Highly selective colorimetric/fluorometric dual-channel fluoride ion probe, and its capability of differentiating cancer cells.

A dual-channel naphthalimide-based chemosensor for rapid and sensitive detection of fluoride ion has been developed. Upon addition of F(-), it undergoes deprotonation reaction through H-bonding interactions, and its maximum absorption wavelength is red-shifted for 214 nm to the far-red region, together with drastically quenched fluorescence. In addition, it shows high selectivity toward F(-) anion, thus could be used for practical applications to detecting F(-) in both solution and solid state. Furthermore, the fluorescence of NIM could be enhanced in protein-containing acidic environments, hence NIM could act as lysosome marker to differentiate cancer cells from normal ones in cell imaging.