Graduate School of Medicine,The univercity of Tokyo

Development of fluorescence imaging probes based on new mechanism of fluorescence switching.

Fluorescence imaging has been used as one of the most powerful techniques currently available for continuous observation of intracellular processes in living samples. Therefore, fluorescence imaging probes or fluorescent labels are of critical importance, but only a limited range of biomolecules can be visualized because of the limited design strategies for small molecule-based fluorescence probes.

In this project, our group aim at developing a series of fluorescence imaging probes based on novel mechanism of fluorescence switching or with novel photo-functions, which can monitor biomolecules that cannot be visualized by conventional fluorescent probes. Examples are as follows;

1. Spontaneously blinking fluorophores for super-resolution imaging.
We have developed so far spontaneously blinking fluorophores for SLM based on intramolcelular spirocyclization reaction which enabled us to perform live-cell SLM without prior laser irradiation or additives (Nat. Chem. 6, 681-689 (2014)). In order to visualize multiple targets with difference colors or to visualize target molecules with different kinetics, we aim at expanding the variation in color and blinking properties of spontaneously blinking fluorophores based on intramolecular spirocyclization or intermolecular nucleophilic addition/dissociation of intracellular nucleophiles.

2. Fluorescence probes for quantitative imaging of intracellular redox-related biomolecules.
We have found recently that some xanthene dyes exhibit fluorescence on/off switching based on intermolecular nucleophilic addition/dissociation of redox-related biomolecules, and the equilibrium can be shifted by photoirradiation. Based on these findings, we aim at developing novel imaging probes which can monitor redox-related biomolecules in a quantitative manner.