Chiral Discrimination of Ofloxacin Enantiomers Using DNA Double Helix Regulated by Metal Ions

DNA‐based chiral selectors are constructed to discriminate ofloxacin enantiomers through metal‐ion anchoring on a special DNA double helix that contains successive GC pairs. The effects of metal ions involving Mg²⁺, Ni²⁺, Cu²⁺, Ag⁺, and Pt²⁺ were studied on the regulation of DNA chiral discrimination towards ofloxacin enantiomers. It is shown that DNA‐Cu(II) complexes exhibit the highest enantioselectivities at the [Cu²⁺]/base ratio of 0.1. The enantiomeric excess can reach 59% in R‐enantiomer after being adsorbed by the RET‐Cu(II) complex. Stereoselective recognition of ofloxacin enantiomers on the double helix is tunable via external stimulus, providing a programmable desorption process to regenerate DNA. This DNA‐based chiral selector exhibits excellent reusability without apparent loss of enantioselectivity after three cycles of adsorption and desorption. Chirality 26:249–254, 2014. © 2014 Wiley Periodicals, Inc.