Description
Iron oxides and ferrite nanoparticles have been intensively researched as alternative MRI contrast agents[1]. However, the biomedical application of magnetic nanoparticles is limited by aggregation [2]. The use of polymer coatings can prevent this negative phenomenon[3,4]. We showed that the coatings based on ionic derivatives of chitosan [5,6] ensured the stability and biocompatibility of the SPIONs aqueous suspension. Furthermore, the applied derivatives can form durable metal-polymer connections by chelating relevant metal ions. However, there are reports that the attachment of ligands via anchor groups to nanoparticles may cause changes on the particle surface, such as oxidation or surface degradation [7]. Oxidation processes reduce the saturation magnetization of iron nanoparticles[8], but the appropriate ligands can reduce spin slanting in the surface region.
The project's main goal was to investigate the influence of the polymer layer (a cationic derivative of chitosan and dextran, PEG) on the magnetic structure of copper-zinc ferrite nanoparticles. For the application of copper-zinc ferrite nanoparticles as contrast agents in magnetic resonance imaging (MRI) or in magnetic hyperthermia, their surface has to be coated by a polymer or surfactant layer. This modification can influence the surface oxidation state and the magnetic properties of the particles. In this work, we evaluated the effect presence of the layer of three polymers, cationic chitosan, cationic dextran, and polyethene glycol on copper-zinc ferrite nanoparticles. For this purpose, X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements were used, thanks to which the local magnetic and electronic properties of the particles’ surface area were examined with and without surface modification.
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[2] Adv Coll. Interface Sci. 2019 (265), 29-44.
[3] J. Nanoparticle Res.2014(16), 1–11.
[4] Coll. Surf. B, 2017 (150), 402–407 .
[5] J. Mater. Chem. B, 2019 (7), 2962–2973
[6] Soft Matter 2009(5), 4726–4732.
[7] Zeitschrift fur Phys.Chemie,2018(232), 819–844.
[8] J.Phys.Chem.C,2015(119),19404-19414.
