Superparamagnetic perfluorooctylbromide nanoparticles as a multimodal contrast agent for US, MR, and CT imaging

Background: Multimodal contrast agents usually containing two or more signal components can be used for several imaging modalities. Thus, complimentary information can be obtained by using just one kind of contrast agents. Purpose: To investigate the potential of superparamagnetic perfluorooctylbromide nanoparticles (MPFOBNP) as a multimodal contrast agent for ultrasonography (US)/magnetic resonance (MR)/computed tomography (CT) multimodality imaging. Material and Methods: The composite agent M-PFOBNP was developed by introducing superparamagnetic Fe3O4 nanoparticles into perfluorooctylbromide nanoparticles (PFOBNP). Several analytical tools were employed to characterize the agent. The potential of M-PFOBNP for US/MR/CT multimodality imaging were assessed in vivo. The cellular uptake and cytotoxicity of the agent were studied in vitro. Results: M-PFOBNP with well-defined spherical morphology and homogeneous size of 200-250 nm was obtained. Fe3O4 nanoparticles were successfully integrated into PFOBNP and preserved their superparamagnetic characteristics after encapsulation. The in vivo studies showed that M-PFOBNP produced higher echogenicity than PFOBNP and possessed strong magnetic susceptibility and radiopacity for multimodality imaging. Macrophages incubated with different concentrations of M-PFOBNP resulted in a dose-dependent cellular uptake, which did not affect the viability of the cells. Conclusion: M-PFOBNP may potentially serve as a multimodal contrast agent for enhanced US, MR, and CT imaging.