Single-stranded DNA modified protonated graphitic carbon nitride nanosheets: A versatile ratiometric fluorescence platform for multiplex detection of various targets

Publication date: 15 May 2019

Source: Talanta, Volume 197

Author(s): Lumin Wang, Fawei Zhu, Sen Liao, Miao Chen, Yu Qiu Zhu, Qi Liu, Xiaoqing Chen

Abstract

Facile and cost-effective detection of multiple targets is essential for a variety of applications ranging from life sciences to environmental monitoring. Here, we report a versatile ratiometric fluorescence platform for multiple detection of various targets based on the conjugation of single-stranded DNA (ssDNA) with protonated graphitic carbon nitride nanosheets (Pg-C₃N₄ NSs). We demonstrate that intrinsic peroxidase-like activity of Pg-C₃N₄ NSs is enhanced by conjugating with ssDNA, and thus the oxidation of substrate o-phenylenediamine (OPD) is promoted in the presence of H₂O₂. The oxidation product 2,3-diaminophenazine (DAP) can deliver a new fluorescence signal at 564 nm, and concurrently quench the intrinsic fluorescence of conjugates ssDNA/Pg-C₃N₄ NSs at 443 nm upon excitation at 370 nm. The transformation of fluorescence provides us a novel strategy for ratiometric fluorescence-based analytical sensing. Taking ssDNA as the target-recognition element of the conjugates ssDNA/Pg-C₃N₄ NSs, we favorably present ratiometric fluorescence detection of various targets including heavy metal ions (Hg²⁺) and biomolecules (Aflatoxin B1 (AFB1) and adenosine triphosphate (ATP)) in real samples by varying the ssDNA sequences. The present work provides a new strategy to develop facile methods for quantitative determination of various analytes and uncovers an innovative horizon for Pg-C₃N₄ NSs-based sensing platform fabrication.

Graphical abstract

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