Osaka University, Japan

In vivo Chemical Probes for MRI and Fluorescence Imaging


One of the great challenges in the post-genome era is to clarify the biological significance of intracellular molecules directly in living cells. If we can visualize a molecule in action, it is possible to acquire biological information, which is unavailable if we deal with cell homogenates. One possible approach is to design and synthesize chemical probes that can convert biological information to chemical output. In this talk, molecular design strategies for MR and fluorescence imaging probes are introduced.

MRI (Magnetic Resonance Imaging) is an imaging technique using nuclear magnetic resonance phenomenon. MRI has been clinically used since it yields highly spatial resolution images of deep regions in living animal bodies. A novel 19F MRI contrast agent, fluorine accumulated silica nanoparticle for MRI contrast enhancement (FLAME) is developed, which is composed of a perfluorocarbon core and a robust silica shell. FLAME has advantages such as high sensitivity, stability, modification of the surface, and biocompatibility. The activatable derivative of FLAME will also be introduced.

Intravital imaging by two-photon excitation microscopy (TPEM) has been widely utilized to visualize cell functions. The combination of the rationally designed small molecular probes with a fluorescent protein as a reporter of cell localization enabled quantitation of osteoclast activity and time-lapse imaging of its in vivo function.