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Title: Electrochemical sensing at nanoporous film‐coated electrodes

In this paper, we highlight the uniqueness of nanoporous film‐coated electrodes as electrochemical sensing platforms. Specifically, we focus on discussing electrodes coated with insulator‐based monolithic films comprising vertically‐oriented, rigid cylindrical nanopores of uniform diameters (2–200 nm). The electrode coating results in the formation of an array of recessed nanodisk electrodes, and thus we named them recessed nanodisk‐array electrodes (RNEs). We first summarize the properties of nanoporous films commonly used for RNE fabrication, including nanoporous anodic alumina membranes, track‐etched polymer membranes, block copolymer‐derived nanoporous films, and mesoporous silica films. Subsequently, we discuss representative works that take advantage of the uniform size/shape of the nanopores for enhancing electrochemical detection selectivity and sensitivity. RNE‐based sensors measure faradaic currents from redox‐active analytes or exogenously‐added electroactive species that penetrate through the nanopores, or those from redox‐active moieties tethered to the surface of the nanopores or underlying electrodes. The enhanced detection selectivity of these sensors is attributed to the preferential partitioning of analytes into the nanopores or steric/electrostatic exclusion of interfering species. In particular, the uniform sizes/shapes of RNE nanopores play key roles in their higher molecular sieving selectivity and also in the better control of the detection selectivity based on electrostatic/chemical interactions. The detection sensitivity of RNE‐based sensors can be improved by tailoring the chemical environments of the nanopores for analyte preconcentration or for steric/electrostatic manipulation of the dynamics of redox‐tagged binding moieties. These unique characteristics of RNEs, in addition to the mitigation of electrode fouling by the nanoporous films, will enable the development of pretreatment‐free electrochemical sensors for complex matrix solutions.

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Author(s) / Creator(s):
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Electrochemical Science Advances
Medium: X
Sponsoring Org:
National Science Foundation
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