resumo
A combination of sol-gel synthesis and thermal decomposition was developed for preparing nanosized, perovskite-type LnFeO(3) (Ln = Eu, Gd, Tb) powders. Perovskite-type powders with crystalline particles of 100 nm average size, as determined by transmission electron microscopy (TEM), could be obtained after a thermal treatment at 800 degrees C. The perovskite nanoparticles (NPs) were further characterized by X-ray powder diffraction and Mossbauer spectroscopy. These were in agreement with the pure perovskite LnFeO(3) structure with the expected Zeeman sextet corresponding to a magnetically ordered phase. Magnetization measurements [M(H)] at 5 K and 300 K showed a behavior that is dominated by antiferromagnetic interactions and weak ferromagnetism in EuFeO3, while for Ln = Gd, Tb, they were dominated by the low ordering temperature Ln magnetic sublattice. The colloidal aqueous NPs suspensions exhibited no significant leaching of free Ln(3+) ions. Their relaxivities define them as potential T-2 MRI contrast agents for further biomedical applications. The NPs showed fast uptake and no cytotoxicity at concentrations below 62.5 mu g/mL with respect to Hela cells.
palavras-chave
MULTIFUNCTIONAL MAGNETIC NANOPARTICLES; IRON-OXIDE NANOPARTICLES; PEROVSKITE-TYPE OXIDES; MRI CONTRAST AGENTS; MOSSBAUER-SPECTROSCOPY; HYDROTHERMAL SYNTHESIS; THERMAL-DECOMPOSITION; GD2O3 NANOPARTICLES; GADOLINIUM OXIDE; THIN-FILMS
categoria
Chemistry
autores
Pinho, SLC; Amaral, JS; Wattiaux, A; Duttine, M; Delville, MH; Geraldes, CFGC
nossos autores
João Cunha de Sequeira Amaral
Investigador AuxiliarProjectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Projeto de Investigação Exploratória: João Amaral (IF/01089/2015)
agradecimentos
This work was supported by the FundacAo para a Ciencia e Tecnologia (FCT), Portugal [grants to SLCP (SFRH/BPD/96048/2013), and project /PTDC/CTM73243/2006], the Centre National de la Recherche Scientifique (CNRS), the Region Aquitaine France, FEDER, COST Action D38 "Metal-Based systems for Molecular Imaging Applications". This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FundacAo para a Ciencia e Tecnologia (FCT)/Ministerio de Educacion y Ciencia (MEC) and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. JSA acknowledges FCT IF/01089/2015 grant.