title: Label-free electrochemical lead (II) aptasensor using thionine as the signaling molecule and graphene as signal-enhancing platform.
abstract: A label-free and highly sensitive electrochemical aptasensor for Pb(2+) was constructed using thionine (TH) as the signaling molecule and graphene (GR) as the signal-enhancing platform. The electrochemical sensing interface was fabricated by stepwise assembly of GR and TH on the lead (II) specific aptamer (LSA) modified electrode. Upon interaction with Pb(2+), the aptamer probe on the sensor underwent conformational switch from a single-stranded DNA form to the G-quadruplex structure, causing the GR with assembled TH released from the electrode surface into solution. As a result, the electrochemical signal of TH on the aptasensor was substantially reduced. Under the optimal experimental conditions, the attenuation of peak currents presented a good linear relationship with the logarithm of Pb(2+) concentrations over the range from 1.6×10(-13) to 1.6×10(-10)M. The detection limit was estimated to be 3.2×10(-14)M. The aptasensor also exhibited good regenerability, excellent selectivity, and acceptable reproducibility, indicating promising application in environment monitoring of lead.
authors.affiliation: College of Chemistry and Environment, Fujian Province Key Laboratory of Morden Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: College of Chemistry and Environment, Fujian Province Key Laboratory of Morden Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China.
authors.forename: Cai
authors.initials: C
authors.lastname: Gao
authors.affiliation: College of Chemistry and Environment, Fujian Province Key Laboratory of Morden Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China.
authors.forename: Suyu
authors.initials: S
authors.lastname: He
authors.affiliation: College of Chemistry and Environment, Fujian Province Key Laboratory of Morden Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China. Electronic address: axiang236@126.com.
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: College of Chemistry and Environment, Fujian Province Key Laboratory of Morden Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, PR China.
authors.forename: Aiqun
authors.initials: A
authors.lastname: Wu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002413:Cations, Divalent / Q000032:analysis; D004277:DNA, Single-Stranded / Q000737:chemistry; D060766:Drinking Water / Q000032:analysis; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D004867:Equipment Design; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D007854:Lead / Q000032:analysis*; D057230:Limit of Detection; D010640:Phenothiazines / Q000737:chemistry*; D015203:Reproducibility of Results; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D002413:Cations, Divalent; D004277:DNA, Single-Stranded; D060766:Drinking Water; D010640:Phenothiazines; D014874:Water Pollutants, Chemical; D007854:Lead; D006046:Gold; D006108:Graphite; C009469:thionine
keywords: Aptasensor; Graphene; Lead ion; Thionine