3D matrixed DNA self-nanocatalyzer as electrochemical sensitizers for ultrasensitive investigation of DNA 5-methylcytosine

DNA methylation plays an important role in a variety of human diseases. Thus, accurately analyze 5-methylcytosine in different DNA segments is of great significance. Herein, we proposed a novel 3D matrixed DNA self-nanocatalyzer via gold nanoparticles (AuNPs) supporting DNA self-hybridization with hemin as biomimetic enzyme and methylene blue (MB) as electrochemical mediator, which was employed as an efficient electrochemical sensitizer for the ultrasensitive bioassay of DNA 5methylcytosine. Meanwhile, the AuNPs, graphitic carbon nitride (g-C3N4) and reduced graphene oxide (rGO) was prepared as AuNPs/g-C3N4@rGO nanocomposites to coat on the electrode surface to immobilize the capture hairpin DNA (CH). In the presence of target DNA with 5-methylcytosine, the target DNA could hybridize with CH via the hyperstable triple-helix formation. Based on the specific biorecognition between biotin and streptavidin and immune recognition between anti-5-methylcytosine antibodies and 5-methylcytosine sites on the target DNA, the 3D matrixed DNA self-nanocatalyzer could be captured onto the electrode surface to generate an amplified electrochemical signal related to the concentration of 5-methylcytosine. Under the optimal conditions, the proposed strategy performed a linear range from 10(-17) M to 10(-8) M with a detection limit of 8.6 aM. Remarkably, this strategy could be expanded easily to various biomarkers, including protein, DNA, phosphorylation and glycosylation, providing a promising strategy for clinical diagnosis and mechanism investigation of various diseases. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A novel 3D matrixed DNA self-nanocatalyzer based on gold nanoparticles was proposed for the ultrasensitive bioassay of DNA 5-methylcytosine, showing potential applications in clinical diagnosis and disease mechanism investigation.