High Catalytic Activity of Fluorophore-Labeled Y-Shaped DNAzyme/3D MOF-MoS2NBs as a Versatile Biosensing Platform for the Simultaneous Detection of Hg2+, Ni2+, and Ag+ Ions

ACS Appl Mater Interfaces. 2021 Jul 14;13(27):31710-31724. doi: 10.1021/acsami.1c07086. Epub 2021 Jul 2.

Abstract

In this study, we have designed a three-fluorophore-labeled Y-shaped DNAzyme with a high catalytic cleavage activity and a three-dimensional (3D) MOF-MoS2NB (metal-organic framework fused with molybdenum disulfide nanobox), which was synthesized as an efficient quencher of the fluorescent biosensor. The synthesized porous 3D MOF-MoS2NBs and Y-shaped DNAzyme exhibited a good analytical response toward the simultaneous multiple detections of Hg2+, Ni2+, and Ag+ ions over the other coexisting metal ions. More specifically, the three kinds of enzyme aptamer and substrate aptamer (SA) were hybridized and annealed to form the Y-shaped DNAzyme structure and labeled with three different fluorophores such as FAM, TAMRA, and ROX over the 3'-end of SA. When the targets were induced, the DNAzyme was triggered to cleave the fluorophore-labeled SAs. Then, the cleaved SAs (FAM-SA, TAMRA-SA, and ROX-SA) were adsorbed on the 3D MOF-MoS2NB surface to quench the fluorescence signal due to a noncovalent interaction (van der Waals and π-π stacking interaction), which transmuted the fluorescence on-state to off-state. As a result, the fluorescence assay confiscated the high selectivity and sensitivity for the target analytes of Hg2+, Ni2+, and Ag+ ions achieved for the detection limits of 0.11 nM, 7.8 μM, and 0.25 nM, respectively. Accordingly, the sensitivity of the developed sensor was explored with a better lower detection limit than the previously reported biosensors. The utility of the designed Y-shaped DNAzyme may find a broad field of application in real water sample analysis with interfering contaminants.

Keywords: 3D MOF-MoS2NBs; Y-shaped DNAzyme; biosensor; mercury; nickel; silver.

MeSH terms

  • Adsorption
  • Biocatalysis*
  • Biosensing Techniques / methods*
  • Catalysis
  • DNA, Catalytic / chemistry
  • DNA, Catalytic / metabolism*
  • Disulfides / chemistry*
  • Fluorescent Dyes / chemistry*
  • Limit of Detection
  • Mercury / analysis
  • Metal-Organic Frameworks / chemistry*
  • Metals, Heavy / analysis*
  • Molybdenum / chemistry*
  • Nickel / analysis
  • Silver / analysis

Substances

  • DNA, Catalytic
  • Disulfides
  • Fluorescent Dyes
  • Metal-Organic Frameworks
  • Metals, Heavy
  • Silver
  • Nickel
  • Molybdenum
  • Mercury
  • molybdenum disulfide