Balla, Ryan James
(2021)
Advanced Nanoscale Approaches for Electrochemical Imaging and Sensing.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Electrochemical imaging and sensing are powerful techniques that enable quantitative studies of chemical reactions with high spatial and temporal resolution. Introduced in this thesis are novel approaches to advance the spatial resolution of electrochemical imaging and the time resolution of electrochemical sensing. To achieve these goals, nanometer-wide gaps are produced and controlled between two electrodes. In the first part of this thesis, a nanometer wide gap is produced between a tip nanoelectrode and a target substrate electrode in an intelligent manner to improve the spatial resolution of scanning electrochemical microscopy (SECM). Target substrates have variable redox reactivity and nanoscale topographical changes including step edges and grooves. New imaging software and algorithms are developed to separately obtain non-contact topography and reactivity images, which can not be resolved by a widely used SECM approach. The intelligent mode of SECM will be useful for imaging of non-flat substrates with heterogeneous reactivities such as the nuclear pore complexes of biological cells as medically important targets for drug delivery into the nucleus. In the second part of this thesis, a nanometer-wide gap is produced between two carbon fiber ultramicroelectrodes for fast electrochemical sensing. In the dual electrode system, an analyte is electrolyzed at one electrode voltammetrically. The product can diffuse across the nanometer wide gap during the fast scan of the generator electrode potential, thereby enabling fast temporal electrochemical detection of the analyte at low concentrations owing to the suppressed background response of the collector electrode. This is advantageous over fast scan cyclic voltammetry with a single electrode, which requires accurate background measurement and subtraction to qualitatively determine the analyte concentration. Fast-scan cyclic voltammetry with double carbon fiber electrodes will be useful for the in-vivo detection of neurotransmitters such as dopamine at low basal concentration levels.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
3 May 2021 |
| Date Type: |
Publication |
| Defense Date: |
16 February 2021 |
| Approval Date: |
3 May 2021 |
| Submission Date: |
16 February 2021 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
164 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Nanoscale |
| Date Deposited: |
03 May 2021 14:39 |
| Last Modified: |
03 May 2021 14:39 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/40266 |
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