Sensitive and selective fluorometric determination of DNA by using layered hexagonal nanosheets of a covalent organic framework prepared from p-phenylenediamine and benzene-1,3,5-tricarboxaldehyde

Mikrochim Acta. 2019 Nov 22;186(12):833. doi: 10.1007/s00604-019-3944-1.

Abstract

A modified method is described for the preparation of amino-functionalized covalent organic framework nanosheets (COF-NSs). These consist of hexagonal layered sheets and were prepared from commercially available starting materials (p-phenylenediamine and benzene-1,3,5-tricarboxaldehyde). The interlayer stacking interactions between the ultra-thin COF-NSs became weak because the π stacking is destroyed by sonication. This result in the exfoliation of COF-NSs. As an application, the COF-NSs used for sensitive and selective fluorometric determination of DNA. To reach this goal, H1 and H2 hairpin-like DNA probes were chosen; H1 used Texas Red-labeled dye as a fluorescent probe. The addition of the COF-NSs, the hairpin probes was adsorbed onto the porous surface of the COFNSs. The π stacking and hydrogen-bond interactions between COFNSs and nucleic acid quench the fluorescence of the Texas red-labeled probe. The target DNA enables the recovery of the quenched fluorescence of the Texas red-labelled probe by triggering an inter-chain hybridization within hairpin probes. This results in a weaker interaction of double-stranded DNA (dsDNA) with the COFNSs. Consequently, the dsDNA detaches from the COFNSs, thereby recovering the dye's fluorescence (excitation/emission maxima at 590/612 nm) with increasing target DNA concentration. The findings were applied to design a method for the determination of DNA that has a 2 pM detection limit. This is significantly lower than the limit of detection reported previously for 2D nanomaterial-based fluorometric DNA assays. Graphical abstractSchematic representation of 2D-covalent organic framework nanosheets (COF-NSs) probe act as a quencher allowing the highly sensitive and selective fluorescence turn-on detection for biomolecules. Here the H1 H2 are hairpin DNAs. H1 is associated with the fluorescent tag (red circle), while the "fluorescence off" state it denoted as a black circle.

Keywords: Biomarker; Biomolecules; Bond; Diagnostics; Diseases; Fluorescence; Porous nanomaterials; Sensor; Signal; Target.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry*
  • Biosensing Techniques
  • DNA / analysis*
  • Fluorometry*
  • Humans
  • Metal-Organic Frameworks / chemistry*
  • Molecular Probes / chemistry*
  • Molecular Structure
  • Nanoparticles / chemistry*
  • Nucleic Acid Amplification Techniques
  • Particle Size
  • Phenylenediamines / chemistry*
  • Sensitivity and Specificity
  • Surface Properties

Substances

  • Aldehydes
  • Metal-Organic Frameworks
  • Molecular Probes
  • Phenylenediamines
  • benzene-1,3,5-tricarboxaldehyde
  • DNA
  • 4-phenylenediamine