title: Effective covalent immobilization of quinone and aptamer onto a gold electrode via thiol addition for sensitive and selective protein biosensing.
abstract: Effective covalent immobilization of quinone and aptamer onto a gold electrode via thiol addition (a Michael addition) for sensitive and selective protein (with thrombin as the model) biosensing is reported, with a detection limit down to 20 fM for thrombin. Briefly, the thiol addition reaction of a gold electrode-supported 1,6-hexanedithiol (HDT) with p-benzoquinone (BQ) yielded BQ-HDT/Au, and the similar reaction of thiolated thrombin aptamer (TTA) with activated BQ-HDT/Au under 0.3V led to formation of a gold electrode-supported novel electrochemical probe TTA-BQ-HDT/Au. The thus-prepared TTA-BQ-HDT/Au exhibits a pair of well-defined redox peaks of quinone moiety, and the TTA-thrombin interaction can sensitively decrease the electrochemical signal. Herein the thiol addition acts as an effective and convenient binding protocols for aptasensing, and a new method (electrochemical conversion of Michael addition complex for signal generation) for the fabrication of biosensor is presented. The cyclic voltammetry (CV) was used to characterize the film properties. In addition, the proposed amperometric aptasensor exhibits good sensitivity, selectivity, and reproducibility. The aptasensor also has acceptable recovery for detection in complex protein sample.
authors.affiliation: College of Science, Hunan Agricultural University, Changsha 410128, PR China. Electronic address: zhaohongsu@hunau.edu.cn.
authors.forename: Zhaohong
authors.initials: Z
authors.lastname: Su
authors.affiliation: College of Science, Hunan Agricultural University, Changsha 410128, PR China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Xu
authors.affiliation: College of Science, Hunan Agricultural University, Changsha 410128, PR China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Xu
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Science, Hunan Agricultural University, Changsha 410128, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: College of Science, Hunan Agricultural University, Changsha 410128, PR China.
authors.forename: Chaorong
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China. Electronic address: xieqj@hunnu.edu.cn.
authors.forename: Qingji
authors.initials: Q
authors.lastname: Xie
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D016227:Benzoquinones; D013438:Sulfhydryl Compounds; C004532:quinone; D006046:Gold; D013917:Thrombin
keywords: 1,6-hexanedithiol; Protein biosensing; Quinone; Thiol addition; Thiolated aptamer