Synthesis, characterization and in vitro cytotoxicity of self-regulating magnetic implant material for hyperthermia application

Gd-substituted zinc ferrite nanoparticles with low Curie temperatures (T,) were synthesized by a chemical co-precipitation method. The magnetic properties and heat generation characteristics of these magnetic nanoparticles were investigated. The T(c) of ZnGd(x)Fe(2-x)O(4) nanoparticles increased with increasing Gd(3+) substitution, and was similar to 318 K at x = 0.02, which was a suitable Curie temperature for thermal seeds implanted in human body. The study on heat generation ability under external alternating magnetic field showed that the temperatures of these nanoparticles could be safely controlled around Tc without the temperature probe and controller. Furthermore, in vitro cytotoxicity of the ferrite nanoparticles was assessed using MTT assay. The results demonstrated that exposure to the bare ferrite nanoparticles for 48 h resulted in concentration-dependent toxicity. Cell growth inhabitation was observed when 4.0 mg/ml of bare ferrite nanoparticles was used. In contrast, PEG-capped nanoparticles had no significant effect on cell viability at any of the concentrations tested. (C) 2009 Elsevier B.V. All rights reserved.