BODIPY-functionalized gold nanoparticles as a selective fluoro-chromogenic chemosensor for imaging Cu2+ in living cells.

A new fluoro-chromogenic chemosensor based on BODIPY-functionalized gold nanoparticles 1 is prepared. Addition of Cu(2+) ions to aqueous solutions of 1 gave an instantaneous color change along with a blue-shift of the absorption band and quenching of the emission spectrum at room temperature. The chemosensor 1 exhibits a high affinity and selectivity for Cu(2+) over competing metal ions tested. Moreover, confocal microscopy experiments establish that 1 can be used for detecting Cu(2+) levels within living cells.