Single‐Molecule Electrical Detection with Real‐Time Label‐Free Capability and Ultrasensitivity

Abstract

Single‐molecule detection based on electricity can realize direct, real‐time, and label‐free monitoring of the dynamic processes of either chemical reactions or biological functions at the single‐molecule/single‐event level. This provides a fascinating platform to probe detailed information of chemical and biological reactions, including intermediates/transient states and stochastic processes that are usually hidden in ensemble‐averaged experiments, which is of crucial importance to chemical, biological, and medical sciences. Here, the focus is on a valuable survey of the state‐of‐art progress in single‐molecule dynamics studies that are based on electrical nanocircuits formed from one‐dimensional nanoarchitectures and molecular‐tunneling junctions. Further interesting applications, useful statistical‐analysis methods, and future promising directions toward the study of chemical‐reaction dynamics and biomolecular activities are also discussed.

Direct observation of single-molecule hydrogen-bond dynamics with single-bond resolution

“…To directly uncover heterogeneous molecular behaviours in chemical and biological reactions that are usually inaccessible in ensemble experiments, several approaches have been developed to realise single-molecule electrical measurements of molecular interactions by using different device architectures, such as nanotubes 17 – 20 , nanowires 21 , 22 , nanopores 23 and STM break junctions 14 . Among these approaches, single-molecule techniques 24 , 25 , in particular graphene electrode-molecule single-molecule junctions (GM-SMJs) 26 , are promising because they are able to covalently integrate individual molecular systems tested as the conductive channel into electrical nanocircuits, thus solving the key issues of the device fabrication difficulty and the poor stability. These techniques prove to be a robust platform of single-molecule electrical detection that is capable of probing the dynamic processes of chemical reactions at the single-event level with high temporal resolution and high signal-to-noise ratios, for example photoinduced conformational transition 27 , temperature-dependent σ-bond rotation 28 and host–guest interaction 29 .…”

The Characterization of Electronic Noise in the Charge Transport through Single‐Molecule Junctions

“…Guo et al. have made much progress in this field, [ 69 ] and although they did not point out that these studies were based on noise characterization, their analysis of the two‐level or multilevel signals was similar to that of RTS noise. Therefore, we consider these studies as one kind of RTS noise characterization.…”

Functional molecular electronic devices through environmental control

“…However, the advantages of single-molecule devices are their small size and their ability to reflect the unique behaviors of individual molecules. Notably, a special technique that combines chemical stimuli with high time-resolution acquisition was developed to monitor single-molecule junctions [30]. By real-time measurement, the dynamic process of chemical reactions can be revealed at the single-molecule/single-event level.…”