title: An "off-on" electrochemiluminescent biosensor based on DNAzyme-assisted target recycling and rolling circle amplifications for ultrasensitive detection of microRNA.
abstract: In this study, an off-on switching of a dual amplified electrochemiluminescence (ECL) biosensor based on Pb(2+)-induced DNAzyme-assisted target recycling and rolling circle amplification (RCA) was constructed for microRNA (miRNA) detection. First, the primer probe with assistant probe and miRNA formed Y junction which was cleaved with the addition of Pb(2+) to release miRNA. Subsequently, the released miRNA could initiate the next recycling process, leading to the generation of numerous intermediate DNA sequences (S2). Afterward, bare glassy carbon electrode (GCE) was immersed into HAuCl4 solution to electrodeposit a Au nanoparticle layer (depAu), followed by the assembly of a hairpin probe (HP). Then, dopamine (DA)-modified DNA sequence (S1) was employed to hybridize with HP, which switching off the sensing system. This is the first work that employs DA to quench luminol ECL signal, possessing the biosensor ultralow background signal. Afterward, S2 produced by the target recycling process was loaded onto the prepared electrode to displace S1 and served as an initiator for RCA. With rational design, numerous repeated DNA sequences coupling with hemin to form hemin/G-quadruplex were generated, which could exhibit strongly catalytic toward H2O2, thus amplified the ECL signal and switched the ON state of the sensing system. The liner range for miRNA detection was from 1.0 fM to 100 pM with a low detection limit down to 0.3 fM. Moreover, with the high sensitivity and specificity induced by the dual signal amplification, the proposed miRNA biosensor holds great potential for analysis of other interesting tumor markers.
authors: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
authors: Pu
authors: P
authors: Zhang
authors: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
authors: Xiaoyan
authors: X
authors: Wu
authors: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
authors: Ruo
authors: R
authors: Yuan
authors: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
authors: Yaqin
authors: Y
authors: Chai
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D045744:Cell Line, Tumor; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021881:DNA, Catalytic / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D054856:G-Quadruplexes; D005898:Glass / Q000737:chemistry; D006427:Hemin / Q000378:metabolism; D006801:Humans; D055029:Inverted Repeat Sequences; D007854:Lead / Q000378:metabolism; D057230:Limit of Detection; D008163:Luminescent Measurements; D035683:MicroRNAs / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D021141:Nucleic Acid Amplification Techniques; D015203:Reproducibility of Results
chemical_list: D015342:DNA Probes; D021881:DNA, Catalytic; C524942:MIRN155 microRNA, human; D035683:MicroRNAs; D007854:Lead; D006427:Hemin; D002244:Carbon