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Title: Creating novel biofunctionalized nanorod-dye conjugates as bright tags for surface-enhanced resonance Raman scattering
Author: McLintock, Alison
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2013
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Gold nanorods have attracted much attention in the literature due to the ability to tune the aspect ratio and hence localized surface plasmon resonance (LSPR) of these materials. When co-assembled with molecular dyes this provides new opportunities yet to be explored for the design of multimodal optical probes compatible with a range of spectroscopies, in particular surface-enhanced resonance Raman scattering (SERRS). This research describes the preparation and characterization of novel SERRS tags, capable of providing very bright Raman signals whilst remaining non-aggregated and thus hotspot-free. Additional advantages of this approach are the excellent control afforded over the dye surface coverage and surface orientation along with the very high level of stability displayed by these nanotags. An approach enabling a systematic study was developed where both the LSPR of the nanorod and the molecular resonance of the dye adsorbed onto the rod surface were varied with respect to the laser excitation wavelengths. Resonance coupling between dyes and nanorods was found to be a significant factor in the overall SERRS enhancement. Also when directly compared to quasi-spherical gold nanoparticles, significantly higher Raman intensities were obtained. The controlled side-by-side assembly of the nanorod-dye conjugates and subsequent stabilization of the suspended clusters for upwards of eight months was also demonstrated. A new class of tags, known as universal SERRS tags (USTs) were proposed. By co-assembling multiple dyes on the same nanorod, bright Raman signals were obtained at wavelengths ranging from 514 - 1064 nm, without requiring nanoparticle aggregation. In addition, correlated SEM and Raman mapping analysis showed it was possible to perform single particle SERRS, with close to 100% of the nanotags found to be SERRS active. The application of the USTs for cellular imaging was clearly demonstrated and the non-cytotoxicity of this system to dendritic cells was confirmed. Finally, a new methodology was introduced for the covalent functionalization of both polymer wrapped rod and spherical shaped nanoparticles.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available