Novel reversible fluorescent probe for relay recognition of Zn2+ and PPi in aqueous medium and living cells

Abstract

Abstract A new fluorescent probe 4′-hydroxy-3′-((8-quinolineimino) methyl)-4-biphenylcarbonitrile (L) has been synthesized for the sequential detection of Zn 2+ and PPi in aqueous ethanolic (3/2 v/v) HEPES buffer (pH 7.1). Addition of Zn 2+ to the solution of L resulted in a red shift (Δλ = 18 nm) with a pronounced enhancement in the fluorescence intensity, while there was no enhancement in presence of other metal ions. The subsequent addition of PPi anion can switch off the fluorescence signal by bringing the Zn 2+ ion out of the coordination cavity of the chemosensor L. No interference was observed from other anions, making the L–Zn 2+ ensemble a highly sensitive and selective PPi probe. The detection limit is 5.31 × 10 −8 M and 9.41 × 10 −8 M for Zn 2+ and PPi, respectively. The sensing process is reversible and the probe may be recycled for further use. Cell imaging studies demonstrate that this sensor is capable of sensing Zn 2+ and PPi in living cells.