title: Label free detection of lead using impedimetric sensor based on ordered mesoporous carbon-gold nanoparticles and DNAzyme catalytic beacons.
abstract: A novel label-free impedimetric sensing system based on DNAzyme and ordered mesoporous carbon-gold nanoparticle (OMC-GNPs) for the determination of Pb(2+) concentration was developed in the present study. Firstly, gold nanoparticles deposited on the modified electrode surface were employed as a platform for the immobilization of thiolated probe DNA, and then hybridized with DNAzyme catalytic beacons. Subsequently, in the presence of Pb(2+), the DNAzyme could be activated to cleave the substrate strand into two DNA fragments, which causes differences in the electrical properties of the film. Randles equivalent circuit was employed to evaluate the electrochemical impedance spectroscopy (EIS) result. The charge transfer resistance (R(CT)) value for the [Fe(CN)6](3-/4-) redox indicator was remarkably decline after hybridization with Pb(2+). The difference in RCT values before and after hybridization with Pb(2+) showed a linear relation with the concentration of the Pb(2+) in a range of 5×10(-10)-5×10(-5) M, with a detection limit of 2×10(-10) M (S/N=3). Furthermore, with the application of Pb(2+) dependent 8-17DNAzyme, the proposed sensing system exhibited high selectivity without using any labeled probes. This biosensor demonstrated a promising potential for Pb(2+) detection in real sample.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China. Electronic address: tanglin@hnu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Tang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China. Electronic address: zgming@hnu.edu.cn.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Xie
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan, China.
authors.forename: Yaocheng
authors.initials: Y
authors.lastname: Deng
mesh_terms: D001483:Base Sequence; D055162:Biocatalysis; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry* / Q000235:genetics; D021881:DNA, Catalytic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D058266:Dielectric Spectroscopy; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D004785:Environmental Pollutants / Q000032:analysis / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D016062:Porosity
chemical_list: D015342:DNA Probes; D021881:DNA, Catalytic; D004785:Environmental Pollutants; D007854:Lead; D002244:Carbon; D006046:Gold
keywords: 8-17DNAzyme; Impedimetric sensor; Lead; Ordered mesoporous carbon–gold nanoparticles