title: Carbon Nanotubes Labeled with Aptamer and Horseradish Peroxidase as a Probe for Highly Sensitive Protein Biosensing by Postelectropolymerization of Insoluble Precipitates on Electrodes.
abstract: Carbon nanotubes (CNTs) labeled with aptamer and horseradish peroxidase (HRP) were used as a probe to amplify the impedimetric sensing of the aptamer-protein (with thrombin as the model) interaction. The HRP-biocatalyzed oxidation of 3,3-diaminobenzidine (DAB) in the presence of H2O2 and the postelectropolymerization of insoluble precipitates produced on the electrode supports were used as a signal amplification route for the sensing process. Thrombin was sensed by aptamer 1 immobilized on a glassy carbon electrode. The multiwalled CNT-aptamer 2-HRP probe was linked to the aptamer 1-thrombin complex through the thrombin-aptamer 2 interaction. The postelectropolymerization of biocatalyzed precipitates of DAB on the electrode greatly increased the electron-transfer resistance at the electrode-solution interface. Cyclic voltammetry and electrochemical impedance spectroscopy were employed to follow the stepwise fabrication of the aptasensor and impedimetric detection of thrombin. Thrombin concentration as low as 0.05 pM could be detected by this method. In addition, the proposed impedimetric aptasensor exhibits good sensitivity (5195 Ω decade(-1)), selectivity, and reproducibility. The aptasensor also has acceptable recovery for thrombin detection in complex protein sample.
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.|‡Department of Chemical Engineering and Textile, Shaanxi Polytechnic Institute, Xianyang 721000, P. R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Wang
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Guo
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Peng
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.affiliation: †Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China.|∥State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, P. R. China.
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004566:Electrodes; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D057230:Limit of Detection; D018625:Microscopy, Atomic Force; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D013917:Thrombin / Q000032:analysis
chemical_list: D037742:Nanotubes, Carbon; D011506:Proteins; D006735:Horseradish Peroxidase; D013917:Thrombin