Sophisticated acoustofluidic patterns generated in quasi-Sierpiński-carpet shaped chambers with heterogeneous radiation surface distributions

Abstract

In this research, an original strategy to generate diversified acoustofluidic fields in quasi-Sierpiński-carpet shaped chambers has been proposed and simulated for patterned manipulation of massive micro-scale particles. All of the structural elements in the fractalized chambers are symmetrical in spatial arrangement, and all radiation surfaces possess the same setting of input frequency point and oscillation amplitude along individual normal direction. Plenty of splendid acoustofluidic patterns can be obtained in the originally-static quasi-Sierpiński-carpet shaped chambers generated at different levels of recursion without complicated parameter modulation. The simulation results of acoustofluidic distributions together with micro-scale particle movement trajectories under different oscillation conditions further demonstrate the manipulation functionality of these artificially-designed devices. In comparison with the existing structural design schemes of miniaturized lab-on-a-chip systems, the introduction of fractal features like Sierpiński carpet/triangle and Koch snowflake can provide extraordinary insights and broaden application prospects of acoustofluidics, which is conducive to ultrasonic micro/nano manipulations from simplification to pluralism. The preliminary work shows the possibility of utilizing Sierpiński-type fractal structures as amenable components to customize acoustofluidic fields for the investigation of topographical manipulation of biological samples and orientational manoeuvre of micro/nano-scale machines in ways that are not achievable via traditional approaches.

2D acoustofluidic distributions in micro-chambers modulated by Sierpiński-type structural plates

“…By means of modulating the input frequency point, oscillation waveform, and radiation source surface arrangement of these artificially designed acoustofluidic chambers with different Sierpinśki-type structural plates, diversified acoustic streaming vortices can be generated for noncontact and non-invasive manipulation of micro-/nano-scale particles or biological samples. Compared with the existing method of actively combining/regulating the radiation surface distributions mentioned in our published paper [47], the complicated fractal structures are no longer directly used as the vibration sources in this work. Instead, the quasi/pseudo-Sierpinśki-carpet shaped structural plates located in the sound propagation path can easily induce a variety of acoustic streaming vortices by passively modulating the incident sound field at different input frequency points.…”