A simple naphthalimide based PET probe for Fe3+ and selective detection of pyrophosphate through displacement approach: Cell imaging studies and logic interpretation

The present work describes design, synthesis and photophysical behavior of a new molecular fluorescent probe 5. The probe 5 upon interaction with different metal ions in phosphate buffer (THF:H2O; 1:99, v/v; pH 7.2) exhibited enhanced emission (turn-on with Fe3+ (LOD = 1.05 x 10(-9) M) selectively due to the formation of an ensemble, 5.Fe3+. On the other hand the interaction of ensemble 5.Fe3+ with different class of anionic species fluorescence quenching (turn-Off) was observed with pyrophosphate ions (PPi) (LOD = 4.2 x 10(-7) M) selectively due to the formation of ferricpyrophosphate in the medium. The Off-On-Off emission behavior exhibited by the probe in the presence of Fe3+ and PPi is attributed to PET-Off-On mechanism, respectively. The live cell imaging and in vivo studies in zebra fish suggested about the potential biological application of probe to detect both the ions. The ensemble, 5.Fe3+ has also been tested to detect PPi in DNA polymerase chain reaction (PCR) product. Additionally, the probe upon providing Fe3+ and PPi ions as chemical inputs sequentially mimic write-readerase-read functions through the formation of an INHIBIT gate.