δ-FeOOH: a superparamagnetic material for controlled heat release under AC magnetic field

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology Vol. 15; no. 4
• Main Authors: Chagas, Poliane, da Silva, Adilson Cândido, Passamani, Edson Caetano, Ardisson, José Domingos, de Oliveira, Luiz Carlos Alves, Fabris, José Domingos, Paniago, Roberto M., Monteiro, Douglas Santos, Pereira, Márcio César
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.04.2013; Springer
• Subjects: Brief Communication; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from solutions; Inorganic Chemistry; Lasers; Magnetic properties and materials; Magnetic properties of nanostructures; Materials Science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Ferrofluid; δ-FeOOH nanoparticles; Iron oxides; Hyperthermia; Magnetic properties; Particle size; Iron oxide; Moessbauer spectroscopy; Iron; XRD; Nanoparticles; Transmission electron microscopy; Coercive force; Crystal growth from solutions; Oxidation; Iron additions; Nanostructured materials; Nanomaterial synthesis; Saturation magnetization
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-013-1544-2

Experimental evidences on its in vitro use reveal that δ-FeOOH is a material that release-controlled amount of heat if placed under an AC magnetic field. δ-FeOOH nanoparticles were prepared by precipitating Fe(OH) 2 in alkaline solution followed by fast oxidation with H 2 O 2 . XRD and 57 Fe Mössbauer spectroscopy data confirmed that δ-FeOOH is indeed the only iron-bearing compound in the produced sample. TEM images evidence that the averaged particle sizes for this δ-FeOOH sample is 23 nm. Magnetization measurements indicate that these δ-FeOOH particles behave superparamagnetically at 300 K; its saturation magnetization was found to be 13.2 emu g −1 ; the coercivity and the remnant magnetization were zero at 300 K. The specific absorption rate values at 225 kHz were 2.1, 6.2, and 34.2 W g −1 , under 38, 64, and 112 mT, respectively. The release rate of heat can be directly controlled by changing the mass of δ-FeOOH nanoparticles. In view of these findings, the so-prepared δ-FeOOH is a real alternative to be further tested as a material for medical practices in therapies involving magnetic hyperthermia as in clinical oncology.