title: Carbon nanospikes grown on metal wires as microelectrode sensors for dopamine.
abstract: Carbon nanomaterials are advantageous as electrodes for neurotransmitter detection, but the difficulty of nanomaterials deposition on electrode substrates limits the reproducibility and future applications. In this study, we used plasma enhanced chemical vapor deposition (PECVD) to directly grow a thin layer of carbon nanospikes (CNS) on cylindrical metal substrates. No catalyst is required and the CNS surface coverage is uniform over the cylindrical metal substrate. The CNS growth was characterized on several metallic substrates including tantalum, niobium, palladium, and nickel wires. Using fast-scan cyclic voltammetry (FSCV), bare metal wires could not detect 1 μM dopamine while carbon nanospike coated wires could. The highest sensitivity and optimized S/N ratio was recorded from carbon nanospike-tantalum (CNS-Ta) microwires grown for 7.5 minutes, which had a LOD of 8 ± 2 nM for dopamine with FSCV. CNS-Ta microelectrodes were more reversible and had a smaller ΔE(p) for dopamine than carbon-fiber microelectrodes, suggesting faster electron transfer kinetics. The kinetics of dopamine redox were adsorption controlled at CNS-Ta microelectrodes and repeated electrochemical measurements displayed stability for up to ten hours in vitro and over a ten day period as well. The oxidation potential was significantly different for ascorbic acid and uric acid compared to dopamine. Growing carbon nanospikes on metal wires is a promising method to produce uniformly-coated, carbon nanostructured cylindrical microelectrodes for sensitive dopamine detection.
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA. jventon@virginia.edu.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Zestos
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Jacobs
authors.forename: Dale
authors.initials: D
authors.lastname: Hensley
authors.forename: B Jill
authors.initials: BJ
authors.lastname: Venton
mesh_terms: D000327:Adsorption; D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D000077482:Carbon Fiber; D004298:Dopamine / Q000032:analysis* / Q000737:chemistry; D004566:Electrodes; D057230:Limit of Detection; D008670:Metals / Q000737:chemistry*; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D018377:Neurotransmitter Agents / Q000032:analysis; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D015203:Reproducibility of Results; D013499:Surface Properties; D014527:Uric Acid / Q000032:analysis
chemical_list: D000077482:Carbon Fiber; D008670:Metals; D037742:Nanotubes, Carbon; D018377:Neurotransmitter Agents; D014527:Uric Acid; D002244:Carbon; D001205:Ascorbic Acid; D010100:Oxygen; D004298:Dopamine