title: Binding induced colocalization activated hybridization chain reaction on the surface of magnetic nanobead for sensitive detection of adenosine.
abstract: Herein, a sensitive and enzyme-free assay for adenosine detection has been developed on the basis of binding induced colocalization activated hybridization chain reaction (HCR) strategy on the surface of magnetic nanobead. First, the recognition probe was fabricated and divided into two parts: the Apt-1 that composed a part of adenosine aptamer and toehold domain, and the Apt-2 that consisted of another part of adenosine aptamer and branch migration domain. The Apt-1 was immobilized on a streptavidin-magnetic nanobead (streptavidin-MNBs) that played the roles of enrichment and separation. Then the recognition event of adenosine could bring the two parts of aptamer together and induce the colocalization of toehold domain and branch migration domain, which could serve as an integrated initiator to trigger the HCR, producing a long nicked double-stranded polymer. Finally, the intercalating dye SYBR Green I was inserted into the polymer, generating an enhanced fluorescence signal. In this strategy, the initiator was divided into two parts and could be suppressed effectively in the absence of adenosine. Utilizing the separated function, the spontaneous hybridization of H1 and H2 could be avoided, and a low background could be acquired. Moreover, through the double amplification of HCR and multimolecules binding of SYBR Green I, highly sensitive and enzyme-free detection were achieved. The detection limit for adenosine detection was 2.0×10(-7)mol/L, which was comparable or superior to the previous aptasensors. Importantly, adenosine analysis in human urines has been performed, and this strategy could significantly distinguish the adenosine content in normal human urines and cancer patient urines, suggesting that this proposed assay will become a reliable and sensitive adenosine detection method in early clinical diagnosis and medical research.
authors: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmacy, Shandong University, Jinan 250012, PR China.
authors: Chunjing
authors: C
authors: Feng
authors: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmacy, Shandong University, Jinan 250012, PR China.
authors: Zhun
authors: Z
authors: Hou
authors: School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China.
authors: Wei
authors: W
authors: Jiang
authors: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmacy, Shandong University, Jinan 250012, PR China.
authors: Lihong
authors: L
authors: Sang
authors: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmacy, Shandong University, Jinan 250012, PR China. Electronic address: wangl-sdu@sdu.edu.cn.
authors: Lei
authors: L
authors: Wang
mesh_terms: D000241:Adenosine / Q000032:analysis* / Q000235:genetics; D000327:Adsorption; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D015342:DNA Probes / Q000737:chemistry* / Q000235:genetics; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D017404:In Situ Hybridization, Fluorescence / Q000295:instrumentation*; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D058185:Magnetite Nanoparticles; D000241:Adenosine
keywords: Adenosine; Colocalization; Hybridization chain reaction; Magnetic nanobead