Facile one-pot synthesis of different surfactant-functionalized water-soluble Fe3O4 nanoparticles as magnetic resonance imaging contrast agents for melanoma tumors

Abstract

A facile and efficient solvothermal strategy is described to synthesize modified Fe₃O₄ nanoparticles (NPs) as magnetic resonance (MR) imaging contrast agents. In this study, glycerine was used not only as a solvent but also as a reducing agent due to its nontoxicity and high viscosity, which result in the advantages of good dispersibility and narrow size distribution of the Fe₃O₄ NPs. In addition, sodium citrate, L-asparagine and polyvinylpyrrolidone were employed as surfactants for the surface modification of Fe₃O₄ NPs on account of their non/low-toxicity, water-solubility and biocompatibility. The modification process was completed by one step rather than complicated grafting approaches. Moreover, the resultant aqueous solution of the modified Fe₃O₄ NPs turned out to be stable for more than 6 months with no flocculates or precipitates appearing in the stock fluids. Then, T₂ weighted images and T₂ relaxation times of the modified Fe₃O₄ NPs were examined to investigate their biological applications for magnetic resonance (MR) imaging as T₂ contrast agents. As a consequence, the sodium citrate-modified Fe₃O₄ NPs exhibit a higher r₂ relaxivity than that of sodium citrate combined with PVP and L-asparagine-modified Fe₃O₄ NPs. Furthermore, in order to investigate their contrast effect for melanoma tumors, we also carried out a study of in vitro cytotoxicity and an observation of the tissue sections. The results suggest that these modified Fe₃O₄ NPs may be potential contrast agents for detecting melanoma tumors.