Aptamers Joined with a Peroxidase-Mimicking DNAzyme as Potential Reporters for Colorimetric Detection of Protein Biomarkers

A quantitative assessment of protein biomarkers levels in blood is extremely important for disease diagnosis and monitoring. Enzyme-linked immunosorbent assay recruiting monoclonal antibody that recognizes an analyte and protein enzyme that generates an analytical signal, is one of the most widely used. This assay can become more advantageous by employing non-protein alternatives: aptamers as analyte binders and DNAzymes as enzyme mimics. Here, we rationally designed, chemically synthesized and characterized chimeric molecules consisting of hemin-binding DNAzyme and 2’-F-RNA aptamers that bind a proinflammatory cytokine, human interleukin-17 A.The resulting constructs retained the functionalities of both parts and were shown to be able both to bind IL-17 A and to catalyze the oxidation of chromogenic substrate in the presence of hydrogen peroxide. Therefore, aptamer and peroxidase-like DNAzyme can be directly joined into a single molecule that serves simultaneously as a biorecognizing module and as a reporter and look very promising for colorimetric assays. We have also shown that IL-17 A can also bind hemin, and this property of protein analyte have to be accounted when designing analytical assays that involve hemin-binding DNAzyme.