Electrochemical and mechanical thin ?lm sensors

Abstract: This thesis focuses on the study of thin-?lm sensor technologies, novel microfabrication technologies, and thin-?lm technology in general. The work discusses electrochemical sensors and mechanical sensor technologies as well as fabrication strategies for them. Also included are mechano-chemical studies of the vancomycin DAla (Bacteria membrane analogue motif ) binding reaction in different chemical environments using thin-film sensor technology. One part of this thesis concentrates on the fabrication of sub-micron systems using electron beam and nanoimprint lithography in combination with UV and DUV lithography. Through these processes we successfully constructed interdigitated electrodes from gold (Au) and carbon that had electrode gaps as small as 100 nanometres. Papers discussed here present several different photo-resist systems, among them bi-layer lift-off compositions and single-layer negative tone photo- and electronbeam patterning. Additionally we demonstrated fabrication schemes using nanoimprint lithography. In addition, a pyrolysis technique for creating half-pitch carbon structures from thin ?lm polymer resins on a sub-micron scale has been established. Carbon electrodes are often used in electroanalytical systems due to their chemical inertness and wide operation potential range There-fore, establishing a feasible scheme to create nano-scale carbon structures could have myriad implication for electroanalytical applications as well as battery and fuel cell research. And ?nally, aspects of mechano-chemical detection using silicon cantilever technology are presented here. The research used silicon micro-cantilevers as static de?ection mode cantilever transducers to study vancomycin surface-binding reactions in a model system for a bacterial cell membrane. Vancomycin is an extremely important drug used to treat Methicillin-resistant Staphylococcus areus (MRSA) infections, which are often acquired in hospital. Electrostatic reactions were found to significantly in?uence the rate constants. Measuring the in-plane mechanical response induced by the binding process contributed useful information to our current understanding of how the drug behaves. The studies further elucidated aspects of the transduction mechanism for static deflection mode sensing cantilevers. While a complete understanding of transduction principles has not been established yet, we have formed an experimental basis for further theoretical and experimental studies.