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Séminaire Sampo Tuukkanen

Positioning of DNA using dielectrophoresis and the humidity effects on the electrical conductivity of nanoscale DNA


Sampo Tuukkanen

Laboratoire d’Electronique Moléculaire, DRECAM/SPEC
CEA/Saclay, France

Dielectrophoresis (DEP) of different length DNA fragments (27 bp – 8 kbp) was studied using in situ confocal microscopy. The experimental results combined with the FEM-simulation reveal information about the polarizability of DNA [1]. Confocal microscopy was also applied to study the thiol-based DNA immobilization to gold electrodes [1] and use of carbon nanotube (CNT) for more efficient dielectrophoretic trapping [2] of DNA.

Utilizing the previously developed trapping and immobilization technique, the electrical conductivity of 414 bp long double-stranded DNA was studied on the single molecule level. Increase of the ambient humidity accomplished a remarkable increase in the electrical (DC) conductivity, which was explained by the conformational recovery of the double-helix [3].

[1] S. Tuukkanen, A. Kuzyk, J.J. Toppari, H. Häkkinen, V.P. Hytönen, E. Niskanen, M. Rinkiö, and P. Törmä, Nanotechnology 18, 295204 (2007).

[2] S. Tuukkanen, J.J. Toppari, A. Kuzyk, L. Hirviniemi, V.P. Hytönen, T. Ihalainen, and P. Törmä, Nano Lett. 6, 1339 (2006).

[3] S. Tuukkanen, A. Kuzyk, J.J. Toppari, V.P. Hytönen, T. Ihalainen, and P. Törmä, Appl. Phys. Lett. 87, 183102 (2005).