A Simple Fluorescent Chemosensor for Detection of Zinc Ions in Some Real Samples and Intracellular Imaging in Living Cells

A new designed fluorescent chemosensor TYMN ((E)-1-((thiazol-2-ylimino)methyl)naphthalen-2-ol) for highly sensitive and selective tracing of trace amount of Zn2+ ions in some real samples was synthesized and characterized. The sensor TYMN can detect Zn2+ ions via fluorescence enhancement with a high selectivity over a wide range of metal ions, especially Cd2+. The sensor showed large fluorescence enhancement upon complexation with Zn2+ and simultaneous color change from yellow to orange. The limit of detection was analyzed to be 0.0311 μM with a linear dynamic range 0.1-1.0 μM. The sensor could work in a pH span of 5.0-8.0. Based on the physicochemical and analytical methods like electrospray ionization (ESI)-mass, Job plot, 1H nuclear magnetic resonance (NMR) and theoretical calculations, the detection mechanism for Zn2+ was explained based on restriction of internal charge transfer (ICT) mechanism. TYMN sensor was potentially utilized for Zn2+ ions concentration evaluation in some real samples. Fluorescence microscopy experiments revealed that probe TYMN may have application as a fluorophore to detect the Zn2+ in living cells.

本研究合成并表征了一种新型荧光化学传感器TYMN [(E)-1-((噻唑-2-基亚胺基)甲基)萘-2-醇]，可对多种实际样品中的痕量锌离子(Zn²⁺)实现高灵敏、高选择性的检测。该传感器通过荧光增强效应识别Zn²⁺，对一系列常见金属离子均表现出优异的选择性，尤其对镉离子(Cd²⁺)的抗干扰能力突出。该传感器与Zn²⁺络合后可产生显著的荧光增强信号，同时伴随溶液颜色由黄色向橙色的转变。经测定，其检测限为0.0311 μM，线性动态范围为0.1~1.0 μM。该传感器可在pH 5.0~8.0的宽区间内正常工作。通过电喷雾电离(ESI)质谱、Job图(Job plot)、1H核磁共振(NMR)及理论计算等理化与分析手段，阐明了该传感器对Zn²⁺的识别机制为分子内电荷转移(ICT)受限机制。TYMN传感器有望用于部分实际样品中Zn²⁺的浓度定量评估。荧光显微镜实验结果表明，该探针TYMN可作为荧光探针应用于活细胞内Zn²⁺的检测。