Photoacoustic forceps

Abstract

The application discloses a method and device for realizing capturing and manipulating particles, and belongs to the field of acoustic control and manipulation. In view of the fact that the prior art cannot realize contactless, flexible, selective and universal manipulation method of particles, the application discloses a photoacoustic tweezers, a strong sound wave and a weak sound wave are generated by using a double-mode transducer, the strong sound wave is used as a gain medium to amplify the acoustic radiation force of the weak sound wave, enhanced acoustic radiation force is generated through interference of the strong sound wave and the weak sound wave, and the capturing and manipulation of particles are realized. The application can be used for simultaneous manipulation of multiple particles, realizes high throughput, and can manipulate particles of different sizes from 1 mu m to 1 mm. A reconfigurable sound field can be generated without a complex acoustic array, and flexible manipulation is realized. Through adjustment of the phase difference between the strong sound wave and the weak sound wave, the direction of the acoustic radiation force can be reversed. The application is a flexible, biocompatible, selective and high-throughput manipulation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acoustic manipulation, and more particularly, to a method and device for capturing and manipulating particles. BACKGROUND

[0002] Arthur Ashkin first disclosed the optical method for capturing and manipulating particles in 1986, which uses the force generated by a strong focusing light beam to capture and move objects with sizes ranging from tens of nanometers to tens of microns. This method can achieve high spatial resolution and high selectivity of particle manipulation, but it is still difficult to manipulate particles larger than 1 μm due to the small capture force. And the use of high-intensity laser and high-numerical-aperture objective lens is easy to cause overheating damage to cells or other organisms. Some alternative methods that are more biocompatible than optical methods have also been explored, such as magnetic methods, electrical methods (electrophoresis, dielectrophoresis), fluid mechanics methods, and acoustic methods. These methods can be used for the capture, focusing, and ordering of various particles. Acoustic tweezers are not affected by the electrical, optical, and magnetic properties of the medium when applied, and are a label-free particle manipulation method.

[0003] The prior art has not yet had an ideal solution for realizing biocompatibility, non-standard, medium insensitivity, selectivity, and high-throughput particle manipulation. For example, the magnetic field method requires the coupling of magnetic particles with antibodies on the surface of the particles to be manipulated for labeling, and the design of antibodies is costly and labor-intensive, and needs to be adjusted differently according to different cell types. And this method has low resolution because it requires high magnetic field gradients so that magnetic particles or magnetically labeled particles / cells can be attracted to high magnetic fields. It is challenging to achieve high resolution with the current method.

[0004] The electric field method is only suitable for poor conductive media, and this method is associated with the polarizability of the particles and the conductivity of the medium, and an unsuitable medium can easily affect the cell activity. Electrophoresis (EP) is the movement of a charged surface relative to a stationary liquid, which requires a relatively low conductivity of the liquid, so this method is limited by the particles and the liquid. Dielectrophoresis (DEP) relies on the dielectric force acting on the dielectric particles in a non-uniform electric field. The requirements of low conductivity medium and particle polarization limit the application of dielectric method.

[0005] The fluid mechanics method mainly uses fluid flow to control particles by balancing the opposing lateral forces acting on the particles in the microchannel. This method has the characteristics of high throughput and high efficiency, but is limited by the structure of the microchannel and the concentration of the particles.

[0006] Acoustic methods use acoustic waves to non-contact manipulate particles from nanometer to millimeter in size. Since the speed of light is five orders of magnitude greater than the speed of sound, at the same power density, acoustic methods can provide 100,000 times greater force than optical methods. However, acoustic methods have poor selectivity, even the latest research of selective acoustic vortex transducers can only achieve low flux manipulation, and can only manipulate one particle at a time.

[0007] Different non-contact particle manipulation methods are compared as shown in Table 1 below:

[0008] Table 1

[0009]

[0010] Therefore, there is no ideal method for particle manipulation at present. In principle, to achieve selective and flexible particle manipulation, a programmable acoustic array or mechanical movement of the sound source must be designed. However, acoustic array-based manipulation requires ultra-high-end multi-channel electronics, and even a transducer with a resolution as low as 32*32 is prohibitive. Mechanical movement-based manipulation of sound sources is prone to wear and tear, and almost no overlap between multiple sound sources is allowed, so that particle assembly applications cannot be achieved. Therefore, the method for accurate, non-contact, flexible and selective manipulation of cells and particles is still under research. In particular, a universal method that can selectively operate multiple microparticles and manipulate particles of various sizes at the same time has not been proposed. This also hinders the assembly and manipulation of particles, as this application requires the simultaneous selective manipulation of multiple particles.

[0011] At present, people can use light to generate sound waves, which is called photoacoustic method (PA) to replace complex miniaturized transducer arrays. This method uses pulsed laser irradiation on materials with high light absorption to generate transient heat, which causes thermal expansion and thus generates sound waves. The photoacoustic method (PA) has diversity in substrate material selection and aperture size selection, and can generate sound waves with high amplitude and high frequency. The light-generated sound wave mode can be customized by adjusting the light signal mode, without the need for complex acoustic arrays. However, this method has low light-to-sound conversion efficiency, and most of the light is converted into heat rather than sound waves, and is prone to high temperature, affecting cell activity. SUMMARY

[0012] The purpose of the present application is achieved by the following technical solutions.

[0013] In order to solve the problem that the prior art cannot realize non-contact, flexible, selective and universal manipulation of particles, the present application discloses a photoacoustic tweezers, which is a dual-mode transducer, also known as an electro / photoacoustic device, generates a strong acoustic wave and a weak acoustic wave, the weak acoustic wave provides spatial information and spatial movement information of the manipulated particles, and the strong acoustic wave acts as a gain medium to amplify the acoustic radiation force of the weak acoustic wave, so that the strong acoustic wave and the weak acoustic wave are interfered to generate enhanced acoustic radiation force, and the particles are captured and manipulated.

[0014] A method for capturing and manipulating particles, a dual-mode transducer is driven to generate a weak acoustic wave and a strong acoustic wave, the weak acoustic wave and the strong acoustic wave are interfered, the strong acoustic wave acts as a gain medium to amplify the acoustic radiation force of the weak acoustic wave, so that the particles are captured and manipulated; wherein the amplitude of the strong acoustic wave is greater than the amplitude of the weak acoustic wave.

[0015] The dual-mode transducer comprises an electroacoustic transducer unit and a photoacoustic transducer unit.

[0016] The photoacoustic transducer unit excited by the light signal mode generates a weak acoustic wave field through the photoacoustic effect. The light signal mode can be a laser spot or a more complex mode, which can be obtained by optomechanical modulation, including but not limited to a spatial light modulator, an acousto-optic modulator, a Pockels unit, a piezoelectric and micromechanical deformation mirror array, a galvanometer, a translation platform, etc.

[0017] The strong acoustic wave is generated by driving the electroacoustic transducer unit. Preferably, the strong acoustic wave is driven by a sine wave.

[0018] The strong acoustic wave is a plane wave.

[0019] The amplitude and phase of the strong acoustic wave in the manipulation area are spatially uniform.

[0020] The uniform phase of the strong acoustic wave means that the phase change is not more than π / 2, preferably the phase change of the strong acoustic wave is not more than π / 6, and even not more than π / 10. The amplitude change of the strong acoustic wave is not more than the amplitude change of the weak acoustic wave, preferably the amplitude change of the strong acoustic wave is not more than 10% of the amplitude change of the weak acoustic wave.

[0021] The strong acoustic wave is synchronized with the weak acoustic wave.

[0022] Preferably, when the ratio of the size of the manipulated particles to the wavelength of the generated acoustic wave is less than 1, the synchronization of the strong acoustic wave and the weak acoustic wave exists an adjustable excitation delay between the electroacoustic transducer unit and the photoacoustic transducer unit.

[0023] Preferably, the direction of the acoustic radiation force of the particles is reversed by adjusting the phase difference between the strong acoustic wave and the weak acoustic wave.

[0024] The direction of the acoustic radiation force of the particle can be reversed by adjusting the phase difference between the weak acoustic wave and the strong acoustic wave, which can be changed by adjusting the excitation delay of the electro-acoustic transducer unit and the photo-acoustic transducer unit. That is, changing the phase difference can reversely change the acoustic radiation force of the particle from an attractive force (repulsive force) to a repulsive force (attractive force).

[0025] The weak acoustic wave is generated by driving the photo-acoustic transducer unit by a pulsed laser.

[0026] The particle includes a polystyrene particle, a bubble, a droplet, or a biological particle.

[0027] Preferably, the biological particle includes a cell, a microorganism, or a small tissue block. The biological particle includes a cell, an organic tissue, DNA, an embryo, a protein, or a virus, and a small tissue block such as an organelle or a DNA particle. Compared with the existing conventional optical tweezers method, the present application uses a small laser power, avoids cell damage caused by excessive temperature, and can better protect the viability of the cell.

[0028] A non-contact operation system includes a signal generator and an electro / photo-acoustic device, the electro / photo-acoustic device includes an electro-acoustic transducer unit and a photo-acoustic transducer unit; the signal generator is used to excite the electro / photo-acoustic device, the electro-acoustic transducer unit generates a strong acoustic wave by signal excitation, and the photo-acoustic transducer unit generates a weak acoustic wave by signal excitation, the weak acoustic wave provides spatial information and particle spatial movement information of the manipulated particle, and the strong acoustic wave amplifies the acoustic radiation force of the weak acoustic wave as a gain medium, so as to realize the capture and manipulation of the particle.

[0029] Preferably, the photo-acoustic transducer unit includes a nanoparticle-polydimethylsiloxane (PDMS) composite with spectral selectivity for converting a laser pulse into a photo-acoustic pulse.

[0030] Preferably, the nanoparticle is a gold nanoparticle (AuNP) for absorbing a nanosecond pulse with a wavelength of 510-540 nm.

[0031] Preferably, the electro-acoustic transducer unit includes a transparent ITO electrode, which can be used to observe the particle manipulation when the system is placed under a microscope.

[0032] Compared with the prior art, the novel tweezers of the present application has the following advantages:

[0033] (1) The present application uses a lower power laser than the optical tweezers, does not require cell labeling treatment or direct contact between the laser and the cell, and can avoid damage to the cell caused by excessive temperature;

[0034] (2) The present application can flexibly reconstruct the acoustic field pattern, can simultaneously manipulate multiple particles and particles of various sizes from 1 μm to 1 mm, and can realize high-throughput particle manipulation, such as particle assembly function.

[0035] (3) The photoacoustic tweezers can change the direction of acoustic radiation force by adjusting the phase difference between strong sound wave and weak sound wave, so as to realize attraction and repulsion of particles;

[0036] (4) The method does not need complex sound array or mechanical movement of sound source to realize selective control, and is a method of combining biocompatibility, non-labeling, medium insensitivity, selectivity and high-throughput non-contact particle control. BRIEF DESCRIPTION OF DRAWINGS

[0037] The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein like elements and components are numbered alike and references are made to them throughout. Details of the application with regard to its construction and operation can best be understood by reference to the accompanying drawings, wherein the same reference numerals and letters refer to the same elements throughout.

[0038] Figure 1 The schematic diagram of the gain medium photoacoustic tweezers of the application is disclosed.

[0039] Figure 2 The schematic diagram of the photoacoustic tweezers prepared in Example 1 of the application is disclosed.

[0040] Figure 3 The schematic diagram of the photoacoustic tweezers prepared in Example 2 of the application is disclosed.

[0041] Figure 4 The schematic diagram of the sound wave signal excitation and photoacoustic signal excitation of the application is disclosed.

[0042] The labels shown in the figure are:

[0043] 100, glass slide; 101, medium; 102, particle; 103, piezoelectric material; 104, PDMS microchannel; 105, AuNP-PDMS photoacoustic composite material; 106, ITO electrode; 107, PDMS; 108, piezoelectric ceramic. DETAILED DESCRIPTION

[0044] The application will be described in detail below with reference to the accompanying drawings and specific examples.

[0045] Example 1:

[0046] Figure 1 The schematic diagram of the gain medium photoacoustic tweezers of the application is disclosed. The application discloses a method for realizing enhancement of photoacoustic tweezers trapping force by constructing gain medium amplification of weak sound wave to realize acoustic radiation force.

[0047] As Figure 1As shown in a, a transparent indium tin oxide (ITO) electrode 106 is coated on a lithium niobate (Y-cut 36° LiNbO3) piezoelectric material 103 as an electro-acoustic transducer unit, a polydimethylsiloxane (PDMS) 107 is spin-coated on the electro-acoustic transducer unit as an intermediate layer, and an AuNP-PDMS photo-acoustic composite material 105 is prepared by generating gold nanoparticles on the surface of the intermediate layer through an in-situ synthesis method as a photo-acoustic transducer unit. The electro-acoustic transducer unit generates a strong acoustic wave through a sine burst pulse drive, and the photo-acoustic transducer unit is driven by a laser pulse to generate a weak acoustic wave through thermal expansion. The particles 102 are suspended in the medium 101. In this embodiment, the medium 101 is taken as water, and the particles 102 are taken as cells.

[0048] As shown in a, a transparent indium tin oxide (ITO) electrode 106 is coated on a lithium niobate (Y-cut 36° LiNbO3) piezoelectric material 103 as an electro-acoustic transducer unit, a polydimethylsiloxane (PDMS) 107 is spin-coated on the electro-acoustic transducer unit as an intermediate layer, and an AuNP-PDMS photo-acoustic composite material 105 is prepared by generating gold nanoparticles on the surface of the intermediate layer through an in-situ synthesis method as a photo-acoustic transducer unit. The electro-acoustic transducer unit generates a strong acoustic wave through a sine burst pulse drive, and the photo-acoustic transducer unit is driven by a laser pulse to generate a weak acoustic wave through thermal expansion. The particles 102 are suspended in the medium 101. In this embodiment, the medium 101 is taken as water, and the particles 102 are taken as cells. Figure 1 As shown in b, when only a sine burst pulse is applied to the electro-acoustic transducer unit, a strong acoustic wave is generated, which acts on the water medium 101 as a gain medium, and the sine burst pulse is a solid line waveform as shown in b. The strong acoustic wave is spatially uniform, so as shown in c, the resultant force acting on the particles 102 is zero. When only a laser pulse is applied to the photo-acoustic transducer unit, a weak acoustic wave is generated, as shown by a dashed line waveform in d. As shown in e, the acoustic radiation force of the weak acoustic wave is small, so the particles 102 cannot be manipulated. As shown in f, the present application amplifies the acoustic radiation force of the weak acoustic wave by using the strong acoustic wave as a gain medium 101, generates a resultant force F as shown in g, and realizes the capture and manipulation of the particles 102. The direction of the resultant force can be reversed by adjusting the phase difference between the strong and weak acoustic waves, and the manipulation of the particles 102 appears as attraction or repulsion. Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1

[0049] In this embodiment, the capture of the photo-acoustic tweezers is realized by constructing an effective gain medium 101 to enhance the acoustic radiation force of the weak acoustic wave. The frequency range of the strong acoustic wave is 1 Hz to 1 GHz, and the amplitude range is 1 Pa to 10 10 Pa.

[0050] The strong acoustic wave cannot make the particles 102 move in a plane perpendicular to the propagation axis (hereinafter referred to as a transverse plane or a manipulation plane). In this embodiment, the frequency range of the weak acoustic wave is 1 Hz to 1 GHz, and the amplitude range is 1 Pa to 10 ８ Pa, and the amplitude of the strong acoustic wave is greater than that of the weak acoustic wave.

[0051] ​​​​​​By adjusting the acoustic signal pattern of the weak sound wave, selective, multi-functional and high-throughput particle manipulation can be achieved. This acoustic signal pattern adjustment is achieved by a tunable light signal pattern to excite the opto-acoustic transducer unit. The light signal pattern can be a laser spot or more complex pattern, which can be modulated by opto-mechanical means, including but not limited to spatial light modulators, acousto-optic modulators, Pockels cells, piezoelectric and micro-mechanical deformable mirror arrays, galvanometer mirrors, translation stages, etc.

[0052] In this embodiment, the weak sound wave and the strong sound wave interfere to generate a non-uniform spatial sound field of the movable particles 102, and the amplitude of the interference sound field is proportional to the product of the amplitudes of the strong and weak sound waves. Because the strong sound wave is spatially uniform in the manipulation region, the water medium 101 acted on by the strong sound wave field can be regarded as a constant gain of the weak sound wave. In other words, the medium 101 in the uniform strong sound wave field is a gain medium 101 of the acoustic radiation force of the weak sound wave.

[0053] Figure 2 The figure shows a schematic diagram of the opto-acoustic tweezers prepared in Example 1. A transparent indium tin oxide (ITO) electrode 106 is coated on a lithium niobate (Y-cut 36° LiNbO3) piezoelectric material 103 as an electro-acoustic transducer unit, a polydimethylsiloxane (PDMS) 107 is spin-coated on the electro-acoustic transducer unit as an intermediate layer, and an AuNP-PDMS composite material 105 is prepared by generating gold nanoparticles on the surface of the intermediate layer through an in-situ synthesis method. The opto-acoustic composite material serves as an opto-acoustic transducer unit. The manipulation medium containing the target manipulation particles 102 is above the electro-acoustic transducer unit and the opto-acoustic transducer unit. The electro-acoustic transducer unit generates a strong sound wave by driving a sine burst pulse, and the opto-acoustic transducer unit generates a weak sound wave by thermal expansion under the excitation of a laser pulse. The strong and weak sound waves interfere effectively in the manipulation medium 101, and the strong sound wave amplifies the acoustic radiation force of the weak sound wave to achieve the capture and manipulation of the particles 102.

[0054] This embodiment describes a specific implementation method of a gain medium amplifying acoustic radiation force. The medium containing the target manipulation particles 102 is above the opto-acoustic tweezers formed by assembling the electro-acoustic transducer unit and the opto-acoustic transducer unit together through the intermediate layer. Other methods that can achieve the gain of the medium also belong to the protection scope of the present application. The method of realizing the weak sound wave is generated by low-intensity laser pulse irradiation of the opto-acoustic composite material. The opto-acoustic composite material serves as an opto-acoustic transducer unit, which converts a laser pulse into an opto-acoustic pulse to generate a weak sound wave. This method can achieve the capture and manipulation of particles 102 in the size range of 1 μm to 1 mm.

[0055] Figure 4 is a schematic diagram of the sine burst pulse signal for generating a strong sound wave and the opto-acoustic pulse signal for generating a weak sound wave according to the present application. The specific analysis is as follows. The pressure and velocity of the strong sound wave are set as p (Z) and v(Z) Similarly, the pressure and velocity of the weak acoustic wave are set as p (L) and v (L) This embodiment is not limited to the method of generating waves, and other methods of generating waves that achieve the same effect are also applicable, provided that the Z field of the strong acoustic wave is at least one order of magnitude stronger than the L field of the weak acoustic wave.

[0056] The total field of the combination of the strong acoustic wave and the weak acoustic wave generated by the two driving signals is:

[0057]

[0058] As mentioned above, in a non-uniform electric field, the expression of the acoustic radiation force of the particle 102 pulse sound field on the small sphere is:

[0059]

[0060] The acoustic radiation force potential U is calculated using the Gor'kov formula:

[0061]

[0062] In formula (3), p c 0 represents the speed of sound in the fluid medium, p 0 represents the density of the fluid medium, and represent the monopole and dipole scattering parameters. The pressure p p and the velocity v v in formulas (1a) and (1b) are brought into formula (3), and (L) 2 is ignored. It is assumed that the strong acoustic field is a plane wave propagating in the z direction with uniform amplitude, v (Z) = v z (Z) e z , U = U (ZZ) + U (ZL) is obtained, U (ZZ) is the uniform Gor'kov acoustic radiation force potential, so its gradient is zero, and U is mainly dominated by U (ZL) In order to analyze and evaluate the mixed radiation force potential U (ZL) , we only consider the strongest harmonic of the L field, and set the phase reference on the Z pressure field. Note that the Z acoustic field is a plane wave, and its average pressure field and average velocity field are p

[0063]

[0064] where is a controllable spatial uniform phase difference, which is generated by the excitation delay of the strong and weak acoustic waves. Here, it is obvious that the background pressure field p (Z)Consider it as a uniform gain of the mixed acoustic radiation potential energy. Through trigonometric transformation, we obtain:

[0065]

[0066] The radiation force component along the x-direction (the y-direction will produce a completely similar result):

[0067]

[0068] Equation (6a) discloses the following: First, the acoustic radiation force can be proportionally amplified by strong sound waves; second, the direction of the acoustic radiation force can be reversed by adjusting the phase difference between the strong sound wave Z field and the weak sound wave L field.

[0069] This invention utilizes strong sound waves to construct a gain medium, thereby amplifying the acoustic radiation force of weak sound waves to achieve particle capture and manipulation. Strong and weak sound waves are acoustically connected through the manipulation medium, producing effective interference.

[0070] Example 2

[0071] This embodiment is based on the same principle as Embodiment 1, except that the medium 101 containing the target manipulated particle 102 is located between the electroacoustic transducer unit and the photoacoustic transducer unit in this embodiment.

[0072] like Figure 3 The schematic diagram of the photoacoustic tweezers in this embodiment shows a piezoelectric ceramic 108 bonded to a transparent glass slide 100 as an electroacoustic transducer unit. The AuNP-PDMS composite material 105 is prepared by in-situ synthesis of gold nanoparticles on the inner surface of a PDMS microchannel 104, serving as the photoacoustic transducer unit. A manipulation medium 101 containing the target manipulated particle 102 is located between the photoacoustic and electroacoustic transducer units. The electroacoustic transducer unit generates a strong acoustic wave driven by a sinusoidal burst pulse, while the photoacoustic transducer unit converts a laser pulse into a photoacoustic pulse to generate a weak acoustic wave. The strong and weak acoustic waves are acoustically connected through the manipulation medium 101, and effective interference occurs within this medium. The strong acoustic wave amplifies the acoustic radiation force of the weak acoustic wave, enabling precise and flexible capture and manipulation of the particle 102.

[0073] This embodiment describes a specific method for amplifying acoustic radiation force using a gain medium. The medium 101 containing the target manipulation particle 102 is located between the electroacoustic transducer unit and the photoacoustic transducer unit. Any other method that can achieve the gain of this medium is within the protection scope of this invention.

[0074] The above description of the application and its embodiments is illustrative and not restrictive, and the application can be practiced in other specific forms without departing from the spirit or essential character thereof. The drawings are intended to be illustrative, and not limiting, and the appended claims should not be limited to the drawings. Thus, if a person of ordinary skill in the art is inspired to design a similar structure and embodiment to the technical solution without departing from the spirit of the invention, it should be within the scope of protection of the patent. In addition, the word "comprising" does not exclude other elements or steps, and the word "one" before an element does not exclude the inclusion of "multiple" such elements. Multiple elements stated in a product claim can also be implemented by one element through software or hardware. The words "first", "second", etc. are used to indicate names, not any specific order.

Claims

1. A method of trapping and manipulating particles, characterized by, The driving bimodal transducer generates a weak sound wave and a strong sound wave, the weak sound wave and the strong sound wave interfere, the strong sound wave amplifies the acoustic radiation force of the weak sound wave as a gain medium, and the particle capture and manipulation are realized; wherein the amplitude of the strong sound wave is greater than the amplitude of the weak sound wave.

2. The method of claim 1, wherein, The strong sound wave is generated by driving the electro-acoustic transducer unit.

3. A method of trapping and manipulating particles according to claim 2, wherein, The amplitude and phase of the strong sound wave in the manipulation region are spatially uniform.

4. The method of claim 2, wherein, The strong sound wave is a plane wave.

5. The method of claim 1, wherein, The strong sound wave is synchronized with the weak sound wave.

6. A method of trapping and manipulating particles according to claim 5, wherein, When the size of the manipulated particle is less than 1 times the wavelength of the sound wave, the synchronization of the strong sound wave and the weak sound wave has an adjustable excitation delay between the electro-acoustic transducer unit and the photo-acoustic transducer unit, which is used to adjust the phase difference between the strong sound wave and the weak sound wave.

7. A method of trapping and manipulating particles according to claim 6, wherein, The direction of the acoustic radiation force of the particle is reversed by changing the phase difference between the strong sound wave and the weak sound wave.

8. The method of claim 3, wherein, In the manipulation region, the phase change of the strong sound wave is not more than π / 2, and the amplitude change of the strong sound wave is not more than the amplitude change of the weak sound wave.

9. The method of claim 1, wherein, The weak sound wave field can be adjusted to generate a capture force for all particles or part of the particles.

10. The method of capturing and manipulating particles of claim 9, wherein, The adjustment of the weak sound wave field is realized by adjusting the light signal mode.

11. The method of capturing and manipulating particles of claim 9, wherein, The weak sound wave is generated by photo-acoustic conversion of the adjustable light signal mode, and the light source is a pulsed laser generator.

12. The method of claim 1, wherein, The particles include polystyrene particles, bubbles, droplets or biological particles.

13. The method of capturing and manipulating particles of claim 12, wherein, Biological particles include cells, microorganisms or small tissue blocks.

14. A contactless steering system, characterized by The system includes a signal generator and an electro-opto-acoustic device, the electro-opto-acoustic transducer includes an electro-acoustic transducer unit and a photo-acoustic transducer unit, the signal generator is used to excite the electro-opto-acoustic device, the electro-acoustic transducer unit generates a strong sound wave by signal excitation, the photo-acoustic transducer unit generates a weak sound wave by signal excitation, the strong sound wave amplifies the acoustic radiation force of the weak sound wave as a gain medium, and the particle capture and manipulation are realized.

15. A touchless steering system according to claim 14, characterized in that The photo-acoustic transducer unit includes a nanoparticle-polydimethylsiloxane composite with spectral selectivity for converting laser pulses into photo-acoustic pulses.

16. A touchless steering system according to claim 15, characterized in that The nanoparticles are gold nanoparticles for absorbing nanosecond pulses with a wavelength of 510 nm-540 nm.

17. The non-contact manipulation system according to claim 16, wherein the electro-acoustic transducer unit includes a transparent ITO electrode, and the transparent electrode can be used to observe the particle manipulation when the system is placed under a microscope.

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