Electrochemical Biosensor for DNA Methylation Detection through Hybridization Chain-Amplified Reaction Coupled with a Tetrahedral DNA Nanostructure.

DNA methylation is a key factor in the pathogenesis of gene expression diseases or malignancies. Thus, it has become a significant biomarker for the diagnosis and prognosis of these diseases. In this paper, we designed an ultrasensitive and specific electrochemical biosensor for DNA methylation detection. The platform consisted of stem-loop-tetrahedron composite DNA probes anchoring at a Au nanoparticle-coated gold electrode, a restriction enzyme digestion of HpaII, and signal amplification procedures including electrodeposition of Au nanoparticles, hybridization chain reaction, and horseradish peroxidase enzymatic catalysis. Under optimal conditions, the design showed a broad dynamic range from 1 aM to 1 pM and a detection limit of about 0.93 aM. The approach also showed ideal specificity, repeatability, and stability. The recovery test demonstrated that the design is a promising platform for DNA methylation detection under clinical circumstances and could meet the need for cancer diagnosis.