Electrical conduction of thiol modified 60bp poly (dG)-Poly(dC) DNA molecules through Au nanoparticles

A novel transport measurement scheme of 60 base pairs of poly (dG) -poly (dC) DNA molecules using Au nanoparticles is devised and implemented. Thiol (-SH) terminations are synthesized at both 5' and 3' ends of the double stranded DNA molecules and they can be chemisorbed on the Au surface through sulfur atoms by covalent bonding. These thiol-modified ends make chemical bindings with Au nanoparticles and Au nano-gap electrodes, forming a stable electrode-DNA-nanoparticle-DNA-electrode conduction channel. This transport channel is self-formed and is stable due to robust bonding of thiol and Au. The current-voltage characteristic measured from our device shows a nonlinear behavior and the voltage gap is comparable to the result of previous experiment using the same molecules. This self-trapping method by thiol modified DNA molecules would also be a promising technique for efficient nanoparticle trapping.