A turn-on fluorescent pyrene-based chemosensor for Cu(ii) with live cell application

Abstract

A pyrene-based fluorescent sensor (PHP) was synthesized for Cu(II) detection. It had high selectivity towards Cu²⁺ ions via photoinduced electron transfer (PET) based fluorescence enhancement. In the presence of Cu²⁺, PHP provided significant blue emission, while Ag⁺, Al³⁺, Ca²⁺, Cd²⁺, Co²⁺, Cr³⁺, Fe²⁺, Fe³⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Zn²⁺ metal ions produced only minor changes in the fluorescence spectra. The association constant (K_a) for Cu²⁺ binding to PHP had a value of 1.0 × 10⁴ M⁻¹. The maximum emission change induced by Cu²⁺ binding to the chemosensor PHP was observed over the pH range 5.0–10.0. Confocal fluorescence microscopy imaging using RAW264.7 cells showed that PHP can be used as an effective fluorescent probe for detecting Cu²⁺ in living cells.