Double-integrated mimic enzymes for the visual screening of Microcystin-LR: Copper hydroxide nanozyme and G-quadruplex/hemin DNAzyme.

Journal: Analytica chimica acta
PMID: 30712583

Abstract

Recently, mimic enzymes have obtained particular interest by their high activity, stability, and biocompatibility. In this work, by coupling copper hydroxide nanozyme and G-quadruplex/hemin DNAzyme to form a double-integrated mimic enzyme, a visual, sensitive and selective immunosensor was established to detect microcystin-LR (MC-LR). In this immunoassay, the microplates were modified with core-shell silica/nickel silicate as the substrate to capture MC-LR antigens. Then, Cu(OH) nanocages with fine regulation were used as the label to capture the secondary antibody for immunoreaction and the DNA primer for propagation, followed by using hybridization chain reaction to amplify the DNA primer, thus numerous DNAzymes (G-quadruplex/hemin) can be formed on the surface of Cu(OH) nanocages with the aid of hemin. Such double-integrated mimic enzyme including Cu(OH) nanozymes and DNAzymes showed excellent peroxidase activity for the chromogenic reaction of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), which realized the visual detection of MC-LR in the range from 0.007 to 75 μg/L with the detection limit of 6 ng/mL, and thus provided the probability for the portable assessment of MC-LR in real sample.

Authors

  • Weipeng Liu
    College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China.
  • Cuifen Gan
    College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China; Guangdong Institute of Microbiology, Guangzhou, 510070, China.
  • Weidan Chang
    College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China; The Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou, 510642, China.
  • Aori Qileng
    College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China.
  • Hongtao Lei
    Key Laboratory of Food Quality and Safety of Guangdong Province, College of Food Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address: hongtao@scau.edu.cn.
  • Yingju Liu
    College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China. Electronic address: liuyingju@hotmail.com.

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