Nanoparticle control method and device based on acoustic streaming suppression principle

Abstract

The invention relates to the technical field of nano control, in particular to a nano particle control method and device based on an acoustic streaming suppression principle, and the method comprises the following steps: S1, arranging a micro-fluidic chip with a cavity; s2, a target standing wave sound field is established on the cross section of the cavity, and the sound pressure node plane of the target standing wave sound field is parallel to the adjacent side wall of the cavity; s3, fluid containing nano particles is introduced into the cavity channel, the nano particles can be migrated and driven to a sound pressure node area under the action of sound radiation force, and stable aggregation clusters are formed; the device comprises a micro-fluidic chip, the micro-fluidic chip is provided with a cavity channel, the surface of the micro-fluidic chip is provided with a sound wave driving structure, and a sound pressure node plane of a standing wave sound field generated by the sound wave driving structure is parallel to an adjacent side wall of the cavity channel. According to the method, the directional or fixed-point control of the nano particles can be realized under the action of actively inhibiting the sound stream interference.

Description

Technical Field

[0001] The present invention relates to the technical field of nano - manipulation, and more specifically, to a method and device for manipulating nanoparticles based on the principle of suppressing acoustic streaming. Background Art

[0002] With the rapid development of nanotechnology, the applications of nanoparticles in the fields of biomedical detection, targeted drug delivery, micro - nano device assembly, etc. are becoming increasingly widespread. To achieve efficient and non - destructive manipulation of nanoparticles, existing acoustic manipulation technologies are regarded as highly potential particle manipulation means due to their advantages such as non - contact, label - free, and good biocompatibility. Among them, acoustic radiation force, as the core physical mechanism, can apply a controllable force to particles by adjusting the acoustic field parameters, and then achieve precise manipulations such as directional migration and spatial arrangement.

[0003] However, there are still some problems in the existing nano - manipulation methods based on acoustic radiation force: when sound waves act on a liquid medium, in addition to generating acoustic radiation force, acoustic streaming drag caused by acoustic streaming will also be induced. Especially in a microfluidic system, the vortex flow caused by acoustic streaming will form a competitive mechanism with acoustic radiation force, resulting in unexpected diffusion of nanoparticles, deviation of migration trajectories, or destruction of aggregation structures. Although the acoustic streaming effect is reduced or balanced by reducing the sound pressure intensity or introducing an external physical field, such as electric - field assistance, these methods often sacrifice manipulation efficiency or increase system complexity and are difficult to achieve high - throughput operation. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiency of the existing technology in which the accuracy of particle manipulation is affected by the acoustic streaming effect, and to provide a method and device for manipulating nanoparticles based on the principle of suppressing acoustic streaming, which can achieve directional or fixed - point manipulation of nanoparticles under the action of actively suppressing acoustic streaming interference.

[0005] To solve the above - mentioned technical problems, the technical solution adopted by the present invention is:

[0006] Provide a method for manipulating nanoparticles based on the principle of suppressing acoustic streaming, including the following steps:

[0007] S1. Set up a microfluidic chip with a channel;

[0008] S2. Establish a target standing - wave acoustic field in the cross - section of the channel, wherein the sound - pressure node plane of the target standing - wave acoustic field is parallel to the adjacent side walls of the channel;

[0009] S3. Introduce a fluid containing nanoparticles into the channel, and the nanoparticles can be migrated and driven to the sound - pressure node region under the action of acoustic radiation force and form a stable aggregated cluster.

[0010] A method for manipulating nanoparticles based on the principle of acoustic streaming suppression. When the sound pressure node plane of the target standing wave sound field is parallel to the adjacent side walls of the channel, the boundary layer-driven acoustic streaming in the channel will be completely suppressed or eliminated. Thus, the acoustic radiation force generated by the radial sound pressure gradient can drive the nanoparticles to the sound pressure node plane, achieving the directional or fixed-point manipulation of the nanoparticles.

[0011] Further, in step S1, the microfluidic chip is any one of a glass microfluidic chip, a silicon microfluidic chip, a metal microfluidic chip, and a plastic microfluidic chip.

[0012] Further, in step S2, the target standing wave sound field is established based on the following target acoustic mode:

[0013]

[0014] In the formula, u L represents the limiting velocity, ω represents the angular frequency, u1 represents the first-order acoustic velocity, * represents the complex conjugate, u 1|| represents the component of u1 along the tangent direction of the fluid-solid boundary, || represents the tangent direction of the fluid-solid boundary, and d represents the differential operator.

[0015] Further, in step S2, the number of sound pressure nodes is set to one or more, and a radial gradient sound pressure distribution is formed in the target standing wave sound field, which can be used to generate an acoustic radiation force pointing to the sound pressure nodes on the nanoparticles in the fluid in step S3.

[0016] Further, in step S2, by setting a signal generator and one or more ultrasonic transducers, a sine wave signal is generated by the signal generator and transmitted to the ultrasonic transducers to generate the target standing wave sound field.

[0017] Further, in step S2, the ultrasonic excitation frequency of the ultrasonic transducer is the resonance frequency of the target standing wave sound field in the channel.

[0018] Further, in step S2, a single-frequency sound field of 1 - 10 MHz is applied to the microfluidic chip.

[0019] Further, in step S3, the radius r of the nanoparticles p is 50 - 500 nm.

[0020] The present invention also provides a manipulation device applied to the method for manipulating nanoparticles, including a microfluidic chip. The microfluidic chip is provided with a channel, and a sound wave driving structure is installed on the surface of the microfluidic chip. The sound pressure node plane of the standing wave sound field generated by the sound wave driving structure is parallel to the adjacent side walls of the channel.

[0021] Preferably, inlets and outlets communicating with the outside are respectively provided at both ends of the channel, a cover glass is provided at the outlet, a right-angle prism is provided at one end of the outlet, the inclined surface of the right-angle prism faces the outlet, and an aluminum film is plated on the inclined surface of the right-angle prism.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. When the sound pressure node plane of the target standing wave sound field is parallel to the adjacent side walls of the channel, the boundary layer-driven acoustic streaming in the channel will be completely suppressed or eliminated, so that the acoustic radiation force generated by the radial sound pressure gradient can drive the nanoparticles to the sound pressure node plane, realizing the directional or fixed-point manipulation of the nanoparticles;

[0024] 2. The setting of the right-angle prism facilitates the imaging of the particle pattern during observation with a microscope. Description of the Drawings

[0025] Figure 1 is a flowchart of a method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to the present invention;

[0026] Figure 2 is a schematic diagram of a target standing wave sound field with different numbers of sound pressure node planes when the cross-section of the channel of the present invention is of any shape;

[0027] Figure 3 is a simulation result diagram of the acoustic dynamics behavior of nanoparticles with different particle sizes under different target standing wave sound fields when the cross-section of the channel of the present invention is circular;

[0028] Figure 4 is a channel model when the cross-section of the channel of the present invention is rectangular with rounded corners;

[0029] Figure 5 is a diagram showing the evolution law of the sound pressure node plane in the channel under different rounded corner radius ratios according to the present invention;

[0030] Figure 6 is a comparison diagram of the boundary acoustic streaming velocity when the cross-section of the channel of the present invention is rectangular with rounded corners;

[0031] Figure 7 is an experimental effect diagram of nanoparticle aggregation under different numbers of sound pressure node planes when the cross-section of the channel of the present invention is circular;

[0032] Figure 8 is a schematic structural diagram of the first embodiment of the manipulation device according to the present invention;

[0033] Figure 9 is a schematic structural diagram of the second embodiment of the manipulation device according to the present invention.

[0034] In the accompanying drawings: 100, microfluidic chip; 110, channel; 200, acoustic drive structure; 300, cover glass; 400, right-angle prism; 500, chip holder. Detailed implementation manners

[0035] The present invention will be further described below in conjunction with the detailed implementation manners. Among them, the accompanying drawings are only for illustrative purposes, showing only schematic diagrams, rather than physical diagrams, and should not be construed as a limitation on this patent; in order to better illustrate the embodiments of the present invention, some components in the accompanying drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0036] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects.

[0037] It should be noted that the terms "including" and "having" in the description and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily 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.

[0038] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the accompanying drawings are only for illustrative purposes and should not be construed as a limitation on this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] Embodiment 1

[0040] As Figures 1 to 7 shown in the first embodiment of a method for manipulating nanoparticles based on the principle of acoustic flow suppression of the present invention, the following steps are included:

[0041] S1. Set a microfluidic chip 100 having a channel 110;

[0042] S2. Establish a target standing wave sound field in the cross-section of the channel 110, where the sound pressure node plane of the target standing wave sound field is parallel to the adjacent side walls of the channel 110;

[0043] S3. Introduce a fluid containing nanoparticles into the channel 110. The nanoparticles can be migrated and driven to the sound pressure node region under the action of acoustic radiation force and form stable aggregated clusters.

[0044] In this embodiment, the microfluidic chip 100 is any one of a glass microfluidic chip, a silicon microfluidic chip, a metal microfluidic chip, and a plastic microfluidic chip.

[0045] In step S2, establish the target standing wave sound field based on the following target acoustic mode:

[0046]

[0047] where u L represents the limiting velocity, ω represents the angular frequency, u1 represents the first-order sound wave velocity, * represents the complex conjugate, u 1|| represents the component of u1 along the tangent direction of the fluid-solid boundary, || represents the tangent direction of the fluid-solid boundary, and d represents the differential operator.

[0048] In this embodiment, the number of sound pressure nodes is set to one or more, and a radial gradient sound pressure distribution is formed in the target standing wave sound field, which can be used to generate an acoustic radiation force pointing to the sound pressure nodes on the nanoparticles in the fluid in step S3. As Figure 2 shown in the cross-section of the channel 110, the cross-section of the channel 110 is of any shape, where the dashed line represents the sound pressure node plane, and the sound pressure node plane is parallel to the adjacent side walls of the channel 110. At this time, the boundary layer-driven acoustic streaming in the channel 110 will be completely suppressed or eliminated, so that the acoustic radiation force generated by the radial sound pressure gradient can drive the nanoparticles to the sound pressure node plane in step S3, realizing the directional or fixed-point manipulation of the nanoparticles.

[0049] Specifically, in step S2, by setting a signal generator and one or more ultrasonic transducers, a sine wave signal is generated by the signal generator and transmitted to the ultrasonic transducers to generate the target standing wave sound field. In this embodiment, the ultrasonic excitation frequency of the ultrasonic transducers is the resonance frequency of the target standing wave sound field in the channel 110. Preferably, a single-frequency sound field of 1 - 10 MHz is applied to the microfluidic chip 100.

[0050] Specifically, for one of the verification methods of acoustic streaming suppression, select the cross-section of the channel 110 to be circular, the cross-section diameter D is 1.6 mm, the fluid introduced is an aqueous solution, and the nanoparticles are polystyrene nanoparticles; the verification operation steps include:

[0051] Calculate the distribution of the target standing wave sound field and its resonant frequency in the cavity 110;

[0052] Set the boundary vibration intensity to generate the target standing wave sound field in the cross-section of the cavity 110;

[0053] Calculate the acoustic streaming and the distribution of acoustic radiation force under the target standing wave sound field;

[0054] Solve the acoustic dynamics behavior of nanoparticles with different particle sizes in the cavity 110 under the combined action of acoustic radiation force and acoustic streaming drag force in the target standing wave sound field;

[0055] Change the value of the diameter D and repeat the above steps to calculate the acoustic dynamics behavior of nanoparticles in cavities 110 with different sizes.

[0056] As Figure 3 shown, where (a), (b), and (c) respectively represent the target standing wave sound fields containing single, double, and triple sound pressure node planes. The sound pressure node planes of the target standing wave sound field are parallel to the adjacent side walls of the cavity 110. Under this sound field condition, the acoustic streaming velocity at each point in the cross-section is 0, and the radial sound pressure gradient can generate an acoustic radiation force distribution pointing to the sound pressure nodes. Figure 3 In (d), (e), and (f) respectively represent the movement and aggregation of nanoparticles under the target standing wave sound fields of single, double, and triple sound pressure node planes. The results of particle acoustophoresis show that under different target standing wave sound fields, polystyrene nanoparticles of different sizes can be driven by the acoustic radiation force to the sound pressure nodes. In addition, the change in the cross-sectional diameter D of the cavity 110 only affects the resonant frequency under the same sound field structure, but does not affect the distribution law of the acoustic radiation force and its manipulation accuracy.

[0057] Specifically, for the second verification method of acoustic streaming suppression, select the cross-section of the cavity 110 to be a rectangular shape with rounded corners, the cross-sectional width L is 1.6 mm, and the rounded corner radius R is variable, as Figure 4 shown. The fluid introduced is an aqueous solution, and the nanoparticles are polystyrene nanoparticles; the verification operation steps include:

[0058] Calculate the distribution of the target standing wave sound field and its resonant frequency in the cavity 110 for different values of R;

[0059] Set the boundary vibration intensity to generate a sound field with the same sound pressure amplitude in the cavity 110 for different values of R, and set this sound pressure amplitude to be the same as the sound pressure amplitude in the first verification method;

[0060] Calculate and compare the magnitudes of the acoustic streaming velocities in the cavity 110 for different values of R;

[0061] Solve the acoustic dynamics behavior of nanoparticles with different particle sizes in the cavity for different values of R under the combined action of acoustic radiation force and acoustic streaming drag force; compare the lower limit of the particle size that can be manipulated by the acoustic radiation force in the cavity for different values of R.

[0062] Among them, as Figure 5 shown, as the round-corner radius ratio (0.05 ≤ R / L < 0.5) increases, the shape of the sound pressure node plane gradually transitions to a round-corner square and finally approaches a circle, and the parallelism between the sound pressure node plane and the sidewall of the channel 110 is significantly enhanced. The acoustic radiation force can overcome the acoustic streaming interference and gradually approaches complete overcoming; as Figure 6 shown, by adjusting the round-corner radius ratio and analyzing, it can be obtained that at the same sound pressure amplitude, the limit velocity u L of the channel 110 shows a rapid downward trend as R increases. From this, it can also be obtained that when the sound pressure node plane is parallel to the adjacent sidewall of the channel 110, the boundary layer-driven acoustic streaming in the channel 110 will be completely suppressed or eliminated.

[0063] Specifically, for one of the experimental methods for manipulating nanoparticles, a glass microfluidic chip is selected, and a channel 110 with a circular cross-section and a diameter D of 1.6 mm is selected. The operating frequency of the ultrasonic transducer is the resonance frequency f r of the channel 110; the operation steps include:

[0064] Inject an aqueous solution containing polystyrene nanoparticles into the channel 110, where the radius r p of the nanoparticles is 50 - 500 nm;

[0065] Apply an ultrasonic drive of 20 Vpp and a frequency of f r , where the signal generator generates a continuous sine wave signal to drive the ultrasonic transducer to generate ultrasonic frequency vibrations;

[0066] Observe the aggregation of polystyrene nanoparticles under the target standing wave sound field through a microscope.

[0067] As Figure 8 shown, polystyrene nanoparticles with a radius r p in the range of 50 - 500 nm can be accurately migrated and driven to the sound pressure node plane region under the action of the acoustic radiation force and form stable aggregated clusters; by changing the excitation frequency of the ultrasonic transducer, different order resonant sound fields in the channel 110 can be excited, and different numbers of sound pressure node planes can be generated in the cross-section of the channel 110, realizing the efficient directional manipulation of nanoparticles to single nodes or multiple nodes.

[0068] Example Two

[0069] As Figure 8The following shows the first embodiment of a control device of the present invention, which is applied to the method for manipulating nanoparticles based on the principle of acoustic streaming suppression described in the first embodiment. The control device includes a microfluidic chip 100, the microfluidic chip 100 is provided with a channel 110, and an acoustic wave driving structure 200 is installed on the outer surface of the microfluidic chip 100. The sound pressure node plane of the standing wave sound field generated by the acoustic wave driving structure 200 is parallel to the adjacent side walls of the channel 110. In this embodiment, the acoustic wave driving structure 200 includes one or more ultrasonic transducers, and also includes a signal generator electrically connected to the ultrasonic transducers. The ultrasonic transducers are pasted on the outer surface of the microfluidic chip 100.

[0070] Embodiment III

[0071] This embodiment is the second embodiment of a control device. This embodiment is similar to the second embodiment, and the difference lies in that, as Figure 9 shown, an inlet and an outlet communicating with the outside are respectively provided at both ends of the channel 110. A cover glass 300 is abutted at the outlet, and a right-angle prism 400 is provided at one end of the outlet. The inclined surface of the right-angle prism 400 faces the outlet, and an aluminum film is plated on the inclined surface of the right-angle prism 400. This embodiment also includes a chip holder 500. The microfluidic chip 100 and the right-angle prism 400 are both placed on the chip holder 500, which can facilitate the placement of the control device under a microscope for observation. Preferably, the right-angle prism 400 is an isosceles right-angle prism.

[0072] During use, the ultrasonic transducers excite an ultrasonic standing wave field in the channel 110 of the microfluidic chip 100; the ultrasonic transducers are driven by a sine signal generated by the signal generator, amplified by a power amplifier, and the signal is monitored by an oscilloscope; the outlet of the channel 110 is sealed with a cover glass 300 to block fluid flow and provide an optical observation window. An isosceles right-angle prism is placed beside the cover glass 300, and the inclined surface of the isosceles right-angle prism faces the cover glass 300, and the particle pattern of the cross-section of the channel 110 is imaged at a magnification of 40 times.

[0073] In the specific content of the above specific embodiments, each technical feature can be combined arbitrarily without contradiction. For the sake of concise description, not all possible combinations of the above technical features are described. However, as long as the combinations of these technical features do not exist in contradiction, they should all be considered as the scope described in this specification.

[0074] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for manipulating nanoparticles based on the principle of acoustic streaming suppression, characterized in that, It includes the following steps: S1. Set a microfluidic chip (100) having a channel (110); S2. Establish a target standing wave sound field in the cross-section of the channel (110), wherein the sound pressure node plane of the target standing wave sound field is parallel to the adjacent side walls of the channel (110); S3. Introduce a fluid containing nanoparticles into the channel (110), and the nanoparticles can be migrated and driven to the sound pressure node region under the action of acoustic radiation force and form a stable aggregated cluster.

2. The nanoparticle manipulation method based on the principle of acoustic streaming suppression according to claim 1, characterized in that In step S1, the microfluidic chip (100) is any one of a glass microfluidic chip, a silicon microfluidic chip, a metal microfluidic chip, and a plastic microfluidic chip.

3. The nanoparticle manipulation method based on the principle of acoustic streaming suppression according to claim 1, characterized in that, In step S2, the target standing wave sound field is established based on the following target acoustic mode: where u L represents the limit velocity, ω represents the angular frequency, u1 represents the first-order acoustic wave velocity, * represents the complex conjugate, and u 1|| represents the component of u1 along the tangential direction of the fluid-solid boundary, || represents the tangential direction of the fluid-solid boundary, and d represents the differential operator.

4. The method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to claim 1, wherein In step S2, the number of the sound pressure nodes is set to one or more, and a radial gradient sound pressure distribution is formed in the target standing wave sound field, which can be used to generate an acoustic radiation force pointing to the sound pressure nodes on the nanoparticles in the fluid in step S3.

5. The method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to claim 1, wherein In step S2, by setting a signal generator and one or more ultrasonic transducers, a sine wave signal is generated by the signal generator and transmitted to the ultrasonic transducers to generate the target standing wave sound field.

6. The method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to claim 5, characterized in that, In step S2, the ultrasonic excitation frequency of the ultrasonic transducer is the resonance frequency of the target standing wave sound field in the channel (110).

7. The method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to claim 1, characterized in that, In step S2, a single-frequency sound field of 1 - 10 MHz is applied to the microfluidic chip (100).

8. The method for manipulating nanoparticles based on the principle of acoustic streaming suppression according to claim 1, wherein In step S3, the radius r of the nanoparticles p is 50 - 500 nm.

9. A manipulation device for the nanoparticle manipulation method according to any one of claims 1 to 8, characterized in that, It includes a microfluidic chip (100), the microfluidic chip (100) is provided with a channel (110), and a sound wave driving structure (200) is installed on the surface of the microfluidic chip (100), and the sound pressure node plane of the standing wave sound field generated by the sound wave driving structure (200) is parallel to the adjacent side walls of the channel (110).

10. The control device according to claim 9, characterized in that, Both ends of the channel (110) are respectively provided with an inlet and an outlet communicating with the outside. A cover glass (300) is provided at the outlet, and a right-angle prism (400) is provided at one end of the outlet. The inclined surface of the right-angle prism (400) faces the outlet, and the inclined surface of the right-angle prism (400) is coated with an aluminum film.

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