A highly selective fluorescent anthracene-based chemosensor for imaging Zn²⁺ in living cells and zebrafish

A new fluorescent chemosensor (An3) bearing anthracenyl rings was designed and developed for detection of Zn²⁺. Addition of Zn²⁺ into An3 gave rise to a fluorescent turn-on response at 424 nm whereas Al³⁺, Cd²⁺, Co²⁺, Cu²⁺, K⁺, Mg²⁺, Zn²⁺, Ca²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Hg²⁺ did not induce any emission intensity enhancement. Furthermore, the probe exhibited high selectivity toward Zn²⁺ and a very low detection limit (36 nM) based on chelation-enhanced fluorescence. Theoretical calculations revealed the possible formation of 1:1 and 1:2 complexes between An3 and Zn²⁺. In bioimaging experiments, the chemosensor displayed low cytotoxicity and good biocompatibility, rendering it an effective tool for fluorescent visualization of Zn²⁺ in living cells and zebrafish models.