title: A label-free electrochemical impedance aptasensor for cylindrospermopsin detection based on thionine-graphene nanocomposites.
abstract: It is important to develop methods to determine cylindrospermopsin (CYN) at trace levels since CYN is a kind of widespread cyanobacterial toxin in water sources. In this study, a label-free impedimetric aptasensor has been fabricated for detecting CYN. In this case, the amino-substituted aptamer of CYN was covalently grafted onto the surface of the thionine-graphene (TH-G) nanocomposite through the cross-linker glutaraldehyde (GA). The reaction of the aptamer with CYN was monitored by electrochemical impedance spectroscopy because the CYN induced conformation change of the aptamer can cause a remarkable decrease of the electron transfer resistance. Under optimum conditions, the aptasensor exhibits high sensitivity and a low detection limit for CYN determination. The CYN can be quantified in a wide range of 0.39 to 78 ng mL(-1) with a good linearity (R(2) = 0.9968) and a low detection limit of 0.117 ng mL(-1). In addition, the proposed aptasensor displays excellent stability, reusability and reproducibility.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China. malina@ciac.ac.cn wangzx@ciac.ac.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhao
authors.forename: Hongda
authors.initials: H
authors.lastname: Chen
authors.forename: Lina
authors.initials: L
authors.lastname: Ma
authors.forename: Dianjun
authors.initials: D
authors.lastname: Liu
authors.forename: Zhenxin
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000470:Alkaloids; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001427:Bacterial Toxins; D015374:Biosensing Techniques / Q000379:methods*; D000087522:Cyanobacteria Toxins; D058266:Dielectric Spectroscopy / Q000379:methods*; D017097:Electric Impedance; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry*; D010640:Phenothiazines / Q000737:chemistry*; D015203:Reproducibility of Results; D014498:Uracil / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D000470:Alkaloids; D052157:Aptamers, Nucleotide; D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D010640:Phenothiazines; C089595:cylindrospermopsin; D014498:Uracil; D006046:Gold; D006108:Graphite; C009469:thionine