On-demand manipulation of nanoparticles in acousto-microfluidics: Investigating surface acoustic wave driven whole system resonances (ResoSAW)

• Applicant: Dr.-Ing. Armaghan Fakhfouri, Ph.D.
• Subject Area: Fluid Mechanics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 514021251

Precise manipulation of submicron particles is a central process to numerous applications in nanotechnology, biology, and medicine, whereby highly selective manipulation is key for preparation, enrichment and quality control. A number of strategies have been employed to achieve size-based manipulation. However, and despite marked improvement in the last decade, research and development on this enabling technology has not reached a conclusion yet and current nanoparticle manipulation tools often suffer from specimen damage, low throughput and high cost. One advanced biomedical technology for nanoscale manipulation could be acoustically driven microfluidics. By providing sufficiently strong forces whilst being non-contact and bio-compatible, acoustic microfluidics offer excellent ability to manipulate bio-particles in a highly controllable manner based on the particle’s intrinsic properties. In such systems, it is critical to establish a careful balance between two competing mechanisms, acoustic radiation and acoustic streaming effects, to realize a selective manipulation. These mechanisms have shown to compete for dominance in acoustic systems, with the cut off being based on the particle size. Whilst larger particles collect in the resonant sound field, smaller particles’ behavior is dictated by the acoustic streaming field. The key challenge in realizing full potential of acoustic technologies for nanoparticles manipulation is to overcome the dominance of acoustic streaming that can be disruptive to the radiation-induced manipulation of nanoparticles. This project aims to explore the fundamental physics of surface acoustic waves driven whole-system resonances in fluid-filled microfluidic channels bound by solid (acoustically “hard”) walls. The innovative approach has at its heart imparting cortical capabilities for acoustic modes excited within a single microfluidic platform, which will allow the creation of complex pressure fields for precise particle and fluid manipulation. In addition, the expected suppression of acoustic streaming is envisaged to facilitate a controlled manipulation of nanoscale particles based on radiation-effect, unlocking new application spaces currently deemed impossible.

• DFG Programme: Research Grants