Carbon Nanotubes as Electrodes for Dielectrophoresis of DNA

Abstract

.Dielectrophoresis can potentially be used as an efficient trapping tool in the fabrication of molecular devices. For nanoscale objects, however, the Brownian motion poses a challenge. We show that the use of carbon nanotube electrodes makes it possible to apply relatively low trapping voltages and still achieve high enough field gradients for trapping nanoscale objects, e.g., single molecules. We compare the efficiency and other characteristics of dielectrophoresis between carbon nanotube electrodes and lithographically fabricated metallic electrodes, in the case of trapping nanoscale DNA molecules. The results are analyzed using finite element method simulations and reveal information about the frequency dependent polarizability of DNA.

Dielectrophoresis at the nanoscale

“…As suggested by Brody and co-workers [26], carbon nanotubes (CNT) present a natural candidate for DEP nanoelectode due to their small diameter ($1 nm in the case of single-walled carbon nanotube and a few nanometers in the case of multiwalled carbon nanotube). Several groups reported application of CNTs as electrodes for DEP trapping [27][28][29][30][31]. Nanoscale gaps in CNTs can be created by several methods such as FIB lithography [29,30], electrical breakdown [31] or oxidative plasma ablation [32].…”

“…Törmä and co-workers used DEP to assemble 140 nm long DNA molecules between 100 nm spaced electrodes for electrical characterization of DNA [50]. The same group used DNA molecules to test the efficiency of carbon nanotube as an electrode for DEP [28]. In addition, the group studied the polarizability of DNA molecules and its dependence on DEP frequency and DNA length [36].…”

Enhancing the Performance of Surface-based Biosensors by AC Electrokinetic Effects - a Review

“…Due to the field non-uniformity, stretched DNA dielectrophoretically moves towards the electrode edge until one end comes into contact. On the basis of this behaviour many researchers have used AC electrokinetics to manipulate DNA (Walti et al, 2007;Lapizco-Encinas & Palomares, 2007;Washizu et al, 1995Washizu et al, & 2004Dewarrat et al, 2002;Asbury et al, 2002;Washizu, 2005;Tuukkanen et al, 2006;Chou et al, 2002;Kawabata & Washizu, 2001;Yamamoto et al, 2000;Wang et al, 2005). For example, a modified interdigitated microelectrode array, termed "zipper electrode" by the authors, has been reported to concentrate a wide range of nanoparticles of biological interest, such as the influenza virus and DNA (Hübner et al, 2007).…”

Fabrication of bio/nano interfaces between biological cells and carbon nanotubes using dielectrophoresis

“…One important application of CNT forming the high electric field is an electron emission source for the flat panel display device (Bonard et al 2002). CNT is also applicable as a ''nanoelectrode'' generating higher intensity electrical field gradients, which can produce high DEP force without the need for large electrode potentials (Tuukkanen et al 2006). When CNTs are trapped and attached to a microelectrode under positive DEP force as illustrated in Fig.…”