title: A sensitive, label free electrochemical aptasensor for ATP detection.
abstract: A sensitive, label free electrochemical aptasensor for small molecular detection has been developed in this work based on gold nanoparticles (AuNPs) amplification. This aptasensor was fabricated as a tertiary hybrid DNA-AuNPs system, which involved the anchored DNA (ADNA) immobilized on gold electrode, reporter DNA (RDNA) tethered with AuNPs and target-responsive DNA (TRDNA) linking ADNA and RDNA. Electrochemical signal is derived from chronocoulometric interrogation of [Ru(NH(3))(6)](3+) (RuHex) that quantitatively binds to surface-confined DNA via electrostatic interaction. Using adenosine triphosphate (ATP) as a model analyte and ATP-binding aptamer as a model molecular reorganization element, the introduction of ATP triggers the structure switching of the TRDNA to form aptamer-ATP complex, which results in the dissociation of the RDNA capped AuNPs (RDNA-AuNPs) and release of abundant RuHex molecules trapped by RDNA-AuNPs. The incorporation of AuNPs in this strategy significantly enhances the sensitivity because of the amplification of electrochemical signal by the RDNA-AuNPs/RuHex system. Under optimized conditions, a wide linear dynamic range of 4 orders of magnitude (1 nM-10 microM) was reached with the minimum detectable concentration at sub-nanomolar level (0.2 nM). Those results demonstrate that our nanoparticles-based amplification strategy is feasible for ATP assay and presents a potential universal method for other small molecular aptasensors.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
authors.forename: Wang
authors.initials: W
authors.lastname: Li
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.forename: Xiahong
authors.initials: X
authors.lastname: Xu
authors.forename: Qinpeng
authors.initials: Q
authors.lastname: Shen
authors.forename: Chunyan
authors.initials: C
authors.lastname: Deng
authors.forename: Jinhua
authors.initials: J
authors.lastname: Chen
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D052157:Aptamers, Nucleotide; D004563:Electrochemistry / Q000379:methods*; D006046:Gold; D053768:Metal Nanoparticles
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D000255:Adenosine Triphosphate