Development and characterization of water-soluble, photo-luminescent gold nanoparticles for bio-imaging

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Publication Type dissertation
School or College College of Engineering
Department Bioengineering
Author Lee, Chang-won
Title Development and characterization of water-soluble, photo-luminescent gold nanoparticles for bio-imaging
Date 2010-08
Description In this dissertation, we explored the synthesis of water-soluble and photoluminescence behavior near infrared emitting (610 nm) gold nanoparticles terminated by mercaptoalkanoic acid and possessing UV range (200~350 nm) excitation. Different effects were monitored as a function of reaction condition including different gold and ligand concentrations, types of ligands, solvents and pH. It is understood that Gold-thiol complexes were formed and developed into nanoparticle-supported complexes. Analyses of the excitation spectra suggests the origin of the photoluminescence to be transitions from the triplet energy state of LMMCT with the electrons transferred from excited orbitals of Au/Au(I) sites of the gold surface. It is also the reason for the enhanced photostability compared with those produced as free molecules via other synthesis methods. The pH dependency of the emission intensity and excitation spectra alteration of the gold nanoparticles was also explored. The emission intensity of the gold nanoparticle showed linear dependency on the pH change in the weak acidic to basic region above the pH 6 with a small peak appearance at pH 4. This trend was accompanied by a distinctive excitation peak wavelength change from 280-290 nm to 250-260 nm at pH 6.. A brush configuration change of the surface ligands was proposed to explain the pH dependency. In the charged and extended form of the carboxylic acid ligands, the accessibility of water to the gold nanoparticles surface is greater than in the uncharged collapsed form. Thus, in the collapsed form, the local hydrophobicity at the gold surface is higher and theCT excitation spectrum shifts to the blue. Its biocompatibility, as suggested by the cytotoxicity test and reactive oxygen species (ROS) generation test, provides broader opportunities for this product to be utilized in biological systems.
Type Text
Publisher University of Utah
Subject Bioimaging; Gold nanoparticle; PH sensor
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © Chang-won Lee 2010
Format Medium application/pdf
Format Extent 3,047,660 bytes
Source Original in Marriott LIbrary Special Collections, RC39.5 2010 .L44
ARK ark:/87278/s6sj21bt
Setname ir_etd
Date Created 2012-04-24
Date Modified 2016-07-12
ID 194790
Reference URL https://collections.lib.utah.edu/ark:/87278/s6sj21bt