一种超氧阴离子荧光探针的合成与应用

文章以咖啡酸基团作为超氧阴离子 $ \left(\mathrm{O}_{2}^{\bullet-}\right) $识别位点合成了一种吩噻嗪类荧光探针PTZ-C，通过荧光开启的方式来检测 $ O_{2}^{\bullet-} $。在 $ O_{2}^{\bullet-} $存在的情况下，PTZ-C中咖啡酸残基的给电子邻苯二酚可以被氧化形成吸电子的邻苯二酮，发生荧光共振能量转移，在470 nm处出现新峰，并且在紫外灯下观察到溶液由无色荧光变为蓝色荧光，响应时间在5 s内。PTZ-C探针能够特异性识别 $ O_{2}^{\bullet-} $，抗干扰能力较强，pH值适用范围较广，检测限为12.8 nmol/L，且对交替加入 $ O_{2}^{\bullet-} $和抗坏血酸的氧化还原过程表现出良好的可逆性。此外，该探针的细胞毒性小，可应用于巨噬细胞RAW264.7的内源性 $ O_{2}^{\bullet-} $荧光成像。

In this paper, a phenothiazine fluorescent probe PTZ-C was synthesized using caffeic acid group as the recognition site of superoxide anion( $ O_{2}^{\cdot-} $), and $ O_{2}^{\cdot-} $ was detected by fluorescence activation. In the presence of $ O_{2}^{\cdot-} $, the electron-donating pyrocatechol of caffeic acid residues in PTZ-C can be oxidized to form electron-withdrawing o-benzoquinone, and the fluorescence resonance energy transfer occurs. A new peak appears at 470 nm, and the solution is observed to change from colorless fluorescence to blue fluorescence under ultraviolet lamp, and the response speed is within 5 s. Probe PTZ-C can specifically recognize $ O_{2}^{\cdot-} $, has strong anti-interference ability and a wide range of pH value, and the detection limit is 12.8 nmol/L. It shows good reversibility to the redox process of alternately adding $ O_{2}^{\cdot-} $ and ascorbic acid. In addition, it shows little cytotoxicity, and can be applied in endogenic $ O_{2}^{\cdot-} $ fluorescence imaging of macrophage RAW264.7.