Free-Radical Formation by the Peroxidase-Like Catalytic Activity of MFe 2 O 4 (M = Fe, Ni, and Mn) Nanoparticles

MORENO MALDONADO, ANA CAROLINA; WINKLER, ELIN L.; RAINERI, MARIANA; TORO CÓRDOVA, ALFONSO; RODRÍGUEZ, LUIS M.; TROIANI, HORACIO E.; MOJICA PISCIOTTI, MARY LUZ; MANSILLA, MARCELO VASQUEZ; TOBIA, DINA; NADAL, MARCELA S.; TORRES, TEOBALDO E.; DE BIASI, EMILIO; RAMOS, CARLOS A.; GOYA, GERARDO F.; ZYSLER, ROBERTO D.; LIMA, ENIO

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2019 vol. 123 p. 20617 - 20627

1932-7447

ABSTRACT: Ferrite magnetic nanoparticles (MNPs) haveperoxidase-like activity and thus catalyze the decomposition ofH2O2-producing reactive oxygen species (ROS). Increasinglyimportant applications of these ferrite MNPs in biology andmedicine require that their morphological, physicochemical,and magnetic properties need to be strictly controlled.Usually, the tuning of their magnetic properties is achievedby the replacement of Fe by other 3d metals, such as Mn orNi. Here, we studied the catalytic activity of ferrite MNPs(MFe2O4, M = Fe2+/Fe3+, Ni, and Mn) with the meandiameter ranging from 10 to 12 nm. Peroxidase-like activitywas studied by electron paramagnetic resonance (EPR) usingthe spin-trap 5,5-dimethyl-1-pyrroline N-oxide at differentpHs (4.8 and 7.4) and temperatures (25 and 40 °C). We identified an enhanced amount of hydroxyl (?OH) and perhydroxyl(?OOH) radicals for all samples, compared to a blank solution. Quantitative studies show that [?OH] is the dominant radicalformed for Fe3O4, which is strongly reduced with the concomitant oxidation of Fe2+ or its substitution (Ni or Mn). Acomparative analysis of the EPR data against in vitro production of ROS in microglial BV2 cell culture provided additionalinsights regarding the catalytic activity of ferrite MNPs, which should be considered if biomedical uses are intended. Our resultscontribute to a better understanding of the role played by different divalent ions in the catalytic activity of ferrite nanoparticles,which is very important because of their use in biomedical applications.