Filter-less submicron hydrodynamic size sorting for sample pre-treatment
A particularly important function of sample preparation is fractionation, defined as the sorting by size independently of other physical and chemical parameters. A simple, passive sorting method is hydrodynamic filtration. Its principle, as explicated in Figure 1, is based on the exclusion of large objects from the streamlines located close to a wall: after a bifurcation between a main channel and a small lateral one, the lateral output channel contains only small particles. The hydrodynamic filtration method answers an essential constraint related to robustness (critical, for example, for in situ sample preparation): it is less prone to clogging than filter-based geometries, since the minimal dimension of channels can be more than one order of magnitude superior to the critical sorting size.
Revisiting this approach, we propose two original configurations (two-level design and 3D networks of channels) in order to sort sub-micronic particles.
We introduce a new two-level design. It allows drastically reducing the total channel length needed for sub-micron sorting, reduces its footprint, and makes possible its application for reasonable pressures (a fraction of Bar) and residence times (a few minutes). We experimentally validate the extension to the sub-micron regime (exclusion of ~200 nm diameter particles). We also experimentally demonstrate the efficiency of an original 3D configuration, suitable to extract a larger fraction of fluid with similar sorting size.
Filter-less submicron hydrodynamic size sorting, M. Fouet, M.-A. Mader, S. Iraïn, Z. Yanha, A. Naillon, S Cargou, A.-M. Gué, and P. Joseph,
Lab on chip 2016, (16), 4, 720-33