A sensitive and selective fluorescent sensor for Zinc(II) and its application to living cell imaging

A new dipyrromethene derivative (DP1) exhibits an enhanced fluorescence in the presence of Zn2+ ions and a high selectivity for Zn2+ ions over competing metal ions in methanol; Ag+, Ca2+, Co2+, Cr3+, Fe2+, Fe3+, Hg2+, K+, Mg2+, Mn2+, Ni2+, and Pb2+ produced only minor changes in the fluorescence of DP1. The binding ratio of the DP1-Zn2+ complexes was determined from a Job plot to be 1:1. The binding constant (Ka) of Zn2+ binding to DP1 was found to be 6.12 × 104 M−1, with a detection limit of 0.236 μM. Fluorescence microscopy imaging using RAW264.7 cells showed that DP1 could be used as an effective fluorescent probe for detecting Zn2+ in living cells.