基于铱配合物的铜离子(II)及pH双功能荧光探针研究

Study of Fluorescent Probe for Copper Ion（II） and pH Detection Based on Iridium Complex

摘要:

铜是人体必须的一种微量元素，铜离子的实时快速检测对于环境监测、疾病诊断具有重要意义。将salen配体与金属铱（Ⅲ）相结合合成了一种双功能荧光探针Ir-ppy-pbm，并利用紫外吸收光谱、荧光光谱、激光共聚焦成像等技术研究了其对铜离子(II)及pH的检测效果。结果表明，Ir-ppy-pbm可选择性地与铜离子（II）结合，结合后表现出灵敏的荧光on-off现象，检测限度达58 nmol?L^-1，该值远低于世界卫生组织建议的饮用水中铜离子（II）允许含量（约30 μmol?L^-1）及人体血液中的铜离子（II）水平(1.7—3.9 μmol?L^-1)。激光共聚焦显微成像的结果显示：Ir-ppy-pbm可穿透细胞膜进入细胞核中，并可对细胞核内的铜离子(II)水平进行监测； Ir-ppy-pbm还表现出灵敏的pH荧光响应效果，其在590 nm处的荧光信号可用于较宽范围内的pH检测，而525和590 nm处的荧光强度比值则可用作强酸条件下的比例型荧光pH探针。

Abstract:

Copper is an essential trace element for the human body. Rapid and real-time detection of copper ions is of great significance for environmental monitoring and disease diagnosis. In this paper， a bifunctional fluorescent probe Ir-ppy-pbm was synthesized by combining the salen ligands with metal iridium （Ⅲ）， and its effect on copper ions（II） and pH detection were studied using ultraviolet absorption spectroscopy， fluorescence spectroscopy， laser confocal imaging and other techniques. The results show that Ir-ppy-pbm can selectively combine with copper ions （II） and shows a sensitive fluorescence on-off phenomenon after combination， with a detection limit of 58 nmol?L^-1， which is much lower than the allowable content of copper ion（II） in drinking water recommended by the World Health Organization （30 μmol?L^-1） and copper ion levels in human blood （1.7—3.9 μmol?L^-1）. The results of cell imaging showed that Ir-ppy-pbm could penetrate the cell membrane， accumulating in the nucleus， and monitoring the copper ion level in the cell. Meanwhile， Ir-ppy-pbm exhibits a sensitive fluorescence response to pH. Its fluorescence signal at 590 nm can be used for pH detection in a wide range， while the ratio of fluorescence intensity at 525 nm to 590 nm can be used as a ratiometric pH fluorescent probe under strong acid conditions.