A "turn-on" fluorescent chemosensor for the meticulous detection of gallium (III) ion and its use in live cell imaging, logic gates and keypad locks

A pyrene-based fluorescence sensor PyAP [(Z)-2-((pyren-1-ylmethylene)amino)phenol] was developed by a simple Schiff base reaction. In the presence of other metal ions, the PyAP fluorescence chemosensor recognizes only Ga3+ ions. Additionally, PyAP showed good selectivity and sensitivity for the detection of Ga3+. In a solution containing DMSO/H2O (2:8, v/v) the binding constant for PyAP with Ga3+ was 7.03 x 104 M-1, and the detection limits were 3.35 nM. The quantum yield for PyAP and PyAP-Ga3+ was calculated and found to be 0.0006 and 0.227. This chemosensor PyAP was based on the photo-induced electron transfer (PET) mechanism, which was further validated by DFT studies. The capacity of PyAP to specifically detect Ga3+ in living cells and its cell permeability were both validated by live cell imaging in T24 cells. Finally, the chemosensor PyAP was offered applications for molecular logic gates and keypad locks.