A Zn2+-specific turn-on fluorescent probe for ratiometric sensing of pyrophosphate in both water and blood serum

A novel fluorescent sensor composed of a naphthalene functionalized tetraazamacrocycle ligand 3,6,9,15-tetraazabicyclo[9.3.1] pentadeca-1(15), 11,13-triene-3-methyl naphthalene (1) and Zn2+ has been designed and prepared, which can be utilized for selective and ratiometric sensing of pyrophosphate (PPi) over other phosphate-containing anions in aqueous solution at physiological pH. Notably, the water soluble 1 itself also exhibits a selective enhanced fluorescent response to Zn2+, and the complex 1-Zn2+ thus formed eventually fulfils the synergic Zn2+ coordination-altered strategy with PPi. Furthermore, the ratiometric sensing of 1-Zn2+ towards PPi performed well even in blood serum milieu. Finally, the sensor 1-Zn2+ was successfully employed to monitor a real-time assay of inorganic pyrophosphatase (PPase) by means of ratiometric fluorescent measurements for the first time.