A droplet manipulation device and manipulation method based on ultrasonic phased array

Abstract

The present invention provides a droplet manipulation device and a manipulation method based on an ultrasonic phased array, which relates to the technical field of microfluidics. The manipulation device includes: a host computer, a drive board, and an ultrasonic generation array; the ultrasonic generation array includes a plurality of ultrasonic generation units, an array support unit, and a wettable surface. The array support unit includes an upper support and a lower support connected to each other. An ultrasonic generation unit is provided on the inner wall of each of the upper support and the lower support. The ultrasonic generation unit on the upper support is inclined downward, and the ultrasonic generation unit points to the center of a circle. A wettable surface is arranged in the middle area surrounded by the circle, and a controlled droplet is placed on the wettable surface. The present invention can realize non-contact programmable precise movement of droplets along any trajectory, movement of droplets against gravity, droplet over-obstacle, droplet passing through narrow gaps, etc. without pre-treating the surface or the droplet.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, and in particular, to a droplet manipulation device and a manipulation method based on an ultrasonic phased array. Background Art

[0002] Controllable droplet manipulation has value in many practical applications, such as biological detection, chemical reactions, and water collection. To achieve more flexible and precise droplet manipulation on a wettable surface, external stimuli need to be introduced, such as magnetism, electricity, and light. For magnetic stimulation, a magnet can be used to deform a magnetically responsive surface, causing the droplet to move along with the continuous indentations formed on the surface; alternatively, magnetic beads can be embedded in the droplet to control the droplet through the magnetic beads. For electric field stimulation, the Coulomb force is mainly utilized to rapidly drive the droplet through electrostatic repulsion or electrostatic attraction. For light stimulation, the photoelectric effect is used to generate dielectrophoretic force between the droplet and the surface, and rich fluid operations and droplet patterning can also be achieved.

[0003] In the existing droplet manipulation methods, it is necessary to first prepare a surface with specific properties or pre-change the electrostatic properties of the droplet, and this operation is called pre-treatment of the surface or the droplet. However, in the case of no need to pre-treat the surface or the droplet, the prior art cannot achieve non-contact droplet manipulation. If the surface does not have magnetic or light responsiveness and the droplet is not pre-charged, the existing manipulation techniques cannot control the droplet, let alone achieve flexible and complex non-contact droplet manipulation functions. In addition, in the field of traditional acoustic levitation, ultrasonic phased array technology has been used to manipulate suspended particles. However, the acoustic radiation force generated by the sound field on the particles is mainly used to offset their gravity to suspend the particles in the air, so the flexibility and stability of the manipulation are poor. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a droplet manipulation device and a manipulation method based on an ultrasonic phased array to solve the technical problem that the prior art needs to pre-treat the surface or the droplet to achieve non-contact droplet manipulation.

[0005] The technical means adopted by the present invention are as follows:

[0006] A droplet manipulation device based on ultrasonic phased array, comprising: a host computer, a driving board, and an ultrasonic generating array; the ultrasonic generating array includes a plurality of ultrasonic generating units, an array support unit, and a wettability surface. The array support unit is distributed in a circular ring shape. The array support unit includes an upper support and a lower support connected to each other. The upper support inclines downward, and the lower support is vertically arranged. An ultrasonic generating unit is provided on the inner wall of each of the upper support and the lower support. The ultrasonic generating unit on the upper support inclines downward, and the ultrasonic generating unit points to the center of the circle. A wettability surface is arranged in the middle area surrounded by the circle, and a controlled droplet is placed on the wettability surface.

[0007] Further, the host computer generates ultrasonic control signals with different phases and changes and controls the intensity and position of the sound field in real time, and the host computer sends the generated ultrasonic control signals to the driving board;

[0008] The driving board includes a signal generating module and a signal amplifying module. The driving board receives the ultrasonic control signals, generates ultrasonic signals by the signal generating module, and sends the amplified ultrasonic signals to the ultrasonic generating unit after being amplified by the signal amplifying module.

[0009] Further, the wettability surface includes a superhydrophobic surface, a hydrophobic surface, and a hydrophilic surface with low contact angle hysteresis.

[0010] Further, the number of the array support units is 14, the number of the ultrasonic generating units is 28, the ultrasonic generating units on the upper support and the upper support incline downward by 30°, and the inner diameter of the circle is 51 mm.

[0011] Further, the ultrasonic generating unit generates a 40 kHz sinusoidal ultrasonic wave.

[0012] Further, the model of the signal generating module is Arduinomega.

[0013] Further, the array support unit is fabricated by 3D printing technology.

[0014] A droplet manipulation method based on ultrasonic phased array is realized based on the above-mentioned droplet manipulation device based on ultrasonic phased array, and includes the following steps:

[0015] Use the host computer to control the ultrasonic generating array to generate a double-well acoustic trap on the wettability surface, and the specific position of the acoustic trap is controlled by changing the focal point of the acoustic trap in the host computer;

[0016] Use a micropipette to place a droplet with a certain volume at the focal point of the double-well acoustic trap on the wettability surface, and the droplet is controlled at the focal point under the action of the acoustic trap;

[0017] Control the host computer to change the focal point of the acoustic trap, thereby changing the position of the acoustic trap, and further controlling the movement of the droplet.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention can achieve non-contact programmable precise movement of droplets along arbitrary trajectories, movement of droplets against gravity, droplet over-obstacle, droplet passing through narrow gaps, etc. without pre-treating the surface or the droplets, that is, without preparing a surface with specific properties in advance or pre-changing the electrostatic characteristics of the droplets.

[0020] Using the droplet manipulation device and method proposed by the present invention, by generating a double-well acoustic trap on the wettable surface and controlling its position, non-contact remote non-destructive manipulation of droplets is achieved, which is applicable to different types of droplets. Compared with traditional droplet manipulation methods, there is no need to specially pre-treat the surface to make the surface have magnetic responsiveness or light responsiveness, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic diagram of the device of the present invention.

[0023] Figure 2 It is a schematic diagram of the ultrasonic generating array structure of the present invention.

[0024] Figure 3 It is a schematic diagram of the array support unit structure of the present invention.

[0025] Figure 4 It is a diagram showing the manipulation of droplets along arbitrary trajectories of the present invention.

[0026] Figure 5 It is a diagram showing the droplet passing through a narrow slit of the present invention.

[0027] Figure 6 It is a diagram showing the droplet climbing over a steep slope of the present invention.

[0028] Figure 7 It is a diagram showing the reciprocating movement of droplets against gravity of the present invention.

[0029] Figure 8 a is a diagram showing the directional ejection of droplets of the present invention, Figure 8 b is a diagram showing the quantitative distribution of droplets of the present invention, Figure 8Figure c shows the controllable chemical reaction of droplets according to the present invention. Figure 8 Figure d shows the surface cleaning achieved by the present invention.

[0030] In the figures: 1, host computer; 2, drive board; 3, ultrasonic array; 4, ultrasonic generating unit; 5, array support unit; 6, wettable surface; 7, upper bracket; 8, lower bracket; 9, droplet. Detailed implementation mode

[0031] In order to enable those skilled in the art of this technology to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0033] As Figures 1-8 shown, the present invention provides a droplet manipulation device based on an ultrasonic phased array, including: a host computer 1, a drive board 2, and an ultrasonic array 3;

[0034] The host computer 1 is a computer equipped with control software. The host computer 1 generates ultrasonic control signals with different phases and changes and controls the intensity and position of the sound field in real time. The host computer 1 sends the generated ultrasonic control signals to the drive board 2;

[0035] The drive board 2 includes a signal generation module and a signal amplification module. The drive board 2 receives the ultrasonic control signal and generates an ultrasonic signal by the signal generation module, and the ultrasonic signal is amplified by the signal amplification module and then sent to the ultrasonic generating unit 4.

[0036] The ultrasonic generating array 3 includes 28 ultrasonic generating units 4, 14 array support units 5, and a wettable surface 6. A number of array support units 5 are distributed in a circular ring shape. The inner diameter of the circular ring is 51 mm. The array support unit 5 includes an upper support 7 and a lower support 8 connected to each other. The angle α at which the upper support 7 inclines downward is 30°. The lower support 8 is vertically arranged. One ultrasonic generating unit 4 is provided on the inner walls of both the upper support 7 and the lower support 8. The ultrasonic generating unit 4 on the upper support 7 inclines downward. The ultrasonic generating unit 4 points to the center of the circular ring to concentrate the ultrasonic energy. A wettable surface 6 is arranged in the middle area surrounded by the circular ring. A controlled droplet 9 is placed on the wettable surface 6. The ultrasonic generating unit 4 can generate a 40 kHz sinusoidal ultrasonic wave. The array support unit 5 is fabricated by using 3D printing technology.

[0037] The controlled droplet 9 is placed on the wettable surface 6. This surface only needs to be subjected to necessary superhydrophobic treatment and does not require other special pre-treatments for magnetic responsiveness, optical responsiveness, or thermal responsiveness.

[0038] Although the droplet manipulation currently involved in the present invention is carried out on a superhydrophobic surface, the droplet manipulation based on an ultrasonic phased array that can be achieved by this invention includes, but is not limited to, superhydrophobic surfaces, and can also be achieved on hydrophobic surfaces and hydrophilic surfaces with low contact angle hysteresis.

[0039] The present invention also provides a method for droplet manipulation based on an ultrasonic phased array, which is implemented by using a device for droplet manipulation based on an ultrasonic phased array, and includes the following steps: First, the upper computer 1 controls the ultrasonic generating array 3 to generate a double-well acoustic trap at a specific position on the wettable surface 6. The specific position of the acoustic trap can be controlled by changing the focus point of the acoustic trap in the upper computer 1. Subsequently, a droplet 9 with a certain volume is placed at the focus point of the double-well acoustic trap on the surface by using a micropipette. At this time, the droplet 9 is controlled at the focus point under the action of the acoustic trap. Subsequently, the upper computer 1 can be used to change the focus point of the acoustic trap, thereby changing the position of the acoustic trap, and further controlling the movement of the droplet 9.

[0040] By using the droplet manipulation device and manipulation method proposed by the present invention, the following functions can be achieved:

[0041] The droplet can be manipulated to move along an accurate, fast, real-time, and programmable arbitrary trajectory, such as Figure 4 shown. First, a droplet 9 with a volume of 4 μL is placed on the surface. Subsequently, the upper computer 1 is used to gradually change the position of the focus point of the acoustic trap. At this time, the position of the acoustic trap also changes accordingly, and further the droplet 9 is manipulated to make its movement trajectory present the characters of "D, U, T".

[0042] The droplet can be made to pass through a narrow gap smaller than its own diameter, such as Figure 5As shown in the figure. First, place a 20-μL droplet 9 on the left side of a narrow slit with a width of 2 mm. The side walls of the narrow slit are in a mesh structure to facilitate the propagation of ultrasonic waves. Subsequently, use the host computer 1 to control the acoustic trap to move to the right. As the acoustic trap moves, the droplet will be subjected to acoustic radiation force and be squeezed into the narrow slit, and finally pass through the narrow slit.

[0043] It can enable the droplet to cross a steep slope equivalent to or even higher than its own height. For example, Figure 6 As shown in the figure. First, place a 3-μL droplet 9 on the left side of a steep slope with a height of 2 mm and a slope of 80°. Subsequently, use the host computer 1 to control the acoustic trap to move to the right. At this time, the droplet 9 moves to the right following the acoustic trap. During the movement, the droplet 9 can cross a steep slope equivalent to its own height.

[0044] It can enable the droplet to perform reciprocating motion against gravity. For example, Figure 7 As shown in the figure. First, place a 4-μL droplet 9 on a vertically placed arc surface. Subsequently, use the host computer 1 to control the acoustic trap to move downward, and the droplet will move downward accordingly. Subsequently, control the acoustic trap to move upward again, and the droplet 9 will move upward accordingly. Repeating this way can enable the droplet 9 to perform reciprocating motion against gravity on the vertically placed surface.

[0045] Based on the above basic droplet manipulation functions, the present invention can also achieve non-contact droplet directional ejection. For example, Figure 8 As shown in a; First, place a 6-μL droplet 9 on the right side of a triangular narrow slit. Subsequently, use the host computer 1 to control the acoustic trap to move to the left, and the droplet 9 is squeezed into the triangular narrow slit accordingly. Then, turn off the ultrasonic wave generating array 3, and the droplet 9 will immediately eject to the right at a speed of up to 100 mm per second.

[0046] It can achieve quantitative distribution of micro-droplets. For example, Figure 8 As shown in b; First, place a 5-μL droplet 9 on the left side of a circular hydrophilic pit array with a diameter of 1 mm. Subsequently, use the host computer 1 to control the acoustic trap to move to the right. As the droplet 9 comes into contact with the pits, a part of the liquid in each hydrophilic pit is retained to form sub-droplets. Due to the strong control of the droplets by the present invention, the mother droplet passes through the hydrophilic pits in sequence, thereby forming a series of sub-droplets, and finally completing the quantitative distribution of micro-droplets.

[0047] It can achieve controllable chemical reactions of micro-droplets. For example, Figure 8 As shown in c; A 4-μL acetic acid droplet fuses with a 4-μL litmus droplet under the guidance of the device proposed in the present invention, and the color changes from purple to orange after the reaction. The merged droplet can break away from the anchored hydrophilic point and be guided to a designated position.

[0048] It can achieve functions such as surface cleaning. For example, Figure 8 As shown in d. A 10-μL droplet 9 can clean stains accurately in real time.

[0049] The serial numbers of the embodiments of the present invention above are only for description and do not represent the superiority or inferiority of the embodiments.

[0050] In the above embodiments of the present invention, the descriptions of the various embodiments each have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0051] In the several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of units or modules can be in an electrical or other form.

[0052] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0053] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0054] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing storage medium includes: USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs and other various media that can store program codes.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A droplet manipulation device based on an ultrasonic phased array, characterized in that Including: A host computer (1), a driving board (2) and an ultrasonic generating array (3); The ultrasonic generating array (3) includes a plurality of ultrasonic generating units (4), an array support unit (5) and a wettability surface (6). The array support unit (5) is distributed in a circular ring shape. The inner diameter of the circular ring is 51 mm. The array support unit (5) includes an upper support (7) and a lower support (8) connected to each other. The upper support (7) inclines downward, and the lower support (8) is vertically arranged. An ultrasonic generating unit (4) is arranged on the inner walls of the upper support (7) and the lower support (8) respectively. The ultrasonic generating unit (4) on the upper support (7) inclines downward. The ultrasonic generating unit (4) on the upper support (7) and the ultrasonic generating unit (4) on the upper support (7) incline downward by 30°. The ultrasonic generating unit (4) points to the center of the circular ring. A wettability surface (6) is arranged in the middle area surrounded by the circular ring. The wettability surface (6) includes a superhydrophobic surface, a hydrophobic surface and a hydrophilic surface with low contact angle hysteresis. A controlled liquid droplet (9) is placed on the wettability surface (6).

2. The droplet manipulation device based on ultrasonic phased array according to claim 1, wherein The host computer (1) generates ultrasonic control signals with different phases and changes and controls the intensity and position of the sound field in real time. The host computer (1) sends the generated ultrasonic control signals to the driving board (2); The driving board (2) includes a signal generation module and a signal amplification module. The driving board (2) receives the ultrasonic control signals and the signal generation module generates ultrasonic signals. The signal amplification module amplifies the ultrasonic signals and then sends them to the ultrasonic generating unit (4).

3. The droplet manipulation device based on ultrasonic phased array according to claim 1, characterized in that, The number of the array support units (5) is 14, and the number of the ultrasonic generating units (4) is 28.

4. The droplet manipulation device based on an ultrasonic phased array according to claim 1, wherein The ultrasonic generating unit (4) generates a 40 kHz sine ultrasonic wave.

5. The droplet manipulation device based on ultrasonic phased array according to claim 2, wherein The model of the signal generation module is Arduino mega.

6. The droplet manipulation device based on ultrasonic phased array according to claim 1, wherein The array support unit (5) is made by using 3D printing technology.

7. A droplet manipulation method based on ultrasonic phased array, which is realized by the droplet manipulation device based on ultrasonic phased array according to any one of claims 1-6, characterized in that Including the following steps: Using the host computer (1) to control the ultrasonic generating array (3) to generate a double-well acoustic trap on the wettability surface (6). The specific position of the acoustic trap is controlled by changing the focal point of the acoustic trap in the host computer (1); Using a micropipette to place a liquid droplet (9) with a certain volume at the focal point of the double-well acoustic trap on the wettability surface (6). The liquid droplet (9) is controlled at the focal point under the action of the acoustic trap; Controlling the host computer (1) to change the focal point of the acoustic trap, thereby changing the position of the acoustic trap, and further controlling the movement of the liquid droplet (9).

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