title: Cationic-perylene-G-quadruplex complex based fluorescent biosensor for label-free detection of Pb(2+).
abstract: In this work we use a water-soluble cationic perylene derivative (compound 1) as the G-quadruplex (G4) structure fluorescence indicator to construct a fluorescent biosensor for simple, rapid and label-free detection of Pb(2+). In the absence of Pb(2+), strong electrostatic interactions between compound 1 and the G-rich DNA probe (PW17) induced the aggregation of compound 1 and resulted in the fluorescence quenching. In the presence of Pb(2+), the PW17 formed Pb(2+)-stabilized G4 structure, which reduced the aggregation of compound 1 and gave rise to high fluorescence. This allowed us to use convenient "mix-and-detect" protocol for quantitative analysis of Pb(2+). Since Pb(2+) can specially induce PW17 to form compact DNA fold, our proposed biosensor displayed high selectivity for Pb(2+). It also exhibited a high sensitivity to Pb(2+), with a limit of detection of 5.0nM observed. Furthermore, the biosensor was applied for the detection of Pb(2+) in urine and paint samples, and both showed satisfactory results.
authors.affiliation: Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, PR China.
authors.forename: Xu-Hua
authors.initials: XH
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Gong
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: xbzhang@hnu.edu.cn.
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi 030001, PR China. Electronic address: xiejunty@yahoo.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
mesh_terms: D015374:Biosensing Techniques; D015342:DNA Probes; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D010150:Paint / Q000032:analysis; D010569:Perylene / Q000737:chemistry*; D014556:Urine / Q000737:chemistry
chemical_list: D015342:DNA Probes; D005456:Fluorescent Dyes; D007854:Lead; D010569:Perylene
keywords: Biosensor; Fluorescence; G-quadruplex; Label-free; Pb(2+) detection; Perylene derivative