Fabrication and optimisation of high-performance nanoplasmonic sensors for biosensing applications

Christie, Iain (2024) Fabrication and optimisation of high-performance nanoplasmonic sensors for biosensing applications. PhD thesis, University of Glasgow.

Abstract

Plasmonic sensors are established as an effective, label-free technique for many applications. This thesis focuses on localised surface plasmon resonance (LSPR) sensors and how to optimise them for sensing applications. Although there are examples of lithographically-defined nanostructures being deployed in biosensing applications, few of these studies make attempts to use nanostructures optimised for sensing performance. For this reason, in this thesis we examine different ways of optimising plasmonic nanostructures with the aim of improving their performance in biosensing applications.

We first focus on the properties and sensing abilities of different nanostructure geometries including experimentally assessing both the bulk and localised refractive index sensitivity of different nanostructure arrays. This includes a discussion of the merits of different nanostructure geometries for different applications and the important role which resonance wavelength plays in a sensors refractive index sensing capability.

Next, we focus on the optimisation of nanostructure arrays using annealing techniques. There are few studies on the effect of annealing on the sensing performance of nanostructure arrays and this chapter serves as a discussion as to the benefits and drawbacks of thermal annealing for plasmonic nanostructure sensing arrays. As well as discussing the positive effects of annealing, remedies to the main drawback of annealing, structure deformation, are investigated. Structure deformation results in a reduced electromagnetic field concentration, resulting in diminished sensing performance. To mitigate these issues, we explore the use of a protective layer during annealing to prevent deformation as well as the use of a femtosecond laser as an alternative method for annealing.

Finally, we present work towards a cross-reactive method of sensing proteins. This begins by presenting different methods of making the plasmonic sensors reusable after proteins have adhered to the surface including optimising a cleaning protocol and investigating different surface chemistries that may allow for temporary protein interactions. This culminates in initial testing of a cross-reactive system which shows some success in discriminating between different proteins in solution without the need for specific receptors.

• Item Type: Thesis (PhD)
• Subjects: T Technology > TA Engineering (General). Civil engineering (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Clark, Professor Alasdair and Peveler, Dr. William
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84496
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 21 Aug 2024 15:03
• Last Modified: 23 Aug 2024 13:27
• Thesis DOI: 10.5525/gla.thesis.84496
• URI: https://theses.gla.ac.uk/id/eprint/84496

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