title: Hairpin assembly circuit-based fluorescence cooperative amplification strategy for enzyme-free and label-free detection of small molecule.
abstract: Here, we developed an enzyme-free, label-free, and sensitive fluorescence cooperative amplification strategy based on a hairpin assembly circuit which coupled catalytic hairpin assembly (CHA) with hybridization chain reaction (HCR) for small molecule adenosine. A double-strand DNA probe with aptamer-catalysis strand (Apt-C) and inhibit strand (Inh) was designed for adenosine recognition and signal transduction which was named as Apt-C/Inh. Hairpins H1 and H2 were employed for constructing the CHA, and hairpins H3 and H4 for the HCR. Through the binding of adenosine and the Apt-C, the Inh was released from the Apt-C/Inh. Then the free Apt-C initiated the CHA through successively opening H1 and H2, generating H1/H2 complex and recyclable Apt-C. Next, the released Apt-C entered another CHA cycle, and the H1/H2 complex further initiated the HCR of H3 and H4 which induced the formation of the concatemers of H3/H4 complex. Such a process brought the two ends of hairpins H3 into close proximity, yielding numerous integrated G-quadruplexes which were initially sequestered in the stem and two terminals of H3. Finally, N-methyl mesoporphyrin IX (NMM) was added to generate an enhanced fluorescence signal. In the proposed strategy, driven only by the energy from hybridization, one target could trigger multiple HCR events via CHA-based target-cycle, leading to a remarkable enzyme-free amplification for adenosine. The detection limit could achieve as low as 9.7 × 10(-7) mol L(-1). Furthermore, G-quadruplexes were applied to construct label-free hairpin assembly circuit, which made it more simple and cost-effective. The satisfactory recoveries were obtained when detecting adenosine in spiked human serum and urine samples, demonstrating the feasibility of this detection strategy in biological samples.
authors.affiliation: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China; Department of Pharmacy, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, PR China.
authors.forename: Chunjing
authors.initials: C
authors.lastname: Feng
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: Jiewei
authors.initials: J
authors.lastname: Sun
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China. Electronic address: wjiang@sdu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
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 / Q000032:analysis* / Q000097:blood / Q000652:urine; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics; D015374:Biosensing Techniques / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry* / Q000235:genetics; D005240:Feasibility Studies; D006801:Humans; D055029:Inverted Repeat Sequences; D057230:Limit of Detection; D021141:Nucleic Acid Amplification Techniques; D009693:Nucleic Acid Hybridization; D013050:Spectrometry, Fluorescence
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D000241:Adenosine
keywords: Enzyme-free; Fluorescence cooperative amplification; Hairpin assembly circuit; Label-free; Small molecule