In vitro selection of DNA to chloroaromatics using magnetic microbead-based affinity separation and fluorescence detection.

In vitro selection (SELEX) of DNA ligands to the chloroaromatics, 4-chloroaniline (4-CA), 2,4,6-trichloroaniline (TCA) and pentachlorophenol (PCP), was performed by a novel method utilizing magnetic beads (MBs) having a linker arm for immobilization. Use of MBs was advantageous in obviating elution and precipitation of DNA as conjugated MBs with surface-captured template DNA could be directly added to PCR mixtures. In addition, a simplified PCR scheme requiring only one type of primer and a rapid fluorescence microscopic method for assessing nucleic acid binding after each round of SELEX were demonstrated.