Date of Award

2016

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Physical Sciences

First Advisor

Dr. Alan O'Riordan

Second Advisor

Dr. Guillaume Huyet

Abstract

Compared to traditional macroelectrodes, nanoscale electrodes have tremendous potential when employed in electrochemistry due to enhanced sensitivity arising from increased mass transport to the electrode and low background charging currents. Electrochemically- based diagnostic products such as sensors require sensing elements with greatly enhanced performance and nanoelectrodes offer a viable route to attaining this performance improvement.

Firstly, the fabrication of a polymer microneedle array-based sensor is described and employed to demonstrate a mediated approach for the detection of glucose in solution. This was to demonstrate the feasibility of the system for in-vivo sensing. Cyclic voltammetry was used to achieve detection of glucose in the concentration range of 2 - 13.5 mM which is the relevant range associated with the physiological concentrations expected in-vivo and in the presence of common interferents such as ascorbic acid, mannose, fructose and salicylic acid.

Further development of the microneedle array towards in-vivo glucose detection is undertaken. The sensor array was further modified with an on-chip counter and reference electrode with a modification process of the microneedle tips described. The array shows selective detection of glucose in the relevant physiological range with discrimination against common interferents such as ascorbic acid, mannose, fructose and salicylic acid. Also, cytotoxicity testing was carried out to determine the bio-compatibility of the arrays with the sensors displaying little to no adverse effects to cells from both leachables and local toxicity.

Finally, a glassy carbon interdigitated microband electrode platform is developed. A collection efficiency of 95 % for the fabricated arrays is achieved at a scan rate of 5 mV s'' making the platform ideal for generator-collector type analysis. We show generator- collector studies on one and two electron transfer molecules (ferrocene monocarboxylic acid and acetaminophen, respectively) using both cyclic voltammetry and square wave voltammetry.

Access Level

info:eu-repo/semantics/openAccess

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