Electrochemical biosensor based on microfabricated electrode arrays for life sciences applications

dc.check.embargoformatNot applicableen
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dc.contributor.advisorOgurtsov, Vladimir I.en
dc.contributor.advisorHerzog, Grégoireen
dc.contributor.authorMohd Said, Nur Azura
dc.contributor.funderMalaysian Agricultural Research and Development Instituteen
dc.date.accessioned2015-01-19T10:03:20Z
dc.date.available2015-01-19T10:03:20Z
dc.date.issued2014
dc.date.submitted2014
dc.description.abstractIn 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.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationMohr Said, N. A. 2014. Electrochemical biosensor based on microfabricated electrode arrays for life sciences applications. PhD Thesis, University College Cork.en
dc.identifier.endpage300
dc.identifier.urihttps://hdl.handle.net/10468/1759
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2014, Nur Azura Mohd Saiden
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectElectrochemical biosensoren
dc.subjectMicroelectrode arraysen
dc.subjectSurface biofunctionalisationen
dc.subjectElectrochemical impedance spectroscopy (EIS)en
dc.thesis.opt-outfalse
dc.titleElectrochemical biosensor based on microfabricated electrode arrays for life sciences applicationsen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
ucc.workflow.supervisorvladimir.ogourtsov@tyndall.ie
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