Fluorescence turn-on of easily prepared fluorescein derivatives by zinc cation in water and living cells

By combining a sulfonated β-naphtol as receptor, a hydrophilic fluorescence probe with extreme sensitivity (7 ppb) and selectivity for zinc ion has been designed and synthesized in a simple and efficient way. Based on the inhibition of internal charge transfer (ICT) process, This “turn-on” type fluorescent sensor molecule features high fluorescence increase (13 fold) at 508 nm as well as a red-shift from 371 to 430 nm over most competitive heavy and transition metal (HTM) ions in water (pH 7.4). Furthermore, cell imaging experiments show that this fluorescence probe might be used for monitoring Zn2+ within biological samples. The role of this sensor molecule in living cells was further confirmed with the treatment of N,N,N′,N′-Tetrakis(2-pyridylmethyl)ethylenediamine. And the impact of water-solubility and liposolubility of such fluorescence probe on biological application has been deeply discussed.