Concentration and separation of dna employing insulator-based dielectrophoresis and DC electric fields uri icon

Abstract

  • Dielectrophoresis (DEP) is an electrokinetic technique where particles move due to polarization effects when exposed to non-uniform electric fields, which can be induced either by direct current (DC) or alternating current (AC). This novel technique has a great potential for miniaturization, and it has been successfully applied for the manipulation of a wide array of bioparticles, from biomolecules to microorganisms. Insulator-based dielectrophoresis (iDEP), a method where non-uniform electric fields are created with arrays of insulating structures, has advantages over the traditional electrode-based DEP such as inexpensive fabrication processes and the ability of employing electroosmotic flow to pump liquid when direct current (DC) electric fields are applied; making miniaturization more viable. In this work, iDEP is used to immobilize and concentrate linear DNA (pET28b) particles inside a microchannel with cylindrical insulating structures fabricated from glass. Results showed successful manipulation of DNA particles with a combination of electroosmotic, electrophoretic and dielectrophoretic forces. DNA particles were observed to be immobilized due to negative dielectrophoretic trapping under applied fields between 500 and 1500 V/cm, in suspending mediums with conductivity of 104 ¿S/cm and pH of 11.15. Finally, concentration factors varying from 8 up to 24 times the feed concentration were measured employing fields of 2000 V/cm after concentration time-periods of 20 and 40 seconds. The results presented here demonstrate the potential of iDEP for DNA concentration, and open the possibility for fast DNA manipulation for laboratory and large-scale applications.

Publication date

  • December 1, 2009