Separation of microscale chiral objects by shear flow.
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.
Marcos
Department of Mechanical Engineering, MIT, Cambridge, Massachusetts 02139, USA.
Fu
Henry C
HC
Powers
Thomas R
TR
Stocker
Roman
R
D007536:Isomerism; D044085:Microfluidics; D009154:Mutation / Q000235:genetics; D033081:Shear Strength; D013144:Spirochaetales / Q000166:cytology* / Q000648:ultrastructure