A near-infrared chemodosimeter with Pi-selective colorimetric and fluorescent sensing and its application in vivo imaging

A near-infrared colorimetric and fluorescent chemosensor for detecting phosphate ion (Pi) has been developed. The chemosensor's sensing mechanism is based on the Pi-driven cleavage of an amide bond which releases a fluorophore. The chemosensor exhibits a rapid response and high sensitivity towards Pi in DMSO-HEPES buffer (0.02 M, pH = 7.0) (v/v = 9 : 1). A colorimetric change with a 70 nmred-shift in the UV-vis absorbance spectrum and a 72-fold enhancement in the ratio of fluorescence intensities at 656 nm and 552 nm were observed. The practical utility of this chemosensor was demonstrated by employing it to detect Pi in Paramecium and C. elegans.