Branagan, David (2014) The Formation of Metal Nanoparticle-Carbon Nanotube Composite Materials for the Non-enzymatic Detection of Glucose. PhD thesis, National University of Ireland Maynooth.

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Abstract

Nano composite materials consisting of gold nanoparticles (AuNPs) and functionalised multiwalled carbon nanotubes (fMWCNTs) were initially prepared using simple synthetic reduction methods, involving the chemical agents sodium borohydride and trisodium citrate. These composites were named fMWCNT-Aunano(NaBH4) and fMWCNT-Aunano(TriSodCit). AuNPs of a face-centred cubic structure were successfully formed on the sidewalls of the fMWCNTs. The fMWCNT-Aunano(NaBH4) composite had an Au loading of 2.0% wt. and contained AuNPs with a mode diameter of 7.5 nm. The fMWCNT-Aunano(TriSodCit) composite had an Au loading of 5.0% wt. and contained AuNPs with a mode diameter of 23 nm. These composites were used to form films on glassy carbon and screen printed electrodes for the non-enzymatic electrochemical detection of glucose in PBS buffer at physiological pH. Electrochemical pre-treatments in sodium hydroxide and sulfuric acid provided films with improved sensitivity. These films were combined with a Nafion® membrane to improve selectivity towards glucose in the presence of commonly occurring interferants. The fMWCNT-Aunano(NaBH4) composite was also combined with palladium nanoparticles (PdNPs) to form a composite named fMWCNT-Aunano/Pdnano. This bi-metallic composite was formed using a potentiostatic electrodeposition of Pd onto the surface of pre-existing fMWCNT-Aunano(NaBH4) films. These PdNPs had a mode diameter of 95 nm and the Pd loading was close to 3.0%. This composite film was used for the electrochemical detection of glucose, whereby it facilitated its oxidation at more negative potentials in comparison to the fMWCNT-Aunano composites. Interference studies were carried out using chemical species commonly present in the blood; ascorbic acid, uric acid, fructose, galactose, serum albumins, chloride and acetaminophen. The severity of interference varied at each electrode and it was shown that Nafion® reduced the level of interference. Sensor reusability and shelf-life studies were also carried out using the composite modified films. These films provided accurate glucose detection over twelve successive uses, although they were not deemed to be suitable for storage. The materials were characterised using TEM, SEM, EDX, AAS, XRD, EIS, UV-Vis and Raman spectroscopy. An electrochemical characterisation also showed that a significant electroactive area of Au was present in the fMWCNT-Aunano(NaBH4) and fMWCNT-Aunano(TriSodCit) composite when cast onto an electrode surface. Overall these composite materials show good initial promise for use as non-enzymatic glucose sensors based on these preliminary studies.

Item Type:	Thesis (PhD)
Keywords:	Formation; Metal Nanoparticle-Carbon Nanotube Composite Materials; Non-enzymatic Detection; Glucose;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	9134
Depositing User:	IR eTheses
Date Deposited:	09 Jan 2018 14:59
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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