title: Distinct mechanisms of DNA sensing based on N-doped carbon nanotubes with enhanced conductance and chemical selectivity.
abstract: N-doped capped carbon nanotube (CNT) electrodes applied to DNA sequencing are studied by first-principles calculations. For the face-on nucleobase junction configurations, a conventional conductance ordering is obtained where the largest signal results from guanine according to its high highest occupied molecular orbital (HOMO) level, whereas for the edge-on counterparts a distinct conductance ordering is observed where the low-HOMO thymine provides the largest signal. The edge-on mode is shown to operate based on a novel molecular sensing mechanism that reflects the chemical connectivity between N-doped CNT caps that can act both as electron donors and electron acceptors and DNA functional groups that include the hyperconjugated thymine methyl group.
authors.affiliation: Graduate School of EEWS KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea.
authors.forename: Han Seul
authors.initials: HS
authors.lastname: Kim
authors.forename: Seung Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Yong-Hoon
authors.initials: YH
authors.lastname: Kim
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis*; D004553:Electric Conductivity; D004566:Electrodes; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry
chemical_list: D037742:Nanotubes, Carbon; D004247:DNA; D009584:Nitrogen
keywords: DNA sequencing; carbon nanotube; electron tunneling; first-principles calculations; molecular sensing