Selective Zinc(II)-Ion Fluorescence Sensing by a Functionalized Mesoporous Material Covalently Grafted with a Fluorescent Chromophore and Consequent Biological Applications

Authors

  • Krishanu Sarkar,

    1. Department of Materials Science and Centre for Advanced Materials Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
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  • Koushik Dhara,

    1. Department of Inorganic Chemistry Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
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  • Mahasweta Nandi,

    1. Department of Materials Science and Centre for Advanced Materials Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
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  • Partha Roy,

    1. Department of Inorganic Chemistry Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
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  • Asim Bhaumik,

    Corresponding author
    1. Department of Materials Science and Centre for Advanced Materials Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
    • Department of Materials Science and Centre for Advanced Materials Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India).
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  • Pradyot Banerjee

    Corresponding author
    1. Department of Inorganic Chemistry Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India)
    • Department of Inorganic Chemistry Indian Association for the Cultivation of Science Jadavpur, Kolkata-700 032 (India).
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Abstract

A highly ordered 2D-hexagonal mesoporous silica material is functionalized with 3-aminopropyltriethoxysilane. This organically modified mesoporous material is grafted with a dialdehyde fluorescent chromophore, 4-methyl-2,6-diformyl phenol. Powder X-ray diffraction, transmission electron microscopy, N2 sorption, Fourier transform infrared spectroscopy, and UV-visible absorption and emission have been employed to characterize the material. This material shows excellent selective Zn2+ sensing, which is due to the fluorophore moiety present at its surface. Fluorescence measurements reveal that the emission intensity of the Zn2+-bound mesoporous material increases significantly upon addition of various concentrations of Zn2+, while the introduction of other biologically relevant (Ca2+, Mg2+, Na+, and K+) and environmentally hazardous transition-metal ions results in either unchanged or weakened intensity. The enhancement of fluorescence is attributed to the strong covalent binding of Zn2+, evident from the large binding constant value (0.87 × 104M−1). Thus, this functionalized mesoporous material grafted with the fluorescent chromophore could monitor or recognize Zn2+ from a mixture of ions that contains Zn2+ even in trace amounts and can be considered as a selective fluorescent probe. We have examined the application of this mesoporous zinc(II) sensor to cultured living cells (A375 human melanoma and human cervical cancer cell, HeLa) by fluorescence microscopy.

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