A “turn-on” chemodosimeter for detection of Cu2+ in living cells

Abstract

We synthesized an analogue of rhodamine B hydrazide via alkylation with butyl bromide. The resulting reagent, BuCh, exhibits optimal lipophilicity, maintaining both aqueous solubility and efficient cell membrane permeability. BuCh itself is weakly fluorescent, but in the presence of Cu²⁺ it undergoes hydrolysis to release strongly fluorescent rhodamine B. We demonstrated that BuCh is well suited for monitoring chelatable intracellular Cu²⁺ ions in mammalian cells.