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Advancing squarewave voltammetry at PEDOT/fCNT carbon fiber microelectrodes for in vivo basal dopamine detection

Freedman, Noah/C (2019) Advancing squarewave voltammetry at PEDOT/fCNT carbon fiber microelectrodes for in vivo basal dopamine detection. Undergraduate Thesis, University of Pittsburgh. (Unpublished)

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Abstract

Dopamine is a central nervous system neurotransmitter responsible for vital human functions which operates via two signalling modes. Phasic signalling comprises subsecond
fluctuations in extracellular DA, whereas tonic signalling comprises minute to hour fluctuations. Both signalling modes are critical to study for full characterization of a given in vivo DA system, but currently available methods for sampling tonic signalling possess signifcant limitations, including limited spatial resolution and extensive damage upon implantation among others. In order to provide an alternative electrochemical detection technique for the quantifcation of tonic in vivo DA signalling, squarewave voltammetry (SWV) has been developed at carbon fiber electrodes (CFEs), but has suffered issues of low DA sensitivity and extensive signal interferences from electrochemically active analytes such as ascorbic acid (AA). Thus, a surface coating of poly(3,4-ethylenedioxythiophene) with carboxy-functionalized carbon
nanotubes (PEDOT/fCNT) has been developed for implementation on CFE substrates to increase DA sensitivity. Persistent issues preventing reliable in vivo application of this technology include extensive AA interference and significant discrepancies between conditions of the in vitro calibration environment and in vivo recording environment. The latter issue generalizes to all electrochemical sensing techniques. It was hypothesized that PEDOT/fCNT coatings and the introduction of 0 V static potential periods prior to SWV application may be implemented as strategies to mitigate AA interference. Furthermore, agarose gels and bovine
serum albumin surface adsorption were explored as potential mechanisms through which in vitro conditions may more closely approximate the in vivo for more reliable calibrations and data interpretation. PEDOT/fCNT was found to significantly increase AA sensitivity, de-
crease relative DA to AA peak amplitude, and increase the redox profile separation between AA and DA in the SWV dI trace. 0 V static potential application demonstrated ability to significantly reduce AA peak amplitude while simultaneously increasing DA peak amplitude without exhibiting significant effects on sensitivity. Finally, agarose gel and protein adsorption strategies were unsuccessful in replicating in vivo conditions in vitro, but point to future methods by which this goal may be achieved. This work represents a major step forward in realizing a powerful basal DA sensing tool for the neurosciences and bioengineering.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Freedman, Noah/Cncf11@pitt.eduncf11
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCui, XTxic11@pitt.eduxic110000-0002-0470-2005
Committee MemberTaylor, Ian/IMTimt2@pitt.eduIMT2
Committee ChairElisa, Castagnolaelc11@pitt.eduelc11
Committee ChairKozai, Takashitdk18@pitt.edutdk18
Committee MemberMichael, Adrianamichael@pitt.eduamichael
Date: 29 April 2019
Date Type: Publication
Defense Date: 16 April 2019
Approval Date: 29 April 2019
Submission Date: 19 April 2019
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 54
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
University Honors College
Degree: BS - Bachelor of Science in Engineering
Thesis Type: Undergraduate Thesis
Refereed: Yes
Uncontrolled Keywords: dopamine, square, wave, voltammetry, PEDOT/fCNT, carbon, fiber, microelectrodes
Date Deposited: 29 Apr 2019 15:32
Last Modified: 29 Apr 2019 15:32
URI: http://d-scholarship.pitt.edu/id/eprint/36557

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