Glutathione-magnetite nanoparticles: synthesis and physical characterization for application as MRI contrast agent

In this work a one-pot synthesis of water soluble glutathione capped magnetite nanoparticles is reported. The magnetic characterization of the samples shows the expected superparamagnetic behavior, but a wide range of blocking temperatures is found, since the size and interparticle interactions are very sensitive to preparation conditions. These properties are correlated with the glutathione-iron ratio and oxidant dose, in order to optimize the aqueous colloidal stability and magnetic properties of the superparamagnetic iron oxide nanoparticles for Magnetic Resonance Imaging applications. The efficiency of the glutathione coated nanoparticles as contrast agent is then evaluated by means of the determination of the relaxation times T1 and T2 in H-1 Nuclear Magnetic Resonance experiments. Moreover, the influence of the thickness of the glutathione capping layer on the colloidal stability and, thus, on relaxation times has been studied. Finally, the relaxitivity of the sample that shows the best performance has been determined.