In situ Cu²⁺-triggered wavelength-tunable fluorescent sensor for highly sensitive sensing inorganic pyrophosphatase activity and its logic gate application

As inorganic pyrophosphatase (PPase) gets involved in the regulation of various pathophysiological procedures, rapid and effective detection of its activity is of great value for monitoring and managing PPase-related diseases. Herein, an in situ Cu²⁺-triggered wavelength-tunable fluorescent sensor for high sensitivity monitoring of PPase activity is constructed. The proposed sensor is based on the principle of Cu²⁺-triggered polymerization of dopamine (DA) and m-phenylenediamine (MPD), the stronger coupling effect of pyrophosphate ion (PPi) and Cu²⁺, and the effective hydrolysis of PPase to PPi. With the change of substituents of MPD, the wavelength of fluorescence polymer nanoparticles (FPNPs) exhibits tunable capacity from 535 nm to 565 nm. Compared with the traditional detection method, as developed sensor shows high sensitivity to PPase with a low detection limit of 0.333 mU/mL in green channel and 0.033 mU/mL in orange channel. Additionally, the sensor realizes PPase sensing in the diluted human serum with excellent recovery in both green and orange models. Furthermore, this sensor is also applicable for inhibition assay of PPase (NaF: IC₅₀ of 134.7 μM) and logic gates construction. Summarily, as prepared sensor provides one better way for monitoring PPase in diagnostic as well as drug screening.