Acoustic focusing in polymeric microfluidic systems 

Contacts:

Kirstine Berg-Sørensen, 4525-3101 (kirstine.berg-sorensen@fysik.dtu.dk)

Peter Barkholt Muller, 4525-3329 (Peter.B.Muller@fysik.dtu.dk)

Henrik Bruus, 4525-3307 (bruus@fysik.dtu.dk) 

 

Sound waves at resonance may be applied for focusing of dielectric beads, or cells, in water in a micrometer size fluidic channel. The ease with which the acoustic focusing is implemented experimentally depends critically on the choice of material and the dimensions of the microfluidic system. We have constructed an experimental setup with microfluidic channels made of polymer materials in which we have demonstrated acoustic focusing of e.g. red blood cells. In this project, you will construct microfluidic systems in PDMS and glass, and conduct experiments of acoustic focusing. Further, you will explore a simple theoretical model to understand the experimental results. The work thus involves both experimental and theoretical efforts.

(A) and (B) shows the design of the microfluidic chamber. In (B) the solid line is the result of a numerical simulation of a standing pressure wave. (C) illustrates the good agreement between experimentally recorded resonance frequencies (blue points) and the theoretical model. Panel (D) is a microscope image of acoustically focused red blood cells, shown between tips of two optical fibers.