Cancer is the leading cause of death worldwide and one third of its burden can be decreased with early detection. Surface enhanced Raman spectroscopic (SERS) based imaging is a promising new technique for non-invasive detection of tumours due to its ultra-sensitivity and multiplexing capabilities. For in vivo SERS molecular imaging, a biocompatible, robust and targeted nanoparticle is required to attain high sensitivity and specificity. In this thesis, a SERS capable gold nanoparticle was rationally designed by encapsulation with a phospholipid bilayer which conferred biocompatibility, colloidal stability and versatility to changing surface chemistry. Moreover, validation of this SERS probe with a specific targeting ligand for carcinoma cells was studied through the targeting of a commonly overexpressed cancer receptor, epidermal growth factor receptor. Using this phospholipid design, optimizations with differing chemistries, targeting ligand or modifications for additional functionalities can be achieved for further development as a viable in vivo molecular imaging tool.

Cellulose-based materials are widely used in a number of important applications (e.g. paper, wood, textiles). Additional developments are suggested by the growing interest for natural fibre-based composite and nanocomposite materials. The motivation is not only in the economic and ecological benefits, but is also related to advantageous properties and characteristics. The objective of this thesis is to provide a better understanding of process-structure-property relationships in some novel cellulose network materials with advanced functionalities, and showing potential large-scale processability. An important result is the favourable combination of mechanical properties observed for network-based cellulose materials. Compression-moulding of cellulose pulp fibres under high pressure (45 MPa) and elevated temperature (120 – 180 oC) provides an environmentally friendly process for preparation of stiff and strong cellulose composite plates. The structure of these materials is characterized at multiple scales (molecular, supra-molecular and microscale). These observations are related to measured reduction in water retention ability and improvement in mechanical properties. In a second part, cellulose nanofibrils (NFC) are functionalized with in-situ precipitated magnetic nanoparticles and formed into dense nanocomposite materials with high inorganic content. The precipitation conditions influence particle size distributions, which in turn affect the magnetic properties of the material. Besides, the decorated NFC network provides high stiffness, strength and toughness to materials with very high nanoparticle loading (up to 50 vol.%). Subsequently, a method for impregnation of wet NFC network templates with a thermosetting epoxy resin is developed, enabling the preparation of well-dispersed epoxy-NFC nanocomposites with high ductility and moisture durable mechanical properties. Furthermore, cellulose fibrils interact positively with the epoxy during curing (covalent bond formation and accelerated curing). Potential large scale development of epoxy-NFC and magnetic nanocomposites is further demonstrated with the manufacturing of 3D shaped compression-moulded objects. Finally, the wet impregnation route developed for epoxy is adapted to prepare UV-curable NFC nanocomposite films with a hyperbranched polymer matrix. Different chemical modifications are applied to the NFC in order to obtain moisture durable oxygen barrier properties. / <p>QC 20131111</p>

Cancer is the leading cause of death worldwide and one third of its burden can be decreased with early detection. Surface enhanced Raman spectroscopic (SERS) based imaging is a promising new technique for non-invasive detection of tumours due to its ultra-sensitivity and multiplexing capabilities. For in vivo SERS molecular imaging, a biocompatible, robust and targeted nanoparticle is required to attain high sensitivity and specificity. In this thesis, a SERS capable gold nanoparticle was rationally designed by encapsulation with a phospholipid bilayer which conferred biocompatibility, colloidal stability and versatility to changing surface chemistry. Moreover, validation of this SERS probe with a specific targeting ligand for carcinoma cells was studied through the targeting of a commonly overexpressed cancer receptor, epidermal growth factor receptor. Using this phospholipid design, optimizations with differing chemistries, targeting ligand or modifications for additional functionalities can be achieved for further development as a viable in vivo molecular imaging tool.

This thesis is focused on the fabrication and characterization of self-assembled arrays of magnetic iron oxide (Fe3O4, γ-Fe2O3 and Fe1-xO) nanoparticles. The synthesis of spherical and cubic iron oxide nanocrystals, with sizes between 5 and 30 nm and narrow size distributions, is demonstrated, along with a rigorous morphological characterization of the cubic nanoparticles. The transformation of core|shell Fe1-xO|Fe3-δO4 particles into single-phase Fe3-δO4 particles is studied in detail. It is found that anti-phase boundaries in the particles result in the emergence of anomalous magnetic properties i.e. exchange bias, and a reduced saturation magnetization compared to that of bulk Fe3O4. Cubic nanocrystals are assembled into arrays possessing an exceptionally high degree of translational ordering and a high degree of crystallographic alignment. A combination of electron microscopy and small-angle X-ray scattering is used in the characterization of the 3D nanostructures. The directional (anisotropic) interactions in the 3D structures are modeled in an attempt to find a link between the nanocrystal morphology and the corresponding mesostructure. Here, the cohesive van der Waals energy is estimated for a system of nanocubes with a variable truncation. The assembly of nanocubes in magnetic fields of various strengths is systematically investigated. A perturbed mesocrystal growth habit is observed at intermediate fields, whereas at high field strengths, the assembly is dominated by ferrohydrodynamic instabilities. Last, magnetometry is used to study the collective magnetic properties of self-assembled nanocrystals. The magnetic susceptibility in a weak magnetic field is studied as a function of film thickness and particle size. An increase in the tendency to form ferromagnetic couplings  with decreasing film thickness can be established. This 2D to 3D crossover of the magnetic properties of the nanoparticle arrays can be related to a change in the magnetic vortex states.

Water utilities in Nova Scotia face numerous challenges treating low turbidity water and complying with stringent guidelines and treatment standards. Problems associated with the treatment of low-turbidity water are not confined to Nova Scotia; several other provinces, British Columbia, Manitoba and Ontario share similar water characteristics of drinking water sources. The treatment of low turbidity water is a challenge for these utilities as it requires maintaining the appropriate coagulant dosage that will ensure adequate particle and natural organic matter removal, while at the same time not enhancing the formation of disinfection by-products. Another concern associated with the treatment of such water is that when the particle content of the water is very low, charge neutralization will not be effective due to the weak contact between destabilized particles. Currently, nanoparticles are not regulated as water contaminants, and thus it is unclear whether the existing filtration treatment practices are capable of removing them from drinking water. Obtaining in-depth information on nanoparticle characteristics in drinking water sources will provide a valuable resource that can assist in the development of future treatment strategies. In this research, characteristics of four synthetic nanoparticles cerium dioxide (CeO2), ferric oxide (Fe2O3), silicon dioxide (SiO2) and titanium dioxide (TiO2) were investigated in Milli-Q water for particle size, surface area, and surface potential using different characterization techniques. Water samples from Pockwock Lake were also characterized for naturally occurring nanoparticles. After initial testing, titanium dioxide (TiO2) nanoparticles were selected to examine particle removal at bench-scale filtration experiments, under operating conditions similar to those practiced at the J.D. Kline Water Supply Plant, Halifax, NS, Canada. Filter performance for the deposition of TiO2 nanoparticles was evaluated through the calculation of its attachment efficiency and coefficient under various water chemistry conditions. The calculated filter efficiency was then applied to simulate natural nanoparticles removal from water. The results of the research indicate that the investigated nanoparticles behaved similar to natural particles and formed aggregates with larger particle sizes in Milli-Q water. Among the tested nanoparticles, only titanium dioxide could be coagulated with alum, as its negative surface charge and zero point of charge were closer to that of alum. Filtration experiments revealed that TiO2 nanoparticles, when present in water, could successfully be removed by an alum dose of 8 mg/L. Indeed, removal in excess of 99.5% was achieved under the study conditions. Under the investigated water chemistry conditions, very low attachment efficiencies (?) of 0.001, 0.002 and 0.01, and filter coefficients (?) of -0.003, -0.001 and -0.02 were determined for the filters. Based on the calculated attachment efficiencies, and under the studied conditions, natural nanoparticles remain dispersed in the water and would not likely to be removed by direct filtration. The overall research findings represent a major step forward in nanoparticle removal by direct filtration.

This thesis research investigates the surface properties and performances of gold nanoparticles, microarc oxidation coating, and epitaxial nano-twinned copper film. The research aims to understand the critical behavior of material surfaces in order to facilitate design and development of new materials for tribological applications. The research will focus on improving of the gun barrel performances. Experimental approaches will be used for combining analysis with basic thermal energy transfer principles. Results obtained here will be used for developing new materials to be used in facilitating gun barrels. Experimental approach includes scanning calorimetry-thremogravimetric analysis, tribological testing, and potentiodynamic polarization. The fundamental understanding obtained here will be beneficial for the gun barrel design, manufacturing, and military technologies followed by the results of experiments with different three types of materials. The results of this research showed that the coatings with microarc oxidation and nano-twinned structure improved wear resistance from the tribological examinations and size of AuNPs affected their thermal behaviors measured by differential scanning calorimetry and thermogravimetric analysis method.

This Ph.D. thesis reports the discovery and study of several morphologies of ABC triblock copolymer assemblies in block selective solvents. One block copolymer self-assembled into helices (mostly double and some triple helices), and the other block copolymer formed a mixture of structures resembling hamburgers and striped cylinders. The helices, biomimmetic structures which are unusual from block copolymer self assembly, were prepared from the triblock copolymer poly(n-butyl methacrylate)-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(tert-butyl acrylate) (PBMA-b-PCEMA-b-PtBA). They were formed spontaneously in several binary solvent mixtures including dichloromethane/methanol, tetrahydrofuran (THF)/methanol, and chloroform/methanol. They were formed in the composition ranges where the mixtures were good for the PtBA block, poor for the PCEMA block, and marginal for the PBMA block. The structure was studied and established by TEM, AFM, DLS and 1H NMR and by TEM tomography. The mechanism and kinetics of helix formation was examined. The Hamburger and striped cylinder structures were produced from poly(tert-butyl acrylate)-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(succinated glyceryl monomethacrylate) or (PtBA-b-PCEMA-b-PSGMA) in mixtures of THF, (-)-sparteine and 1- or 2-propanol. Here THF solubilized all the blocks of the copolymer, while propanol was a precipitant for the middle block (PCEMA), and the chiral amine, (-)-sparteine, complexed with PSGMA and made it insoluble. Within the Hamburger-like structure, the “filling” was made of the complexed PSGMA chains and the "buns" were made of PCEMA. The striped cylinders were made of stacking alternating PCEMA and PtBA stubs. The PtBA chains were located on the outer surfaces of both of these structures. With the hamburger structures, after PCEMA crosslinking, we were able to remove the chiral amine by dialysis and make the PSGMA chains soluble again in solvents such as N, N dimethylformamide. The hamburgers were thus separated into two halves, with each half existing as a Janus particle, which had PtBA chains on one side and PSGMA chains on the other side. The Janus particles might have interesting applications, such as in Pickering emulsion stabilization. / Thesis (Ph.D, Chemistry) -- Queen's University, 2010-04-30 18:01:06.281

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<p>In this thesis, I present the electrochemical studies of three dendrimeric polypropylene imine (PPI) nanomaterials and their applications as a platform in the development of a novel label free DNA nanobiosensor based on electrochemical impedance spectroscopy. Cyclic voltammetry (CV), differentia pulse voltammetry (DPV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques were used to study and model the electrochemical reactivities of the nanomaterials on glassy carbon electrode (GCE) as the working electrode.</p>

One of the largest obstacles in drug development is to overcome solubility and bioavailability problems. Preformulation strategies such as nanoparticle formation are often employed but sometimes create new issues and are limited in their effectiveness and applications. Since the majority of drugs are marketed and sold as solid forms, drug delivery systems are not always desirable. This is where solid-state chemistry becomes important. Traditional solid-state chemistry approaches are often successful but are sometimes too restrictive and cannot be applied to certain compounds. Cocrystals have emerged as an alternative solid-state technique that can be applied to a broad range of compounds. However, the technology is still very new and its effectiveness in certain conditions had previously not been evaluated. The studies detailed herein investigated the ability of two different technology platforms for overcoming drug design challenges for two promising bioflavonoids: EGCg and quercetin. Studies have shown that EGCg might be useful for the treatment of Alzheimer's disease and other neurodegenerative diseases. Quercetin is being investigated for numerous bioactivities and is currently being marketed as an energy dietary supplement. Both of these bioflavonoids exhibit poor bioavailability and water solubilities that are at opposite ends of the spectrum. In the chapters to follow, nanoparticle technology was applied to EGCg and evaluated in cell models of AΒ production, a hallmark of Alzheimer's disease. Bioavailability improvements were also evaluated in rats. Additionally, new forms of both flavonoids were created using cocrystallization. These new cocrystals were characterized using powder and single crystal x-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. Solubility and bioavailability changes were also evaluated. These data have strong implications in drug development since they elucidated the strengths and weaknesses of two major technologies in compounds with different design challenges.