DEVELOPMENT OF MINIATURIZED ELECTROCHEMICAL DEVICES FOR DETECTION OF DOPAMINE, L-CYSTEINE AND ANTI-SARS-COV-2 ANTIBODIES

Abstract

This dissertation aims to develop novel electrochemical devices for the detection of important target analytes, which can be divided into two parts. The first part concerned the development of electrochemical paper-based analytical devices for clinical and food applications, and there were two subprojects in this section. The first subproject is the fabrication of electrochemical microfluidic paper-based analytical device (eµPAD) and developed for the highly selective and sensitive detection of dopamine (DA). Nafion was deposited into paper-based microchannel to increase selectivity and multilayered eµPAD was subsequently designed for the flow of the solution. The next subproject is a novelty of poly(cysteine) modified screen-printed graphene electrode, developed for the electroanalysis of L-cysteine (Cys). Furthermore, an all-in-one origami paper-based analytical device was proposed to combine all of the procedures into one device and providing a more convenient method for end-users. The second part was the development of an electrochemical device for COVID-19 diagnosis. In this part, the sequential delivery pump-free microfluidic coupled with screen-printed electrodes (SPE), which were developed for simple and rapid detection of IgG antibodies against SARS-CoV-2 nucleocapsid protein (anti-N antibody). The immunological assay was performed on the nitrocellulose membrane where the SPE was aligned above to perform the sensitive electrochemical detection of anti-N antibodies. As previously mentioned, all electrochemical devices produced from this work had a great analytical performance and a low limit of detection that can be applied to detect specific target analytes in various real samples, e.g., urine, whole blood, and food samples.-