Acoustophoretic manipulation of sub-micron objects enabled by density gradients
Direct and precise manipulation of sub-micron particles such as bacteria, platelets, organelles, microvesicles, exosomes or virus particles is challenging. We describe for the first time how acoustic streaming in the bulk can be efficiently reduced by introducing a density or compressibility gradient and that this enables focusing of 500-nm-diameter particles in a standard acoustophoresis channel.