scholarly journals Acoustohydrodynamic tweezers via spatial arrangement of streaming vortices

2021 ◽  
Vol 7 (2) ◽  
pp. eabc7885
Author(s):  
Haodong Zhu ◽  
Peiran Zhang ◽  
Zhanwei Zhong ◽  
Jianping Xia ◽  
Joseph Rich ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Acoustic Streaming ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Spatial Arrangement ◽  
Label Free ◽  
Droplet Transport ◽  
Dimensional Boundary ◽  
Acoustic Tweezers ◽  
Contact Free

Acoustics-based tweezers provide a unique toolset for contactless, label-free, and precise manipulation of bioparticles and bioanalytes. Most acoustic tweezers rely on acoustic radiation forces; however, the accompanying acoustic streaming often generates unpredictable effects due to its nonlinear nature and high sensitivity to the three-dimensional boundary conditions. Here, we demonstrate acoustohydrodynamic tweezers, which generate stable, symmetric pairs of vortices to create hydrodynamic traps for object manipulation. These stable vortices enable predictable control of a flow field, which translates into controlled motion of droplets or particles on the operating surface. We built a programmable droplet-handling platform to demonstrate the basic functions of planar-omnidirectional droplet transport, merging droplets, and in situ mixing via a sequential cascade of biochemical reactions. Our acoustohydrodynamic tweezers enables improved control of acoustic streaming and demonstrates a previously unidentified method for contact-free manipulation of bioanalytes and digitalized liquid handling based on a compact and scalable functional unit.

scholarly journals Three dimensional acoustic tweezers with vortex streaming

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Junfei Li ◽  
Alexandru Crivoi ◽  
Xiuyuan Peng ◽  
Lu Shen ◽  
Yunjiao Pu ◽  
...  
Keyword(s):  
Acoustic Streaming ◽  
Three Dimensional ◽  
Radiation Force ◽  
Two Dimensions ◽  
Single Beam ◽  
Scale Particle ◽  
Acoustic Tweezers ◽  
Third Dimension ◽  
Contact Free ◽  
Micrometer Scale

AbstractAcoustic tweezers use ultrasound for contact-free manipulation of particles from millimeter to sub-micrometer scale. Particle trapping is usually associated with either radiation forces or acoustic streaming fields. Acoustic tweezers based on single-beam focused acoustic vortices have attracted considerable attention due to their selective trapping capability, but have proven difficult to use for three-dimensional (3D) trapping without a complex transducer array and significant constraints on the trapped particle properties. Here we demonstrate a 3D acoustic tweezer in fluids that uses a single transducer and combines the radiation force for trapping in two dimensions with the streaming force to provide levitation in the third dimension. The idea is demonstrated in both simulation and experiments operating at 500 kHz, and the achieved levitation force reaches three orders of magnitude larger than for previous 3D trapping. This hybrid acoustic tweezer that integrates acoustic streaming adds an additional twist to the approach and expands the range of particles that can be manipulated.

scholarly journals Three dimensional acoustic tweezers with acoustic vortex streaming

2021 ◽  
Author(s):  
Junfei Li ◽  
Alexandru Crivoi ◽  
Xiuyuan Peng ◽  
Lu Shen ◽  
Yunjiao Pu ◽  
...  
Keyword(s):  
Acoustic Streaming ◽  
Three Dimensional ◽  
Radiation Force ◽  
Two Dimensions ◽  
Single Beam ◽  
Scale Particle ◽  
Acoustic Tweezers ◽  
Third Dimension ◽  
Contact Free ◽  
Micrometer Scale

Abstract Acoustic tweezers use ultrasound for contact-free manipulation of particles from millimeter to sub-micrometer scale. Particle trapping originated in either radiation forces or acoustic streaming fields. Acoustic tweezers based on single-beam focused acoustic vortices have attracted considerable attention due to their selective trapping capability, but have proven difficult to use for 3D trapping without a complex transducer array and significant constraints on the trapped particle properties. Here we demonstrate the first 3D acoustic tweezer that uses a single transducer and combines the radiation force for trapping in two dimensions with the streaming force to provide levitation in the third dimension. The idea is demonstrated in both simulation and experiments, and the achieved levitation force reaches three orders of magnitude larger than for previous 3D trapping. This hybrid acoustic tweezer that integrates acoustic streaming adds a new twist to the approach and expands the range of particles that can be manipulated.

scholarly journals Three-dimensional manipulation of single cells using surface acoustic waves

2016 ◽  
Vol 113 (6) ◽  
pp. 1522-1527 ◽  
Author(s):  
Feng Guo ◽  
Zhangming Mao ◽  
Yuchao Chen ◽  
Zhiwei Xie ◽  
James P. Lata ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Single Cells ◽  
Surface Acoustic Waves ◽  
Three Dimensional ◽  
Biological Cells ◽  
Acoustic Vibrations ◽  
Label Free ◽  
Acoustic Tweezers ◽  
Contact Free ◽  
Micrometer Scale

The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving “acoustic tweezers” in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner.

An Assessment of Three-Dimensional Turbulent Boundary Layer Prediction Methods

1973 ◽  
Vol 95 (3) ◽  
pp. 415-421 ◽  
Author(s):  
A. J. Wheeler ◽  
J. P. Johnston
Keyword(s):  
Boundary Layer ◽  
Eddy Viscosity ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Boundary Layer Flows ◽  
Mean Velocity ◽  
Eddy Viscosity Model ◽  
Separating Flow ◽  
Dimensional Boundary ◽  
Stress Models

Predictions have been made for a variety of experimental three-dimensional boundary layer flows with a single finite difference method which was used with three different turbulent stress models: (i) an eddy viscosity model, (ii) the “Nash” model, and (iii) the “Bradshaw” model. For many purposes, even the simplest stress model (eddy viscosity) was adequate to predict the mean velocity field. On the other hand, the profile of shear stress direction was not correctly predicted in one case by any model tested. The high sensitivity of the predicted results to free stream pressure gradient in separating flow cases is demonstrated.

scholarly journals Acoustic Tweezers for Particle and Fluid Micromanipulation

2020 ◽  
Vol 52 (1) ◽  
pp. 205-234 ◽  
Author(s):  
M. Baudoin ◽  
J.-L. Thomas
Keyword(s):  
Optical Tweezers ◽  
Acoustic Radiation ◽  
Wide Spectrum ◽  
Acoustic Streaming ◽  
Input Power ◽  
Three Dimensions ◽  
Particle Sizes ◽  
Future Directions ◽  
Acoustic Radiation Pressure ◽  
Acoustic Tweezers

Acoustic tweezers powerfully enable the contactless collective or selective manipulation of microscopic objects. Trapping is achieved without pretagging, with forces several orders of magnitude larger than optical tweezers at the same input power, limiting spurious heating and enabling damage-free displacement and orientation of biological samples. In addition, the availability of acoustical coherent sources from kilo- to gigahertz frequencies enables the manipulation of a wide spectrum of particle sizes. After an introduction of the key physical concepts behind fluid and particle manipulation with acoustic radiation pressure and acoustic streaming, we highlight the emergence of specific wave fields, called acoustical vortices, as a means to manipulate particles selectively and in three dimensions with one-sided tweezers. These acoustic vortices can also be used to generate hydrodynamic vortices whose topology is controlled by the topology of the wave. We conclude with an outlook on the field's future directions.

scholarly journals Measurement of the acoustic streaming pattern in a standing surface acoustic wave field

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sebastian Sachs ◽  
Christian Cierpka ◽  
Jörg König
Keyword(s):  
Wave Field ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Electrical Power ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Radiation Force ◽  
Flow Measurements

The application of standing surface acoustic waves (sSAW) has enabled the development of many flexible and easily scalable concepts for the fractionation of particle solutions in the field of microfluidic lab-ona-chip devices. In this context, the acoustic radiation force (ARF) is often employed for the targeted manipulation of particle trajectories, whereas acoustically induced flows complicate efficient fractionation in many systems [Sehgal and Kirby (2017)]. Therefore, a characterization of the superimposed fluid motion is essential for the design of such devices. The present work focuses on a structural analysis of the acousticallyexcited flow, both in the center and in the outer regions of the standing wave field. For this, experimental flow measurements were conducted using astigmatism particle tracking velocimetry (APTV) [Cierpka et al. (2010)]. Through multiple approaches, we address the specific challenges for reliable velocity measurements in sSAW due to limited optical access, the influence of the ARF on particle motion, and regions of particle depletion caused by multiple pressure nodes along the channel width and height. Variations in frequency, channel geometry, and electrical power allow for conclusions to be drawn on the formation of a complex, three-dimensional vortex structure at the beginning and end of the sSAW.

scholarly journals Label-Free Biomedical Imaging with High Sensitivity by Stimulated Raman Scattering Microscopy

Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1857-1861 ◽  
Author(s):  
Christian W. Freudiger ◽  
Wei Min ◽  
Brian G. Saar ◽  
Sijia Lu ◽  
Gary R. Holtom ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Biomedical Imaging ◽  
Stimulated Raman Scattering ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Raman Microscopy ◽  
Label Free ◽  
Omega 3 ◽  
Low Sensitivity ◽  
Stimulated Raman

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We show a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis.

scholarly journals Pronounced Linewidth Narrowing of Vertical Metallic Split-Ring Resonators via Strong Coupling with Metal Surface

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2194
Author(s):  
Wei Du ◽  
Youcheng Zhu ◽  
Zhendong Yan ◽  
Xiulian Xu ◽  
Xiaoyong Xu ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Ring Resonators ◽  
Label Free ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Dielectric Substrates ◽  
Biomedical Sensing ◽  
Plasmon Polaritons

We theoretically study the plasmonic coupling between magnetic plasmon resonances (MPRs) and propagating surface plasmon polaritons (SPPs) in a three-dimensional (3D) metamaterial consisting of vertical Au split-ring resonators (VSRRs) array on Au substrate. By placing the VSRRs directly onto the Au substrate to remove the dielectric substrates effect, the interaction between MPRs of VSRRs and the SPP mode on the Au substrate can generate an ultranarrow-band hybrid mode with full width at half maximum (FWHM) of 2.2 nm and significantly enhanced magnetic fields, compared to that of VSRRs on dielectric substrates. Owing to the strong coupling, an anti-crossing effect similar to Rabi splitting in atomic physics is also obtained. Our proposed 3D metamaterial on a metal substrate shows high sensitivity (S = 830 nm/RIU) and figure of merit (FOM = 377), which could pave way for the label-free biomedical sensing.

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