title: Label-free DNAsensor with PCR-like sensitivity based on background reduction and target-triggered polymerization amplification.
abstract: In this work, we have developed a highly sensitive and label-free DNAsensor for nucleic acid detection based on background noise reduction by exonuclease I (Exo I) and target-triggered cycled polymerization amplification. This DNAsensor consists of a long-tail probe, a short primer and polymerase. In the absence of the target, the long-tail probe and short primer are digested by Exo I, which minimizes the intercalation of fluorescence dye and reduces the background noise. In the presence of the target, the specific binding between the long-tail probe and the target triggers cycled polymerization reactions to form long dsDNA products. These long dsDNA products prevent effectively them from degrading by Exo I and amplify the fluorescence signals. In our sensing approach, the combination of the ExoI-assisted background reduction with the cycled polymerization amplification allows us to achieve a PCR-like sensitivity without labeling, washing separation and temperature cycles in a homogenous solution. Using total RNA samples extracted from hepatitis C virus (HCV) as targets, we further demonstrate the detection capability of the DNAsensor for complex nucleic acid samples, indicating its potential applicability for clinic molecular diagnostic assays.
authors.affiliation: College of Biology, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Su
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Meng
authors.forename: Qiuping
authors.initials: Q
authors.lastname: Guo
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Tan
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Cai
authors.forename: Hongtao
authors.initials: H
authors.lastname: Qin
authors.forename: Xiangxian
authors.initials: X
authors.lastname: Meng
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D005090:Exodeoxyribonucleases / Q000737:chemistry; D005456:Fluorescent Dyes; D016174:Hepacivirus / Q000302:isolation & purification*; D006526:Hepatitis C / Q000175:diagnosis*; D006801:Humans; D016133:Polymerase Chain Reaction; D058105:Polymerization; D012367:RNA, Viral / Q000302:isolation & purification*
chemical_list: D005456:Fluorescent Dyes; D012367:RNA, Viral; D004247:DNA; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I
keywords: Background reduction; Cycled polymerization amplification; Label-free; PCR-like sensitivity