Dynamic Chemistry Interactions: Controlled Single-Entity Electrochemistry

Abstract

Single-entity electrochemistry (SEE) provides powerful means to measure single cells, single particles, and even single molecules at the nanoscale by diverse well-defined interfaces. The nanoconfined electrode interface has significantly enhanced structural, electrical, and compositional characteristics that have great effects on the assay limitation and selectivity of single-entity measurement. In this Perspective, after introducing the dynamic chemistry interactions of the target and electrode interface, we present a fundamental understanding of how these dynamic interactions control the features of the electrode interface and thus the stochastic and discrete electrochemical responses of single entities under nanoconfinement. Both stochastic single-entity collision electrochemistry and nanopore electrochemistry as examples in this Perspective explore how these interactions alter the transient charge transfer and mass transport. Finally, we discuss the further challenges and opportunities in SEE, from the design of sensing interfaces to hybrid spectro-electrochemical methods, theoretical models, and advanced data processing.

High-Resolution Low-Power Hyperspectral Line-Scan Imaging of Fast Cellular Dynamics Using Azo-Enhanced Raman Scattering Probes

“…Furthermore, we expect future possibilities for DAERI to synergize with other advanced characterization techniques, such as single-entity electrochemical techniques. Inspired by recent progress of single-entity electrochemistry, − DAERI may provide molecular structure information in both spatial and temporal dimensions combined with transient electrochemical processes of single cells, single particles, or single molecules at nanoconfined electrode interfaces. The diverse azo-type molecular designs and the high signal strength of azo-enhanced Raman probes can potentially relate single-entity electrochemical effects beyond the narrow enhancement zone of SERS obtained on noble metallic surfaces.…”

The new era of high throughput nanoelectrochemistry

“…In selecting material for inclusion in this article, we consider distinct, but related areas, spanning nanopores/pipettes, nanopipette probe microscopy and widefield imaging. These methods are becoming a natural choice for high-throughput single entity nanoelectrochemistry, [7][8][9] where the goal is to detect and analyze, inter alia, single molecules, single cells, and individual particles (and other nanoobjects), as well as to break down the response of complex electrode surfaces and interfaces into a set of simpler elementary features, e.g., terraces, step edges, grain boundaries, etc. Each of the areas we have selected is benefiting from similar developments in experimental capability and analysis tools; there are also efforts to integrate techniques and ideas from each of these areas.…”

Electronic Circuit Simulations as a Tool to Understand Distorted Signals in Single-Entity Electrochemistry

“…The emerging field of “single-entity electrochemistry” (SEE) refers to measurement and interpretation of the electrical transient signals generated when a single entity, e.g., a nanoparticle, a single molecule, a droplet, a micelle, or a living cell, undergoes electrochemical processes at suitable interfaces, including micro- and nano-electrodes or -pipets, nanopores, etc. − The technique’s capability to probe a signal from single entities makes it powerful for delivering both individual and statistical information on these entities. This makes it beneficial for a broad range of investigations, including nanoparticle characterizations and dynamic transformations, − agglomeration study, ion diffusion and solvation studies, , detection and identification of single bacteria or viruses, − catalytic activity investigation of single enzymes, detection of conformation changes of a single DNA, single-molecule detection, battery material characterization, and investigation of the catalytic activity of individual nanoparticles. − …”