Jiaqi Liu, Yuan Yu, Rujun Zhang, Yanru Chen, Yanlong Guo, Yi Zhang, Ran Tao, Jingting Luo, Hairong Zheng, Pingfa Feng, Yongqing Fu, Jianjian Wang, Feiyan Cai
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引用次数: 0
Abstract
Non-contact and label-free acoustic manipulation of particles is crucial for various applications ranging from cell separation and tissue engineering to micromachining and nanofabrication. Surface acoustic waves (SAWs) have been widely used for microscale particle manipulation; their leaky nature in liquid often generates significant bulk acoustic streaming that undermines stable trapping of nanoscale particles. To address this challenge, we introduce an acoustofluidic device comprising a zinc oxide (ZnO) thin film deposited on aluminum foil with one-sided water loading. This design excites quasi-Scholte waves, a specialized nonleaky mode confined to the fluid-solid interface, which effectively suppresses bulk streaming and enables stable nanoparticle trapping. Both theoretical modeling and experiments confirm that the resulting strongly evanescent field operated at 5.11 MHz generates negative vertical forces and strong lateral (in-plane) trapping forces, successfully trapping 250 nm-radius particles on the foil surface. As the particle radius decreases to 150 nm, streaming-induced drag becomes the dominant manipulation mechanism. Operable at low frequencies with a simple and scalable design, our platform offers a versatile route for precise nanoscale particle trapping, with significant potential for bioengineering and nanofabrication applications.
期刊介绍:
Lab on a Chip is the premiere journal that publishes cutting-edge research in the field of miniaturization. By their very nature, microfluidic/nanofluidic/miniaturized systems are at the intersection of disciplines, spanning fundamental research to high-end application, which is reflected by the broad readership of the journal. Lab on a Chip publishes two types of papers on original research: full-length research papers and communications. Papers should demonstrate innovations, which can come from technical advancements or applications addressing pressing needs in globally important areas. The journal also publishes Comments, Reviews, and Perspectives.