Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/25830
Title: MAGNETIC NANOPARTICLES FOR BIOMEDICAL APPLICATIONS
Authors: DIPAK MAITY
Keywords: Nanoparticles, Ferrofluids, Iron oxide, Superparamagnetic, MRI, Hyperthermia
Issue Date: 4-Jan-2011
Source: DIPAK MAITY (2011-01-04). MAGNETIC NANOPARTICLES FOR BIOMEDICAL APPLICATIONS. ScholarBank@NUS Repository.
Abstract: Superparamagnetic nanoparticles have been under intensive investigation in various biomedical applications. However, it is still a challenge to synthesize high quality water stable ultrafine magnetite nanoparticles for better magnetic performance and less side effects in clinical MRI and thermotherapy (magnetic hyperthermia). In this work, monodispresed and control sized hydrophobic superparamagnetic magnetite (Fe3O4) nanoparticles have been synthesized by thermal decomposition method optimizing the reaction parameters like temperature, time, solvent and surfactant effects. These hydrophobic Fe3O4 nanoparticles are converted into hydrophilic (i.e. water soluble) by functionalization and polymeric encapsulation to make them useful for biomedical applications. Direct synthesis of hydrophilic Fe3O4 nanoparticles and nanoclusters with high saturation magnetization (Ms ~ 73 - 86 emu/g) have also been performed using one-step polyol method. The Fe3O4 nanoparticles and nanoclusters are systematically characterized to identify their structure, surface coating, magnetic properties, cytotoxicity, cellular uptake, magnetic resonance imaging (MRI) contrast and specific absorption rate (SAR) properties. In vitro experiments have demonstrated high cellular uptake and low cytotoxicity and the AC magnetic field heating experiments showed effectiveness in temperature rise and 60-74% cancer cell death due to magnetic hyperthermia. The Fe3O4 nanoclusters yielded high specific absorption rate (SAR~500 Watt/g) values as compared to the Fe3O4 nanoparticles (SAR~135 Watt/g) upon exposure to AC magnetic field. The Fe3O4 nanoparticles have showed high r2* relaxivity (617.5 s-1mM-1) and very promising contrast in vivo tumor imaging. Thus, the Fe3O4 nanoparticles are proficient for MRI imaging and magnetic hyperthermia applications.
URI: http://scholarbank.nus.edu.sg/handle/10635/25830
Appears in Collections:Ph.D Theses (Open)

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