title: Amplified and selective detection of Ag+ ions based on electrically contacted enzymes on duplex-like DNA scaffolds.
abstract: In the present study, ultrasensitive detection of Ag(+) is demonstrated by a biocatalytic signal amplification system which is realized by only one DNA sequence based electrical contacted enzyme structure and the Au nanoparticles/Carbon nanodots (AuNPs/C-dots) composite immobilization platform. In the presence of Ag(+), with the interaction of cytosine-Ag(+)-cytosine (C-Ag(+)-C), cytosine-rich DNA sequence labeled with methylene blue (MB) molecules near 5' end and Glucose Oxidase (GOx) at 3' end, has a self-hybridization and then forms a duplex-like structure which makes MB and GOx approach the AuNPs/C-dots modified electrode. MB units can then act as a relay that electrically contacts GOx with the AuNPs/C-dots modified electrode and activate the bioelectrocatalyzed oxidation of glucose to glucose acid. In consequence, based on the bioelectrocatalyzed signal amplification on the AuNPs/C-dots platform, Ag(+) could be quantitatively detected in the range of 10(-11)-10(-5) M with a low detection limit of 3 pM. Also, there is an excellent selectivity against other interferential metal ions. The detection of Ag(+) ions was realized by Ag(+) self-induced conformational change of DNA scaffold which involved only one oligonucleotide showing its convenience and availability.
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.
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
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.
authors.forename: Guangfeng
authors.initials: G
authors.lastname: Wang
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.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhu
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.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
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.
authors.forename: Xiuping
authors.initials: X
authors.lastname: He
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.
authors.forename: Lun
authors.initials: L
authors.lastname: Wang
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: xjzhang@mail.ahnu.edu.cn.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry*; D002414:Cations, Monovalent / Q000032:analysis; D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D004867:Equipment Design; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry; D012834:Silver / Q000032:analysis*
chemical_list: D002414:Cations, Monovalent; D004800:Enzymes, Immobilized; D012834:Silver; D002244:Carbon; D006046:Gold; D003596:Cytosine; D004247:DNA; D005949:Glucose Oxidase; D005947:Glucose
keywords: Ag(+); Carbon nanodots; Cytosine; Electrical contacted enzyme