A rhodamine chromene-based turn-on fluorescence probe for selectively imaging Cu2+ in living cell

We describe the development of a rhodamine chromene-based turn-on fluorescence probe to monitor the intracellular Cu2+ level in living cells. The new fluorescent probe with a chlorine group in chromene moiety exhibits good membrane-permeable property than previous reported because the predicted lipophilicity of present probe 4 is stronger than that of methoxyl substituted probe in our previous work (CLogP of 4: 8.313, CLogP of methoxyl substituted probe: 7.706), and a fluorescence response toward Cu2+ under physiological conditions with high sensitivity and selectivity, and facilitates naked-eye detection of Cu2+. The fluorescence intensity was remarkably increased upon the addition of Cu2+ within 1 or 2 min, while the other sixteen metal ions caused no significant effect.

Graphical abstractRhodamine chromene-based “turn-on” fluorescence probe can monitor the intracellular Cu2+ level in living HeLa cells with high sensitivity and selectivity in shorter time.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A new fluorescence probe was synthesized to improve membrane-permeable property. ► The probe can monitor Cu2+ in living cells with high sensitivity and selectivity. ► The probe can monitor intracellular Cu2+ in HeLa cells in shorter time.