title: Separation of microscale chiral objects by shear flow.
abstract: We show that plane parabolic flow in a microfluidic channel causes nonmotile, helically shaped bacteria to drift perpendicular to the shear plane. Net drift results from the preferential alignment of helices with streamlines, with a direction that depends on the chirality of the helix and the sign of the shear rate. The drift is in good agreement with a model based on resistive force theory, and separation is efficient (>80%) and fast (<2 s). We estimate the effect of Brownian rotational diffusion on chiral separation and show how this method can be extended to separate chiral molecules.
authors.affiliation: Department of Mechanical Engineering, MIT, Cambridge, Massachusetts 02139, USA.
authors.lastname: Marcos
authors.forename: Henry C
authors.initials: HC
authors.lastname: Fu
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Powers
authors.forename: Roman
authors.initials: R
authors.lastname: Stocker
mesh_terms: D007536:Isomerism; D044085:Microfluidics; D009154:Mutation / Q000235:genetics; D033081:Shear Strength; D013144:Spirochaetales / Q000166:cytology* / Q000648:ultrastructure