Superparamagnetic cobalt ferrite nanoparticles as T₂ contrast agent in MRI: in vitro study

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 r₁ and r₂ 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 T₂ weighted imaging cell phantoms. The superparamagnetic CoFe2O4 NPs with an average stable size of 10.45 nm were synthesized. Relaxivity r₁,₂ calculations resulted in suitable r₂ and r₂/ r₁ 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 T₂ weighted contrast agent because of its high r₂/r₁ value.