Facile one-pot synthesis of different surfactant-functionalized water-soluble Fe3O4 nanoparticles as magnetic resonance imaging contrast agents for melanoma tumorsElectronic supplementary information (ESI) available: Additional experimental results. See DOI: 10.1039/c4ra05786d

A facile and efficient solvothermal strategy is described to synthesize modified Fe 3 O 4 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 Fe 3 O 4 NPs. In addition, sodium citrate, l -asparagine and polyvinylpyrrolidone were employed as surfactants for the surface modification of Fe 3 O 4 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 Fe 3 O 4 NPs turned out to be stable for more than 6 months with no flocculates or precipitates appearing in the stock fluids. Then, T 2 weighted images and T 2 relaxation times of the modified Fe 3 O 4 NPs were examined to investigate their biological applications for magnetic resonance (MR) imaging as T 2 contrast agents. As a consequence, the sodium citrate-modified Fe 3 O 4 NPs exhibit a higher r 2 relaxivity than that of sodium citrate combined with PVP and l -asparagine-modified Fe 3 O 4 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 Fe 3 O 4 NPs may be potential contrast agents for detecting melanoma tumors. A facile and efficient one-pot solvothermal strategy is described to synthesize Fe 3 O 4 nanoparticles (NPs) modified with sodium citrate, polyvinylpyrrolidone and l -asparagine for in vivo magnetic resonance (MR) imaging of melanoma cells.