| Over the years, a variety of physical principles for glucose sensing have been investigated. One concept that has found wide application in the development of glucose biosensors is the peroxide-based amperometric electrode. Despite having to compete with more sophisticated emerging technologies, the peroxide-based, enzymatic sensor remains a popular choice due to its simple configuration, which would facilitate miniaturization. However, for this type of sensor, interference from other electro-active species, such as ascorbate, urate and the widely used analgesic acetaminophen, is a major problem.; The work described in this dissertation is centered on the development of a peroxide-selective amperometric glucose biosensor. Acetaminophen, an uncharged molecule, was chosen as a representative interferent. A mathematical model was developed to explore values of various parameters that could improve the performance of the sensor. Interestingly, the transport properties of both a selective internal membrane and a protective external membrane can be manipulated to design a peroxide-selective glucose sensor.; An internal membrane, in contact with the electrode surface, was systematically selected based on the permeability of hydrogen peroxide relative to that of acetaminophen through the material. A rotating disk electrode (RDE) was employed to determine the permeability of the solutes through the membrane. Cross-linked poly(vinyl alcohol), which was considered as a potential inner layer, was found to be only moderately selective to hydrogen peroxide.; Since glucose sensitivity of the sensor depends highly on the activity of its enzymatic component, an enzyme immobilization technique to minimize loss of enzymatic activity was also investigated. Immobilization of glucose oxidase to moderately cross-linked poly(vinyl alcohol) was shown to be a promising technique as it resulted in a glucose oxidase layer with satisfactory glucose sensitivity. The transport properties of this enzymatic membrane were also investigated.; The performance of a partial glucose sensor was tested using the internal membrane and the enzyme layer. As expected, the addition of a moderately selective internal layer did not significantly improve the ability of the sensor to retard interference from acetaminophen, However, a mathematical simulation predicted that the internal layer could be employed together with an appropriate outer layer to construct a glucose sensor with acceptable properties. |
