title: Electrochemical impedance spectroscopy aptasensor for ultrasensitive detection of adenosine with dual backfillers.
abstract: A highly sensitive and label-free electrochemical impedance spectroscopy (EIS) aptasensor for the detection of adenosine was fabricated by co-assembling thiolated aptamer, dithiothreitol (DTT) and 6-mercaptohexanol (MCH) on gold electrode surface, forming Au/aptamer-DTT/MCH. The interfacial electron transfer resistance (Ret) of the aptasensor using [Fe(CN)6](3-/4-) as the probe increased with adenosine concentration, and the change in Ret (∆Ret) against the logarithm of adenosine concentration was linear over the range from 0.05 pM to 17 pM with a detection limit of 0.02 pM. Compared to that of aptasensors fabricated with MCH or DTT alone as the backfiller, the detection limit was improved dramatically (LOD was 0.03 nM and 0.2 pM for Au/aptamer/MCH and Au/aptamer-DTT, respectively), which was attributed primarily to the coupling of the cyclic- and linear -configuration backfillers. The coupling showed remarkably higher resistance to nonspecific adsorption, leading to low background noise and high response signal. The aptasensor reported herein is applicable for the detection of other kinds of aptamer-binding chemicals and biomolecules.
authors.affiliation: Anhui Key Laboratory of Chemo-biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Yitan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Anhui Key Laboratory of Chemo-biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Feng
authors.affiliation: Anhui Key Laboratory of Chemo-biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Zhian
authors.initials: Z
authors.lastname: Tan
authors.affiliation: Anhui Key Laboratory of Chemo-biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China. Electronic address: hywang@mail.ahnu.edu.cn.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
mesh_terms: D000241:Adenosine / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D052157:Aptamers, Nucleotide / Q000235:genetics*; D003217:Conductometry / Q000295:instrumentation*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008832:Microchemistry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D000241:Adenosine
keywords: 6-mercaptohexanol; Adenosine; Aptasensor; Dithiothreitol; Electrochemical impedance spectroscopy