Multifunctional core-shell silica nanoparticles for highly sensitive ¹⁹F magnetic resonance imaging

¹⁹F magnetic resonance imaging (¹⁹F MRI) is useful for monitoring particular signals from biological samples, cells, and target tissues, because background signals are missing in animal bodies. Therefore, highly sensitive ¹⁹F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: 1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and 2) the restriction of the molecular mobility attenuates the ¹⁹F MRI signals. Herein, we developed novel multifunctional core-shell nanoparticles to solve these issues. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core-shell nanoparticles have superior properties such as high sensitivity, modifiability of the surface, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by ¹⁹F MRI. Highly sensitive ¹⁹F magnetic resonance imaging (MRI) is a useful method for in vivo imaging without background signals. However, the low sensitivity of ¹⁹F MRI limits its practical application. Novel multifunctional nanoparticles for highly sensitive ¹⁹F MRI are reported, which consist of a liquid perfluorocarbon core and a silica shell (see picture).