Citrate-coated gadolinium trifluoride (Cit-GdF3) and poly(acrylic acid)-coated nanoparticles (PAA-GdF3 NPs) were synthesized, the former reproduced from literature (though using more refined conditions), the latter through a new, two-step, ligand exchange method. Diamagnetic nanoparticle analogs (Cit-YF3 NPs) were prepared to investigate citrate interactions with the nanoparticle surface using NMR. Citrate was found to bind in numerous conformations, with a total of between 29 – 46 % bound at 0 ºC. Exchange studies revealed short residence lifetimes of one and twelve seconds respectively for bound and free forms of citrate (0 ºC), perhaps explaining the colloidal instability of these nanoparticles. PAA-GdF3 NPs were synthesized by first producing their Cit-GdF3 counterparts, and then exchanging citrate for PAA. The impetus behind this latter synthesis was the relative enhancement in stability and relaxivity attainable by these nanoparticles. The displacement of citrate by PAA was verified using diffusion NMR studies.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/18226 |
| Date | 07 January 2010 |
| Creators | Alvares, Rohan |
| Contributors | Prosser, Robert Scott, Macdonald, Peter Moore |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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