title: Reusable electrochemical sensing platform for highly sensitive detection of small molecules based on structure-switching signaling aptamers.
abstract: Aptamers are nucleic acids that have high affinity and selectivity for their target molecules. A target may induce the structure switching from a DNA/DNA duplex to a DNA/target complex. In the present study, a reusable electrochemical sensing platform based on structure-switching signaling aptamers for highly sensitive detection of small molecules is developed using adenosine as a model analyte. A gold electrode is first modified with polytyramine and gold nanoparticles. Then, thiolated capture probe is assembled onto the modified electrode surface via sulfur-gold affinity. Ferrocene (Fc)-labeled aptamer probe, which is designed to hybridize with capture DNA sequence and specifically recognize adenosine, is immobilized on the electrode surface by hybridization reaction. The introduction of adenosine triggers structure switching of the aptamer. As a result, Fc-labeled aptamer probe is forced to dissociate from the sensing interface, resulting in a decrease in redox current. The decrement of peak current is proportional to the amount of adenosine. The present sensing system could provide both a wide linear dynamic range and a low detection limit. In addition, high selectivity, good reproducibility, stability, and reusability are achieved. The recovery test demonstrates the feasibility of the designed sensing system for an adenosine assay.
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, P. R. China.
authors.forename: Zai-Sheng
authors.initials: ZS
authors.lastname: Wu
authors.forename: Meng-Meng
authors.initials: MM
authors.lastname: Guo
authors.forename: Song-Bai
authors.initials: SB
authors.lastname: Zhang
authors.forename: Chen-Rui
authors.initials: CR
authors.lastname: Chen
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Jiang
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D000241:Adenosine / Q000032:analysis*; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D012680:Sensitivity and Specificity; D014439:Tyramine / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D000241:Adenosine; D014439:Tyramine