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

• Main Authors: Noorsharmimi Omar, Qiuting Loh, Gee Jun Tye, Yee Siew Choong, Rahmah Noordin, Jörn Glökler, Theam Soon Lim
• Format: Article
• Language: English
• Published: MDPI AG 2013-12-01
• Series: Sensors
• Subjects: G-quadruplex; DNAzyme; gold nanoparticles; antibody
• Online Access: http://www.mdpi.com/1424-8220/14/1/346

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.