Colloidal stability of carboxylated iron oxide nanomagnets for biomedical use

Abstract

Magnetite nanoparticles (MNP) were synthesized and stabilized with carboxylated compounds citric acid – CA, poly(acrylic acid) – PAA, poly(acrylic acid-co-maleic acid) – PAM, humic acid – HA and gallic acid – GA (polymerizing in situ on the surface). Adsorption isotherms and bonding feature were determined and used to explain the changes in charge and aggregation states and salt tolerance of the MNPs. The thicker layer of macromolecular acids PAA, PAM and HA provides better stability at physiological pH and salt concentration compared to the CA and GA coatings. In addition, Fe(III)-CA complexation promotes the dissolution of the nanoparticles. The biocompatibility of the polyacid-coated MNPs was tested in cell proliferation experiments.