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UBC Theses and Dissertations

Developing a novel heterogeneous three electrode system for a PDMS-based microfluidic electrochemical sensor To, Josiah


Biosensors have seen an increased use in recent years as an in situ testing device for various industries such as agriculture, environmental sustainability, food, health, etc. On-site testing devices have an advantage over traditional testing system because they can be used for real-time monitoring and improving the accuracy of time-sensitive detection results. Out of all the industries, the health industry benefits most from in situ devices as point-of-care diagnostic devices. Point-of-care devices are useful tools to quickly diagnose diseases and direct patients’ course of treatment in low-income countries with few resources. In 2014 there were approximately 9.6 million global cases of tuberculosis (TB) and 1.5 million deaths due to TB (caused by the infection of Mycobacterium Tuberculosis [MTB]). Globally, this made TB the second most common cause of death by an infection disease in 2014. With a rising incidence of multi drug-resistant and extensive drug-resistant TB, TB is again becoming a global issue that wealthy countries will likely be unable to ignore. Since transmission is commonly through airborne particulates, early diagnosis and correct treatment of TB are fundamental to not only preventing the spread of the disease, but also eradicating it. Currently, the screening and detection tools that lower resource countries have are limited. Although the MTB genome has been sequenced since 1998, cost-effective, point-of-care, gene-based detection technology has had limited development. Since the integration of MEMS technology to biologically relevant needs in the late 90s there has been much development in creating small, portable detection systems for point-of-care use. Furthermore, this work details the development of a novel heterogeneous 3-material 3-electrode electrochemical sensor in a PDMS based bonded device. This sensor was developed with the intention of integration into a biosensor system. The final 3-electrode system was composed of 3 different materials: Au counter electrode, carbon working electrode, and Ag/AgCl reference electrode. The 3 material 3-electrode system was tested as an electrochemical system by detection of aqueous 5 μM carminic acid in room temperature and post 65◦C heating conditions. Parallel work was done to develop a robust, leak-free bonding method that survived 65◦C heating conditions and preserved electrochemical functionality.

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Attribution-NonCommercial-NoDerivs 2.5 Canada