title: DNAzyme-based highly sensitive electronic detection of lead via quantum dot-assembled amplification labels.
abstract: An electronic DNAzyme sensor for highly sensitive detection of Pb(2+) is demonstrated by coupling the significant signal enhancement of the layer-by-layer (LBL) assembled quantum dots (QDs) with Pb(2+) specific DNAzymes. The presence of Pb(2+) cleaves the DNAzymes and releases the biotin-modified fragments, which further hybridize with the complementary strands immobilized on the gold substrate. The streptavidin-coated, QD LBL assembled nanocomposites were captured on the gold substrate through biotin-streptavidin interactions. Subsequent electrochemical signals of the captured QDs upon acid dissolution provide quantitative information on the concentrations of Pb(2+) with a dynamic range from 1 to 1000 nM. Due to the dramatic signal amplification by the numerous QDs, subnanomolar level (0.6 nM) of Pb(2+) can be detected. The proposed sensor also shows good selectivity against other divalent metal ions and thus holds great potential for the construction of general DNAzyme-based sensing platform for the monitoring of other heavy metal ions.
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Zhang
authors.forename: Bingying
authors.initials: B
authors.lastname: Jiang
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiang
authors.forename: Jiao
authors.initials: J
authors.lastname: Su
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic / Q000737:chemistry*; D055664:Electrochemical Techniques; D007854:Lead / Q000032:analysis*; D045663:Quantum Dots; D012680:Sensitivity and Specificity
chemical_list: D021881:DNA, Catalytic; D007854:Lead