Ultrasound Assisted Non-Seeded Method On Surface Modification Of Superparamagnetic Iron Oxide Nanoparticles For Magnetic Resonance Imaging Probe
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Date
2015-09
Authors
SODIPO, BASHIRU KAYODE
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Abstract
In this thesis, a new non-seeded and facile ultrasonic method of incorporating SPION into silica was developed and analysed. Mixture of both SPION and silica nanoparticles synthesized separately by co-precipitation and sol-gel method, respectively was ultrasonically irradiated at different pH ranges between 3 and 5. The tremendous force generated from the acoustic cavitation (formation, growth and collapse of bubbles) and shockwave of the ultrasonic irradiation was employed to induce inelastic collision and incorporation of SPION into the silica nanoparticles. Electrophoresis measurement of the as-synthesized SPION/silica demonstrated that at lower pH, SPION was found embedded into the silica. However, at pH greater than 4, SPION was unstable and unable to withstand the turbulence flow from the ultrasonic field. The results suggested that the formation of the SPION/silica composite nanoparticles is strongly related to the inelastic collision induced by ultrasonic irradiation. More so, the formation the composite nanoparticles are dependent on the zeta potential and colloidal stability of the particles. The formation of the composite nanoparticles was analysed using TEM, ESI, XRD, FTIR, XPS, BET, Zeta-Sizer and VSM. The composite nanoparticles developed by this method were able to retain nearly 70% of its initial saturation magnetization. The reactivity of the SPION/silica was demonstrated via binding of decanethiol monolayer on the composite nanoparticles. The SPION/silica nanoparticles were then tested for
MRI contrast agent. The magnetic nanoparticles demonstrate ability to shorten T2 and T1 relaxation time by more than 99% and 95% respectively. Importantly, the results demonstrate that all the set objectives of this thesis were achieved.
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Ultrasound Assisted Non-Seeded Method On Surface Modification Of Superparamagnetic Iron Oxide Nanoparticles , For Magnetic Resonance Imaging Probe