SiO2 versus chelating agent@ iron oxide nanoparticles: interactions effect in nanoparticles assemblies at low magnetic field

摘要

Hydrophilic magnetic nanoparticles present many interest for various medical applications due to their unique properties: immunoassays, imaging and hyperthermia. With regards to their applicability in the biomedical field, colloidal stability is a key parameter related to nanoparticle surface functionalization. In this paper, we report the water transfer of hydrophobic oleic acid coated iron oxide nanoparticles comparing two methodologies to obtain water dispersible iron oxide nanoparticles: exchange ligands with small strong chelating agent (caffeic acid) and SiO2 shell passivation. Both strategies are leading to stable aqueous ferrofluid but differing by their interactions. The non linear magnetic behavior at high and low magnetic field and second derivative signature of water dispersed superparamagnetic Fe(3)0(4) nanoparticles samples are studied using conventional SQUID equipment and miniaturized detector MIAplex(A (R)) device. We demonstrated those samples differing only by their interparticle interactions present different magnetic behavior at very low magnetic field whereas at high magnetic field both samples are very similar.