A Rhodamine B hydrazide based Cu2+ selective “turn-on” fluorescent sensor for detection in living cells

In this work, we present the rhodamine B hydrazide-based Cu(II) sensor EM21 that is excellently suited for selectively detecting Cu(II) under physiological conditions. We were able to demonstrate that it acquired cell permeability through n-alkylation at the hydrazide group and therefore capable to detect and compare Cu(II) concentrations sensitively in living human cells (cancer and normal cells).