CN203196648U - Device for realizing digital microfluid fracture by adopting acoustic surface wave - Google Patents

Abstract

The utility model discloses a device for realizing digital microfluid rupture by surface acoustic waves, which comprises a piezoelectric substrate and a signal generating device. The piezoelectric substrate is provided with interdigital transducers for exciting surface acoustic The first hydrophobic layer of the digital microfluidics to be ruptured, the sound-absorbing coating for attenuating the intensity of the surface acoustic waves excited by the interdigital transducers, and the second hydrophobic layer for receiving the digital microfluidics after rupture, the first The hydrophobic layer, the sound-absorbing coating, and the second hydrophobic layer are sequentially located on the acoustic transmission path of the surface acoustic wave, and the power of the RF electrical signal loaded by the signal generating device on the interdigital transducer decreases instantaneously when the power is greater than or equal to 15dBm. Digital microfluidics When a rupture occurs, the digital microfluidics after the rupture fly out and fall on the second hydrophobic layer. The advantage is that the device uses an unweighted interdigital transducer, so only low RF electrical signal power is required to achieve digital microfluidic disruption; moreover, the device is simple in structure, small in size, and easy to integrate.

Description

A Surface Acoustic Wave Device for Digital Microfluidic Disruption

technical field

The utility model relates to a digital microfluid rupture technology in a microfluidic chip, in particular to a device for realizing digital microfluid rupture by surface acoustic waves.

Background technique

Microfluidic technology can integrate a series of sampling, sample pretreatment, separation, reaction, detection and data analysis on a microfluidic substrate, which greatly reduces the cost of microfluidic analysis and shortens the time of microfluidic analysis, thus obtaining developed rapidly. Correspondingly, microfluidic analysis systems based on microfluidic technology have gradually been widely used, especially in disease diagnosis, medical and health, etc., which require expensive analytical reagents, expensive analytical instruments, and relatively high requirements for analysis time and analysis accuracy. The occasion is applied. Compared with the traditional analysis system, the microfluidic analysis system has many advantages, such as shorter reaction time, lower analysis cost, flexible and diverse device structure, very little microfluidic volume and relatively small system size, etc. Therefore, microfluidic analysis systems are widely used in DNA sequencing, protein analysis, single cell analysis, drug detection and food safety and other fields. According to the microfluidic working form in the microfluidic analysis system, it has two types, including continuous flow form and digital flow form. Generally speaking, the microfluidic analysis system working in the form of digital flow has the advantages of less reagent volume, shorter analysis time and higher analysis accuracy, so the microfluidic analysis system working in the form of digital flow has been applied in microfluidic transportation, Microfluidic manipulation and microfluidic analysis such as mixing, fusion, separation and analysis.

In the microfluidic analysis system working in the form of digital flow, in order to reduce the amount of reagents or samples, it is often necessary to rupture the digital microfluidics on the microfluidic substrate, so as to reduce the volume of digital microfluidics and reduce the cost of microfluidic analysis.

In the microfluidic analysis system working in the form of digital flow, a commonly used method of breaking digital microfluidics is to use a microchannel with a "T-junction" structure, and the digital microfluidic to be analyzed is floated on an immiscible fluid. In the carrier fluid, the carrier fluid flows under the drive of external pressure, and drives the digital microfluidic transport in the carrier fluid. When the digital microfluid in the carrier fluid passes through the "T-junction", the digital microfluidic is affected by the "T-junction". When the shear force caused by the deformation is greater than the surface tension of the digital microfluidics, the digital microfluidics will rupture. The advantage of this method is that the volume of the digital microfluidic rupture can be flexibly adjusted according to the flow velocity of the carrier fluid and the structural size of the "T-junction", but this method requires an additional carrier fluid for carrying the digital microfluidic transport, Moreover, an external pressure driving source such as a pressure pump is required, which not only increases the cost, but also the pressure pump is difficult to integrate on the microfluidic substrate, which increases the size of the microfluidic analysis system.

In the microfluidic analysis system working in the form of digital flow, another common method of breaking digital microfluidics is to set isolated PDMS micro-obstacles in the microfluidic channel, and the PDMS micro-obstacles are fixed in the microfluidic channel, when the external pressure When driving, the digital microfluidic is transported in the microfluidic channel along with the carrier fluid, and when encountering the PDMS micro-obstacle fixed in the microfluidic channel, the digital microfluidic is deformed and causes shear force, and ruptures under the carrying action of the carrier fluid . The advantage of this method is that compared with the "T-junction", its structure is relatively simple, and the volume of the digital microfluidic rupture can be adjusted according to the distance between the isolated PDMS micro-obstacle and the microfluidic channel, but this method requires additional The pressure-driven source is not easy to integrate on the microfluidic substrate.

In addition to the above-mentioned shortcomings, the above two common methods for realizing digital microfluidic rupture in microfluidic channels are often difficult to apply to open digital microfluidic systems. The open digital microfluidic system is to place the digital microfluidics to be operated directly on the surface of the microfluidic substrate, and move in the two-dimensional plane on the surface of the microfluidic substrate under the action of external forces such as sound and electricity to realize digital microfluidics. Microfluidic analysis of microfluidic systems. The advantage of the open digital microfluidic system is that it is simple in structure and does not require carrier fluid. A common open digital microfluidic system is an open digital microfluidic system based on dielectric electrowetting, which uses an electric field to change the degree of electrowetting on the surface of a microfluidic substrate to achieve digital microfluidic rupture. The electrode array is photoetched on the surface of the flow substrate, and the power on and off of each electrode in the electrode array is controlled, and the operation is relatively complicated.

The open digital microfluidic system based on surface acoustic wave can overcome some shortcomings of the above-mentioned open digital microfluidic system based on dielectric electrowetting. Two-dimensional in-plane manipulation of digital microfluidics along the surface of a piezoelectric substrate under the force of acoustic radiation. The existing method of rupturing digital microfluids based on surface acoustic waves is to apply a large electrical signal voltage to the focusing interdigital transducer, and the focusing interdigital transducer excites a relatively high-intensity surface acoustic wave to make the digital microfluidic to be broken Fluid escapes to realize the rupture of digital microfluidics. In order to make digital microfluidics fly away, this method needs to load higher electrical signal power on the focusing interdigital transducer to excite higher intensity surface acoustic waves, so piezoelectric ceramics are often used as substrates, while This makes it difficult to apply this method. For example, the journal "Microelectromechanical Systems" 2008, Volume 17, No. 1, Page 147-156 (Journal of microelectromechanical systems, Vol. 17 (1), 2008: 147-156) published "Based on micro-droplet oil-encapsulated micro Reactor" ("Droplet-Based Microreactions With Oil Encapsulation"), it is to place oil-phase digital microfluidics on the surface of the glass substrate, and the digital microfluidics of the reaction solution to be reacted is placed on the PZT piezoelectric substrate. The RF electrical signal amplified by the amplifier is loaded onto the focusing interdigital transducer set on the PZT piezoelectric substrate to excite strong acoustic surface waves, so that the reaction liquid digital microfluidics on the sound propagation path breaks and flies to the PZT piezoelectric substrate. On the oil-phase digital microfluidics of the glass substrate above the substrate, an oil-encapsulated reaction liquid digital microfluidics is formed to reduce the evaporation of the reaction liquid and complete the chemical reaction in the oil-phase microfluidics. This method of fracturing digital microfluidics requires high electrical signal power, so piezoelectric ceramics are often used as substrates. However, in piezoelectric microfluidic systems, lithium niobate with a large electromechanical coupling coefficient and low cost is generally used. If the surface acoustic wave is excited by such a high-power electrical signal, the lithium niobate substrate is easily broken; at the same time, the design of the focusing interdigital transducer is relatively complicated, so the surface acoustic wave rupture digital microfluidic The method is difficult to be popularized and applied.

Contents of the invention

The technical problem to be solved by the utility model is to provide a device for digital microfluid rupture by surface acoustic waves, which has a simple structure, small volume, and is easy to integrate, and can realize digital microfluid rupture only with low electrical signal power .

The technical scheme adopted by the utility model to solve the above-mentioned technical problems is: a device for realizing digital microfluid rupture by surface acoustic waves, which is characterized in that it includes a piezoelectric substrate and a signal generating device for generating RF electrical signals. The upper surface of the piezoelectric substrate is a working surface, and the working surface of the piezoelectric substrate is provided with an interdigital transducer connected to the signal generating device and used to excite surface acoustic waves, for placing the the first hydrophobic layer of the ruptured digital microfluidics, the sound-absorbing coating for attenuating the intensity of the surface acoustic wave excited by the interdigital transducer and the second hydrophobic layer for receiving the ruptured digital microfluidics, The first hydrophobic layer, the sound-absorbing coating and the second hydrophobic layer are sequentially located on the acoustic transmission path of the surface acoustic wave excited by the interdigital transducer, and the signal generating device The digital microfluid placed on the first hydrophobic layer ruptures when the power of the RF electrical signal loaded on the interdigital transducer decreases instantaneously by greater than or equal to 15 dBm, and the digital microfluid after the rupture breaks away out and fall on the second hydrophobic layer.

The signal generating device is composed of an adjustable signal generator for generating RF electrical signals and a power amplifier connected to the adjustable signal generator, and the power amplifier is connected to the interdigital transducer .

Before the digital microfluidics placed on the first hydrophobic layer breaks, the power of the RF electrical signal loaded on the interdigital transducer after the adjustable signal generator passes through the power amplifier is: 12dBm ~ 18 dBm, after 0.5s ~ 2s, the power of the RF electrical signal loaded on the interdigital transducer after the adjustable signal generator passes through the power amplifier is instantly reduced to -3dBm ~3dBm, the digital microfluidics placed on the first hydrophobic layer burst and escape.

The lower surface of the piezoelectric substrate is connected with a PCB board, and a plurality of lead pins are arranged on the PCB board, and the interdigital transducer includes two bus bars, and the bus bars pass through wires It is connected with the lead pin, and the lead pin is connected with the power amplifier through wires.

A reflective grid for reducing the power of the RF electrical signal loaded on the interdigital transducer is also arranged on the working surface of the piezoelectric substrate.

The thickness of the sound-absorbing coating is 100 μm-1 mm.

The width of the sound-absorbing coating is consistent with the aperture of the interdigital transducer.

The sound-absorbing coating is a polyimide sound-absorbing rubber layer or a PDMS coating layer.

The second hydrophobic layer is provided with a baffle for preventing the ruptured digital microfluids from flying out and falling on the piezoelectric substrate, and the baffle faces towards the side of the interdigital transducer. A hydrophobic thin layer is arranged on one side, and the height of the baffle is greater than or equal to 3 cm.

The baffle is fixed on the second hydrophobic layer through a fixing block made of PDMS material.

Compared with the prior art, the utility model has the advantages of: by setting the piezoelectric substrate and the signal generating device, and setting the interdigital transducer connected with the signal generating device and used to excite the surface acoustic wave on the piezoelectric substrate , the first hydrophobic layer for placing the digital microfluidics to be ruptured, the sound-absorbing coating for attenuating the intensity of the surface acoustic waves excited by the interdigital transducers, and the second hydrophobic layer for receiving the ruptured digital microfluidics At the same time, the first hydrophobic layer, the sound-absorbing coating and the second hydrophobic layer are sequentially located on the acoustic transmission path of the surface acoustic wave excited by the IDT, so that the surface acoustic wave excited by the IDT directly acts on the Placed on the digital microfluidics on the first hydrophobic layer, an acoustic flow is generated in the digital microfluidics to form an acoustic flow force, so that the digital microfluidics has a tendency to move upwards at a certain angle, but cannot move in the first After this state lasts for a period of time, the power of the RF electrical signal loaded by the control signal generating device on the interdigital transducer drops by more than 15 dBm. At this time, the digital microfluidic placed on the first hydrophobic layer breaks and flies Escape, and finally fall on the second hydrophobic layer, this device realizes the rupture of the digital microfluid by controlling the power of the RF electrical signal loaded by the signal generating device on the interdigital transducer, because there is no need for interdigital transducer Weighted design, that is, the use of interdigital transducers with equal finger lengths and even intervals, so the design and manufacture of interdigital transducers are simple; at the same time, only low RF electrical signal power can realize the rupture of digital microfluidics; in addition On the one hand, the device does not require an external pressure drive source, has a simple structure, small size, and is easy to integrate, and can be used for microfluidic pretreatment operations on piezoelectric microfluidic chips.

Description of drawings

Fig. 1 is the structural representation of the utility model device;

FIG. 2 is an enlarged schematic view of part A in FIG. 1 .

Detailed ways

The utility model is described in further detail below in conjunction with the accompanying drawings.

The utility model proposes a device for realizing digital microfluid rupture by surface acoustic waves, as shown in the figure, which includes a piezoelectric substrate 1 and a signal generating device 2 for generating RF electrical signals, and the upper part of the piezoelectric substrate 1 The surface is the working surface, and the working surface of the piezoelectric substrate 1 is provided with an interdigital transducer 3 connected to the signal generating device 2 and used to excite the surface acoustic wave, and a first digital microfluidic 8 for placing to be ruptured. The hydrophobic layer 4, the sound-absorbing coating 5 for attenuating the intensity of the surface acoustic wave excited by the interdigital transducer 3, the second hydrophobic layer 6 for receiving the ruptured digital microfluidics, and the signal generating device 2 for reducing The reflective grid 7 of the power of the RF electrical signal loaded on the interdigital transducer 3, the first hydrophobic layer 4, the sound-absorbing coating 5 and the second hydrophobic layer 6 are located in sequence in the surface acoustic wave excited by the interdigital transducer 3 On the acoustic transmission path, the reflection grid 7 is located in the opposite direction of the acoustic transmission path of the surface acoustic wave excited by the IDT 3, that is, the reflection grid 7 and the first hydrophobic layer 4 are respectively located on both sides of the IDT 3 , when the power of the RF electrical signal loaded by the signal generating device 2 on the interdigital transducer 3 is lowered instantaneously by greater than or equal to 15 dBm, the digital microfluidics 8 placed on the first hydrophobic layer 4 ruptures, and the digital microfluidics after rupture Fly out and fall on the second hydrophobic layer 6. Here, the IDT 3 and the reflective grating 7 are both photolithographically etched on the working surface of the piezoelectric substrate 1 using the existing microelectronics process, and the reflective grating 7 is used to reflect the energy excited by the IDT 3. SAW to reduce the power of the RF electrical signal.

In this embodiment, the signal generating device 2 is composed of an adjustable signal generator 21 for generating RF electrical signals and a power amplifier 22 connected to the adjustable signal generator 21, and the power amplifier 22 is connected to the interdigital transducer 3 , the adjustable signal generator 21 outputs an RF electrical signal, the RF electrical signal is amplified by the power amplifier 22 and loaded onto the IDT 3, and the IDT 3 excites the surface acoustic wave under the action of the RF electrical signal; Before the digital microfluidic 8 placed on the first hydrophobic layer 4 breaks, the power of the RF electrical signal loaded on the interdigital transducer 3 by controlling the adjustable signal generator 21 after passing through the power amplifier 22 is 12 dBm to 18 dBm. After 0.5s～2s, control the adjustable signal generator 21 to pass through the power amplifier 22, and then the power of the RF electrical signal loaded on the interdigital transducer 3 is instantly reduced to -3dBm～3dBm. At this time, it is placed on the first hydrophobic layer 4 The digital microfluidics 8 on the surface break and fly out, and finally fall on the second hydrophobic layer 6 . Here, the adjustable signal generator 21 can use an existing signal generator with an output voltage adjustment accuracy of 0.1V; the power amplifier 22 uses a commercially available product; in the actual operation process, the adjustable signal generator 21 and the power amplifier After 22, the adjustable signal generator 21 can be controlled and the power of the RF electrical signal loaded on the interdigital transducer 3 after passing through the power amplifier 22 is 15 dBm, and the surface acoustic wave excited by the interdigital transducer 3 is radiated at a radiation angle Put the digital microfluid 8 to be broken on the first hydrophobic layer 4, and generate an acoustic flow in the digital microfluid 8 to be broken to form an acoustic flow force, so that the digital microfluid 8 to be broken has an upward direction at a certain angle. The trend of movement, but can not move on the first hydrophobic layer 4, after this state lasts 0.5s, control the power of the RF electrical signal loaded on the interdigital transducer 3 by the adjustable signal generator 21 after passing through the power amplifier 22 Drop above 15 dBm, down to -1dBm, at this time, the digital microfluidics 8 placed on the first hydrophobic layer 4 burst and escape, and finally fall on the second hydrophobic layer 6 .

In this embodiment, a PCB board 9 is connected to the lower surface of the piezoelectric substrate 1, and two lead pins 91 are arranged on the PCB board 9. The IDT 3 includes two bus bars 31, and one bus bar passes through The wire is connected to one lead pin through pressure welding or conductive silver glue, the other bus bar is connected to the other lead pin through pressure welding or conductive silver glue, and the two lead pins 91 are connected to the power amplifier 22 through wires. Here, the PCB board 9 can also be replaced by other existing substrates on which wires can be fixed.

In this embodiment, the second hydrophobic layer 6 is provided with a baffle 61 for preventing the broken digital microfluid from flying out and falling on the piezoelectric substrate 1. A hydrophobic thin layer (not shown in the figure) is arranged on one side, and the baffle plate 61 can adopt an existing thin glass sheet, and coat the working surface of the thin glass sheet, that is, the side facing the IDT 3 Cover Teflon AF 1600 hydrophobic thin layer, the height of the baffle 61 can be designed to be greater than or equal to 3cm, a layer of PDMS material can be coated on the bottom of the baffle 61 during processing, and then the baffle 61 is bonded to the first on the second hydrophobic layer, or can also be fixed on the second hydrophobic layer 6 through a fixing block 62 made of PDMS material. Here, the baffle 61 is arranged on the side of the second hydrophobic layer 6 away from the sound-absorbing coating 5 , and the width of the baffle 61 can be designed to be the same as the aperture of the IDT 3 . When designing the second hydrophobic layer 6, if the length of the second hydrophobic layer 6 is greater than 6 cm, no baffle 61 is set on the second hydrophobic layer 6, and the digital microfluidics after rupture will not fly away from the second hydrophobic layer 6. Here, the hydrophobic thin layer is formed by coating a layer of Teflon AF 1600 hydrophobic material on one side of the baffle 61, and then drying in a 160-degree thermostat for about 1 hour.

In this embodiment, the sound-absorbing coating 5 is coated with a layer of PDMS (polydimethylsiloxane) material on the acoustic transmission path of the surface acoustic wave excited by the interdigital transducer 3, and after 24 hours of natural It is formed after curing, and the thickness of the formed PDMS coating layer is required to be 100 μm to 1 mm. For example, the thickness of the PDMS coating layer can be 100 μm in actual operation. If the sound-absorbing coating 5 adopts the PDMS coating layer, the first The hydrophobic layer 4 and the second hydrophobic layer 6 can be integrally formed by directly coating the hydrophobic layer with PDMS material. The sound-absorbing coating 5 can also use a polyimide sound-absorbing rubber layer with a thickness of 100 μm to 1 mm. If a polyimide sound-absorbing rubber layer is used, generally the polyimide sound-absorbing rubber layer can only be placed on the piezoelectric substrate 1. Here, the width of the sound-absorbing coating 5 is consistent with the aperture of the IDT 3, that is, the width of the sound-absorbing coating 5 relative to the direction of the first hydrophobic layer 4 and the second hydrophobic layer 6 is the same as that of the IDT 3. The pore diameters are the same, so that the surface acoustic waves excited by the interdigital transducer 3 all pass through the sound-absorbing coating, and the intensity is attenuated by the sound-absorbing coating 5. Of course, in the actual design process, the width of the sound-absorbing coating 5 can be It is designed to be larger than the aperture of the interdigital transducer 3; the length of the sound-absorbing coating 5 is 4 mm to 6 mm, that is, the distance for the surface acoustic wave excited by the interdigital transducer 3 to pass through the sound-absorbing coating 5 is 4 mm to 6 mm, In the actual design process, it can be designed to be 5mm. Generally, it is not recommended to design it too narrow, so that the intensity attenuation effect of the surface acoustic wave is not ideal, and it is not recommended to design it too wide, which will not only waste materials, but also may cause cracking. The digital microfluidics fly out and land on the sound-absorbing coating 5 .

Here, the setting of the sound-absorbing coating 5 is to prevent the cracked digital microfluidics falling on the second hydrophobic layer 6 from continuing to break on the second hydrophobic layer 6, and sound-absorbing materials such as the sound-absorbing coating 5 are used to attenuate the sound. The strength of the surface wave, the sound-absorbing coating 5 does not affect the rupture of the original digital microfluidics 8 on the first hydrophobic layer 4, but it will greatly reduce the sound added to the ruptured digital microfluidics on the second hydrophobic layer 6. The strength of the surface wave, thus avoiding further rupture of the digital microfluidics after rupture.

In this embodiment, both the first hydrophobic layer 4 and the second hydrophobic layer 6 are coated with a layer of Teflon AF 1600 hydrophobic material on the acoustic transmission path of the surface acoustic wave excited by the interdigital transducer 3, and then through 160 degrees It is formed by drying in an incubator for about 1 hour. Because if the first hydrophobic layer 4 and the second hydrophobic layer 6 are too thick, the attenuated surface acoustic wave is too large, and the required RF signal power increases. If the first hydrophobic layer 4 and the second hydrophobic layer If the layer 6 is too thin, the hydrophobicity of the working surface of the piezoelectric substrate 1 is not good enough, so that the digital microfluidics placed on the first hydrophobic layer 4 and the second hydrophobic layer 6 will not be droplet-shaped, and cannot guarantee the surface acoustic wave Therefore, a large number of experiments have been carried out, and the experimental results show that when the thickness of the first hydrophobic layer 4 and the second hydrophobic layer 6 are controlled within the range of 1 ~ 3? Get great results.

In this embodiment, the piezoelectric substrate 1 can be a piezoelectric substrate with a slightly larger electromechanical coupling coefficient, basically a piezoelectric substrate with an electromechanical coupling coefficient greater than 5.5%, such as a 128 ⁰ -YX LiNbO ₃ piezoelectric substrate.

In the process of specifically designing the device, a plurality of interdigital transducers can be arranged on the piezoelectric substrate 1 to form an interdigital transducer array, and each interdigital transducer is connected to the signal generating device 2, so that The digital microfluid after rupture can be transported to the first hydrophobic layer 4 through the interdigital transducer array as required and then ruptured to obtain a smaller volume of digital microfluid. Transport of small volumes of digital microfluidics.

The process of using the above-mentioned device to realize digital microfluidic rupture is as follows:

① Connect the adjustable signal generator 21 and the power amplifier 22 of the signal generating device 2, and connect the power amplifier 22 and the IDT 3.

② Place the digital microfluidic 8 to be ruptured on the first hydrophobic layer 4 , and make the digital microfluidic 8 to be ruptured be located on the acoustic transmission path of the surface acoustic wave excited by the interdigital transducer 3 .

3. start the adjustable signal generator 21 and the power amplifier 22 of the signal generating device 2, the adjustable signal generator 21 outputs the RF electrical signal, and transmits the RF electrical signal to the power amplifier 22, and controls the amplified RF electrical signal output by the power amplifier 22 simultaneously. The power of the signal is 12dBm~18dBm, and it can be controlled to 15dBm for specific operation. In fact, the power of the RF electrical signal loaded on the interdigital transducer 3 can be determined according to the volume of the digital microfluid 8 to be ruptured. Generally, if the volume of the digital microfluid 8 to be ruptured is relatively large, such as When it is 10 microliters to 20 microliters, the power of the RF electrical signal loaded on the interdigital transducer 3 can be controlled at about 18dBm. If the volume of the digital microfluidic fluid 8 to be broken is small, such as 1 microliter When it reaches 10 microliters, the power of the RF electrical signal loaded on the IDT 3 can be controlled at about 12 dBm.

④ The amplified RF electrical signal output by the power amplifier 22 of the signal generating device 2 is transmitted to the IDT 3, and the IDT 3 excites the surface acoustic wave after being connected to the RF electrical signal, and the IDT 3 excites The surface acoustic wave acts on the digital microfluidic 8 to be ruptured placed on the first hydrophobic layer 4. At this time, an acoustic flow is generated in the digital microfluidic 8 to be ruptured to form an acoustic flow force, so that the digital microfluidic 8 to be ruptured exists Trend of upward movement.

⑤ After the digital microfluidic fluid 8 to be ruptured maintains a trend of oblique upward movement for 0.5s to 2s (for example, after 1s), adjust the RF electrical signal output by the adjustable signal generator 21 of the signal generating device 2 to make the power amplifier 22 output The power of the amplified RF electrical signal drops to -3dBm ~ 3dBm instantly, and if it drops to -1 dBm during the specific operation, the digital microfluid 8 to be broken will break due to inertia overcoming its surface tension, and the broken digital microfluidic The fluid escapes and falls on the second hydrophobic layer 6 . In fact, the time to maintain the trend of the digital microfluidic 8 to be ruptured can be more than 0.5 seconds. For the convenience of application and time saving, in general, 1 second is selected; and the range of instantaneously reducing the power of the RF electrical signal It needs to be above 15 dBm, that is, if the power of the RF electrical signal originally loaded on the interdigital transducer 3 is 12 dBm, it needs to drop below -3dBm instantaneously, such as -5dBm, if the power originally loaded on the fork It means that the power of the RF electrical signal on the transducer 3 is 18 dBm, and it needs to drop below 3 dBm instantaneously, such as 1 dBm.

⑥ Turn off the adjustable signal generator 21 and the power amplifier 22 of the signal generating device 2 .

In the specific operation process, the power of the RF electrical signal loaded to the interdigital transducer 3 should not be too small, otherwise the acoustic flow force generated by the digital microfluidic 8 to be ruptured is not strong enough, and the inertia is not enough to overcome the surface tension of the digital microfluidic , the rupture of the digital microfluidics cannot be realized; the power of the RF electrical signal loaded to the IDT 3 cannot be too large, otherwise the surface acoustic wave excited by the IDT 3 will drive the digital microfluidics 8 to be ruptured. Sliding on a hydrophobic layer 4, even if the intensity of the RF electric signal is reduced instantaneously, the rupture of the digital microfluidics cannot be realized. When the RF electrical signal loaded on the interdigital transducer 3 lasts for more than 0.5 seconds, and the RF electrical signal is reduced by a sufficient amount in an instant, the rupture of the digital microfluidics can be realized. Experiments show that when the power of the RF electrical signal loaded on the interdigital transducer 3 is in the range of 12dBm-18dBm, the power range of the RF electrical signal is instantly reduced to more than 15dBm, and the digital microfluidic rupture can be realized.

Claims (10)

1. A device for surface acoustic wave to realize digital microfluidic rupture is characterized in that it comprises a piezoelectric substrate and a signal generating device for generating RF electrical signals, and the upper surface of the piezoelectric substrate is a working surface, so The working surface of the piezoelectric substrate is provided with an interdigital transducer connected to the signal generating device and used to excite surface acoustic waves, a first hydrophobic layer for placing digital microfluidics to be broken, and The sound-absorbing coating for attenuating the intensity of the surface acoustic wave excited by the interdigital transducer and the second hydrophobic layer for receiving the ruptured digital microfluidics, the first hydrophobic layer, the absorbing The acoustic coating and the second hydrophobic layer are sequentially located on the acoustic transmission path of the surface acoustic wave excited by the interdigital transducer, and the signal generating device is loaded on the interdigital transducer The digital microfluid placed on the first hydrophobic layer ruptures when the power of the RF electrical signal drops greater than or equal to 15 dBm instantaneously, and the ruptured digital microfluid escapes and lands on the second hydrophobic layer . 2. A kind of surface acoustic wave according to claim 1 realizes the device of digital microfluid rupture, it is characterized in that described signal generating device is used for generating the adjustable signal generator of RF electrical signal and described adjustable It is composed of a power amplifier connected to the modulation signal generator, and the power amplifier is connected to the interdigital transducer. 3. A device for realizing digital microfluidic rupture by surface acoustic wave according to claim 2, characterized in that before the digital microfluidic rupture on the first hydrophobic layer, the adjustable signal generator The power of the RF electrical signal loaded on the interdigital transducer after passing through the power amplifier is 12dBm ~ 18dBm, and after 0.5s ~ 2s, the adjustable signal generator passes through the The power of the RF electrical signal loaded on the interdigital transducer after the power amplifier drops to -3dBm-3dBm instantaneously, and the digital microfluidics placed on the first hydrophobic layer break and fly out. 4. A kind of surface acoustic wave according to claim 2 realizes the device of digital microfluid rupture, it is characterized in that the lower surface of described piezoelectric substrate is connected with PCB board, and described PCB board is provided with many The IDT includes two bus bars, the bus bars are connected to the lead pins through wires, and the lead pins are connected to the power amplifier through wires. 5. A device for realizing digital microfluid rupture by surface acoustic waves according to any one of claims 1 to 4, characterized in that the working surface of the piezoelectric substrate is also provided with a device for reducing the load on the The reflection grid of the power of the RF electrical signal on the IDT described above. 6 . The device for realizing digital microfluidic rupture by surface acoustic waves according to claim 1 , characterized in that the thickness of the sound-absorbing coating is 100 μm˜1 mm. 7. A device for realizing digital microfluidic rupture by surface acoustic wave according to claim 6, characterized in that the width of the sound-absorbing coating is consistent with the aperture of the interdigital transducer. 8. A device for realizing digital microfluidic rupture by surface acoustic wave according to claim 6 or 7, characterized in that said sound-absorbing coating is a polyimide sound-absorbing rubber layer or a PDMS coating layer. 9. A device for digital microfluidic rupture by surface acoustic waves according to claim 5, characterized in that the second hydrophobic layer is provided with a digital microfluidic device used to stop the rupture from escaping and falling on the said second hydrophobic layer. The baffle on the piezoelectric substrate, the side of the baffle facing the IDT is provided with a thin hydrophobic layer, and the height of the baffle is greater than or equal to 3cm. 10 . The device for rupturing digital microfluidics by surface acoustic waves according to claim 9 , wherein the baffle is fixed on the second hydrophobic layer through a fixing block made of PDMS material. 11 .

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