Dipak Maity, Giorgio Zoppellaro, Radek Zboril and Jun Ding


Department of Mechanical Engineering, Shiv Nadar University, UP, India
Regional Centre of Advanced Technologies and Materials, Palacky University, Czech Republic
Materials Sciece &Engineering, National University of Singapore, Singapore

Abstract:

In this work, we have synthesized superparamagnetic iron oxide (SPIO) nanoparticles by thermolysis and aqueous co-precipitation method and in situ functionalized with various robust organic coating molecules such as tri(ethylene glycol) (TEG, –OH), terephthalic acid (TA, –COOH) etc to form core–shell structure with hydrophilic surfaces that provide aqueous solubility, biocompatibility and low toxicity to the SPIO systems. In comparison to the reported core–shell SPIO nanoparticles, our surface design aimed to reduce the dimension of the diamagnetic spacer (<1 nm) that favor effective spin-transfer from the metallic core to the external surfaces in contact with the bulk to improve the r2 relaxivity for their better performance as a negative contrast in magnetic resonance imaging (MRI) application. The structure and magnetic properties of the SPIO nanoparticles are characterized by XRD, TEM and VSM/SQUID while the relaxivity are measured at 20°C using a MRI scanner (1.5-3 T). Our investigation has indicated that the TEG and TA functionalized SPIO nanoparticles showed higher relaxivity r2* as high as 617.5 (at 1.5T) and 735.3 (at 3T) s-1mM-1 than the SPIO based commercial and synthetic MRI contrast agents reported in the literature. Thus, the SPIO nanoparticles have great potential to be applied for clinical MRI.