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A selective colorimetric sensing strategy for cysteine based on an indicator-displacement mechanism

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Abstract

Rapid determination of cysteine in aqueous solution is important for the diagnosis and treatment of some diseases. We herein present a simple yet facile colorimetric indicator-displacement assay for cysteine in aqueous solution with a sensitive optical readout based on the competitive binding affinity between the 1-(2-pyridylazo)-2-naphthol (PAN) indicator and cysteine target towards the host Zn2+. In the absence of cysteine, Zn2+ can induce an appreciable yellow-to-pink color change for the PAN solution through the formation of a PAN–Zn2+ complex. However, adding cysteine to the above PAN–Zn2+ complex solution resulted in a ligand exchange reaction between PAN and cysteine with about 57 nm blue-shift in the absorbance maximum (from 527 nm to 470 nm), accompanied by a visible color change of the solution from pink to yellow. The obtained indicator-displacement assay provides a good detecting performance for cysteine with a detection limit of 7.32 μM (S/N = 3) using a UV/vis spectrometer as well as with a good linear range from 25 to 1000 μM. In particular, the proposed sensing system could be successfully used for the fabrication of a colorimetric INHIBIT logic gate and converted into the test paper and image capture analytical devices for the onsite visual determination of cysteine in practical applications.

Graphical abstract: A selective colorimetric sensing strategy for cysteine based on an indicator-displacement mechanism

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Publication details

The article was received on 10 Oct 2017, accepted on 07 Feb 2018 and first published on 08 Feb 2018


Article type: Paper
DOI: 10.1039/C7NJ03887A
Citation: New J. Chem., 2018, Advance Article
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    A selective colorimetric sensing strategy for cysteine based on an indicator-displacement mechanism

    Z. Xue, L. Xiong, H. Peng, H. Rao, X. Liu and X. Lu, New J. Chem., 2018, Advance Article , DOI: 10.1039/C7NJ03887A

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