Scanning photoelectrochemical microscopy and its application to living cells

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dc.contributor.authorThomas, Nikita Maria
dc.contributor.examiningcommitteeChen, Aicheng (University of Guelph)
dc.contributor.examiningcommitteeGertsein, Aleeza ( Microbiology and Statistics)
dc.contributor.examiningcommitteeTommy, Gregg (Chemistry)
dc.contributor.examiningcommitteeSean, McKenna (Chemistry)
dc.contributor.supervisorKuss, Sabine
dc.date.accessioned2025-04-01T16:42:38Z
dc.date.available2025-04-01T16:42:38Z
dc.date.issued2025-03-27
dc.date.submitted2025-03-27T17:03:35Zen_US
dc.degree.disciplineChemistry
dc.degree.levelDoctor of Philosophy (Ph.D.)
dc.description.abstractLiving cell electrochemistry enables the non-invasive qualitative and quantitative measurement of metabolite and biomarker flux from individual or groups of cells. Scanning electrochemical microscopy (SECM) is an electroanalytical technique that allows for real-time detection of species flux from living cells. This thesis emphasizes the importance of maintaining optimal physiological conditions during SECM and explores the advancement of SECM to scanning photoelectrochemical microscopy (SPECM) for studying living cells. The first part of this thesis investigates the effects of experimental parameters such as temperature, media composition, and light on cellular electrochemical signals. It is shown that maintaining ideal physiological conditions is crucial for reliable SECM and SPECM data. Studies on Adenocarcinoma cervical cancer (HeLa) cells across different temperature ranges reveal inconsistent cellular electrochemical reactivity with small deviations from physiological temperature. However, HeLa cells demonstrate enhanced and stable electrochemical signals when cultured in serum-free media under constant light exposure. To advance SECM to SPECM, the integration of optical fiber (OF) probes is explored to enhance both electrochemical and spectroscopic capabilities. A new, easy-to-fabricate micro-optical ring electrode (MORE) is introduced, with its functionality assessed through electrochemical analysis, numerical modeling, scanning electron microscopy (SEM), and spectroelectrochemistry. The MORE, integrated into SPECM, is used for localized irradiation and as an electrochemical sensor for quantitative analysis of single algal cells. This proof-of-concept demonstrates the potential of applying SPECM to mammalian cells. SPECM is further applied to skin cells for the detection of reactive oxygen species (ROS) and melanin production, which are elevated in response to external stimuli. Overall, a comprehensive exploration of the application of SPECM to mammalian cell studies is investigated with suggestions for future research, highlighting its potential in diverse applications.
dc.description.noteMay 2025
dc.identifier.urihttp://hdl.handle.net/1993/38973
dc.language.isoeng
dc.subjectScanning Electrochemical Microscopy
dc.subjectScanning Photoelectrochemical Microscopy
dc.subjectLiving Cells
dc.subjectElectrochemistry
dc.subjectBioelectrochemistry
dc.subjectMicroelectrodes
dc.subjectMicro-Optical Ring Electrodes
dc.titleScanning photoelectrochemical microscopy and its application to living cells
local.subject.manitobano
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