Research group of Professor Huo Yanping, Guangdong University of Technology: fluorescence probe of tetrastyrene and quinoline based on aggregation induced luminescence

Among many types of sensors, the fluorescent chemical sensor based on organic small molecules has attracted much attention because of its advantages of high sensitivity, low detection limit, fast response, low cost and simple operation, and its design and research have important applications in the fields of medical diagnosis and treatment and environmental protection The high content of heavy metal ions such as mercury and copper ions has a great impact on the survival and health of organisms Hg 2 + is considered to be one of the most dangerous toxic metal pollutants Even if its concentration is very low, it can damage the central nervous system and digestive system of human beings, leading to organ failure and fatal injury to organisms Excessive Cu 2+ in human body will destroy the cell homeostasis, leading to some serious neurodegenerative diseases, such as Menke, Alzheimer 's disease and so on However, cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are essential molecules in organisms They play a key role in signal transduction and redox balance in the metabolism of organisms The abnormal content of any kind of thiol may lead to various diseases Therefore, it is of great significance for biological health and environmental protection to study fluorescent chemical sensors which can monitor the concentration of heavy metal ions such as Hg 2 +, Cu 2 + and specific bio mercaptan qualitatively and quantitatively Recently, Professor Huo Yanping's research group of Guangdong University of technology has constructed a series of organic small molecule fluorescence probes with high sensitivity and selectivity, which can effectively monitor the concentration changes of mercury, copper and specific biological mercaptan in water or living cells First of all, two new fluorescent probes (S1 and S2) were designed and synthesized by connecting tetrastyrene with Schiff base This kind of probe can successfully recognize and monitor the change of Hg 2 + concentration in aqueous solution and living cells with very low detection limits of 19.4 and 9.84 nm (< 2 ppb) S2 can also be used to detect the content of Hg 2 + by naked eyes The fluorescence response mechanism is based on the aggregation induced luminescence (AIE) In the solvent system containing 90% water, the probe fluorescence is very strong because of the AIE effect When its Schiff base structure is combined with the specific recognition of Hg 2 +, the fluorescence of the probe is significantly quenched, achieving the effect of sensitive and specific recognition of Hg 2 + Relevant research results were published in new J chem (DOI: 10.1039 / c8nj02245c) Fig 1 Response mechanism of S1 and S2 to Hg 2 + and cell imaging (source: new J chem.) in addition, with 8-hydroxyquinoline as the mother, the research group designed and synthesized four new renewable mercury ion ratio / enhanced fluorescent probes (1-4) The detection limit of probe (2 - 4) for mercury ion can be as low as 10 - 9m Finally, the reversible reaction between the probe and mercury ion can be realized by adding sodium borohydride, which can recover the probe and detect mercury ion repeatedly Relevant research results were published on spectrochim Acta A (DOI: 10.1016 / j.saa 2019.04.004) Fig 2 Fluorescence response mechanism of probe 1-4 (source: spectrochim Acta A.) Then, the research group designed two Quenched Copper Ion fluorescence probes with obvious aggregation induced luminescence effect based on tetrastyrene and quinoline, which have high specificity and low detection limit (detection limit can reach 1.3 × 10-8m) for detection of copper ion And the probe can be recycled by adding Na 2S In addition, we loaded the probe on the filter paper, and prepared the portable copper ion detection test paper It is convenient, fast and portable for the detection of Cu2 + in the actual water sample, and has a very strong practical application prospect In fact, until the group designed and synthesized these two probes with aggregation induced luminescence effect, there was almost no quinoline derivative probe based on Cu2 +, which has aggregation induced luminescence effect This work has important guiding significance for the development of quinoline derivative probes with AIE effect The results were selected as back cover papers after publication, and related research results were published on Analyst (DOI: 10.1039/c8an00940f) Figure 3 Fluorescence response of probes 1 and 2 to copper ion (source: Analyst) Figure 4 Back cover paper - copper ion probe (source: Analyst) Although scientists have had extensive research and attention on Biophenol fluorescence sensing, few sensors can effectively transfer cysteine（ Cys), homocysteine (Hcy) and glutathione (GSH) were identified and analyzed qualitatively and quantitatively In order to solve this problem, the research group designed and synthesized two fluorescent off on probes, which are used to distinguish and detect high - / cysteine Among them, the stilbene derivative with AIE effect is used as the luminescent group, and maleimide is used as the recognition group of the target This study found that the two isomer probes did not emit fluorescence due to the action of pet before the corresponding bio mercaptan was added However, after the probe interacted with Cys or Hcy, the fluorescence of the two isomer probes increased greatly, even 2000 times in the presence of Cys Compared with the literature, the sensitivity of the two isomer probes increased more than 10 times, and compared with glutathione（ Compared with GSH and other amino acids, these thiol probes show excellent selectivity and sensitivity to Cys and Hcy, which can be used for quantitative analysis of Cys and Hcy In addition, the two isomer probes were successfully used in living H1299 lung cancer cells for fluorescence imaging of Cys and Hcy responses Relevant research results were published in taranta (DOI: 10.1016/j.talanta 2019.120177) Figure 5 Reaction mechanism diagram of the probe (source: taranta) Figure 6 Cell imaging diagram (source: taranta) In summary, the research group has successfully designed and synthesized a series of organic small molecule fluorescent chemical sensors based on tetrastyrene and quinoline as the mother, which are used for Hg 2 +, Cu 2+ The qualitative and quantitative detection of ion and bio mercaptan has high selectivity and sensitivity, which provides an important idea for the development of efficient tools for biological environment and medical detection The first authors of the above related achievements are Wang Kai, master degree candidate, Xiong Jingwen, and Dong Fangdi, undergraduate of the school of light industry and chemical engineering of Guangdong University of technology The corresponding authors are Shaomin, associate professor of Guangdong University of technology, Huo Yanping, and Zhang Jianye, Professor of Guangzhou Medical University of the cooperative unit The above research work was supported by NSFC, Department of science and technology of Guangdong Province, Department of education of Guangdong Province and Guangzhou Science and Technology Bureau.