Streching of (DNA/functional molecules) complex between electrodes towards DNA molecular wire

DNA/functional molecules such as (Ru(bpy) 3 2+ complex, conducting polymer etc.) complex was prepared to study molecular structure and I-V characteristics towards DNA molecular wire. For example, Ru(bpy) 3 2+ was associated with duplex of DNA by not only electrostatic interaction but also intercalation in the aqueous solution. Singlemolecular structure of DNA/Ru(bpy) 3 2+ complex was analyzed with AFM. We found a network structure of DNA/Ru(bpy) 3 2+ complex on the mica substrate, which is similar to native DNA. The height of DNA/Ru(bpy) 3 2+ complex on the mica substrate was ranging from 0.8 to 1.6 nm, which was higher than the naked DNA (0.5-1.0 nm). This indicates that single-molecular DNA/Ru(bpy) 3 2+ complex also connects to each other to form network structure on a mica substrate. In order to stretch DNA complex between electrodes, we employed high frequency and high electric field stretching method proposed by Washizu et al. We stretched and immobilized DNA single molecules between a pair of electrodes and its structures were analyzed with AFM technique. The I-V characteristics of DNA single molecules between electrodes were improved by the association of functional molecules with DNA. The molecular structure and I-V characteristics of DNA complex were discussed.