Facile synthesis of water-stable magnetite nanoparticles for clinical MRI and magnetic hyperthermia applications

Aims: Superparamagnetic magnetite nanoparticles have been under intensive investigation in nanomedicine. However, it is still a challenge to synthesize high-quality water-stable magnetite nanoparticles for better magnetic performance and less side effects in medical MRI and nanothermotherapy. Materials & methods: We successfully synthesized hydrophilic magnetite nanoparticles through thermal decomposition of Fe(acac)(3) in triethylene glycol, which were coated with a triethylene glycol layer and thus demonstrated excellent water stability. Results: The optimized deposition temperature has been found to be 250 degrees C (10-250 NPs). The magnetic and thermal properties as well as the cytotoxicity of 10-250 NPs were investigated. In vitro experiments have demonstrated high cellular uptake and low cytotoxicity. The hyperthermia experiments showed effectiveness in temperature rise and cancer cell death. 10-250 NPs showed promising MRI with relaxivity r(2)* as high as 617.5 s(-1) mM(-1) Fe. In vivo MRI showed excellent tumor imaging. Conclusion: The 10-250 NPs have great potential to be applied for clinical MRI and magnetic thermotherapy.