title: Nanopipet-Based Liquid-Liquid Interface Probes for the Electrochemical Detection of Acetylcholine, Tryptamine, and Serotonin via Ionic Transfer.
abstract: A nanoscale interface between two immiscible electrolyte solutions (ITIES) provides a unique analytical platform for the detection of ionic species of biological interest such as neurotransmitters and neuromodulators, especially those that are otherwise difficult to detect directly on a carbon electrode without electrode modification. We report the detection of acetylcholine, serotonin, and tryptamine on nanopipet electrode probes with sizes ranging from a radius of ≈7 to 35 nm. The transfer of these analytes across a 1,2-dichloroethane/water interface was studied by cyclic voltammetry and amperometry. Well-defined sigmoidal voltammograms were observed on the nanopipet electrodes within the potential window of artificial seawater for acetylcholine and tryptamine. The half wave transfer potential, E1/2, of acetylcholine, tryptamine, and serotonin were found to be -0.11, -0.25, and -0.47 V vs E(1/2,TEA) (term is defined later in experimental), respectively. The detection was linear in the range of 0.25-6 mM for acetylcholine and of 0.5-10 mM for tryptamine in artificial seawater. Transfer of serotonin was linear in the range of 0.15-8 mM in LiCl solution. The limit of detection for serotonin in LiCl on a radius ≈21 nm nanopipet electrode was 77 μM, for acetylcholine on a radius ≈7 nm nanopipet electrode was 205 μM, and for tryptamine on a radius ≈19 nm nanopipet electrode was 86 μM. Nanopipet-supported ITIES probes have great potential to be used in nanometer spatial resolution measurements for the detection of neurotransmitters.
authors: Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors: Michelle L
authors: ML
authors: Colombo
authors: Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors: Jonathan V
authors: JV
authors: Sweedler
authors: Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors: Mei
authors: M
authors: Shen
mesh_terms: D000109:Acetylcholine / Q000737:chemistry / Q000378:metabolism; D004563:Electrochemistry; D004566:Electrodes; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D018377:Neurotransmitter Agents / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D012701:Serotonin / Q000737:chemistry / Q000378:metabolism; D014363:Tryptamines / Q000737:chemistry / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D014363:Tryptamines; D012701:Serotonin; C030820:tryptamine; D000109:Acetylcholine