Superparamagnetic cobalt ferrite nanoparticles as <i>T</i> ₂ contrast agent in MRI: in vitro study

Abstract

Superparamagnetic cobalt ferrite nanoparticles (CoFe₂O₄) possess favourite advantages for theranostic applications. Most of previous studies reported that CoFe₂O₄ magnetic nanoparticles (MNPs) are suitable candidates for induction of hyperthermia and transfection agents for drug delivery. The present study synthesized and investigated the potential use of CoFe₂O₄ as a contrast agent in magnetic resonance imaging (MRI) by using a conventional MRI system. The CoFe₂O₄ were synthesized using co-precipitation method and characterized by TEM, XRD, FTIR, EDX and VSM techniques. Relaxivities <i>r</i>₁ and <i>r</i>₂ of CoFe₂O₄ were then calculated using a 1.5 Tesla clinical magnetic field. The cytotoxicity of CoFe₂O₄ was evaluated by the MTT assay. Finally, the optimal concentrations of MNPs for MRI uses were calculated through the analysis of <i>T</i>₂ weighted imaging cell phantoms. The superparamagnetic CoFe2O4 NPs with an average stable size of 10.45 nm were synthesized. Relaxivity <i>r</i>₁,₂ calculations resulted in suitable <i>r</i>₂ and <i>r</i>₂/ <i>r</i>₁ with values of 58.6 and 51 that confirmed the size dependency on relaxivity values. The optimal concentration of MNPs for MR image acquisition was calculated as 0.154 mM. Conclusion: CoFe₂O₄ synthesized in this study could be considered as a suitable <i>T</i>₂ weighted contrast agent because of its high <i>r</i>₂/<i>r</i>₁ value.