Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion （Hg2＋） and organic methylmerc...Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion （Hg2＋） and organic methylmercury （CH3Hg＋）. Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg2＋ and CH3Hg＋. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg2＋ or CH3Hg＋, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg2＋ or CH3Hg＋, leading to significantly enhanced fluorescent emission. The response induced by Hg2＋ is much stronger than CH3Hg＋; but for specific detection of CH3Hg＋, we introduced a T-rich DNA fragment which could completely mask Hg2＋ in solution. Furthermore, we have employed the sensor for confocal imaging of rig2＋ and CH3Hg＋in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.展开更多
基金funded by the National Basic Research Program of China(2013CB932800)the National Natural Science Foundation of China(21375130,31571010,21204089 and 21475132)
文摘Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion （Hg2＋） and organic methylmercury （CH3Hg＋）. Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg2＋ and CH3Hg＋. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg2＋ or CH3Hg＋, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg2＋ or CH3Hg＋, leading to significantly enhanced fluorescent emission. The response induced by Hg2＋ is much stronger than CH3Hg＋; but for specific detection of CH3Hg＋, we introduced a T-rich DNA fragment which could completely mask Hg2＋ in solution. Furthermore, we have employed the sensor for confocal imaging of rig2＋ and CH3Hg＋in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.
