Fixed-gap tunnel junction for reading DNA nucleotides.
Previous measurements of the electronic conductance of DNA nucleotides or amino acids have used tunnel junctions in which the gap is mechanically adjusted, such as scanning tunneling microscopes or mechanically controllable break junctions. Fixed-junction devices have, at best, detected the passage of whole DNA molecules without yielding chemical information. Here, we report on a layered tunnel junction in which the tunnel gap is defined by a dielectric layer, deposited by atomic layer deposition. Reactive ion etching is used to drill a hole through the layers so that the tunnel junction can be exposed to molecules in solution. When the metal electrodes are functionalized with recognition molecules that capture DNA nucleotides via hydrogen bonds, the identities of the individual nucleotides are revealed by characteristic features of the fluctuating tunnel current associated with single-molecule binding events.
Biodesign Institute, ‡Department of Physics, §Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287, United States.
Pei
P
Pang
Brian Alan
BA
Ashcroft
Weisi
W
Song
Peiming
P
Zhang
Sovan
S
Biswas
Quan
Q
Qing
Jialing
J
Yang
Robert J
RJ
Nemanich
Jingwei
J
Bai
Joshua T
JT
Smith
Kathleen
K
Reuter
Venkat S K
VS
Balagurusamy
Yann
Y
Astier
Gustavo
G
Stolovitzky
Stuart
S
Lindsay
D004247:DNA / Q000737:chemistry; D004553:Electric Conductivity; D004566:Electrodes; D006860:Hydrogen Bonding; D046210:Microfluidic Analytical Techniques; D016252:Microscopy, Scanning Tunneling / Q000295:instrumentation*; D009711:Nucleotides / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D012825:Silicon / Q000737:chemistry
D009711:Nucleotides; D010165:Palladium; D004247:DNA; D012825:Silicon
DNA sequencing; chemical recognition; recognition tunneling; tunnel junction