Effects of surfactants on the magnetic properties of iron oxide colloids.
Iron oxide nanoparticles are having been extensively investigated for several biomedical applications such as hyperthermia and magnetic resonance imaging. However, one of the biggest problems of these nanoparticles is their aggregation. Taking this into account, in this study the influence of three different surfactants (oleic acid, sodium citrate and Triton X-100) each one with various concentrations in the colloidal solutions stability was analyzed by using a rapid and facile method, the variation in the optical absorbance along time. The synthesized nanoparticles through chemical precipitation showed an average size of 9 nm and a narrow size distribution. X-ray diffraction pattern and Fourier Transform Infrared analysis confirmed the presence of pure magnetite. SQUID measurements showed superparamagnetic properties with a blocking temperature around 155 K. In addition it was observed that neither sodium citrate nor Triton X-100 influences the magnetic properties of the nanoparticles. On the other hand, oleic acid in a concentration of 64 mM decreases the saturation magnetization from 67 to 45 emu/g. Oleic acid exhibits a good performance as stabilizer of the iron oxide nanoparticles in an aqueous solution for 24h, for concentrations that lead to the formation of the double layer.
CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Paula I P
PI
Soares
CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Ana M R
AM
Alves
IST/CTN, Instituto Superior Técnico, UTL, Estrada Nacional 10, ao km 139,7, 2695-066 Bobadela LRS, Portugal.
Laura C J
LC
Pereira
IST/CTN, Instituto Superior Técnico, UTL, Estrada Nacional 10, ao km 139,7, 2695-066 Bobadela LRS, Portugal.
Joana T
JT
Coutinho
CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. Electronic address: imf@fct.unl.pt.
Isabel M M
IM
Ferreira
Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, IHMT/UNL, 1349-008 Lisboa, Portugal.
Carlos M M
CM
Novo
CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. Electronic address: jpb@fct.unl.pt.
João P M R
JP
Borges
D003102:Colloids; D003287:Contrast Media / Q000737:chemistry* / Q000494:pharmacology; D005290:Ferric Compounds / Q000737:chemistry* / Q000494:pharmacology; D005334:Fever / Q000188:drug therapy; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry* / Q000494:pharmacology
D003102:Colloids; D003287:Contrast Media; D005290:Ferric Compounds; D013501:Surface-Active Agents; C000499:ferric oxide
Colloids; Iron oxide nanoparticles; Magnetic characterization; Magnetite; Oleic acid; Sodium citrate; Stability; Surfactants; Triton X-100; UV–VIS