Fluorescein‐Functionalized Silica Nanoparticles as a Selective Fluorogenic Chemosensor for Cu²⁺ in Living Cells

Abstract

Abstract Fluorescein‐functionalized silica nanoparticles ( 1 ) were prepared by sol–gel reaction, and their optical sensing abilities were studied towards finding a new type of synthetic fluorogenic chemosensor for imaging Cu 2+ ions in living cells. Interestingly, upon addition of Cu 2+ in a H 2 O suspension of 1 at pH 7.4, 1 displays large chelation‐enhanced quenching (CHEQ) effects with Cu 2+ . With the exception of Cu 2+ , no significant fluorescence intensity changes were observed in the experiments with the other metal ions. These findings confirm that 1 can be useful as a fluorogenic‐sensing material for the selective detection of Cu 2+ in the presence of other metal ions. This is a rare example of chromogenic sensing of a specific metal ion by functional inorganic nanomaterials. The emission change observed for chemosensor 1 in the presence of Cu 2+ is reversible by the addition of EDTA. Furthermore, the fluorescein‐functionalized silica nanoparticles act as a new type of synthetic fluorogenic chemosensor for imaging Cu 2+ ions in living cells.