The design of ultrasensitive immunosensors based on a new multi-signal amplification gold nanoparticles-dotted 4-nitrophenylazo functionalised graphene sensing platform for the determination of deoxynivalenol

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dc.contributor.advisorIwuoha, Emmanuel
dc.contributor.advisorBaker, Priscilla G. L.
dc.contributor.authorSunday, Christopher Edozie
dc.date.accessioned2014-06-18T13:03:34Z
dc.date.accessioned2024-05-13T12:41:08Z
dc.date.available2014-06-18T13:03:34Z
dc.date.available2024-05-13T12:41:08Z
dc.date.issued2014
dc.descriptionPhilosophiae Doctor - PhDen_US
dc.description.abstractA highly dispersive gold nanoparticle-dotted 4-nitrophenylazo functionalised graphene nanocomposite (AuNp/G/PhNO2) was successfully synthesised and applied in enhancing sensing platform signals. Three label-free electrochemical immunosensors for the detection of deoxynivalenol mycotoxin (DON) based on the systematic modification of glassy carbon electrodes (GCE) with AuNp/G/PhNO2 was effectively achieved. General electrochemical impedance method was employed for the sensitive and selective detection of DON in standard solutions and reference material samples. A significant increase in charge transfer resistance (Rct) of the sensing interface was observed due to the formation of insulating immune-complexes by the binding of deoxynivalenol antibody (DONab) and deoxynivalenol antigen (DONag). Further attachments of DONab and DONag resulted in increases in the obtained Rct values, and the increases were linearly proportional to the concentration of DONag. The three immunosensors denoted as GCE/PDMA/AuNp/G/PhNH2/DONab, GCE/Nafion/[Ru(bpy)3]2+/AuNp/G/PhNH2/DONab and GCE/Nafion/[Ru(bpy)3]2+/G/PhNH2/DONab have detection range of 6 – 30 ng/mL for DONag in standard samples. Their sensitivity and detection limits were 43.45 ΩL/ng and 1.1 pg/L; 32.14ΩL/ng and 0.3 pg/L; 9.412 ΩL/ng and 1.1 pg/L respectively. This result was better than those reported in the literature and compares reasonably with Enzyme Linked Immunosorbent Assay (ELISA) results. The present sensing methodology represents an attractive alternative to the existing methods for the detection of deoxynivalenol mycotoxin and other big biomolecules of interest due to its simplicity, stability, sensitivity, reproducibility, selectivity, and inexpensive instrumentation. And they could be used to develop high-performance, ultra-sensitive electrochemiluminescence, voltammetric or amperometric sensors as well.en_US
dc.identifier.urihttps://hdl.handle.net/10566/14787
dc.language.isoenen_US
dc.publisherUniversity of Western Capeen_US
dc.rights.holderUniversity of Western Capeen_US
dc.subjectDeoxynivalenol mycotoxinen_US
dc.subjectGrapheneen_US
dc.subject4-nitrophenyl diazonium cationen_US
dc.subjectGold nanoparticleen_US
dc.subjectUV-Vis spectroscopyen_US
dc.subjectRaman spectroscopyen_US
dc.subjectCyclic voltammetryen_US
dc.subjectElectrochemical impedance spectroscopyen_US
dc.subjectElectrochemiluminescenceen_US
dc.subjectChronoamperometry/Chronocoulometryen_US
dc.titleThe design of ultrasensitive immunosensors based on a new multi-signal amplification gold nanoparticles-dotted 4-nitrophenylazo functionalised graphene sensing platform for the determination of deoxynivalenolen_US
dc.typeThesisen_US

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Philosophiae Doctor - PhD (Chemistry)