Preparation of visible-light-excited europium biolabels for time-resolved luminescence cell imaging application

► Two kinds of new visible-light-excited europium biolabels have been prepared. ► The labels are highly luminescent with long luminescence lifetimes. ► The labels were used for labeling transferrin and folic acid. ► Two labeled biomarkers were used for imaging HeLa cells with time-resolved mode. ► The cell-surface receptors of two biomarkers were successfully visualized.