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

Abstract

Experimental evidences on its in vitro use reveal that d-FeOOH is a material that release-controlled amount of heat if placed under an AC magnetic field. d-FeOOH nanoparticles were prepared by precipitating Fe(OH)2 in alkaline solution followed by fast oxidation with H2O2. XRD and 57Fe Mo¨ssbauer spectroscopy data confirmed that d-FeOOH is indeed the only iron-bearing compound in the produced sample. TEM images evidence that the averaged particle sizes for this d-FeOOH sample is 23 nm.Magnetization measurements indicate that these d-FeOOH particles behave superparamagnetically at 300 K; its saturationmagnetization 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 d-FeOOHnanoparticles. In view of these findings, the so-preparedd-FeOOHis a real alternative tobe further tested as amaterial formedicalpractices in therapies involving magnetic hyperthermia as in clinical oncology.