A highly selective “turn-on” fluorescent sensor for zinc ion based on a cinnamyl pyrazoline derivative and its imaging in live cells

Abstract

A fluorescence probe based on cinnamyl pyrazoline was developed and synthesized. The probe detected Zn²⁺ ion that was mixed with a series of cations in aqueous ethanol with high selectivity and high sensitivity. After adding Zn²⁺, the fluorescence intensity was significantly enhanced, with a 56-fold increase. The detection limits and binding constants of 2.95 × 10⁻⁸ M and 1.468 × 10⁴ M⁻¹ were calculated by a fluorescence titration experiment. The 1 : 1 binding chemometrics of the 1–Zn²⁺ complex was analyzed by Job's plot. The probe showed good reversibility when adding PPi. Additionally, the “turn-on” fluorescent probe with excellent membrane permeability was satisfactorily applied to microscopic imaging for the detection of Zn²⁺ in baby hamster kidney (BHK)-21 cells.