An 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 disorder diseases or malignancies. So 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 an Au nanoparticle-coated gold electrode, a restriction enzyme digestion of Hpa II and signal amplification procedures of electrodeposition of Au nanoparticles (AuNPs), hybridization chain reaction (HCR) and horseradish peroxidase (HRP) enzymatic catalysis. Under optimal conditions, the design showed a board 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 was a promising platform for DNA methylation detection under clinical circumstances and could meet the need for cancer diag...