Tilted-branch Hydrodynamic Filtration for Length-dependent Sorting of Rod-like Particles

We present here a microfluidic approach to achieve length-dependent sorting of rod-like particles/cells. We have previously developed a technique for continuous and size-dependent separation of particles, named “hydrodynamic filtration (HDF)” [1], and applied it to the shape-based particle sorting [2]. To enhance the effect of either the particle length or width, microchannels having tilted branch channels were employed, and the separation behaviors of rod-like particles were observed. Length-dependent effect was enhanced in the case of steep branch angles, while width-dependent sorting was achieved when the branch angle was gentle. The presented “tilted-branch HDF” is effective to conduct length-dependent sorting of rod-like micro/nanoparticles without necessitating complicated operations and setups.