Synthesis, magnetic properties, surface modification and cytotoxicity evaluation of Y3Fe5-xAlxO12 (0 <= x <= 2) garnet submicron particles for biomedical applications

Yttrium aluminum iron garnet Y3Fe5-xAlxO12 compounds were produced by the c itrate gel process by varying the aluminum content x from 0 to 2. Particles with an average size of about 100 nm and a specific surface area ranging f rom 6 to 28 m(2)/g were obtained. Curie temperatures (T-C) were determined from the temperature dependence of the field-cooled magnetization (FCM) and the remnant magnetization (REM) and range from -40 degreesC to 280 degrees C. According to the magnetic moment variation, the aluminum cation seems to replace the iron cation in the tetrahedral site for compounds with x <0.7. 3-Aminopropyltrimethoxysilane (gamma -APS) was grafted onto the particles surface and its presence confirmed by infra-red spectroscopy. Cytotoxicity assays were carried out during a period of 13 days using human microglia an d rat glioblastoma cell lines. The presence of the amine-functionalized par ticles did not affect the cell viability or the culture growth rate. Finall y, amine-functionalized particles were successfully labeled with covalently linked fluorescing molecules. (C) 2001 Elsevier Science B.V. All rights re served.