Enantioseparation in microfluidic channels

Since the pharmaceutical or biological activity of enantiomers may be significantly different for the two chiral partner molecules, the separation of a racemic mixture into its component enantiomers represents a challenge of immense practical relevance. Established chiral separation techniques rely on the presence of a chiral auxiliary substance. We propose an alternative separation scheme in a microfluidic device without employing such chiral selectors. Using computer simulations and analytical arguments, we reveal that enantiomers migrate with chirality-specific average velocities through a microfluidic channel, provided the driving force field breaks the mirror symmetry. This effect can be exploited for the sorting of chiral molecules. Its origin is attributed to the coupling between rotational and translational degrees of freedom in the molecule motion induced by the nonlinear force fields. Two “basic” types of enantiomers are considered, characterized by mirror-symmetric geometrical conformations and mirror-symmetric charge-distributions in solution.