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Design and Synthesis of Ni-Zn Magnetic Nanoparticles for Hyperthermia Treatment

Delavari, Hamid | 2012

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 42877 (48)
  4. University: Sharif University of Technology
  5. Department: Institute for Nanoscience and Nanotechnology
  6. Advisor(s): Madaah Hosseini, Hamid Reza; Simchi, Abdolreza
  7. Abstract:
  8. Hyperthermia (also called thermal therapy or thermotherapy) is defined as a type of cancer treatment in which body tissue is exposed to high temperatures, to damage and kill cancer cells, or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. The temperature increase required by hyperthermia can be achieved via different heat sources, such as electromagnetic radiation waves (radiofrequency or microwave, ultrasound waves and electrical current. These techniques have shown good results, however, the major problem with present conventional methods is reaching homogenous heat distribution and therapeutic temperatures in the deep region of the tumor to be treated. In this sense, treatment failure results from an insufficient temperature rise in some parts of the tumor, allowing the tumor to recur. On the other hand, the excessive increase in temperature which would causes healthy tissue damage must also be avoided. The magnetic hyperthermia (MHT) technique has partly solved these problems. The goal of this thesis is to design and synthesize metal alloy nanoparticles (NPs) with accurate size and composition which can be used in self-controlling hyperthermia (SCH). SCH is kind of magnetic hyperthermia that the overheating will be prohibited with regulation of Curie temperature of NPs in the therapeutic range, i.e. 42-46 ˚C. Consequently, controlling the Curie temperature is crucial. The Curie temperature decreases due to particle size miniaturization. Therefore, a model based on average coordination number to predict the Curie temperature of nickel nanoparticles has been developed. To confirm the accuracy of this model, the melting enthalpy, entropy and formation energy of Schottky vacancies (VFE) of metallic nanoparticles (NPs) has been investigated. The results show that these models are in good agreement with experimental and modeling results. Then, the heat generation ability of metallic alloys NPS has been investigated based on Stoner–Wohlfarth model based theories (SWTs) and linear response theory (LRT). Ni-Zn alloy NPs with 14.33% of zinc has been considered to create self-controlling hyperthermia dependent upon previous calculation on Curie temperature. It has been shown that a specific particle size is suitable for hyperthermia treatment. In the case of Ni-Zn alloy, particle size of 33.646 nm and 21.05 nm will generate maximum heat in 100 kHz and 200 kHz, respectively. To generate sufficient heat in hyperthermia treatment, the concentration on Ni-Zn NPs should be above the 0.015% in frequency of 100 kHz and magnetic field of 15 kA.m-1, and above 0.16% with considering Atkinson and Johanssen criteria.

  9. Keywords:
  10. Magnetic Nanodot ; Modeling ; Curie Temperature ; Nickel Alloy ; Hyperthermia Method ; Bioheat ; Polyol ; Average Coordination Number ; Melting Enthalpy ; Cancer Treatment

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