title: Highly sensitive electrochemical sensor using a MWCNTs/GNPs-modified electrode for lead (II) detection based on Pb(2+)-induced G-rich DNA conformation.
abstract: A sensitive electrochemical lead ion (Pb(2+)) sensor based on carboxylic acid group functionalized multi-walled carbon nanotubes (MWNTs-COOH) and direct electrodeposited gold nanoparticles (GNPs) was developed for Pb(2+) detection. The DNA capture probe was self-assembled onto the surface of the modified electrode for hybridizing with the guanine-rich (G-rich) aptamer probe and for forming the DNA double helix structure. When Pb(2+) was added in, the DNA duplex unwound and formed a stabilized G-quadruplex (G4) due to the Pb(2+)-induced G-rich DNA conformation. Also, methylene blue (MB) was selected as the G4-binding indicator. Compared with previous Pb(2+) sensors, the proposed sensor had better sensitivity, because the modified MWCNTs/GNPs could provide a large surface area and good charge-transport capacity to dramatically improve the DNA attachment quantity and sensor performance. The sensor could detect Pb(2+) in a range from 5.0 × 10(-11) to 1.0 × 10(-14) M, with a detection of 4.3 × 10(-15) M.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China. zgming@hnu.edu.cn zyi@hnu.edu.cn.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Guang-ming
authors.initials: GM
authors.lastname: Zeng
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Tang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Zhang
authors.forename: Ling
authors.initials: L
authors.lastname: He
authors.forename: Yuan
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiao-xiao
authors.initials: XX
authors.lastname: He
authors.forename: Ming-yong
authors.initials: MY
authors.lastname: Lai
authors.forename: Yi-bin
authors.initials: YB
authors.lastname: He
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D007477:Ions; D037742:Nanotubes, Carbon; D007854:Lead; D006147:Guanine; D006046:Gold; D008751:Methylene Blue