Herein, a highly selective and sensitive squaraine dye (F-0) for Cu²⁺ detection was developed. Upon addition of Cu²⁺, F-0 could greatly decrease absorption peak accompanying with fluorescent quenching about 170 folds. The detection limit can reach as low as 7.2 nmol/L. F-0 showed excellent water solubility and achieved naked eye detection of Cu²⁺. A paper strip pre-stained with F-0 solution was fabricated and showed color changed from blue to colorless upon addition of Cu²⁺. F-0 exhibited highly specific to Cu²⁺ over other metal ions. Furthermore, on the basic of low cell cytotoxicity, F-0 could be utilized to monitor Cu²⁺ in living cell and mice via fluorescence imaging. These results showed that F-0 has great potential for a more complex applications.

^{在此，开发了一种用于Cu 2+}检测的高选择性和灵敏的方酸染料(F-0) 。加入Cu ²⁺后，F-0 可大幅度降低吸收峰，同时荧光猝灭约170 倍。检测限可低至7.2 nmol/L。^{F-0表现出优异的水溶性，实现了对Cu 2+}的肉眼检测。制作了用F-0溶液预染色的纸条，并且在添加Cu ²⁺后显示颜色从蓝色变为无色。与其他金属离子相比，F-0 对 Cu ^{2+表现出高度特异性。}此外，在低细胞毒性的基础上，F-0可用于监测Cu ²⁺通过荧光成像在活细胞和小鼠中。这些结果表明，F-0 在更复杂的应用中具有巨大潜力。