title: An amplified electrochemical aptasensor for thrombin detection based on pseudobienzymic Fe3O4-Au nanocomposites and electroactive hemin/G-quadruplex as signal enhancers.
abstract: A sensitive and selective electrochemical aptasensor for thrombin detection was constructed based on hemin/G-quadruplex as the signal label and Fe3O4-Au nanocomposites with glucose oxidase (GOx-) and peroxide-mimicking enzyme activity as the signal enhancers. Due to their large surface area and good biocompatibility, Fe3O4-Au nanocomposites were employed to immobilize electroactive hemin/G-quadruplex, which was formed by the conjugation between a single-stranded guanine-rich nucleic acid and hemin. Based on the GOx-mimicking enzyme activity, Au nanoparticles on the surface of the Fe3O4-Au nanocomposites effectively catalyzed the oxidization of glucose in the presence of dissolved O2, accompanied by the production of H2O2. Both the Fe3O4 cores of Fe3O4-Au nanocomposites and hemin/G-quadruplex with H2O2-mimicking enzyme activity could catalyze the reduction of the generated H2O2, which promoted the electron transfer of hemin and amplified the electrochemical signal. The proposed electrochemical aptasensor had a wide dynamic linear range of 0.1 pM to 20 nM with a lower detection limit of 0.013 pM, which provided a promising method for a sensitive assay for the detection of proteins in electrochemical aptasensors.
authors: Education Ministry Key Laboratory on Luminescence and Real-TimeAnalysis, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China. xwju@swu.edu.cn.
authors: Pei
authors: P
authors: Jing
authors: Wenju
authors: W
authors: Xu
authors: Huayu
authors: H
authors: Yi
authors: Yongmei
authors: Y
authors: Wu
authors: Lijuan
authors: L
authors: Bai
authors: Ruo
authors: R
authors: Yuan
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry*; D006427:Hemin / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry*; D013499:Surface Properties; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D006427:Hemin; D006046:Gold; D006861:Hydrogen Peroxide; D013917:Thrombin; D052203:Ferrosoferric Oxide