Preparation Of Contrast Agent Of Carbon Tetraoxide Nanoparticles And Its Application In Nuclear Magnetic Resonance Imaging

Magnetic resonance imaging, referred to as nuclear magnetic resonance,magnetic resonance is a new imaging technique developed in the1980s. In order toaddress two issue in MR imaging: the complex-based agents due to a relatively shortincrease the imaging time and the single functional agents have some localizations forthe diagnoses of diseases or tumors. This thesis is focused on two aspects:1) the newtargeted nanoparticle-based agents are designed and synthesized for increasingresidence time in cancer cells or tumor;2) and the formed dual T\/Ti MRI contrastagents used in biological systems.1.Folate-conjugated Mn304@Si02Core-Shell Nanoparticles for TargetedMagnetic Resonance ImagingThe monodisperse silica-coated manganese oxide nanoparticles (NPs) weresynthesized via a thermal decomposition approach and were aminated throughsilanization. The amine-functionalized core-shell NPs enabled the covalentconjugation of organic hydrophilic PEG and folate (FA) onto their surfaces. Theformed Mn3C>4@Si02-FA core-shell nanocomposites are water-dispersible，stable，and biocompatible. Furthermore, we demonstrate that Mn304@Si02-PEG-FA NPsas a T\contrast agent display effective targeting ability，and lower toxicity in vitro andin vivo, enabling them to be developed as multimodel nanoplatform for long-termtargeted imaging.2. Synthesis and biological applications of Dy-complex T1/T2dual modeMagnetic Resonance ImagingIn this part, silica-coated manganese oxide core-shell nanoparticles weresynthesized via a thermal decomposition approach and were aminated throughsilanization. The amine-functionalized Mn304@Si02NPs enabled the covalentconjugation of a paramagnetic gadolinium complex (Dy-DTPA, DTPA:*diethylenetriamine pentaacetic acid) onto their surface. The formed M113O4@mSiO〗@DTPA-Dy NPs are water-dispersible, stable, and biocompatible as confirmed byMTT cell viability assay. Relaxivity measurements show that they have a T\relaxivity (r1) of0.58mM-1s-1and T2relaxivity (r2) of3.21mM-1s-1, suggesting a possibility to use them as both T1positive and T1negative contrast agents. Therefore, the dual contrast T1-and T2-weighted targeted magnetic resonance (MR) imaging of biological systems.