Surfacing engeneering of magnetic nanoparticles for biomedicine: coating with different macromolecules for stabilizing and compatibility in physiological conditions

Author(s)

Mônica Freitas da Silva

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2013-01-31

Examining board members

Laudemir Carlos Varanda; Pedro Paulo Corbi; Osvaldo Novais de Oliveira Junior

• Advisor: Laudemir Carlos Varanda

Abstract

Superparamagnetic iron oxides nanoparticles (SPION) have been highlighted in several areas of biotechnology and biomedicine, for example in cancer treatment, in labeling of cells and as contrast agent in magnetic resonance imaging (MRI). The purpose of this study was synthesizing SPION with intensified saturation magnetization by modified polyol process, and using surface agents to enhance the surface properties. Carboxymethildextran, metylpolietileneglycol, chitosan, silica and 3-aminopropyltrimethoxysilane (APTMS) were utilized as surface modifiers. By transmission electron microscopy (TEM), SPION showed narrow particle size distribution, with an average diameter around 5 nm. The X-ray diffraction studies indicated the formation of magnetite in all synthesized systems in which the modified polyol process was utilized. FTIR measurements showed the presence of vibration modes related to the macromolecules and inorganic compounds used to SPION surface modifications. TEM of the different surface modifications showed the agglomerate formation, which depends on the used surface modifier. SPION coated with APTMS was functionalized with folic acid, showing satisfactory results. However other characterization techniques will be necessary for study this modification. Quantity of free amine groups was determinate in the amount coated with APTMS for functionalization, and UV-Vis spectroscopy determinates a good result. Vibrating sample magnetometry (VSM) indicates similar behaviors in all cases against SPION without surface modifiers. These results suggest that the surface modifications were performed satisfactorily. Utilized methods for changing the hydrophobic to hydrophilic surface showed effectives, however, the quantity of surface modifiers should be better studied. Therefore, SPION functionalized with different hydrophilic surfaces were obtained, which possess high potential to be used as devices in biomedical applications. (AU)

• FAPESP's process: 11/05022-7 - Surface engeenering of magnetic nanoparticles for biomedicine: coatings with macromolecules in order to stabilize and compatibility in physiological environment
• Grantee: Mônica Freitas da Silva
• Support Opportunities: Scholarships in Brazil - Master