Nanopore-Based Electrodes for Quinotrione Detection: Host–Guest-Induced Electrochemical Signal Switching

Abstract

Nanopore-based detection techniques, with a wide range of transport properties, exhibit impressive selectivity and sensitivity for analytes. To expand the application of nanoporous sensors, real-time and fast detection of targets, all within a portable device, is highly desired for nanopore-based sensors. In addition, to improve the accuracy of the output signal, more appropriate readout methods also need to be explored. In this manuscript, we describe a nanopore-based electrode, regarded as NAC-P6-PC@AuE, prepared by coupling a pillararene-based nanoporous membrane with an electrochemical impedance measurement method. The fabricated device is demonstrated by exposing pillararene-based receptors to trace amounts of pesticide molecules. NAC-P6-PC@AuE devices exhibit distinguished selectivity to quinotrione, as well as the ability to quantify quinotrione with a limit of quantitation (LOQ) of 10 nM. The mechanism that allows sensing was verified using finite-element simulations and may be explained as host−guest-induced surface charge shielding, which influences the electrochemical response of probe molecules. The applications of this nanopore-based electrode may be extended toward other target molecules by decorating the nanopore surfaces with specifically chosen receptors.

Novel Paraquat Detection Strategy Enabled by Carboxylatopillar[5]arene Confined in Nanochannels on a Paper-Based Sensor

“…28 To date, a series of amino-decorated pillar [6]arene were synthesized and loaded on the surface of silica surface via carbodiimide coupling or amino-carboxyl electrostatic interaction. 29,30 Here, we developed a facile covalent bonding method to attach water-soluble CP [5]A with APTES amino-functionalized mesoporous silica via classical EDC/NHS condensation reaction. 31 X-ray photoelectron spectroscopy (XPS) was performed to verify that this method can be successfully used for the covalent attachment of CP [5]A to MSN (Figure 1E).…”

Electrochemical sensing at nanoporous film‐coated electrodes

“…The pore diameter (typically, ≥ 10 nm) and pore shape can be adjusted by optimizing etching conditions such as etching solution composition and etching time. RNEs were previously prepared from polycarbonate and poly(ethylene terephthalate) TEPMs via metal deposition [ 6,10,46 ] or physical attachment to electrodes, [ 34 ] and their nanopores were modified via amidation of the surface ‐COOH groups. [ 34,45 ]…”

“…RNEs were previously prepared from polycarbonate and poly(ethylene terephthalate) TEPMs via metal deposition [ 6,10,46 ] or physical attachment to electrodes, [ 34 ] and their nanopores were modified via amidation of the surface ‐COOH groups. [ 34,45 ]…”

“…[6,8,10] Of note, the physical attachment of NAAMs or TEPMs to planar electrodes is a simpler approach to RNE fabrication for electro-chemical sensing. [31][32][33][34] However, the resulting RNEs can suffer from a large background charging current [6,13] and lower reproducibility in electrochemical measurements [6] owing to uncontrollable solution creeping between the membrane and electrode. More importantly, the solution creeping results in the formation of a thin layer, which gives the additional source of electrochemical signals.…”

Aprotic Solvent Accumulation Amplifies Ion Current Rectification in Conical Nanopores

“…An interesting example, reported by Heaton and Platt, is a multiuse nanopore platform whose rectifying behavior is changed by placing a sheet of metal-immobilized paper on top of the nanopore . While aqueous sensors are suitable for environmental − and biological applications, − they have limited use in industrial settings that feature aprotic solvent production processes, such as in pharmaceutical plants . A deeper understanding of the rectifying behavior of nanopores in non-aqueous electrolytes is essential in the development of ICR sensors compatible with organic solvents and will facilitate a wider range of applications than that for which such sensors are currently developed …”