title: Carbon nanofiber multiplexed array and Wireless Instantaneous Neurotransmitter Concentration Sensor for simultaneous detection of dissolved oxygen and dopamine.
abstract: OBJECTIVE
  While the mechanism of Deep Brain Stimulation (DBS) remains poorly understood, previous studies have shown that it evokes release of neurochemicals and induces activation of functional magnetic resonance imaging (fMRI) blood oxygen level-dependent signal in distinct areas of the brain. Therefore, the main purpose of this paper is to demonstrate the capabilities of the Wireless Instantaneous Neurotransmitter Concentration Sensor system (WINCS) in conjunction with a carbon nanofiber (CNF) multiplexed array electrode as a powerful tool for elucidating the mechanism of DBS through the simultaneous detection of multiple bioactive-molecules.
  
  
  METHODS
  Patterned CNF nanoelectrode arrays were prepared on a 4-inch silicon wafer where each device consists of 3 × 3 electrode pads, 200 μm square, that contain CNFs spaced at 1μm intervals. The multiplexed carbon nanofiber CNF electrodes were integrated with WINCS to detect mixtures of dopamine (DA) and oxygen (O2) using fast scan cyclic voltammetry (FSCV)in vitro.
  
  
  RESULTS
  First, simultaneous detection of O2at two spatially different locations, 200 um apart, was demonstrated. Second, simultaneous detection of both O2and DA at two spatially different locations, using two different decoupled waveforms was demonstrated. Third, controlled studies demonstrated that the waveform must be interleaved to avoid electrode crosstalk artifacts in the acquired data.
  
  
  CONCLUSIONS
  Multiplexed CNF nanoelectrode arrays for electrochemical detection of neurotransmitters show promise for the detection of multiple analytes with the application of time independent decoupled waveforms. Electrochemistry on CNF electrodes may be helpful in elucidating the mechanism of DBS, and may also provide the precision and sensitivity required for future applications in feedback modulated DBS neural control systems.
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Marsh
authors.affiliation: Center for Nanotechnology, NASA Ames Research Center, Moffett Field, CA 94035.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Koehne
authors.affiliation: Center for Nanotechnology, NASA Ames Research Center, Moffett Field, CA 94035.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Andrews
authors.affiliation: Center for Nanotechnology, NASA Ames Research Center, Moffett Field, CA 94035.
authors.forename: M
authors.initials: M
authors.lastname: Meyyappan
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Bennet
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905.
authors.forename: Kendall H
authors.initials: KH
authors.lastname: Lee
keywords: DBS; Fast Scan Cyclic-Voltammetry; carbon nanofibers; electrochemistry; multiplexed array electrode