(Nano)materials for electrochemical sensing applications in different fields

Abstract: Health care and the medical industry, environmental monitoring and food sector are just a few examples of human’s major concerns. Design and analytical applications of (bio)sensors and sensing (nano)materials in these fields which have drawn tremendous attention by scientific community, require multidisciplinary knowledge in materials, transducers, and measurement methodologies. Among different types of transducers, electrochemical transducers have gained a lot of interest due to their simplicity, ease of fabrication and integration, selectivity, and sensitivity. Application of sensing materials, in particular nanomaterials, provide several improvements for analytical sensing such as selectivity, sensitivity, robustness, and fast response. Therefore, different nanomaterials due to their excellent characterization are exploited as key instruments for the design of high-performant analytical assays in various fields.Considering this established nanomaterial-based electrochemical sensing applications as alternatives to conventional methods in various fields, in this thesis, we synthesized and characterized some (nano)materials such as gold nanostars (AuNSs), iron oxide/zinc oxide (α-Fe2O3/ZnO) nanocomposite for sensing applications in environmental monitoring. We fabricated screen printed Ruthenium (IV) oxide (RuO2-Nf) pH electrodes and applied them for continuous pH monitoring in milk and during milk coagulation. Although the results indicated the applicability of the RuO2-Nf electrodes for continuous pH measurement in milk as a replacement of traditional glass electrode, they are not suitable for more viscous samples. Later we investigated the cleaning procedure for these pH electrodes, and we showed that soaking them in the solution of 5% pepsin in 0.1 M HCl restores the electrodes to their initial state for pH measurement in food samples. In another work we developed a molecular imprinted polymer-based biosensor for successful detection of prostate-specific antigen. At the end we investigated the effect of pH on the growth of pathogenic bacteria using electrical impedance spectroscopy.