title: Ultrasensitive detection of lead ion based on target induced assembly of DNAzyme modified gold nanoparticle and graphene oxide.
abstract: In this paper, we report a novel colorimetric strategy for the detection of small molecules by using Pb(2+) ion as an example. In this strategy, DNAzyme duplex modified gold nanoparticles (GNPs) are designed to be unable to interact with graphene oxide (GO). However, in the presence of Pb(2+), the substrate strand of the DNAzyme is cleaved at its cleavage site, resulting in the disassembly of the DNAzyme duplex modified GNPs into three parts, i.e., the 3'- and 5'-fragments of substrate strand and the DNAzyme strand modified GNPs. By taking advantage of the efficient cross-linking effect of ssDNA-GNPs to GO, colorimetric sensor for the detection of the metal ion can be fabricated with a detection limit of 100 pM, which is much lower than the previous reports. This colorimetric method has also been used for the determination of Pb(2+) in the tap water of the local city and the water from a reservoir with satisfactory results, so it may have potential applications in the future.
authors.affiliation: Department of Biochemistry and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Biochemistry and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Luming
authors.initials: L
authors.lastname: Wei
authors.affiliation: Department of Biochemistry and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Biochemistry and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lei
authors.affiliation: Department of Biochemistry and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China; Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China. Electronic address: genxili@nju.edu.cn.
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D003124:Colorimetry; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry
chemical_list: D021881:DNA, Catalytic; D007477:Ions; D010087:Oxides; D007854:Lead; D006046:Gold; D006108:Graphite
keywords: Colorimetric detection; DNAzyme; Gold nanoparticle; Graphene oxide; Lead ion