Browsing by Author "Ebrahim, Taskeen"

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    The development of a biosensor for the early detection of pancreatic cancer
    (Stellenbosch : Stellenbosch University, 2023-03) Ebrahim, Taskeen; Perold, Willem; Engelbrecht, Anna-Mart; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: Pancreatic cancer has one of the highest cancer mortality rates, as it is often detected in late stages. Current methods of detection include diagnostic imaging tests or laboratory intensive blood tests such as radioimmunoassays or ELISAs. Researchers have used biosensors for detection and monitoring of different medical conditions, as a more accessible and cheaper alternative. This project focuses on the design of a biosensor toward the early detection of pancreatic cancer, using Carbohydrate Antigen 19-9 (CA19-9) as the selected biomarker for the biosensor. Electrochemical impedance spectroscopy was identified as an appropriate transducer mechanism for this biosensor and uses gold interdigitated electrodes as a sensor transducer surface. Anti-CA19-9 antibodies were immobilized onto gold using covalent bonding and crosslinking chemistries, and binding was validated using fluorescence microscopy. After electrodes were electronically characterized to identify the appropriate impedance and frequency ranges, an impedance analyser was designed, fabricated, and tested, with added computation of complex capacitance. The impedance analyser was calibrated and tested relative to the PalmSens4 Electrochemical Interface. The designed impedance analyser showed mean impedance and phase errors of 0.538% and 0.381% respectively. Similarly, the accuracy of complex capacitance computation showed errors of 1.222% and 0.656% for real and imaginary components respectively. The impedance analyser differentiated between changes in concentration of phosphate buffered saline using complex capacitance. The biosensor was tested with five concentrations of CA19-9 and differentiated between concentrations above and below the thresholds for pancreatic cancer. The design of a novel impedance analyser utilizing complex capacitance computation for the quantification of CA19-9 using IDEs fabricated on an FR4 board is a unique contribution to biosensor research.