Abstract
Uric acid has a long history in clinical analysis and it has served as an important diagnostic within a number of different contexts. The increasing interest in metabolic syndrome has led to uric acid being used in combination with a number of other biomarkers in the assessment of cardiovascular risk. The traditional view of uric acid as principally an interferent in electrochemical measurement is now gradually being replaced with the realization that its measurement could serve as an invaluable secondary (if not primary) marker when monitoring conditions such as diabetes and heart disease. Rather than attempting to wholly exclude uric acid electrochemistry, many strategies are being developed that can integrate the uric acid signal within the device architecture, such that a range of biomarkers can be sequentially assessed. This thesis describes the development and characterization of two main strategies to incorporate uric acid electrochemistry alongside other biomarkers: a tagging process to overcome signals which oxidize at similar potentials (Chapter 3), a novel material, and architecture were created to allow sequential detection within a complex mixture of multiple biomarkers (Chapter 4 and 5). The methodology for the uric acid detection alongside other biomarkers was evaluated using real physiological samples to ensure the clinical viability of the final prototype (Chapter 4 and 5). These experiments were verified versus the standard UV-Vis protocol used to validate clinical investigation data at the Royal Surrey Hospital. Lastly, the novel electrode was combined with the technique which was developed to cater for sequential testing and proven to separate out ascorbic acid, uric acid and glucose in a combined mixture both directly using peroxide detection and in the presence of a mediator. Thus the final product demonstrates the feasibility of multianalyte testing for near patient monitoring of a variety of different clinical conditions.