Electrochemical Sensing at a Confined Space

Abstract

Recently, the rapid developments of sensing methodology, instrumentations, and data analysis methods jointly spurred the growing interests of electrochemistry at a confined space (Figure 1). To present the latest advances in this field, in this review, we mainly cover up-to-date research in electrochemical confinement during the last two years. To provide a full view of this topic for readers, we also selectively cite several representative research before 2017 as well. Herein, we first illustrate typical electrochemically confined spaces, including nano/microelectrode, nanopore, nanopipet, and confined space in other structures. Followed by the discussion of summarized preparation processes and sensing mechanisms of these confined structures, we then highlight the most recent achievements of electrochemically confined space in single entity measurement, from single molecules, single particles, to single cells. Furthermore, we explore the exciting combination of multitechniques at a confined space. Finally, we reach a perspective by presenting the unique requirement of the promising sensors and data mining with brand new capabilities to advance the field of electrochemical sensing at a confined space.Analytical Chemistry pubs.acs.org/ac Review

A Separation‐Sensing Membrane Performing Precise Real‐Time Serum Analysis During Blood Drawing

“…Thea bove-mentioned sensitive detection of five analytes is attributed to the confined effects of nanochannels, whereby regular crystals can serve as many microprobes to promote electrocatalysis on enzyme reactions,D NA,o r antibodies. [27] Based on these results,w ec an conclude that this new type of membrane is widely suitable for various modes of biological recognition, such as enzymatic reactions, DNAh ybridisation, and immune responses,f or the immediate detection of small molecules,enzymes,and biomarkers in whole blood.…”

Four Aspects about Solid‐State Nanopores for Protein Sensing: Fabrication, Sensitivity, Selectivity, and Durability

“…The concept refers to investigation of single entity in a confined space by electrochemical means and is expected to provide additional information related to dynamic electrochemical process (such as redox reactions) and structural features. [ 144,145 ] However, as biological nanopores become commercially available for DNA sequencing, solid‐state nanopores still have a long way to go in precisely differentiating single nucleic acids or amino acids. Innovative materials and fabrication techniques should be developed to produce ultra‐thin, ultra‐small, and ultrastable nanopores.…”

Microscale Electrochemical Cell on a Custom CMOS Transimpedance Amplifier for High Temporal Resolution Single Entity Electrochemistry**

“…At these current scales, the response time of the current amplifier (i. e. its bandwidth) often limits the temporal resolution of the measurement. [17] The current bandwidth and amplifier scale are intimately linked, with efforts to increase the bandwidth introducing higher current noise, which obscures the target electrochemical signal. For instance, commercial current amplifiers operating with an amplification factor of 1 V/nA (1 GΩ) have bandwidths of 10 kHz-50 kHz, but when moving to a current amplification factor of 1 V/pA (1 TΩ) the bandwidth of the current amplifier can drop to just 1 Hz (for example with the DDPCA-300 from FEMTO).…”