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Title: Carbon nanospikes grown on metal wires as microelectrode sensors for dopamine

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 our 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. We characterized the CNS growth on several metallic substrates including tantalum, niobium, palladium, and nickel wires. Using fast-scan cyclic voltammetry (FSCV), bare metal wires could not detect 1 mu M dopamine while carbon nanospike coated wires could. Moreover, 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 Delta E-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 comparedmore » to dopamine. Finally, growing carbon nanospikes on metal wires is a promising method to produce uniformly-coated, carbon nanostructured cylindrical microelectrodes for sensitive dopamine detection.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Virginia, Charlottesville, VA (United States)
  2. Univ. of Virginia, Charlottesville, VA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1295130
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Analyst
Additional Journal Information:
Journal Volume: 140; Journal Issue: 21; Journal ID: ISSN 0003-2654
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE