2012/05/18 by Shuai Chang, Shuo Huang, Hao Liu +9 · 1 citation
Engineering · Materials Science · #Fuel Cells and Related Materials #Nanopore and Nanochannel Transport Studies #Thermal properties of materials
paper · doi:10.1088/0957-4484/23/23/235101
openalex publication_date 2012/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
4(5)-(2-mercaptoethyl)-1H-imidazole-2-carboxamide is a molecule that has multiple hydrogen bonding sites and a short flexible linker. When tethered to a pair of electrodes, it traps target molecules in a tunnel junction. Surprisingly large recognition-tunneling signals are generated for all naturally occurring DNA bases A, C, G, T and 5-methyl-cytosine. Tunnel current spikes are stochastic and broadly distributed, but characteristic enough so that individual bases can be identified as a tunneling probe is scanned over DNA oligomers. Each base yields a recognizable burst of signal, the duration of which is controlled entirely by the probe speed, down to speeds of 1 nm s -1, implying a maximum off-rate of 3 s -1 for the recognition complex. The same measurements yield a lower bound on the on-rate of 1 M -1 s -1. Despite the stochastic nature of the signals, an optimized multiparameter fit allows base calling from a single signal peak with an accuracy that can exceed 80% when a single type of nucleotide is present in the junction, meaning that recognition-tunneling is capable of true single-molecule analysis. The accuracy increases to 95% when multiple spikes in a signal cluster are analyzed.