First-principles study of high-conductance DNA sequencing with carbon nanotube electrodes

摘要: Rapid and cost-effective DNA sequencing at the single nucleotide level might be achieved by measuring a transverse electronic current as single-stranded is pulled through nanometer-sized pore. In order to enhance coupling between nucleotides electrodes hence signals, we employ pair of single-walled close-ended (6,6) carbon nanotubes (CNTs) electrodes. We then investigate electron transport properties sandwiched such using first-principles quantum theory. particular, consider extreme case where separation smallest possible that still allows translocation. The benzene-like ring end cap CNT can strongly couple with nucleobases therefore it both reduce conformational fluctuations significantly improve conductance. As such, when are closely spaced, pass only their base plane parallel caps. optimal molecular configurations, which CNTs, yield largest transmission, first identified. These correspond approximately lowest energy configurations. Then structures these configurations analyzed. typical tunneling currents 50 nA for voltages up 1 V. At higher bias, resonant states possible, several $\ensuremath{\mu}$A. Below V, associated different consistently distinguishable, adenine having current, guanine second largest, cytosine third and, finally, thymine smallest. further calculate transmission coefficient profiles dragged along translocation path effects configurational variations. Based on results, propose protocol combining three data analysis strategies.