Colloidal stability, surface characterisation and intracellular accumulation of Rhodium(II) citrate coated superparamagnetic iron oxide nanoparticles in breast tumour: A promising platform for cancer therapy

摘要

The colloidal stability of a rhodium(II) citrate, Rh_2(H _2cit)_4, coating on the surface of maghemite (γ-Fe_2O_3) nanoparticles was studied and compared in different dispersion media. The adsorption of Rh2(H _2cit)_4 at the water-maghemite interface was evaluated as a function of pH and complex concentration. A slight pH-dependent adsorption of the complex was observed with a maximum at pH 3. The colloidal stability of the functionalised nanoparticles with different amounts of Rh_2(H _2cit)_4 as a function of pH was evaluated using dynamic light scattering measurements. The particles have a mean magnetic core size of 5.6 nm and the hydrodynamic diameters are approximately 60 nm, which remained unchanged in the pH range in which the samples were a stable sol. The tolerance to different dispersion media, which were deionised water, saline, phosphate-buffered saline (PBS), foetal bovine serum (FBS) and NaCl solutions with different concentrations, was investigated. At moderate ionic strength, the colloidal stability of the dispersions was similar in saline and in PBS compared to the stability of dispersions diluted in water. Moreover, the intracellular accumulation of nanoparticles in 4T1 breast tumour was examined by ultrastructural analysis performed by transmission electron microscopy. The rhodium(II) citrate-coated nanoparticles were found mostly in the cytoplasm and nucleus. Thus, we suggest that these SPIO nanoparticles functionalized with Rh_2(H_2Cit)_4 can be potential tools for anticancer therapy.