Development of an Antigen-DNAzyme Based Probe for a Direct Antibody-Antigen Assay Using the Intrinsic DNAzyme Activity of a Daunomycin Aptamer

Abstract

G-Quadruplex (G-4) structures are formed when G-rich DNA sequences fold into intra- or intermolecular four-stranded structures in the presence of metal ions. G-4-hemin complexes are often effective peroxidase-mimicking DNAzymes that are applied in many detection systems. This work reports the application of a G-rich daunomycin-specific aptamer for the development of an antibody-antigen detection assay. We investigated the ability of the daunomycin aptamer to efficiently catalyze the hemin-dependent peroxidase activity independent of daunomycin. A reporter probe consisting of biotinylated antigen and daunomycin aptamer coupled to streptavidin gold nanoparticles was successfully used to generate a colorimetric readout. In conclusion, the daunomycin aptamer can function as a robust alternative DNAzyme for the development of colorimetric assays.

Visual detection of myoglobin via G-quadruplex DNAzyme functionalized gold nanoparticles-based colorimetric biosensor

“…G-quadruplex DNAzyme, which is usually formed by binding G-rich nucleic acid to hemin [19][20][21], can exhibit peroxidase-like activity and effectively catalyze the H 2 O 2 -mediated oxidation of 2,2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) [22][23][24]. In this assay, hemin/G-quadruplex DNAzyme complex showed inherent advantages of simplicity, stability and relatively low cost.…”

Phage Display‐Derived Antibodies: Application of Recombinant Antibodies for Diagnostics

“…The G-quad structure is further stabilized by the presence of cations. The complexation of G-quad structures with a hemin will form a peroxidase mimicking DNAzyme that catalyses the peroxidase-mediated oxidation of ABTS [97,98]. The main difference of this antibody-antigen detection assay is the use of G-quad DNA structures in association with hemin as a reporter system.…”

“…The main difference of this antibody-antigen detection assay is the use of G-quad DNA structures in association with hemin as a reporter system. The addition of hemin to a G-quad structure will allow the transfer of electrons from the guanine to hemin in the presence of peroxide to oxidize the ABTS to form a green complex that is visible to the eye [98].…”

Native and Synthetic G-quartet-based DNAzyme Systems – Artificial Enzymes for Biotechnological Applications

“…Using a close approach with a G-rich DNA sequence grafted on the gold nanoparticles surface, a new DNAzyme biosensor was proposed as a direct antigen-antibody detection assay. [161] i. Interestingly, the DNAzyme methodology was also used to detect bigger living systems, like the bacteria Escherichia coli O157:H7 [162] or Alicyclobacillus acidoterrestris. [163] In the first example, authors used graphene oxide/thionine/gold nanoparticles coated SiO 2 nanocomposites to immobilize DNA, while for the second one, a more classic approach was used, in which G-quadruplex-hemin complexes oxidize the colorless guaiacol, produced by the bacteria, to tetraguaiacol, which is amber.…”