Electrochemical biosensor based on microfabricated electrode arrays for life sciences applications

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dc.contributor.advisor Ogurtsov, Vladimir I. en
dc.contributor.advisor Herzog, Grégoire en
dc.contributor.author Mohd Said, Nur Azura
dc.date.accessioned 2015-01-19T10:03:20Z
dc.date.available 2015-01-19T10:03:20Z
dc.date.issued 2014
dc.date.submitted 2014
dc.identifier.citation Mohr Said, N. A. 2014. Electrochemical biosensor based on microfabricated electrode arrays for life sciences applications. PhD Thesis, University College Cork. en
dc.identifier.endpage 300
dc.identifier.uri http://hdl.handle.net/10468/1759
dc.description.abstract In developing a biosensor, the utmost important aspects that need to be emphasized are the specificity and selectivity of the transducer. These two vital prerequisites are of paramount in ensuring a robust and reliable biosensor. Improvements in electrochemical sensors can be achieved by using microelectrodes and to modify the electrode surface (using chemical or biological recognition layers to improve the sensitivity and selectivity). The fabrication and characterisations of silicon-based and glass-based gold microelectrode arrays with various geometries (band and disc) and dimension (ranging from 10 μm-100 nm) were reported. It was found that silicon-based transducers of 10 μm gold microelectrode array exhibited the most stable and reproducible electrochemical measurements hence this dimension was selected for further study. Chemical electrodeposition on both 10 μm microband and microdisc were found viable by electro-assisted self-assembled sol-gel silica film and nanoporous-gold electrodeposition respectively. The fabrication and characterisations of on-chip electrochemical cell was also reported with a fixed diameter/width dimension and interspacing variation. With this regard, the 10 μm microelectrode array with interspacing distance of 100 μm exhibited the best electrochemical response. Surface functionalisations on single chip of planar gold macroelectrodes were also studied for the immobilisation of histidine-tagged protein and antibody. Imaging techniques such as atomic force microscopy, fluorescent microscopy or scanning electron microscope were employed to complement the electrochemical characterisations. The long-chain thiol of self-assembled monolayer with NTA-metal ligand coordination was selected for the histidine-tagged protein while silanisation technique was selected for the antibody immobilisation. The final part of the thesis described the development of a T-2 labelless immunosensor using impedimetric approach. Good antibody calibration curve was obtained for both 10 μm microband and 10 μm microdisc array. For the establishment of the T-2/HT-2 toxin calibration curve, it was found that larger microdisc array dimension was required to produce better calibration curve. The calibration curves established in buffer solution show that the microelectrode arrays were sensitive and able to detect levels of T-2/HT-2 toxin as low as 25 ppb (25 μg kg-1) with a limit of quantitation of 4.89 ppb for a 10 μm microband array and 1.53 ppb for the 40 μm microdisc array. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Nur Azura Mohd Said en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Electrochemical biosensor en
dc.subject Microelectrode arrays en
dc.subject Surface biofunctionalisation en
dc.subject Electrochemical impedance spectroscopy (EIS) en
dc.title Electrochemical biosensor based on microfabricated electrode arrays for life sciences applications en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.check.info No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Malaysian Agricultural Research and Development Institute en
dc.description.status Not peer reviewed en
dc.internal.school Chemistry en
dc.internal.school Tyndall National Institute en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
ucc.workflow.supervisor vladimir.ogourtsov@tyndall.ie
dc.internal.conferring Summer Conferring 2014

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