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Synthesis and Surface Modification of Gadolinium Oxide Nanoparticles (Gd2O3) for MRI Contrast Agent

Vahdatkhah, Parisa | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45488 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madaah Hosseini, Hamid Reza
  7. Abstract:
  8. In recent years, much attention has been paid to the development of biofunctionalized nanoparticles with special magnetic properties for using in clinical imaging. Targeted magnetic materials with high MRI signal intensity can be used in tissue imaging and molecular and cellular detection as valuable tools. The aim of this study has been to synthesize the nanocomposite including the functional gadolinium oxide (Gd2O3) nanoaprticles for MRI contrast agent. Synthesis and in-situ surface modification of ultrasmall Gd2O3 nanoparticles (2.5nm) with PVP was performed by a microwave modified polyol in 5 min. The structure and size of synthesized nanoparticles were studied using X-ray diffraction spectroscopy (XRD), High resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray spectroscopy (EDS) and Selected area diffraction pattern (SADP). Fourier transform infrared spectroscopy (FTIR) and turbidity analysis were used to investigate the surface properties and stability of coated Gd2O3 nanoparticles. Finally, the longitudinal and transversal relaxation of Gd2O3 nanoparticles were measured with a 3 T MRI scanner to investigate the possible use of as-synthesize particles as a positive contrast agent in MRI. The results showed a considerable relaxivity increase for synthesized particles compared with gadolinium chelates. The corresponding r1 relaxivity for functionalized Gd2O3 nanoparticle with 0.2 gr and 0.4 gr PVP was obtained to be 10.28 s-1mM-1 (r2/r1=1.4) and 6.19 s-1mM-1 (r2/r1=2.41), respectively. Higher signal intensity at low concentration was predicted using simulated signal intensity for both samples and optimal concentration for maximum signal intensity was generated at 0.8 mM Gd. Higher signal intensity was also observed in the functionalized sample with 0.2 gr PVP compared to 0.4 gr PVP at all concentrations. Therefore functionalized Gd2O3 nanoparticle with 0.2 gr PVP was considered as optimal sample for positive MRI contrast agent due to higher r1, r2/r1 ratio close to unity and high specific signal intensity
  9. Keywords:
  10. Magnetic Resonance Imagin (MRI)Contrast Agent ; Microwave ; Surface Functionality ; Relaxation Time ; Gadolinium Oxide Nanoparticles

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