Liquid–Liquid Extraction of Functional Single‐Stranded DNA Using Reverse Micelles with DNA‐Surfactant

Abstract We describe liquid–liquid extraction of short and single‐stranded DNA using reverse micelles (water‐in‐oil microemulsions) with a DNA‐surfactant. A DNA‐surfactant facilitated extraction of single‐stranded target DNA, transporting a target DNA from an aqueous phase to an organic phase via DNA hybridization. Reverse micelles acted as nanoscale containers that can encapsulate the DNA‐surfactant/target DNA complex in the organic phase. Various parameters (such as co‐surfactant concentration, molecular design of the DNA‐surfactant, and length of the target DNA) during extraction were investigated to optimize the conditions. Finally, a thrombin‐binding DNA aptamer was extracted into an organic phase using the reverse micellar system described and then successfully back extracted into an aqueous phase. A thrombin‐binding assay demonstrated that the back‐extracted DNA aptamer retained its intrinsic binding activity.