title: Aptamer/target binding-induced triple helix forming for signal-on electrochemical biosensing.
abstract: Owing to its diversified structures, high affinity, and specificity for binding a wide range of non-nucleic acid targets, aptamer is a useful molecular recognition tool for the design of various biosensors. Herein, we report a new signal-on electrochemical biosensing platform which is based on an aptamer/target binding-induced strand displacement and triple-helix forming. The biosensing platform is composed of a signal transduction probe (STP) modified with a methylene blue (MB) and a sulfhydryl group, a triplex-forming oligonucleotides probe (TFO) and a target specific aptamer probe (Apt). Through hybridization with the TFO probe and the Apt probe, the self-assembled STP on Au electrode via Au-S bonding keeps its rigid structure. The MB on the STP is distal to the Au electrode surface. It is eT off state. Target binding releases the Apt probe and liberates the end of the MB tagged STP to fold back and form a triplex-helix structure with TFO (STP/TFO/STP), allowing MB to approach the Au electrode surface and generating measurable electrochemical signals (eT ON). As test for the feasibility and universality of this signal-on electrochemical biosensing platform, two aptamers which bind to adenosine triphosphate (ATP) and human α-thrombin (Tmb), respectively, are selected as models. The detection limit of ATP was 7.2 nM, whereas the detection limit of Tmb was 0.86 nM.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China.
authors.forename: Yinfei
authors.initials: Y
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China.
authors.forename: Jinquan
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China.
authors.forename: Dinggen
authors.initials: D
authors.lastname: He
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China. Electronic address: xiaoxiaohe@hnu.edu.cn.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: He
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China. Electronic address: kmwang@hnu.edu.cn.
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Wen
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000737:chemistry; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D015342:DNA Probes; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D013917:Thrombin / Q000032:analysis* / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D006046:Gold; D000255:Adenosine Triphosphate; D013917:Thrombin
keywords: Aptamer; Biosensing; Electrochemical; Signal-on; Triple-helix