Direct electron transfer based biofuel cells : operating in vitro and in vivo

Sammanfattning: The focus of this thesis is the development and design of direct electron transfer based enzymatic fuel cells, with the possible use in biomedical applications. For biodevice fabrication, macro- and micro-scaled nanostructured gold electrodes were fabricated and characterized in detail, employing electrochemical techniques, as well as atomic force microscopy and scanning electron microscopy. The nanostructured electrodes were utilized together with suitable (bio)catalysts to achieve efficient catalysis of suitable biofuel and biooxidant. Oxygen was utilized as biooxidant, employing the enzyme bilirubin oxidase together with nanostructured electrodes to achieve efficient bioelectrocatalysis. The mechanism of bioelectrocatalytic reduction of oxygen by bilirubin oxidase was investigated in detail utilizing electrochemical techniques combined with quantum mechanic/molecular mechanic modeling. Carbohydrates were utilized as the main biofuel in most of the studies, by employing cellobiose dehydrogenase immobilized on nanostructured electrodes. Additionally, tetracyanoquinodimethane and tetrathiafulvalene were employed as efficient catalysts of ascorbate. The performance of assembled enzymatic fuel cells were in-vestigated in vitro in complex buffers and human physiological fluids, as well as in vivo evaluated using different electrochemical techniques.