This thesis is focused on the design, synthesis and characterization of magnetite-ionic copolymer complexes as nanocarriers for drug delivery and magnetic resonance imaging. The polymers included phosphonate and carboxylate-containing graft and block copolymers. Oleic-acid coated magnetite nanoparticles (8-nm and 16-nm diameters) were investigated. Cisplatin and carboplatin were used as sample drugs. The potentials of the magnetite-ionomer complexes as dual drug delivery carriers and magnetic resonance imaging agents were evaluated. An acrylate-functional poly(ethylene oxide) macromonomer and hexyl (and propyl) ammonium bisphosphonate methacrylate monomers were synthesized. Conventional free radical copolymerizations were conducted to synthesize the graft copolymers. The acrylate-functional poly(ethylene oxide) macromonomer was also used to form graft copolymers with tert-butyl acrylate. Block ionomers containing poly(tert-butyl acrylate) were synthesized via atom transfer radical polymerization, then the tert-butyl groups were removed to afford anions. All the monomers and polymers were characterized by 1H NMR to confirm their structures and assess their compositions. Phosphonate-containing polymers were also characterized by 31P NMR. Magnetite nanoparticles (8-nm diameter) were synthesized by reducing Fe(acac)3 with benzyl alcohol. The 16-nm diameter magnetite was synthesized by thermal decomposition of an iron oleate precursor in trioctylamine as a high-boiling solvent. The iron-oleate precursor was synthesized with iron (III) chloride hexahydrate and sodium oleate with mixed solvents. TEM images of the magnetite were obtained. Magnetite-ionomer complexes were synthesized by binding a portion of the anions (carboxylate or phosphonate) on the copolymers onto the surfaces the magnetite. The remainder of the anions was used to bind with cisplatin and carboplatin via chelation. Physicochemical properties of the complexes were measured by dynamic light scattering. All the complexes with different polymers and magnetite nanoparticles displayed relatively uniform sizes and good size distributions. The magnetite-ionomer complexes displayed good colloidal stabilities in simulated physiological conditions for at least 24 hours. Those graft and block copolymer-magnetite complexes may be good candidates as drug carriers for delivery applications. After cisplatin and carboplatin loading, the sizes of the complexes increased slightly and the zeta potential decreased slightly, which indicated that the loadings were successful. Minimal loss of iron was found, signaling that the binding strengths between the magnetite and the anions of the graft copolymers were strong. 8.7 wt% of platinum was found in the cisplatin loaded complexes and 6.9% in the carboplatin loaded complexes. The results indicated that the magnetite-graft ionomer complexes were capable of loading drugs. Drug release studies were performed at pH 4.6 and 7.4 to mimick endosomal conditions and the physiological environment. Sustained release of drugs was observed. This further indicated the potential for using the magnetite-ionomer complexes as drug carriers. Transverse relaxivities of the magnetite-ionomer complexes with and without drugs were measured and compared to a commercial T2-weighted iron MRI contrast agent-Feridex®. All the complexes had higher relaxivities compared to Feridex®. Thus, the magnetite-ionomer complexes are promising candidates for dual magnetic resonance imaging and drug delivery.Moreover, the aqueous dispersion of the complexes was found to heat upon exposure to an AC magnetic field, thus potentially allowing heat-induced drug release. / Master of Science

Two novel synthetic routes to formation of gold-magnetite nanoparticles have been designed. Treatment of preformed magnetite nanoparticles with ultrasound in aqueous media with dissolved tetrachloroauric acid resulted in the formation of gold-magnetite nanocomposite materials. The other route involved irradiation of preformed magnetite nanoparticles by UV light in aqueous media with dissolved tetrachloroauric acid. This method resulted in the formation of gold-magnetite nanocomposite materials. These materials maintained the morphology of the original magnetite particles. The morphology of the gold particles could be controlled by adjusting experimental parameters, like addition of small amounts of solvent modifiers such as methanol, diethylene glycol, and oleic acid as well as variation of the concentration of the tetrachloroauric acid solution and time of the reaction. The nanocomposite materials were magnetic and exhibited optical properties similar to gold nanoparticles. Since we were not able to directly synthesize core shell gold magnetite nanoparticles, TiO2 was used as a bridging material. TiO2 nanoparticles with embedded magnetite were suspended in aqueous HAuCl4 and irradiated with ultraviolet light to photodeposit gold. The degree of gold coating and the wavelength of absorbance could be controlled by adjusting concentration of HAuCl4. Absorbance maxima were between 540-590 nm. Particles exhibited superparamagnetic properties (blocking temperature ~170 K) whether or not coated with gold. These particles have potential applications as drug delivery agents, magnetic imaging contrast agents, and magnetically separatable photocatalysts with unique surface properties. Another goal was to synthesize and characterize indium doped magnetite nanoparticles for application as radiotracers for in vivo fate studies. The labeled particles will be useful for determination of pharmacological behavior in biological systems. Indium doped magnetite particles with varying size and surface chemistry were synthesized with wet chemical techniques. The synthesized nanoparticles were characterized in terms of the size and shape with the help of TEM, the elemental composition by ICP and EDS, the crystal structure by XRD and magnetic properties by SQUID measurements. It was found that the indium loading could be controlled even though the magnetic properties were similar to undoped magnetite.

Thesis (M.S.)--State University of New York at Binghamton, Department of Physics, 2006. / Includes bibliographical references.

The metasupracrustal-hosted, often polymetallic REE-Fe-deposits of Bastnäs-type are found along the “REE-line” in the Palaeoproterozoic Bergslagen ore province, south central Sweden. They essentially comprise REE silicate-bearing magnetite skarn mineralisations with variable contents of other metals. Even though these deposits have been important for mining and research for centuries, their origin still remains unclear. In this study, samples from 10 different deposits along the REE-line have been charactarised as to mineralogy, petrography and bulk geochemistry, in addition to their isotope systematics. Mineral separates of magnetite and, when present, co-existing quartz or carbonates have been analysed for their oxygen and (for carbonates) carbon isotope compositions, in order to put constraints on the sources for metals and fluids in these deposits. Magnetites have δ18O-values of -1.79 to 1.12 ‰, while quartzes lie between 7.19 and 8.28 ‰. Carbonates have δ18O-values between 5.77 and 7.15 ‰ and δ13C-values between -5.35 and -3.32 ‰. Thermometric calculations based on mineral pairs (magnetite-quartz, magnetite-calcite/dolomite), combined with available fluid inclusion data, indicate formation of primary magnetite assemblages between c. 650 to 400 °C. At these temperatures, magnetites from some of the deposits would have been in equilibrium with a magmatic fluid (δ18O = 6-8 ‰), while magnetites from other deposits would have been in equilibrium with fluids of lower δ18O (4-6 ‰). Oxygen and carbon isotope trends in carbonates can be explained by interaction between original host carbonates and a fluid of magmatic composition. The combined results indicate that the Bastnäs-type magnetite-REE mineralisations were deposited from an originally magmatic fluid at relatively high temperatures. At local scale, variable modification of the fluid isotopic composition can be explained by mixing with seawater-dominated fluids.

No description available.

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Garmestani, Hamid; Committee Member: Gall, Ken; Committee Member: Thadhani, Naresh.

Thesis (M. Sc.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Thesis supervisor: Michelle M. Scherer. Includes bibliographic references (p. 198-215).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains x, 111 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.