Scanning tunneling spectrosopy study of DNA conductivity

Abstract

Abstract:We used STM to study the conductivity of 32 nucleotide long DNA molecules chemically attached to a gold surface. Two oligonucleotides containing all four base types namely G, A, C, T, one single stranded and one double helical, all showed conductance data significantly higher than DNA containing only T and A that were either single stranded d(T32) or double helical d(T32).d(A32) in confirmation. Within each sequence group, the conductivity of the double helical form was always higher than that of the single strand. We discuss the impact of structure, particular base stacking and affinity to the phase transition.PACS (2008) DNA is an important and promising molecule, not only due to its genetic function, but also as a molecular scaffold for nanotechnology [1]. The double helical DNA architecture, is well stacked consisting of near parallel bases stacked with their π-electron systems overlapping. Such π-electron systems may be good candidates for long distance and one-dimensional (linear) charge transport. In- * E-mail: krat@fzu.cz vestigations of DNA conductivity and its physical origin have significant implications towards the study of DNA damage and repair in biological systems, application of DNA in electronic nano-devices, and DNA-based electrochemical biosensors. The electronic transport of various types of organic molecules operating through π-conjugated systems, including DNA, has been the subject of several recent studies, both theoretical and experimental [2][3][4][5]. Despite significant achievements, results on DNA conductivity published by different research groups present often conflicting and controversial explanations of 422

Conductivity of natural and modified DNA measured by scanning tunneling microscopy. The effect of sequence, charge and stacking

“…The DNA molecule, containing the genetic code of all living species, has recently become a center of great attention on the part of chemists and physicists, one of the reasons being DNA's potential use in nanoelectronic devices [1][2][3][4], both as a template for assembling nanocircuits and as an active element of such circuits. Charge migration along DNA molecules has attracted scientific interest for more than fifty years.…”

Study of phenylpyridyldiketopyrrolopyrrole interaction with hydrogen in gas and in acids

“…We have measured the PPDP electrical surface potential in H and Ar atmospheres by using special setting of a scanning probe microscope – a Kelvin probe under a special hood with apertures for gases flowing through narrow pipes 18, 19. In our case, the surface was investigated by scanning Kelvin probe force microscope (KPFM) 20, 21 INTEGRA Prima NT MDT system (Ireland) under ambient conditions.…”

Charge Carrier Mobility in Phthalocyanines: Experiment and Quantum Chemical Calculations

“…In most areas of science, there are free major steps that need to be taken for understanding to be gleaned: the first is synthesis and preparation, the second is measurements and characterization and third is theory and modelling [12][13][14][15][16][17][18][19][20]. The great advance in measurement and characterization was clearly the advent of scanning probe microscopy which permitted measurements both of structure and of transport at the level of one to a few molecules.…”

“…Since then, it took almost 20 years before the first molecular diode was experimentally realized. By now, molecular electronics is a broad field of research world-wide [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…As we have already mentioned the charge transport in molecular electronic materials is a very complex process which can be affected by many physical and chemical parameters; the knowledge of its nature is crucial for the development and optimization of molecular-based devices. Each step forward in understanding and controlling the charge transport is extremely important for the practical applications of molecular systems in electronics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”