the 21st electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 30th electrode under the action of the dielectrophoretic force; the 39th electrode is connected to the positive pole of the DC power supply, and the 30th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 39th electrode under the action of the dielectrophoretic force; the 48th electrode is connected to the positive pole of the DC power supply, and the 39th electrode is connected to the DC power supply. The negative pole of the DC power supply is connected to the 57th electrode, and the negative pole of the DC power supply is connected to the 48th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 57th electrode. The positive pole of the DC power supply is connected to the 66th electrode, and the negative pole of the DC power supply is connected to the 57th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 66th electrode. The positive pole of the DC power supply is connected to the 75th electrode, and the negative pole of the DC power supply is connected to the 66th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 75th electrode. The negative pole of the DC power supply is connected to the 75th electrode, and the droplet G moves to the storage area under the action of the dielectrophoretic force.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1 The present invention uses sound waves excited by an interdigital transducer. When the sound waves propagate to the end of the nozzle, they are focused at the nozzle. By adjusting the parameter value of the sinusoidal AC voltage, the droplet printing speed at the nozzle can be adjusted, thereby achieving effective control of the size of the printed droplets.

[0033] 2 The digital microfluidic chip of the present invention is easy to clean after use and can be reused many times;

[0034] 3 The biochemical droplet sample preparation process of the present invention can accurately control the amount of reagents used to achieve efficient detection;

[0035] 4 The present invention can realize the preparation of multiple reagent droplets, as well as the fusion and mixing of multiple droplets, laying the foundation for further detection;

[0036] 5 The three-dimensional flow channel structure of the acoustic focusing nozzle assembly of the present invention can be integrated by 3D printing or laser processing, which is simple to process and easy to use;

[0037] 6 The present invention uses a three-axis motion platform to control the acoustic focusing nozzle assembly to achieve precise positioning of the droplet printing position;

[0038] The dielectrophoretic force used in the present invention is particularly suitable for combination with microfluidics. Through the construction of microelectrodes, a large electric field gradient can be formed in the PDMS chamber, and the required applied voltage is low, thus avoiding the generation of bubbles and Joule heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is an axial side view of a biochemical droplet sample preparation device with on-demand regulation of acoustic field and electric field according to the present invention;

[0040] Figure 2 It is a rear view of a biochemical droplet sample preparation device with acoustic field and electric field regulated on demand according to the present invention;

[0041] Figure 3 is an axonometric view of an acoustic focusing nozzle assembly;

[0042] Figure 4 It is a front view of a single sprinkler head;

[0043] Figure 5 It is a side view of a single sprinkler head;

[0044] Figure 6 This is a top view of a single sprinkler head;

[0045] Figure 7 It is an axial view of a single sprinkler head;

[0046] Figure 8 is an axial view of the chip fixture;

[0047] Fig. 9 This is an exploded view of the digital microfluidic chip;

[0048] Fig.10 is an axial view of the digital microfluidic chip;

[0049] Fig.11 It is a schematic diagram of the printing position;

[0050] Fig.12 It is a schematic diagram of the droplet mixing principle. DETAILED DESCRIPTION

[0051] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] like Figure 1-2 As shown, a biochemical droplet sample preparation device regulated by an acoustic field and an electric field, the device comprises a base 1, a first support 2 is fixedly mounted on the base 1, a first drive motor 3 is fixedly mounted on the first support 2, a first driving wheel 4 is rotatably mounted on the output end of the first drive motor 3, a first toothed belt 5 is fixedly connected to a Y-axis moving platform 6, the first drive motor 3 rotates, the first driving wheel 4 drives the first toothed belt 5, so that the Y-axis moving platform 6 can move in the Y direction; a support arm 7 is mounted on both sides of the base 1, the top ends of the two support arms 7 are connected by an upper support arm 8, a second drive motor 9 is fixedly mounted on the two support arms 7, a ball screw 10 is rotatably mounted on the output end of the second drive motor 9, a Z-axis moving platform 11 is connected to the ball screw 10 through a screw nut, the second drive motor 9 rotates, and the Z-axis moving platform 11 can be driven by the ball screw 10 to move in the Z direction; a guide rail 17 is fixedly mounted on the front surface of the Z-axis moving platform 11, and a third drive motor 12 is fixedly mounted on one side of the rear surface of the Z-axis moving platform 11,

[0053] The output end of the third driving motor 12 passes through the Z-axis moving platform 11, and is rotatably installed with a second driving wheel 13, the second toothed belt 14 is installed on the second driving wheel 13, the nozzle fixture 15 is fixedly connected to the second toothed belt 14, the nozzle fixture 15 is slidably connected to the guide rail 17 through the slider 16, the third driving motor 12 rotates, and drives the second toothed belt 14 to move through the second driving wheel 13, so that the nozzle fixture 15 can realize X-direction movement along the guide rail 17; the nozzle fixture 15 is fixedly installed with an acoustic focusing nozzle assembly 18.

[0054] like Figure 3As shown, the acoustic focusing nozzle assembly 18 includes four nozzles, namely a first nozzle 18A, a second nozzle 18B, a third nozzle 18C and a fourth nozzle 18D. The four nozzles have the same structure. Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, each nozzle includes an interdigital transducer and a conical nozzle, the conical nozzle is arranged on the lower surface of the interdigital transducer, the interdigital transducer includes a piezoelectric substrate 18-1, a circular groove is provided on the upper surface of the piezoelectric substrate 18-1, and a first spiral electrode 18-2 and a second spiral electrode 18-3 are fixedly installed in the groove. A vertical flow channel 18-4 and a horizontal flow channel 18-5 are provided inside the conical nozzle, and the vertical flow channel 18-4 and the horizontal flow channel 18-5 are connected, wherein the other end of the horizontal flow channel 18-5 is connected to the inlet 18-6 on the conical surface of the conical nozzle, and the other end of the vertical flow channel 18-4 is connected to the outlet 18-7 at the tip of the conical nozzle.

[0055] The interdigital transducer is used to generate focused sound waves. The flow channel cross-section is circular, and the diameter of the circle is 100 microns. The material of the piezoelectric substrate 18-1 is lithium niobate, and the material of the first spiral electrode 18-2 and the second spiral electrode 18-3 are Cr-Au. The conical nozzle is made on the piezoelectric substrate 18-1 by 3D printing.

[0056] The chip fixture 19 is fixedly installed on the Y-axis moving platform 6, which includes a second support 19-1, two clamping parts 19-2 are symmetrically fixed on both sides of the upper surface of the second support 19-1, and a groove is opened in the middle of the upper surface of the second support 19-1. Two L-shaped protrusions 19-3 are arranged in the groove. The two L-shaped protrusions 19-3 are used to position the digital microfluidic chip 20.

[0057] like Fig. 9 , Fig.10 As shown, the digital microfluidic chip 20 includes a third support 20-1, on which a piezoelectric sheet 20-2, an electrode layer 20-3, a dielectric layer 20-4, a hydrophobic layer 20-5 and a PDMS cavity 20-6 are sequentially arranged. The piezoelectric sheet 20-2 is a rectangular parallelepiped; the electrode layer 20-3 includes a substrate, on the surface of which the electrode layer 20-3 is printed by 3D printing, and the electrode layer includes nine rows and nine columns with a total of 81 electrodes, each electrode is zigzag-shaped on all sides, the substrate is made of glass, and the electrode is made of Au; the dielectric layer 20-4 is made of photoresist SU8, and the hydrophobic layer 20-5 is made of perfluorodecyltrichlorosilane; the dielectric layer 20-4 is 300nm thick; the hydrophobic layer 20-5 is 50nm thick; as shown in FIG. Fig.12As shown, the PDMS cavity 20-6 consists of a fusion zone, a mixing zone and a storage zone. The fusion zone is provided with four openings 20-7, namely a first opening 20-7A, a second opening 20-7B, a third opening 20-7C and a fourth opening 20-7D.

[0058] The mixing area and the storage area are transitioned by an arc to ensure that the mixed liquid droplets enter the storage area smoothly.

[0059] Among them, the first electrode in the first row is electrode 1, the second electrode in the first row is electrode 2, and so on, the ninth electrode in the ninth row is electrode 81; the fusion zone is located above electrodes 7-9, 16-18, and 25-27, the first opening on the fusion zone is located above electrode 7, the second opening is located above electrode 9, the third opening is located above electrode 25, and the fourth opening is located above electrode 27; the mixing zone is located above electrodes 10-14, 19-23, 28-32, 37-41, 46-50, 55-59, 64-68, and 73-77.

[0060] Example 2

[0061] A method for preparing a biochemical droplet sample with acoustic and electric fields regulated on demand comprises the following steps:

[0062] S1: Installing the digital microfluidic chip

[0063] The microfluidic chip 20 is placed between the two L-shaped protrusions 19 - 3 in the groove of the chip fixture 19 , and is fixed by two clamping members 19 - 2 to prevent it from moving.

[0064] S2: Use a dropper to inject silicone oil into the PDMS cavity until the silicone oil fills the PDMS cavity.

[0065] The function of silicone oil is to suspend the mixed droplets in it. There is a difference in dielectric constant between the droplets and the silicone oil, so that the dielectrophoretic force can be used to manipulate the droplets in the silicone oil.

[0066] S3: Connect the corresponding solution to the acoustic focusing nozzle assembly

[0067] Solution A is connected to the inlet on the conical surface of the conical nozzle of the first nozzle 18A of the acoustic focusing nozzle assembly through injection pump A, solution B is connected to the inlet on the conical surface of the conical nozzle of the second nozzle 18B of the acoustic focusing nozzle assembly through injection pump B, solution C is connected to the inlet on the conical surface of the conical nozzle of the third nozzle 18C of the acoustic focusing nozzle assembly through injection pump C, and solution D is connected to the inlet on the conical surface of the conical nozzle of the fourth nozzle 18D of the acoustic focusing nozzle assembly through injection pump D.

[0068] S4: Controlling droplet generation

[0069] Turn on the syringe pumps A, B, C and D. Driven by the syringe pumps, the solution enters and fills the L-shaped three-dimensional flow channel. The controller controls the first drive motor 3, the second drive motor 9 and the third drive motor 12 to align the outlets of the four conical nozzle tips of the acoustic focusing nozzle assembly 18 with the four openings of the fusion zone. Connect the positive electrode of the output signal of the surface acoustic wave signal generator to the spiral electrode on the interdigital transducer, and adjust the output signal of the signal generator to a sinusoidal continuous output. Press the "output" button of the surface acoustic wave signal generator and set the corresponding sinusoidal alternating current. The output value of the pressure is obtained. Under the excitation of the AC voltage signal, the interdigital transducer folds the spherical acoustic vortex to generate sound waves. The sound waves gather at the outlet of the tip of the conical nozzle, squeezing the liquid in the L-shaped three-dimensional flow channel to generate liquid, wherein the first nozzle 18A generates A droplets, the second nozzle 18B generates B droplets, the third nozzle 18C generates C droplets, and the fourth nozzle 18D generates D droplets. The A droplets enter the first opening 20-7A of the fusion zone, the B droplets enter the second opening 20-7B of the fusion zone, the C droplets enter the third opening 20-7C of the fusion zone, and the D droplets enter the fourth opening 20-7D of the fusion zone.

[0070] S5: Controlling droplets for mixing

[0071] The electrodes on the electrode layer 20-3 are energized in sequence. The electric field generated by the adjacent electrodes causes an asymmetric change in the contact angle along the droplet contour, triggering the movement of the droplet. The 8th electrode is connected to the positive pole of the DC power supply, and the 7th and 9th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets A and B move to the position of the 8th electrode, contact and merge into droplet E; the 6th electrode is connected to the positive pole of the DC power supply, and the 25th and 27th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets C and droplet D move to the position of the 26th electrode, contact and merge into droplet F; the 17th electrode is connected to the positive pole of the DC power supply, and the 8th and 26th electrodes are connected to the negative pole of the DC power supply. Under the action of the dielectrophoretic force, droplets E and droplet F move to the position of the 17th electrode, contact and merge into droplet G; the 16th electrode is connected to the positive pole of the DC power supply, and the 8th and 26th electrodes are connected to the negative pole of the DC power supply. The first electrode is connected to the positive electrode of the DC power supply, and the 17th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 16th electrode; the 15th electrode is connected to the positive electrode of the DC power supply, and the 16th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 15th electrode; the 14th electrode is connected to the positive electrode of the DC power supply, and the 15th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 14th electrode; the 13th electrode is connected to the positive electrode of the DC power supply, and the 14th electrode is connected to the negative electrode of the DC power supply. Under the action of the dielectrophoretic force, the droplet G moves to the position of the 13th electrode; the 12th electrode is connected to the positive electrode of the DC power supply, The 13th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 12th electrode under the action of the dielectrophoretic force; the 21st electrode is connected to the positive pole of the DC power supply, and the 12th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 21st electrode under the action of the dielectrophoretic force; the 30th electrode is connected to the positive pole of the DC power supply, and the 21st electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 30th electrode under the action of the dielectrophoretic force; the 39th electrode is connected to the positive pole of the DC power supply, and the 30th electrode is connected to the negative pole of the DC power supply, and the droplet G moves to the position of the 39th electrode under the action of the dielectrophoretic force; the 48th electrode is connected to the positive pole of the DC power supply, and the 39th electrode is connected to the DC power supply. The negative pole of the DC power supply is connected to the 57th electrode, and the negative pole of the DC power supply is connected to the 48th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 57th electrode. The positive pole of the DC power supply is connected to the 66th electrode, and the negative pole of the DC power supply is connected to the 57th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 66th electrode. The positive pole of the DC power supply is connected to the 75th electrode, and the negative pole of the DC power supply is connected to the 66th electrode. Under the action of the dielectrophoretic force, the droplet G moves to the 75th electrode. The negative pole of the DC power supply is connected to the 75th electrode, and the droplet G moves to the storage area under the action of the dielectrophoretic force.

[0072] Of course, different electrodes can also be energized, first allowing droplets A and C to contact and fuse, droplets B and D to contact and fuse, and then fuse into droplet H, and then the mixed droplets move to the top of the 10th electrode in sequence, move along the 19th electrode, 28th electrode, 37th electrode, 46th electrode, 55th electrode, 64th electrode and 73rd electrode in sequence, and finally enter the storage area. There are many permutation and combination methods here, which will not be repeated here.

[0073] S6: Preparing multiple mixed droplets

[0074] Repeat S4-S5 to prepare multiple mixed droplets, which are finally stored in the storage area for use.

[0075] The solution A is a glucose oxidase solution, the solution B is a glucose solution, the solution C is water, and the solution D is a color developing solution of tetramethylbenzidine. The finally prepared biochemical detection droplets will show different colors and are used for the detection of glucose concentration.

[0076] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A biochemical droplet sample preparation device regulated by acoustic field and electric field, the device comprising a base (1), characterized in that: A first support (2) is fixedly mounted on the base (1), a first drive motor (3) is fixedly mounted on the first support (2), a first driving wheel (4) is rotatably mounted on the output end of the first drive motor (3), a first toothed belt (5) is fixedly connected to the Y-axis moving platform (6), the first drive motor (3) rotates, the first driving wheel (4) drives the first toothed belt (5), and the Y-axis moving platform (6) moves in the Y direction; a support arm (7) is mounted on both sides of the base (1), the top ends of the two support arms (7) are connected via an upper support arm (8), and a second drive motor (9) is fixedly mounted on the two support arms (7).

2. The biochemical droplet sample preparation device controlled by acoustic field and electric field according to claim 1, characterized in that: A ball screw (10) is rotatably mounted on the output end of the second drive motor (9); the Z-axis moving platform (11) is connected to the ball screw (10) via a screw nut; the second drive motor (9) rotates, and the ball screw (10) can drive the Z-axis moving platform (11) to move in the Z direction; a guide rail (17) is fixedly mounted on the front surface of the Z-axis moving platform (11); and the third drive motor (12) is fixedly mounted on one side of the rear surface of the Z-axis moving platform (11).

3. The biochemical droplet sample preparation device controlled by acoustic field and electric field according to claim 2, characterized in that: The output end of the third driving motor (12) passes through the Z-axis moving platform (11) and is rotatably mounted with a second driving wheel (13); a second toothed belt (14) is mounted on the second driving wheel (13); a nozzle fixture (15) is fixedly connected to the second toothed belt (14); the nozzle fixture (15) is slidably connected to a guide rail (17) via a slider (16); the third driving motor (12) rotates, and drives the second toothed belt (14) to move via the second driving wheel (13), so that the nozzle fixture (15) moves in the X direction along the guide rail (17); and a sound focusing nozzle assembly (18) is fixedly mounted on the nozzle fixture (15).

4. The biochemical droplet sample preparation device controlled by acoustic field and electric field according to claim 3, characterized in that: The acoustic focusing nozzle assembly (18) comprises four nozzles, namely a first nozzle (18A), a second nozzle (18B), a third nozzle (18C) and a fourth nozzle (18D). The four nozzles have the same structure. Each nozzle comprises an interdigital transducer and a conical nozzle. The conical nozzle is arranged on the lower surface of the interdigital transducer. The interdigital transducer comprises a piezoelectric substrate (18-1). A circular groove is provided on the upper surface of the piezoelectric substrate (18-1). A first spiral electrode (18-2) and a second spiral electrode (18-3) are fixedly installed in the groove. A vertical flow channel (18-4) and a horizontal flow channel (18-5) are provided inside the conical nozzle. The vertical flow channel (18-4) and the horizontal flow channel (18-5) are connected, wherein the other end of the horizontal flow channel (18-5) is connected to an inlet (18-6) on the conical surface of the conical nozzle, and the other end of the vertical flow channel (18-4) is connected to an outlet (18-7) at the tip of the conical nozzle.

5. A method for preparing a biochemical droplet sample with on-demand regulation of acoustic and electric fields according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Install the digital microfluidic chip; S2: Use a dropper to inject silicone oil into the PDMS cavity until the silicone oil fills the PDMS cavity; S3: Connect the corresponding solution to the acoustic focusing nozzle assembly; S4: Control droplet generation; S5: control the droplets to mix; S6: preparing a plurality of mixed droplets; Repeat S4-S5 to prepare multiple mixed droplets, which are finally stored in the storage area for use.

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