Magnetic nanoparticles modified with polyethylene glycol

M. Kubovċikova¹ - I. Antal¹ - M. Koneracka¹ - V. Závišová¹ - A. Jurikova¹ - K. Siposova^{1, 2} - Z. Gazova² - J. Kovaċ¹ - M. Kovarik² - D. Kupka³ - P. Kopċanský¹

¹ Institute of Experimental Physics, SAS, Watsonova 47, 04001 Kosice, Slovakia }
² Department of Biochemistry, Faculty of Science, Pavol Jozef Safarik University, Moyzesova 11, 04001 Kosice, Slovakia }
³ Institute of Geotechnics, SAS, Watsonova 45, 04001 Kosice, Slovakia

Abstract
In this study, the superparamagnetic nanoparticles (Fe ₃O ₄) sterically stabilized by sodium oleate were prepared and consequently modified with polyethylene glycol (PEG) to produce a biocompatible magnetic fluid. The samples were characterized by scanning electron microscopy (SEM) and dynamic light scattering (DLS) to confirm the spherical shape and the size of nanoparticles. The hydrodynamic diameter was increased after PEG-modification of the samples. Moreover, the optimal weight ratio PEG/Fe ₃O ₄ needed for surface modification of magnetite nanoparticles was found out by differential scanning calorimetry (DSC), and zeta potential measurements. Magnetic properties of MFPEGs were investigated by SQUID magnetometry. The SQUID measurements confirmed superparamagnetism and showed the influence of polymer molecular weight on the thermal stability of prepared samples. Biocompatibility of unmodified and PEG-modified magnetic particles was studied through the fluorescence intensity measurements after protein adsorption. Figs 4, Refs 4.