A novel ICT-based chemosensor for F- and its application in real samples and bioimaging.

A novel colorimetric and fluorescent chemosensor MQS-Si with intramolecular charge transfer character has been designed and synthesized. The chemosensor shows exclusively "off-on" fluorescence response toward F- at 620 nm in HEPES (pH 7.4): DMSO solution (7:3, v/v), which is attributed to the specific cleavage of Si-O bond. The ultrasensitive detection limit for F- in the fluorescence measurement is down to 30 nM. Application of the chemosensor has been demonstrated by selective detection of F- in drinking water, urine and serum samples and fluorescence imaging of F- in living cells and zebrafish, which proves that MQS-Si has a promising application in vitro and in vivo detection of F- and may be utilized for the diagnosis of fluorosis and esteofluorosis.