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Fluorescent Bioprobes: Structural Matching in the Docking Processes of Aggregation-Induced Emission Fluorogens on DNA Surfaces

Authors

  • Yuning Hong,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Hao Xiong,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Jacky Wing Yip Lam Dr.,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Matthias Häußler Dr.,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Jianzhao Liu,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Yong Yu,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Yongchun Zhong Dr.,

    1. Department of Physics, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China)
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  • Herman H. Y. Sung Dr.,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Ian D. Williams Prof.,

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
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  • Kam Sing Wong Prof.,

    1. Department of Physics, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China)
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  • Ben Zhong Tang Prof.

    1. Department of Chemistry, Nano Science and Technology Program, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong (P.R. China), Fax: (+852) 23581594
    2. Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China)
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Abstract

Whereas most conventional DNA probes are flat disklike aromatic molecules, we explored the possibility of developing quadruplex sensors with nonplanar conformations, in particular, the propeller-shaped tetraphenylethene (TPE) salts with aggregation-induced emission (AIE) characteristics. 1,1,2,2-Tetrakis[4-(2-triethylammonioethoxy)phenyl]ethene tetrabromide (TPE-1) was found to show a specific affinity to a particular quadruplex structure formed by a human telomeric DNA strand in the presence of K+ ions, as indicated by the enhanced and bathochromically shifted emission of the AIE fluorogen. Steady-state and time-resolved spectral analyses revealed that the specific binding stems from a structural matching between the AIE fluorogen and the DNA strand in the folding process. Computational modeling suggests that the AIE molecule docks on the grooves of the quadruplex surface with the aid of electrostatic attraction. The binding preference of TPE-1 enables it to serve as a bioprobe for direct monitoring of cation-driven conformational transitions between the quadruplexes of various conformations, a job unachievable by the traditional G-quadruplex biosensors. Methyl thiazolyl tetrazolium (MTT) assays reveal that TPE-1 is cytocompatible, posing no toxicity to living cells.

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