Final Activity Report Summary - DNA NANOELECTRONICS (DNA Based Nanoelectronics) Our objective was to study electrical transport in short (12 base pairs) thiol functionalised single DNA molecule. For this purpose we performed transport measurements using the mechanically controllable break junction (MCBJ) technique. Thanks to this method we are able to obtain a reliable value of a single DNA conductance and subsequently measure its current-voltage (I-V) characteristics. The study of transport of short DNA molecules is of fundamental interest for nanotechnology applications. Indeed, the DNA molecule, thanks to its unique intra- and intermolecular recognition properties, is an excellent candidate for use as a building block in molecular electronics. In particular, it has already been used to build-up nanostructures, biomolecule / nanoparticle conjugates or scaffolds for nanoparticles assembly and it can be envisioned for the assembly of devices. In this project, we performed a study of electronic transport in short (12-base-pair) DNA duplexes covalently bonded (via thiol groups) to two gold electrodes obtained by mechanically controllable break junction (MCJB) technique in dry conditions. This method allows obtaining electrodes where their separation is controlled with sub atomic precision. A large number of DNA junctions have been repeatedly formed in order to obtain a conductance histogram that reveals a peak which corresponds to the conductance of a single DNA molecule. We observed that the conductivity of a DNA increases upon increasing the content of G:C base pairs in the duplex. In contrast to the electronic transport measurements performed with long DNA sequences (hundreds of base pairs) where the obtained conductance values vary a lot with the environmental conditions, our values obtained for the short DNA sequences are in consistence with the values reported for the comparable sequences in aqueous solution using the STM break junction method.
