Rhodamine-based 'turn-on' fluorescent probe for Cu(II) and its fluorescence imaging in living cells

RO1 exhibited highly sensitive and exclusively selective fluorescence response toward Cu2+ over other metal ions with a detection limit of 0.56 ppb in mixed aqueous solution. The fluorescence was pH-independent in the wide range pH 3.1-11.6. probe RO1 can penetrate the cell membrane and be applied for in vitro imaging of Cu2+ in living cells.