Abstract
Label-free electrochemical impedance spectroscopy (EIS) has the ability to make cancer monitoring easy, fast, and accessible via cancer cell detection.In this work, prostate cancer cell detection is investigated through the use of EIS in combination with a peptide selector, bombesin [7-13]. When the peptide is successfully immobilised onto an evaporated gold electrode by coupling to a self-assembled monolayer, it can selectively attach to gastrin-releasing peptide receptors which are over-expressed on prostate cancer cell membranes. Therefore, when a functionalised electrode surface is incubated with prostate cancer cells, there is a change of electrode impedance. When PC-3 prostate cancer cells are used, the percentage change in charge-transfer resistance and cell suspension concentration is found to be related by ∆R_ct (%)=7*log(cells per ml)+8 (without outliers, is ∆R_ct (%)=3.6*log(cells per ml)+7.2). Additional work investigating the reaction conditions for peptide immobilisation is needed to make these results more repeatable.
Separately, breast cancer cells have been characterised using microfluidic EIS (μEIS) and so are used as controls in the development of a new μEIS device. Although cell characterisation was not completed due to the dominant effect of contaminants in the microfluidic channel, the fabricated devices were able to detect large-scale differences in impedance regardless of electrode dimensions. A good cleaning procedure for the devices needs to be found before further progress can be made.
Overall, the results here support the vision that EIS could improve on the speed and selectivity of current biosensors and revolutionise cancer monitoring (or even detection) if issues with repeatability and contamination can be overcome.
| Date of Award | 11 Dec 2024 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Pedro Estrela (Supervisor) & Sofia Pascu (Supervisor) |