Abstract
We present a numerical and experimental study of acoustophoretic manipulation in a microfluidic channel using dual-wavelength standing surface acoustic waves (SSAWs) to transport microparticles into different outlets. The SSAW fields were excited by interdigital transducers (IDTs) composed of two different pitches connected in parallel and series on a lithium niobate substrate such that it yielded spatially superimposed and separated dual-wavelength SSAWs, respectively. SSAWs of a singltablee target wavelength can be efficiently excited by giving an RF voltage of frequency determined by the ratio of the velocity of the SAW to the target IDT pitch (i.e., f = cSAW/p). However, the two-pitch IDTs with similar pitches excite, less efficiently, non-target SSAWs with the wavelength associated with the non-target pitch in addition to target SSAWs by giving the target single-frequency RF voltage. As a result, dual-wavelength SSAWs can be formed. Simulated results revealed variations of acoustic pressure fields induced by the dual-wavelength SSAWs and corresponding influences on the particle motion. The acoustic radiation force in the acoustic pressure field was calculated to pinpoint zero-force positions and simulate particle motion trajectories. Then, dual-wavelength SSAW acoustofluidic devices were fabricated in accordance with the simulation results to experimentally demonstrate switching of SSAW fields as a means of transporting particles. The effects of non-target SSAWs on pre-actuating particles were predicted and observed. The study provides the design considerations needed for the fabrication of acoustofluidic devices with IDT-excited multi-wavelength SSAWs for acoustophoresis of microparticles.
Highlights
In recent years, noninvasive and contactless manipulation of suspended micro-objects has garnered substantial interest [1,2,3,4]
The dual-wavelength standing surface acoustic waves (SSAWs) excited by the interdigital transducers (IDTs) can produce distinct acoustic pressure fields in the water domain confined by the channel
We have investigated acoustophoretic control of particle transport in a microfluidic channel using dual-wavelength SSAWs
Summary
Noninvasive and contactless manipulation of suspended micro-objects has garnered substantial interest [1,2,3,4]. Acoustic manipulation in microfluidic channels has emerged to serve as an effective tool in microfluidics to control micron-sized objects for chemical, physical and biological applications [5,6]. Pure and controllable acoustic forces involved in the acoustic manipulation method produce little or no damage to the viability and functionality of biological cells [7]. A trend in acoustic manipulation methods involves creating a standing acoustic-wave field across a microfluidic channel and employing the resulting acoustic pressure field to transport, trap, separate, pattern or sort microparticles or bio-cells suspended in microfluids [8,9,10,11,12,13,14,15]. With respect to the design of efficient and reproducible devices, increasing attention has been focused on SAW-based microfluidic devices owing to their simple geometry, precise definition of dimensions by micro-fabrication and easy integration with channels composed of soft polymers
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
