期刊
BIOSENSORS & BIOELECTRONICS
卷 127, 期 -, 页码 155-160出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2018.12.022
关键词
Electrochemical biosensor; DNA methylation; Hydrophobic sphere; Steric hindrance
类别
资金
- National Natural Science Foundation of China [81572078, 81401722, 81873982]
- Third Military Medical University Medical Creative Research Foundation [SWH2016JCYB-62, SWH2016JCYB-33]
We herein developed a novel electrochemical biosensor to detect DNA methylation level, and to quantitatively analyze multiple methylated sites. Graphene oxide was modified with anti-5-methylcytosine antibody to specifically bind CpG methylation sites, and horseradish peroxidase (HRP)-labeled IgG secondary antibody was bound to the former antibody. In buffer containing H2O2 and hydroquinone, HRP-IgG catalyzed the oxidation of hydroquinone into benzoquinone over H2O2, thereby generating electrochemical reduction signals. The number of 5-methylcytosine was directly proportional to current signal, thereby allowing accurate quantification of methylation level. We also analyzed monomethylated target sequences with different sites, After different methylated sites were captured by the probe, the steric hindrance differences between -CH3 hydrophobic sphere and the electrode surface were induced. The peak current decreased with reducing distance from the electrode surface, so DNA methylation sites were identified by measuring corresponding peak current responses. With a low detection limit (1 fM), this DNA biosensor was suitable for ultrasensitive DNA methylation detection. The linear detection range was 10(-15) M to 10(-8) M. Meanwhile, this method had high specificity, stability and repeatability, thus being widely applicable to the clinical detection of DNA methylation.
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