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Noble metal nanoparticles for assay development

Zhang, Yi (2013) Noble metal nanoparticles for assay development. PhD thesis, Dublin City University.

Noble metal nanoparticles exhibit a unique optical property known as localized surface plasmon resonance (LSPR), which occurs when interacting light couples to the collective oscillations of the surface electrons. This work investigates the use of various nanoparticles for biosensing based on LSPR. Triangular silver nanoplates (TSNPs), synthesized using two different methods, and their derivatives, gold-coated TSNPs (AuTSNPs), were investigated for use in refractive index sensitivity-based solution assays. Refractive index sensitivities of these nanoplates were determined and benchmarked against the theoretical calculation predicted by Miller et al.. The first generation TSNPs and AuTSNPs were used for the detection of human C-reactive protein (CRP) and cardiac troponin I (cTnI) and the second generation AuTSNPs were used for the detection of human CRP. In order to address the complex assay design, a simpler aggregation-based assay for the detection of human IgG was implemented using spherical gold nanoparticles. Furthermore, a preliminary study on incorporating the AuTSNPs into a surface plasmon resonance (SPR) sensor was carried out to explore the enhancement effect of the nanoplates on SPR detection. Nobel metal nanoparticles are found to enhance fluorescence-based biosensing due to a phenomenon known as metal-enhanced fluorescence (MEF) when the nanoparticles are in the vicinity of fluorophores. In this work, the enhancement effects of the AuTSNPs and spherical silver nanoparticles (AgNPs) on the fluorescence were evaluated. A significant enhancement was observed for AgNPs whereas no enhancement was observed for AuTSNPs. Further MEF studies were conducted using various dyes and gold-coated AgNPs. AgNPs were used for enhancing the fluorescence-based assays for human IgG and CRP detection. The limits of detection (LODs) of the IgG and CRP assays were improved by ~ 9-fold and ~ 19-fold, respectively. This work establishes the potential of plasmonic nanoparticles for highly sensitive biosensing and holds much promise for the improvement of biomedical diagnostics.
Item Type:Thesis (PhD)
Date of Award:16 September 2013
Supervisor(s):McDonagh, Colette
Uncontrolled Keywords:Noble metal nanoparticles; Localized Surface Plasmon Resonance (LSPR); Biosensors
Subjects:Physical Sciences > Physics
Physical Sciences > Nanotechnology
Physical Sciences > Photonics
Biological Sciences > Biosensors
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Physical Sciences
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License
ID Code:19380
Deposited On:13 Nov 2013 09:30 by Colette Mcdonagh . Last Modified 13 Nov 2013 09:30

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