Gold nanostructures, with exotic optical behaviours, have been shown to be suitable as high performance refractive index sensors for biochemical reactions. Extensive research has focused both on the fabrication and characterisation of the nanostructures, as well as the surface chemistries of the sensor. Here we present a novel biosensor design, based on the excitation of localised surface plasmon resonances (LSPR) in gold nanowire arrays. Nanostructures arrays are produced by the electrode position of gold into self-assembled porous aluminium oxide templates. Nanostructure growth is precisely monitored by in-situ optical measurements to provide fine tuning of the optical behaviour. This fabrication technique is easily repeatable and scalable. Nanostructure arrays are characterised using high resolution imaging and theoretical models are developed to help understand the rich optical behaviour. Finite element modelling carried out using COMSOL is used to investigate fluid behaviour and localised electric fields in the array. A Retarded Dipole Interaction Model (RDIM) and a Maxwell-Garnett effective medium theory are then used to determine the underlying mechanisms behind the optical behaviour and also to predict future behaviours. These models show good agreement with experimental results. Nanowire arrays are prepared for biochemical studies by the growth self-assembled monolayers (SAMs) on the gold surface. Various monolayers have been investigated to develop a non-fouling surface including simple alkanethiols, synthesised peptides and PEG-thiol derivatives. Activated chips are then integrated into a cuvette based prototype biosensor. This prototype has been used to investigate various binding events e.g. antigen/antibody. Various proteins have been immobilised on the sensor surface using NHS/EDC chemistry and the binding kinetics determined. Binding coefficients calculated have been shown to be comparable with current commercial biosensors, with a simplified experimental setup and a significantly lower cost.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:680075 |
| Date | January 2015 |
| Creators | Hill, Breandán James |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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