Nafion-Based Nanocarriers for Fluorine Magnetic Resonance Imaging

[Image: see text] The aim of our study was to develop a novel method for nanocarriers’ preparation as a fluorine magnetic resonance imaging ((19)F MRI)-detectable drug delivery system. The novelty of the proposed approach is based on the application of fluorinated polyelectrolyte Nafion as a contrast agent since typical MRI contrast agents are based on paramagnetic gadolinium or ferro/superparamagnetic iron oxide compounds. An advantage of using an (19)F-based tracer comes from the fact that the (19)F image is detected at a different resonance frequency than the (1)H image. In addition, the close to zero natural concentration of (19)F nuclei in the human body makes fluorine atoms a promising MRI marker without any natural background signal. That creates the opportunity to localize and identify only exogenous fluorinated compounds with 100% specificity. The nanocarriers were formed by the deposition of polyelectrolytes on nanoemulsion droplets via the layer-by-layer technique with the saturation approach. The polyelectrolyte multilayer shell was composed of Nafion, the fluorinated ionic polymer used for labeling by (19)F nuclei, and poly-l-lysine (PLL). The surface of such prepared nanocarriers was further pegylated by adsorption of pegylated polyanion, poly-l-glutamic acid (PGA). The (19)F MRI-detectable hydrophobic nanocarriers with an average size of 170 nm and a sufficient signal-to-noise ratio have been developed and optimized to be used for passive tumor targeting and drug delivery.