title: An electrochemical sensor based on label-free functional allosteric molecular beacons for detection target DNA/miRNA.
abstract: We report two novel electrochemical sensors (E-sensors) for the detection of target DNA and miRNA. The E-sensors were fabricated using label-free functional allosteric molecular beacons (aMBs), which can form streptavidin aptamers to bind to streptavidin peroxidase polymer and so generate catalytic currents in the presence of the targets. These E-sensors eliminate the antigen antibody interactions which require sophisticated DNA modification. During the experiment, we found a pair of CV peaks located at around 0.17 V. These peaks contributed to the redox reaction between TMB and TMB(+), and the adsorption-desorption process of TMB(+) to the negative aMB backbone. When the E-sensor was hybridized with the complement of the aMB sequence, a pair of CV peaks were found at around 0.47 V which were related to the redox reaction between TMB(+) and TMB(2+), and the process of intercalation of the planar structure of TMB(2+) to dsDNA. The RSV-aMB E-sensor could detect 44 amol RSV DNA in the 4 μL sample and performed well in complicated biological environments. The let-7a-aMB E-sensor reached a detection limit of 13.6 amol let-7a miRNA in the 4 μL sample and showed good selectivity for one base mismatched miRNA.
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Cai
authors.forename: Yanling
authors.initials: Y
authors.lastname: Song
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Wu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhu
authors.forename: Chaoyong James
authors.initials: CJ
authors.lastname: Yang
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000235:genetics; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D052157:Aptamers, Nucleotide; D012333:RNA, Messenger; D004247:DNA