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- Skjolding, Lars Henrik, et al.
(författare)
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Characterisation of nano-interdigitated electrodes
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 100, s. 052045-052045
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Konferensbidrag (refereegranskat)abstract
- Interdigitated electrodes made up of two individually addressable interdigitated comb-like electrode structures have frequently been suggested as ultra sensitive electrochemical biosensors. Since the signal enhancement effects due to cycling of the reduced and oxidized species are strongly dependent on the inter electrode distances, since the nature of the enhancement is due to overlying diffusion layers, inter digitated electrodes with an electrode separation of less the non emicrometer a redesired for maximum signal amplification. Fabrication of submicron structures can only be made by advanced lithography techniques. By use of electron be amlithography we have fabricated arrays of interdigitated electrodes with an electrode separation distance of 200nm and an electrode finger width of likewise 200nm. The entire electrode structure is 100 micrometre times 100 micrometre, and the active electrode area is dictated by the opening in the passivation layer, that is defined by UV lithography. Here we report measurements of redox cycling of ferrocyanide by coupled cyclic voltammograms, where the potential atone of the working electrodes are varied and either an oxidising or reducing potential is applied to the complimentary interdigitated electrode. The measurements show fast conversion and high collection efficiency round 87% as expected for nano-interdigitated electrodes.
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| 5. |
- Skjolding, Lars Henrik, et al.
(författare)
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Negative UV–NIL (NUV–NIL) – A mix-and-match NIL and UV strategy for realisation of nano- and micrometre structures
- 2009
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 86:4-6, s. 654-656
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel strategy for aligning patterns created with nano-imprint lithography (NIL) and UV lithography, similar to a mix-and-match process, which allows for the fabrication of large and small features in a single layer of resist. The resin used to demonstrate this new imprinting scheme is SU-8, a very widely used negative photoresist. Rapid stamp manufacturing using ma-N 2405 photoresist is also demonstrated. The processing scheme is a promising candidate for patterning of sensors featuring nanometre sized electrodes.
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| 7. |
- Skjolding, Lars Henrik
(författare)
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Electrochemical and mechanical thin film sensors.
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the study of thin-film sensor technologies, novel microfabrication technologies, and thin-film 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 film 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 finally, aspects of mechano-chemical detection using silicon cantilever technology are presented here. The research used silicon micro-cantilevers as static deflection 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 influence 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.
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| 8. |
- Spegel, Christer, et al.
(författare)
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Chip Based Electroanalytical Systems for Cell Analysis
- 2008
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Ingår i: Electroanalysis. - : Wiley. - 1040-0397 .- 1521-4109. ; 20:6, s. 680-702
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Forskningsöversikt (refereegranskat)abstract
- This review with 239 references has as its aim to give the reader an introduction to the kinds of methods used for developing microchip based electrode systems as well as to cover the existing literature on electroanalytical systems where microchips play a crucial role for “none-destructive” measurements of processes related to living cells, i.e., systems without lysing the cells. The focus is on chip based amperometric and impedimetric cell analysis systems where measurements utilizing solely carbon fibre microelectrodes (CFME) and other non-chip electrode formats, such as CFME for exocytosis studies and scanning electrochemical microscopy (SECM) studies of living cells have been omitted. Included is also a discussion about some future and emerging nano tools and considerations that might have an impact on the future of “non-destructive” chip based electroanalysis of living cells.
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