Direct electrical measurements on single-molecule genomic DNA using single-walled carbon nanotubes

A unique nanoelectronic platform, based on single-walled carbon nanotubes (SWNTs), has been fabricated for measuring electrical transport in single-molecule DNA. We have tested 80 base pairs of single- and double-stranded DNA (ssDNA and dsDNA, respectively) of complex base sequences. About a 25-40 pA current (at 1 V) was measured for the dsDNA molecule covalently attached to the SWNT electrode at its termini. In the absence of base pair stacking, a ssDNA carries a feeble current of similar to 1 pA or less. Gate-voltage-dependent V V characteristics revealed that the bridging dsDNA molecule acts as a p-type channel between SWNT source and drain electrodes.