Single Entity Electrochemistry in Nanopore Electrode Arrays: Ion Transport Meets Electron Transfer in Confined Geometries

Journal Article · Tue Jan 28 04:00:00 EST 2020 · Accounts of Chemical Research

DOI:https://doi.org/10.1021/acs.accounts.9b00543· OSTI ID:1762420

Fu, Kaiyu ^[1]; Kwon, Seung-Ryong ^[2]; Han, Donghoon ^[3]; Bohn, Paul W. ^[2]

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1. Stanford Univ., CA (United States); University of Notre Dame
2. Univ. of Notre Dame, IN (United States)
3. The Catholic Univ. of Korea, Gyeonggi-do (Korea)

Electrochemical measurements conducted in confined volumes provide a powerful and direct means to address scientific questions at the nexus of nanoscience, biotechnology, and chemical analysis. How are electron transfer and ion transport coupled in confined volumes and how does understanding them require moving beyond macroscopic theories? Also, how do these coupled processes impact electrochemical detection and processing? We address these questions by studying a special type of confined-volume architecture, the nanopore electrode array, or NEA, which is designed to be commensurate in size with physical scaling lengths, such as the Debye length, a concordance that offers performance characteristics not available in larger scale structures. The experiments described here depend critically on carefully constructed nanoscale architectures that can usefully control molecular transport and electrochemical reactivity. We begin by considering the experimental constraints that guide the design and fabrication of zero-dimensional nanopore arrays with multiple embedded electrodes. These zero-dimensional structures are nearly ideal for exploring how permselectivity and unscreened ion migration can be combined to amplify signals and improve selectivity by enabling highly efficient redox cycling. Our studies also highlight the benefits of arrays, in that molecules escaping from a single nanopore are efficiently captured by neighboring pores and returned to the population of active redox species being measured, benefits that arise from coupling ion accumulation and migration. These tools for manipulating redox species are well-positioned to explore single molecule and single particle electron transfer events through spectroelectrochemistry, studies which are enabled by the electrochemical zero-mode waveguide (ZMW), a special hybrid nanophotonic/nanoelectronic architecture in which the lower ring electrode of an NEA nanopore functions both as a working electrode to initiate electron transfer reactions and as the optical cladding layer of a ZMW. Furthermore, while the work described here is largely exploratory and fundamental, we believe that the development of NEAs will enable important applications that emerge directly from the unique coupled transport and electron-transfer capabilities of NEAs, including in situ molecular separation and detection with external stimuli, redox-based electrochemical rectification in individually encapsulated nanopores, and coupled sorters and analyzers for nanoparticles.

• Research Organization: Univ. of Notre Dame, IN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Research Foundation of Korea (NRF); NSF
• Contributing Organization: K.F. was supported by an ACS Division of Analytical Chemistry fellowship, sponsored by Eastman Chemical Company.
• Grant/Contract Number: FG02-07ER15851
• OSTI ID: 1762420
• Alternate ID(s): OSTI ID: 1762422
• Journal Information: Accounts of Chemical Research, Journal Name: Accounts of Chemical Research Journal Issue: 4 Vol. 53; ISSN 0001-4842
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY
Redox reactions
charge transfer
electrodes
nanoparticles
nanopores