Using dielectrophoretic manipulation with nucleic acid sensors

Dielectrophoresis (DEP) arises from the creation of a force acting on an electrically polarized particle when subjected to a non-uniform electric field. Solvated particles can respond to this force by either moving towards (positive DEP) or away (negative DEP) from the electrodes generating the field. The technique can be used to manipulate biological particles including DNA and RNA, opening up new opportunities for nucleic acid based biosensing devices. The aim of the project is to develop a RNA hybridization probe functionalised on a microelectrode, capable of rapid detection and DEP based target sorting. The DEP collection and repulsion of ribosomal RNA on microfabricated interdigitated Au electrodes are observed using total internal reflection (TIRF) microscopy, and measured as a function of the strength and frequency of the applied electric field. The possibility of using quantum dots to increase sensor efficiency is also explored by taking in to consideration the DEP force dependence on particle size and the effect of electrode geometry.