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Colloidal Stability Investigation of Physisorbed and Chemisorbed Poly(ethylene glycol)-Coated Iron Oxide Nanoparticles

Mohammadi, Mohamad Reza | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43928 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madaah Hosseini, Hamid Reza
  7. Abstract:
  8. In the current research, colloidal stability of two different types of coating on the surface of Superparamagnetic Iron Oxide nanoparticles (SPIONs) was studied. In the first triumph, a dual-layer coating was achieved by utilizing optimum amount of Dextran and different PEG (Poly(ethylene glycol)) concentrations which the weight ratios of iron oxide/PEG were 1/1, 2/1, 4/1, 8/1, and 16/1. Then, the presence of the coating was characterized by XRD, FT-IR, DLS and FE-SEM methods. These results together with the TGA ones revealed that as the concentration of PEG surfactant increases, the thickness of coating increases. Moreover, VSM test was performed to specify the effect of coating on the magnetic behavior of coated-SPIONs. Although due to small hysteresis loops the samples had superparamagnetic behavior, the increase in coating layer thickness leaded to considerable decrease in Saturation Magnetization (Ms) which 53.8 emu/g for the wight ratio of 1/1 (PEG/SPION) decreased to 42.6 emu/g for that of 16/1. However, no significant difference in Ms was observed among the ratios 1/1, 2/1, and 4/1. Finally, colloidal stability was investigated via UV-VIS spectrophotometer, and the results were interpreted according to relative absorbance (A/A0). Obtained results ascertained that the sample with weight ratio of 16/1 was the most stable sample among all the samples. Because final goal of our project was to find an optimum coating for in-vivo applications, by juxtaposing the results with the in-vivo requirements, PDS8 was introduced as a promising sample to fulfill the desired requirements. In another triumph, a chemisorbed coating of PEG was carried out with an intermediate of Silane. Colloidal stability of this sample was characterized in RPMI-1640 cell culture medium. Achieved results revealed that after 8000s, only 20% of nanoparticles were sedimented which shows an appropriate amount of stability
  9. Keywords:
  10. Iron Oxide Nanoparticles ; Polyethylen Glycol (PEG) ; Colloidal Stability ; Physisorbed ; Chemisorbed ; Cell Culture Medium

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