title: An electrochemical aptasensor based on enzyme linked aptamer assay.
abstract: An aptamer is an artificial functional oligonucleic acid, which can interact with its target molecule with high affinity and specificity. Enzyme linked aptamer assay (ELAA) is developed to detect cocaine using aptamer fragment/cocaine configuration based on the affinity interaction between aptamer fragments with cocaine. The aptasensor was constructed by cleaving anticocaine aptamer into two fragments: one was assembled on a gold electrode surface, while the other was modified with biotin at 3'-end, which could be further labelled with streptavidin-horseradish peroxidase (SA-HRP). Upon binding with cocaine, the HRP-labelled aptamer fragment/cocaine complex formed on the electrode would increase the reduction current of hydroquinone (HQ) in the presence of H(2)O(2). The sensitivity and the specificity of the proposed electrochemical aptasensor were investigated by differential pulse voltammetry (DPV). The results indicated that the DPV signal change could be used to sensitively detect cocaine with the dynamic range from 0.1 μM to 50 μM and the detection limit down to 20 nM (S/N=3). The proposed aptasensor has the advantages of high sensitivity and low background current. Furthermore, a new configuration for ELAA requiring only a single aptamer sequence is constructed, which can be generalized for detecting different kinds of targets by cleaving the aptamers into two suitable segments.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Biochemistry and Molecular Engineering, College of Chemistry, Peking University, Beijing 100871, China.
authors.forename: De-Wen
authors.initials: DW
authors.lastname: Zhang
authors.forename: Cui-Jin
authors.initials: CJ
authors.lastname: Sun
authors.forename: Fang-Ting
authors.initials: FT
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Ying-Lin
authors.initials: YL
authors.lastname: Zhou
authors.forename: Xin-Xiang
authors.initials: XX
authors.lastname: Zhang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006735:Horseradish Peroxidase / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D006735:Horseradish Peroxidase