gold nanoparticles phd thesis

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Robotically assisted evolution of gold nanoparticles and their hybridation with POMs

Martin Marti, Sergio (2017) Robotically assisted evolution of gold nanoparticles and their hybridation with POMs. PhD thesis, University of Glasgow.

The work presented in this thesis focused on the synthesis of gold nanoparticles, exploring new ways to synthesise them and also using new tools to improve the study and discovery of new nanomaterials. Whilst there has been a special concern in understanding how they are organised and which are the best conditions to achieve specific shapes, there is gap in finding new approaches that can allow fast synthesis of nanoparticles and fast screening of the chemical space and real time observation of the reaction under different reaction conditions. In the first chapter of this thesis we are going to present a new synthesis method to prepare gold nanoparticles-POM hybrids. Also, we will discuss how POMs can influence the aggregation of nanoparticles, depending on the size and charge of the POM. For example, gold nanoparticles will aggregate more easily if they are surrounded by small and less negatively charged POMs. In the next chapters of the thesis, we will aim to demonstrate that an automated system is able to evolve gold nanomaterials, this means that an automated system will use raw materials (simple chemicals, in this specific case HAuCl4, CTAB and NaBH4) to synthesise very simple nanostructures, such as spheres, then reuse those spheres and other chemicals to produce even more complex structures. In chapter 2 we will go through the process of building an automated system, in this case, the system will be designed to synthesise gold nanoparticles. We will start by designing the automated system and testing it, we will see the flaws that those different systems had and how we overcame them by doing some improvements on them, such as more control over the temperature of the reaction, keeping a constant temperature of the reagents, improving the cleaning process, trying different concentrations of the reagents, trying different algorithms and different ways to calculate the fitness factor, etc. until we found a system that was very reliable, which was able to provide reproducible results. In the last chapter of this thesis, we will focus on the results obtained in the different versions of the automated system. First, we will explain our first objective, which was obtaining gold nanorods of very short aspect ratio. We will analyse the results we obtained for that objective, trying different fitness factor calculations and how the different ways to calculate the fitness factor affected the process to obtain the desired product. We will discuss why we changed the fitness factor calculation and how this helped to achieve our objective. Then, we will jump to the next level of the project, which was to synthesise very simple gold nanoparticles from raw chemicals and reuse these simple structures to obtain more complex structures. This demonstrates that we have an automated system able to evolve gold nanomaterials; the first of this kind. In this chapter, we will also talk about the different techniques used to characterise the product, where we used in-line analytical techniques such as UV-Vis or image analysis (which are the ones used to calculate the fitness factor that the algorithm is going to use) and other techniques to fully characterise the final product such as TEM.

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Synthesis and Characterization of Gold Nanostructures for Healthcare Applications

--> Chankhunthod, Navadecho (2019) Synthesis and Characterization of Gold Nanostructures for Healthcare Applications. PhD thesis, University of Leeds.

Functionalized gold nanostructures with well-defined geometry and controlled optical properties can potentially play an important role in healthcare applications such as biosensing, photocatalysis, drug delivery, photothermal therapy and imaging due to their unique properties. This thesis aims to develop a novel Au nanostructure for healthcare applications, using an effective synthesis protocol in order to produce a suitable Au nanostructure with NIR absorption, high thermal stability and low toxicity. Well-controlled, reproducible Au nanostructures with NIR absorption spectra, including gold nanoparticles (NPs), nanorods (NRs), nanobipyramids (NBPs) and nanotriangles (NTs) have been synthesised using a wet-chemical synthesis approach and characterized using dynamic light scattering and transmission electron microscopy. The optical and plasmonic properties of the Au nanostructures were investigated using uv-vis spectroscopy, finite element modelling (FEM) and STEM/low-loss EELS analysis was employed. EELS results exhibited good agreement with uv-vis spectra and FEM modeling and revealed the size- and shape-dependent plasmonic properties and showed that NIR absorption can be altered by increasing the curvature of particles. The thermal stability of Au nanostructures, which is important for photothermal therapy applications, was investigated using in-situ TEM heating. It was found that the thermal stability of Au nanostructures decreased in the order : AuNPs > AuNTs > AuNBPs > AuNRs. The proposed useful temperature ranges whereby heating does not significantly affect the optical properties were up to 100ºC, 200ºC, 800ºC, for CTAB-capped AuNRs, CTAB-capped AuNBPs and CTAC-stabilized AuNTs, respectively. The thermal stability of particles was increased by surface functionalization of the NPs from a CTAB coating, through a PSS coating and finally to a silica coating. Thermal deformation arose from curvature-driven surface diffusion. Finally, the biocompatibility of Au nanostructures, in terms of the effect of size, morphology, and surface coating, was investigated by their electrochemical interaction with a model membrane based on DOPC on an Hg/Pt electrode. Only smaller Au nanostructures with a diameter of ca. 20 nm exhibited a significant interaction. However, the effect of the surface coating was found to be a more significant effect with the order of interaction with the model membrane ranging from CTAB > PSS > CTAC > citrate coated Au nanostructures. Thus overall, potential biocompatible candidates for healthcare applications are proposed to be citrate-, PSS- or silica-coated gold nanostructures with NIR absorption and dimensions larger than approximately 20-25 nm.  

--> Final eThesis - complete (pdf) -->

Filename: N.Chankhunthod, SCAPE PhD Thesis, 2019.pdf

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Digital Commons @ USF > Office of Graduate Studies > USF Graduate Theses and Dissertations > USF Tampa Theses and Dissertations > 6818

USF Tampa Graduate Theses and Dissertations

Bisphosphonate functionalized gold nanoparticles for the study and treatment of osteoporotic disease.

Christopher Conners , University of South Florida Follow

Graduation Year

Document type.

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Chemical Engineering

Major Professor

Vinay K. Gupta, Ph.D.

Co-Major Professor

Venkat Bhethanabotla, Ph.D.

Committee Member

Piyush Koria, Ph.D.

Nathan Crane, Ph.D.

David Mitchell, Ph.D.

osteoclast, osteoblast, pamidronate, alendronate, remodeling

The use of nanoparticles for disease treatment is an increasingly popular area of research. The potential for multi-functionality allows nanoparticles to be used as transport and delivery vehicles for drugs and as diagnostic aides, among other applications, to address the unmet needs of many disease treatments. One such class of disease is osteoporosis including severe disorders, like Paget’s disease, Osteogenesis Imperfecta and Legg Calve Perthes disease. In this dissertation, we discuss a nanoparticle system consisting of gold nanoparticles surface functionalized with primary amine bisphosphonates, which is a classification of pharmaceuticals that is common in the treatment of osteoporosis. Functionalized nanoparticles allow for greater intracellular concentrations of pharmaceutical, while the properties of the gold nanoparticles provide the ability to track the pharmaceutical and enhance imaging.

We have synthesized and characterized bisphosphonate functionalized gold nanoparticles of controlled size of approximately 15 nm, which are suitable for cellular uptake, and functionalized the surface using self-assembly with pamidronate and alendronate. In one major finding of this study, inductively coupled plasma mass spectrometry was used to estimate approximate surface density of the bisphosphonates on the gold nanoparticles. This resulted in concentrations of approximately 0.65 molecules per nm 2 (approximately 154 Å 2 /molecule) for pamidronate functionalized on gold, and approximately 2.6 molecules per nm 2 (approximately 39 Å 2 /molecule) for alendronate functionalized on gold. This allows for more accurate estimates of pharmaceutical concentrations, during in vitro and in vivo studies .

Additionally, we investigated the effects of bisphosphonate functionalized gold nanoparticles on the viability and morphology of osteoclast and osteoblast cells in vitro . We found that attaching the bisphosphonates to the surface of the nanoparticles leads to increased apoptotic effects of the bisphosphonates on the osteoclast cells compared to free bisphosphonates. Further, we showed bisphosphonate functionalized gold nanoparticles may have an effect on nuclei morphology that may provide an additional means of modulating bone resorption rather than just through influencing viability. Further we showed that it may be possible to target concentrations that are safe for osteoblasts, which is critical in determining potential treatment concentrations. These viability results bring to light a number of potential considerations into the optimization of potential treatments, such as dosing concentrations.

Finally, detailed results are given on effects of bisphosphonate functionalized gold nanoparticles on important behavior and activity of osteoclast and osteoblast cells in vitro . We showed that while using concentrations below the toxicity threshold, some of the normal activity of the cells could be maintained. RANKL and ALP expression in osteoblasts were maintained when removing viability as a variable. Additionally, bone nodule formation was also maintained for osteoblasts and co-cultured in vitro systems. Finally, we showed that the introduction of bone in the in vitro studies adds a new degree of consideration as to the interaction of the bisphosphonates with the hydroxyapatite surface. This strong interaction with bone is an important consideration in further developing potential treatments for osteoporotic disease.

This dissertation provides insights into the use of bisphosphonate functionalized gold nanoparticles as a potential treatment and means of study for bone remodeling disorders.

Scholar Commons Citation

Conners, Christopher, "Bisphosphonate Functionalized Gold Nanoparticles for the Study and Treatment of Osteoporotic Disease" (2017). USF Tampa Graduate Theses and Dissertations. https://digitalcommons.usf.edu/etd/6818

Since October 06, 2017

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Study on gold nanoparticles for biological applications

Downloadable content.

• Zhang, Yinan
• Strathclyde Thesis Copyright
• University of Strathclyde
• Doctoral (Postgraduate)
• Doctor of Philosophy (PhD)
• Department of Physics
• Gold nanoparticles have attracted much attention in the field of biological research, especially in biological imaging and sensing due to their unique physical properties. Fluorescence is a highly-sensitive, non-invasive biological study method and has been widely used in a variety of research topics. The aim of this thesis is to study the unique optical properties of gold nanoparticles and demonstrate their application in biological imaging and sensing through fluorescence microscopic and spectroscopic techniques. An introduction of gold nanoparticles and fluorescence techniques used in this project is given in Chapter 1. In Chapter 2, the synthesis method of gold nanoparticles, dependence of optical properties on particle size and shape, the unique spectroscopic characterization and microscopic application of gold nanorods are discussed. Fluorescence lifetime imaging microscopy (FLIM) based on two-photon luminescence lifetime from gold nanorods in cell culture, and the advantages of this method in biological imaging are demonstrated in Chapter 3. In Chapter 4, the energy transfer between a DNA dye, 4'-6-Diamidino-2-phenylindole (DAPI), and different types of gold nanoparticles in solution is demonstrated using FLIM. Biological imaging application based on energy transfer between gold particles and DAPI in cell culture is discussed as well in this chapter. A study on energy transfer process concerning different excitation conditions is reviewed in Chapter 5. Furthermore, application of fluorescence resonant energy transfer (FRET) based FLIM method in the research of intracellular pathway of gold nanoparticles in cells is demonstrated. Chapter 6 presents a systematic study on the cytotoxicity of gold nanorods in cell culture using MTT (3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. The effects of particle shape, surface conditions, dosage, incubation time on the cytotoxicity and the mechanism of cytotoxicity are discussed. In Chapter 7, a brief summary and outlook to future work are presented.
• Doctoral thesis
• 10.48730/0hqv-me33

Hybrid gold nanoparticles coated with organic polymers and antibodies as platform for cancer theranostics

Prof. Stéphane LUCAS, UNamur, Physics of Matter and Radiation (PMR), Laboratory of Analysis by Nuclear Reaction (LARN)

• Prof. Dr. Stéphane Lucas (Promoter)
• Prof. Dr. Carine Michiels (Co-promoter)
• Dr. Ir. An Aerts (Co-promoter)
• Dr. Karen Van Hoecke (Co-supervisor)
• Prof. Dr. Sarah Baatout
• Prof. Dr. Bernard Masereel (Chairman)
• Prof. Dr. Nadine Millot

Hybrid gold nanoparticles coated with organic polymers and antibodies as platform for cancer theranostics: Investigation of the cytotoxicity mechanisms and feasibility study of radioactive labeling

PhD thesis in the framework of a collaboration between UNamur and SCK-CEN

Thanks to their unique optical and physicochemical properties, gold nanoparticles (AuNPs) have emerged as promising radiosensitizers, which can enhance the efficacy of external and internal radiotherapy. In this thesis, we investigated the toxicity mechanism of antibody-functionalized AuNPs in normal liver, kidney and microvascular endothelial cells. Furthermore, we evaluated the pharmacokinetics, biodistribution and toxicity of the AuNPs after a single intravenous injection in healthy mice. Finally, the antibody-functionalized AuNPs were radiolabeled with the radionuclide, 177 Lu, using bifunctional chelators and were tested for their stability, specificity, and internalization in human cancer cells.

The results demonstrated that the antibody-functionalized AuNPs were internalized in normal cells, causing oxidative stress, mitochondrial dysfunction and inhibition of the antioxidant defense system. In vivo , the antibody-functionalized AuNPs were rapidly cleared from the blood circulation and accumulated mainly in the liver and spleen, followed by a long-term retention. Nevertheless, cytokine serum levels showed no significant increase and there was only a slight and transient increase of the liver aminotransferase enzymes. Furthermore, normal kidney, liver, spleen and lung morphology was observed up to 4 weeks post-injection. Finally, the bifunctional chelator diethylenetriaminepentaacetic acid (DTPA) was coupled to the antibody-functionalized AuNPs and rapidly achieved a high radiolabeling efficiency and yield (90%) under mild reaction conditions. The obtained 177 Lu-radiolabeled AuNPs showed an enhanced binding and internalization in receptor-overexpressing cancer cells when compared to receptor-negative cancer cells.

In conclusion, together with the biological inhibition, radiolabeled antibody-functionalized AuNPs could have the potential to increase the efficacy of targeted radionuclide therapy compared to a radiolabeled antibody. However, the rapid sequestration and long-term retention of the AuNPs in the liver and spleen after intravenous administration might restrict the tumor accumulation and thus its therapeutic potential.

NARILIS • Rue de Bruxelles 61 - 5000 Namur - Belgium • [email protected]

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