title: A target-triggered strand displacement reaction cycle: the design and application in adenosine triphosphate sensing.
abstract: A strand displacement reaction (SDR) system that runs solely on oligonucleotides has been developed for the amplification detection of adenosine triphosphate (ATP). It involves a target-induced SDR and an entropy-driven catalytic cycle of two SDRs with five oligonucleotides, denoted as substrate, fuel, catalyst, C-1, and C-2. Catalyst, released from the ATP aptamer-catalyst duplex by ATP molecule, catalyzes the SDRs to finally form the substrate-fuel duplex. All of the intermediates in the catalytic SDR processes have been identified by polyacrylamide gel electrophoresis (PAGE) analysis. The introduction of ATP into the SDR system will induce the ATP aptamer to form G-quadruplex conformation so as to release catalyst and trigger the SDR cycle. When the substrate and C-2 oligonucleotides were labeled with a carboxyfluorescein (FAM) fluorophore and a 4-([4-(dimethylamino)phenyl]azo)benzoic acid (DABCYL) quencher, this SDR catalytic system exhibited a "turn-on" response for ATP. The condition for detecting ATP, such as Mg²⁺ concentration, has been optimized to afford a detection limit of 20 nM. This work provides an enzyme-free biosensing strategy and has potential application in aptamer-based biosensing.
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, People's Republic of China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Cheng
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Mozhen
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Kowloon, People's Republic of China. Electronic address: bhmhwlam@cityu.edu.hk.
authors.forename: Michael Hon-Wah
authors.initials: MH
authors.lastname: Lam
authors.affiliation: CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China. Electronic address: xwge@ustc.edu.cn.
authors.forename: Xuewu
authors.initials: X
authors.lastname: Ge
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D054856:G-Quadruplexes; D057230:Limit of Detection; D008274:Magnesium / Q000737:chemistry; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: C063127:4-(4-dimethylaminophenylazo)benzoic acid; D000255:Adenosine Triphosphate; D004124:p-Dimethylaminoazobenzene; D008274:Magnesium
keywords: Adenosine triphosphate; Amplification; Aptamer; Enzyme-free; Strand displacement reaction