title: Label-free triple-helix aptamer as sensing platform for "signal-on" fluorescent detection of thrombin.
abstract: The design of a label-free aptamer for separation of recognition sequence from signal reporter is significant to ensure the high-efficiency affinity between aptamer and target. This work develops a label-free triple-helix aptamer (THA) as sensing platform for "signal-on" fluorescent detection of thrombin. THA was composed of aptamer sequence and help DNA 1 (H1), which contained the complementary sequence of hexachloro-fluorescein (HEX) labeled help DNA 2 (H2). The specific recognition event between aptamer and thrombin triggered the dismission of THA to release H1. The released H1 then reacted with the signal probe of H2/graphene oxide (GO) nanocomposite to form H1-H2 duplex, leading to the fluorescence recovery of H2 due to the detachment of H1-H2 duplex from the surface of GO. With employment of THA as a signal transducer and GO as a "superquencher", this method shows a sensitive response to thrombin with a wide concentration range from 5 to 1200 nM. The limit of detection is 1.8 nM (S/N=3) with excellent selectivity. Considering the universality of THA, the proposed aptasensor would provide a platform for homogeneous fluorescent detection of a wide range of analytes.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Quanbo
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China. Electronic address: jpl@nju.edu.cn.
authors.forename: Jianping
authors.initials: J
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D052157:Aptamers, Nucleotide / Q000138:chemical synthesis / Q000737:chemistry*; D005452:Fluoresceins / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D057230:Limit of Detection; D009690:Nucleic Acid Conformation; D010087:Oxides; D013050:Spectrometry, Fluorescence; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D005452:Fluoresceins; D005456:Fluorescent Dyes; D010087:Oxides; D006108:Graphite; D006859:Hydrogen; D013917:Thrombin
keywords: Triple-helix aptamer; fluorescent detection; graphene oxide; label-free; thrombin