| Abstract & Overview: The goal of this thesis was to develop portable nanoparticle-based paper sensors for field analysis, with focus on antioxidant detection. The method introduces a novel concept in the sensing arena that relies on the use of redox active inorganic nanoparticles, primarily cerium oxide, as colorimetric probes to replace commonly used soluble dyes. The sensors have an integrated detection mechanism with all the reagents needed for analysis confined to the sensing platform. Research work in this thesis focuses on the study of the redox and surface chemistry of these particles, their reactivity with target analytes and integration into paper-based platforms. A unique feature of these particles is their ability to replace or stabilize enzymes and extend their operational lifetime providing additional opportunities for improved detection schemes for enzyme-based systems. We demonstrate the above principles for the construction of sensors for detection of analytes such as hydrogen peroxide, glucose, and polyphenolic antioxidants. The advantage of the newly designed system include, in addition to portability and stability, the low production costs, the rapid analysis time, and the ability to provide quantitative information without use of advanced instrumentation.;The results of this work opened up new opportunities for designing portable easy-to- use sensors for field analysis. The developed assays are particularly appealing for remote sensing applications where specialized equipment is not available, and also for high throughput analysis of a large number of samples. Our investigation to demonstrate applicability of the system focused primarily on the detection of antioxidants. Therefore, the thesis highlights predominantly this application. |
