Oil/water nano-emulsion loaded with cobalt ferrite oxide nanocubes for photo-acoustic and magnetic resonance dual imaging in cancer: in vitro and preclinical studies

Dual imaging dramatically improves detection and early diagnosis of cancer. In this work we present an oil in water (O/W) nano-emulsion stabilized with lecithin and loaded with cobalt ferrite oxide (Co0.5Fe2.5O4) nanocubes for photo-acoustic and magnetic resonance dual imaging. The nanocarrier is responsive in in vitro photo-acoustic and magnetic resonance imaging (MRI) tests. A clear and significant time-dependent accumulation in tumor tissue is shown in in vivo photo-acoustic studies on a murine melanoma xenograft model. The proposed O/W nano-emulsion exhibits also high values of r2/r1 (ranging from 45 to 85, depending on the magnetic field) suggesting a possible use as T2 weighted image contrast agents. In addition, viability and cellular uptake studies show no significant cytotoxicity on the fibroblast cell line. We also tested the O/W nano-emulsion loaded with curcumin against melanoma cancer cells demonstrating a significant cytotoxicity and thus showing possible therapeutic effects in addition to the in vivo imaging.

Graphical AbstractO/W nano-emulsions, embedding hydrophobic iron-cobalt oxide cubic nanoparticles (NPs), have been used, as photo-acoustic (PA) and MRI dual imaging diagnostic nanotool in cancer. Particularly, they show a PA response in vivo and a significant, time dependent, accumulation, post intravenous injection in tumor parenchyma of melanoma-bearing mice. In addition, shielding of encapsulated NPs decreases the r1 improving the r2/r1 ratio in the range from 45 to 85 making possible a T2 weighted imaging in MRI. Finally, curcumin loaded nano-emulsions provide significant cytotoxicity in melanoma cells showing possible therapy functionality of the proposed nanotool.316