Electrochemical nanoprobes for the chemical detection of neurotransmitters

Shen, Mei; Colombo, Michelle L.

doi:10.1039/c5ay00512d

Cited by 44 publications

(51 citation statements)

References 118 publications

(170 reference statements)

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“…0.7 mm, length=7.5 cm) using a P‐2000 capillary puller (Sutter Instrument Co., Novato, CA). The nanopipets were fabricated using procedures as previously reported …”

Section: Methodsmentioning

confidence: 99%

“…An Ag wire (diameter=250 μm) coated with AgCl (through an oxidation reaction in saturated KCl solution) was placed in the aqueous phase as an outside reference electrode. A two electrode configuration was used as reported previously, where a potential was applied between the inner Pt wire and the outer Ag/AgCl reference electrode . Positive potential is for positive ion transfer from water to oil (1, 2‐DCE), seen as positive current.…”

Section: Methodsmentioning

confidence: 99%

“…Ions transfer either directly across ITIES without an ionophore, or through its complexation with an ionophore, which is known as the assisted ion transfer . A commonly used ionophore in ITIES is dibenzo‐18‐crown‐6 (DB18C6) . Although great progress has been made in synthesizing ionophores with multiple crown either moieties for ion selective electrodes, such ionophores have yet to be tested for amperometric ion detection at ITIES electrodes.…”

Section: Introductionmentioning

confidence: 99%

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A Newly Synthesized Tris(crown ether) Ionophore for Assisted Ion Transfer at NanoITIES Electrodes

et al. 2020

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Assisted ion transfer at a pipet‐supported interface between two immiscible electrolyte solutions (ITIES) have become a prominent method for the detection of various ionic species and for studying ionic complexation. A typical ionophore contains one binding center to ions such as dibenzo‐18‐crown‐6 (DB18C6). It is unknown how the detection of ions changes when assisted by an ionophore with multiple crown ether moieties. Here, we synthesized a new tris(crown ether) ionophore, TriBCE, which is composed of three 18‐crown‐6 moieties connected to a common o‐phenylene ethynylene cyclic trimer center, and employed TriBCE for the assisted ion transfer of various environmentally relevant heavy‐metal ions (i. e. Mg2+, Cu2+, Cd2+ and Li+) and a neurotransmitter (dopamine) at nanoITIES pipet electrodes. The half‐wave transfer potentials for those ions were less positive by 123±28 mV when assisted by tris (crown ether), TriBCE, compared to mono(crown ether), DB18C6. The binding constants, Gibbs free energy, and the stoichiometric coefficients of ionic complexation with TriBCE were measured and compared to that of DB18C6 to reveal that ionophore with multiple binding moieties enables easier transfer of these ions.

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“…0.7 mm, length=7.5 cm) using a P‐2000 capillary puller (Sutter Instrument Co., Novato, CA). The nanopipets were fabricated using procedures as previously reported …”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Newly Synthesized Tris(crown ether) Ionophore for Assisted Ion Transfer at NanoITIES Electrodes

et al. 2020

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“…The development of nanometer-sized carbon electrodes is pivotal for various electrochemical applications including scanning electrochemical microscopy (SECM) (1, 2). Originally, carbon nanoelectrodes were fabricated by exposing the sharp tip of an etched carbon fiber from an insulating sheath.…”

mentioning

confidence: 99%

Focused-Ion-Beam-Milled Carbon Nanoelectrodes for Scanning Electrochemical Microscopy

Chen

et al. 2015

J. Electrochem. Soc.

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Nanoscale scanning electrochemical microscopy (SECM) has emerged as a powerful electrochemical method that enables the study of interfacial reactions with unprecedentedly high spatial and kinetic resolution. In this work, we develop carbon nanoprobes with high electrochemical reactivity and well-controlled size and geometry based on chemical vapor deposition of carbon in quartz nanopipets. Carbon-filled nanopipets are milled by focused ion beam (FIB) technology to yield a flat disk tip with a thin quartz sheath as confirmed by transmission electron microscopy. The extremely high electroactivity of FIB-milled carbon nanotips is quantified by enormously high standard electron-transfer rate constants of ≥10 cm/s for Ru(NH3)63+. The tip size and geometry are characterized in electrolyte solutions by SECM approach curve measurements not only to determine inner and outer tip radii of down to ~27 and ~38 nm, respectively, but also to ensure the absence of a conductive carbon layer on the outer wall. In addition, FIB-milled carbon nanotips reveal the limited conductivity of ~100 nm-thick gold films under nanoscale mass-transport conditions. Importantly, carbon nanotips must be protected from electrostatic damage to enable reliable and quantitative nanoelectrochemical measurements.

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“…21,29,30 Briefly, the diffusion limited steady state current at nanoITIES pipet electrodes can be expressed as 35

i = 4 italicxnFDca

where i is the steady-state current, x is a function of the quantity RG = r g / a ( r g and a are outer and inner tip radii, respectively), 35 n is the number of transferred charges, F is Faraday’s constant, a is the radius of the electrode, D is the diffusion coefficient of the neurotransmitter, and c is the concentration of the neurotransmitter. A proposed disk geometry for the nanopipet tip was used for the calculation.…”

Section: Methodsmentioning

confidence: 99%

GABA Detection with Nano-ITIES Pipet Electrode: A New Mechanism, Water/DCE–Octanoic Acid Interface

et al. 2018

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Interface between two immiscible electrolyte solutions (ITIES) supported on the orifice of a pipet have become a powerful platform to detect a broad range of analytes. We present here the detection of γ-aminobutyric acid (GABA) with the nanoITIES pipet electrodes for the first time. GABA has a net charge of zero in an aqueous solution at pH ≈ 7, and it has not previously been detected at ITIES. In this work, we demonstrated GABA detection at ITIES in an aqueous solution at pH ≈ 7, where we introduced a novel detection strategy based on “pH modulation from the oil phase”. To the best of our knowledge, this is the first report of such. Current increases linearly with increasing concentrations of GABA, ranging from 0.25 mM to 1.0 mM. The measured half-wave transfer potential of GABA is −0.401 ± 0.010 V (n = 22) vs E1/2,TBA. The measured diffusion coefficient for GABA detection at nanoITIES pipet electrode is 6.09 (±0.58) × 10−10 m2/s (n = 5). Experimental results indicate that protons generated from octanoic acid dissociation in the oil phase do not come out from the oil phase into the aqueous phase; neither were protons produced in the aqueous phase. NanoITIES pipet electrodes with radii of 320–340 nm were used in the current study. This new strategy and knowledge presented here lays the groundwork for the future development of ITIES pipet electrodes, especially for the detection of electrochemically nonredox active analytes.

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Electrochemical nanoprobes for the chemical detection of neurotransmitters

Cited by 44 publications

References 118 publications

A Newly Synthesized Tris(crown ether) Ionophore for Assisted Ion Transfer at NanoITIES Electrodes

A Newly Synthesized Tris(crown ether) Ionophore for Assisted Ion Transfer at NanoITIES Electrodes

Focused-Ion-Beam-Milled Carbon Nanoelectrodes for Scanning Electrochemical Microscopy

GABA Detection with Nano-ITIES Pipet Electrode: A New Mechanism, Water/DCE–Octanoic Acid Interface

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