title: A G-quadruplex based label-free fluorescent biosensor for lead ion.
abstract: Many Pb(2+) biosensors based on Pb(2+)-specific RNA-cleaving DNAzyme have been developed in the past years. However, many of them have limited practical use because of high cost (e.g., enzymes), complicated processing and the use of unstable molecules (e.g., RNA). In this study, a novel label-free fluorescent biosensor for Pb(2+) was proposed based on Pb(2+)-induced allosteric G-quadruplex (PS2.M). In the presence of K(+), N-methyl mesoporphyrin IX (NMM) could bind to K(+)-stabilized G-quadruplexes, giving rise to high fluorescence. On addition of Pb(2+), Pb(2+) competitively binded to K(+)-stabilized G-quadruplexes to form more compact DNA folds. The Pb(2+)-stabilized G-quadruplexes did not bind to NMM, which resulted in fluorescence decrease. This allowed us to utilize PS2.M for quantitative analysis of Pb(2+) using the NMM-G-quadruplex system by convenient "mix-and-detect" protocol. The fluorescence emission ratio (F(0)/F) showed a good linear response toward Pb(2+) over the range from 5.0 nM to 1.0 μM with a limit of detection of 1.0 nM. This proposed biosensor was simple and cost efficiency in design and in operation with high sensitivity and selectivity. We validated the practicality of this biosensor for the determination of Pb(2+) in lake water samples.
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China. Electronic address: lqguo@fzu.edu.cn.
authors.forename: Liangqia
authors.initials: L
authors.lastname: Guo
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Nie
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Qiu
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Qishan
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Peirong
authors.initials: P
authors.lastname: Ye
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Hao
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China. Electronic address: fengfu@fzu.edu.cn.
authors.forename: FengFu
authors.initials: F
authors.lastname: Fu
authors.affiliation: Key Lab of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
authors.forename: Guonan
authors.initials: G
authors.lastname: Chen
mesh_terms: D000495:Allosteric Site; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D021881:DNA, Catalytic / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D054856:G-Quadruplexes; D060106:Lakes / Q000032:analysis; D007854:Lead / Q000032:analysis*; D008652:Mesoporphyrins / Q000737:chemistry; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D021881:DNA, Catalytic; D005456:Fluorescent Dyes; D008652:Mesoporphyrins; D014874:Water Pollutants, Chemical; C065420:N-methylmesoporphyrin IX; D007854:Lead