title: G-quadruplex DNAzyme-based microcystin-LR (toxin) determination by a novel immunosensor.
abstract: In this paper, we demonstrate the application of versatile G-quadruplex-hemin DNAzymes in an immunoassay for detecting Microcystin-LR (MC-LR). Taking advantage of the high peroxidase activity of G-quadruplex-hemin complexes and the enhancement effect of gold nanoparticles (AuNPs), the method showed simple, high sensitive and selectivity detection of target toxin residues in water samples. The coated antigen, MC-LR-ovalbumin (OVA) coated on a plate, competed for MC-LR antibody with added target analyte to form antibody-antigen immune complexes. Subsequently, the immune complex reacted with G-quadruplex-labeled secondary antibodies for colorimetric detection of MC-LR. This assay specifically determined MC-LR in the linear range of 0.1-10 ng/ml, with a limit of detection (LOD) of 0.05 ng/mL for MC-LR. The results indicated that the novel immunoassay was an alternative to traditional plate-based immunoassay for MC-LR residue screening due to this method met the standard of World Health Organization (WHO) requirements for MC-LR content in drinking water (1 ng/mL).
authors.affiliation: School of Food Science & Technology, State Key Lab of Food Science & Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: Yingyue
authors.initials: Y
authors.lastname: Zhu
authors.forename: Liguang
authors.initials: L
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Wenjing
authors.initials: W
authors.lastname: Yan
authors.forename: Hua
authors.initials: H
authors.lastname: Kuang
authors.forename: Libing
authors.initials: L
authors.lastname: Wang
authors.forename: Chuanlai
authors.initials: C
authors.lastname: Xu
mesh_terms: D001427:Bacterial Toxins / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D021881:DNA, Catalytic; D054856:G-Quadruplexes; D006046:Gold; D057230:Limit of Detection; D008387:Marine Toxins; D053768:Metal Nanoparticles; D052998:Microcystins / Q000032:analysis*; D010047:Ovalbumin; D014874:Water Pollutants, Chemical / Q000032:analysis; D014881:Water Supply / Q000032:analysis / Q000592:standards
chemical_list: D001427:Bacterial Toxins; D021881:DNA, Catalytic; D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; D006046:Gold; D010047:Ovalbumin; C057862:cyanoginosin LR