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

Abstract

Rapidly 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-napthol (PAN) indicator and cysteine target for the host Zn2+. In the absence of cysteine, Zn2+ can induce an appreciable yellow-to-pink color change for PAN solution through the formation of PAN-Zn2+ complex. However, adding cysteine to 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 an obvious color change of the solution from pink to yellow. The obtained indicator-displacement assay provide good detecting performance for cysteine with a detection limit of 7.32 μM (S/N =3) by a UV/vis spectrometer as well as with a good linear range from 25 to 1000μM. More importantly, the proposed sensing system could be successfully used to the fabrication of a colorimetric INHIBIT logic gate, and converted into the test paper and image capture analytical devices for onsite visual determination of cysteine in practical applications.

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Supplementary files

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, Accepted Manuscript
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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, Accepted Manuscript , DOI: 10.1039/C7NJ03887A

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