title: DNA-gold nanoparticles network based electrochemical biosensors for DNA MTase activity.
abstract: In this work, a highly sensitive electrochemical DNA methyltransferase (MTase) activity assay was fabricated with DNA-gold nanoparticles (Au NPs) network as signal amplification unit and an easy assembly method by the linkage of benzenedithiol bridge. By two complementary AuNPs modified single-stranded DNA, DNA-gold nanoparticles network was self-assembled. With the linkage of benzenedithiol bridge, the DNA network structure was immobilized on the surface of gold electrode through the covalent Au-S bond. In the presence of Dam MTase, the special sites of DNA-AuNPs network were methylated and could not be digested by restriction endonuclease Mbo I. Thus the loaded electrochemical indicator Methylene blue (MB) was MB molecules still remained on the DNA-Au NPs network. The electrochemical response depended on the methylated degree, which could be used to detect MTase activity. By the differential pulse voltammetry (DPV), it was demonstrated that a linear relationship between the DPV response and logarithm of Dam concentration ranged from 0.075 to 30 U/mL, achieving a low detection limit of 0.02 U/mL. The use of benzenedithiol avoided the direct incubation of the solid electrode with the capture DNA probe under complex and harsh conditions. Therefore the immobilization of DNA-AuNPs network was easy to be carried out, which is favorable for the specially high stability and reproducibility of the electrochemical biosensor.
authors.affiliation: Key Laboratory of Chem-Biosensing, Anhui Province, Key Laboratory of Functional Molecular Solids, Anhui Province, College of Chemistry and Materials Science, Center for Nano Science and Technology, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Hong
authors.affiliation: Key Laboratory of Chem-Biosensing, Anhui Province, Key Laboratory of Functional Molecular Solids, Anhui Province, College of Chemistry and Materials Science, Center for Nano Science and Technology, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wan
authors.affiliation: Key Laboratory of Chem-Biosensing, Anhui Province, Key Laboratory of Functional Molecular Solids, Anhui Province, College of Chemistry and Materials Science, Center for Nano Science and Technology, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Chem-Biosensing, Anhui Province, Key Laboratory of Functional Molecular Solids, Anhui Province, College of Chemistry and Materials Science, Center for Nano Science and Technology, Anhui Normal University, Wuhu 241000, PR China; State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, PR China. Electronic address: wangyuz@mail.ahnu.edu.cn.
authors.forename: Guangfeng
authors.initials: G
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques; D019175:DNA Methylation; D004262:DNA Restriction Enzymes / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000032:analysis*; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D013438:Sulfhydryl Compounds; C102217:1,2-benzenedithiol; D006046:Gold; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C499294:dam protein, E coli; D004262:DNA Restriction Enzymes; D008751:Methylene Blue
keywords: DNA–AuNPs network; Methylation; Methyltransferase activity; Signal amplification