title: Label-free fluorescence dual-amplified detection of adenosine based on exonuclease III-assisted DNA cycling and hybridization chain reaction.
abstract: In this work, we constructed a label-free and dual-amplified fluorescence aptasensor for sensitive analysis of adenosine based on exonuclease III (Exo III)-assisted DNA cycling and hybridization chain reaction (HCR). Firstly, we fabricated a trifunctional probe that consisting of the catalytic strand, the aptamer sequence and a streptavidin-magnetic nanobead (streptavidin-MNB). The streptavidin-MNB played a role of enrichment and separation to achieve a low background. The aptamer sequence was employed as a recognition element to bind the target adenosine, leading to the releasing of the catalytic stand. Then, the catalytic strand induced the Exo III-assisted DNA cycling reaction and produced a large amount of DNA fragments, which got a primary amplification. Subsequently, the DNA fragments acted as trigger strands to initiate HCR, forming nicked double helices with multiple G-quadruplex structures, which achieved a secondary amplification. Finally, the G-quadruplex structures bonded with the N-nethyl mesopor-phyrin IX (NMM) and yielded an enhanced fluorescence signal, realizing the label-free detection. In the proposed strategy, a small amount of adenosine can be converted to a large amount of DNA triggers, leading to a significant amplification for the target. This method exhibited a high sensitivity toward adenosine with a detection limit of 4.2×10(-7) mol L(-1), which was about 10 times lower than that of the reported label-free strategies. Moreover, this assay can significantly distinguish the content of adenosine in urine samples of cancer patients and normal human, indicating that our method will offer a new strategy for reliable quantification of adenosine in medical research and early clinical diagnosis.
authors.affiliation: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China.
authors.forename: Jiewei
authors.initials: J
authors.lastname: Sun
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China. Electronic address: wangl-sdu@sdu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D000241:Adenosine / Q000652:urine*; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics; D014408:Biomarkers, Tumor / Q000652:urine; D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005090:Exodeoxyribonucleases / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000295:instrumentation*; D009369:Neoplasms / Q000175:diagnosis / Q000652:urine*; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D052157:Aptamers, Nucleotide; D014408:Biomarkers, Tumor; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D000241:Adenosine
keywords: Adenosine detection; Dual-amplified; Exonuclease III; Hybridization chain reaction; Label-free