title: Cascaded strand displacement for non-enzymatic target recycling amplification and label-free electronic detection of microRNA from tumor cells.
abstract: The monitoring of microRNA (miRNA) expression levels is of great importance in cancer diagnosis. In the present work, based on two cascaded toehold-mediated strand displacement reactions (TSDRs), we have developed a label- and enzyme-free target recycling signal amplification approach for sensitive electronic detection of miRNA-21 from human breast cancer cells. The junction probes containing the locked G-quadruplex forming sequences are self-assembled on the senor surface. The presence of the target miRNA-21 initiates the first TSDR and results in the disassembly of the junction probes and the release of the active G-quadruplex forming sequences. Subsequently, the DNA fuel strand triggers the second TSDR and leads to cyclic reuse of the target miRNA-21. The cascaded TSDRs thus generate many active G-quadruplex forming sequences on the sensor surface, which associate with hemin to produce significantly amplified current response for sensitive detection of miRNA-21 at 1.15 fM. The sensor is also selective and can be employed to monitor miRNA-21 from human breast cancer cells.
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Shi
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Baoting
authors.initials: B
authors.lastname: Dou
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Jianmei
authors.initials: J
authors.lastname: Yang
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yunatswu@swu.edu.cn.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiang
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D055664:Electrochemical Techniques; D054856:G-Quadruplexes; D006801:Humans; D035683:MicroRNAs / Q000032:analysis*
chemical_list: D035683:MicroRNAs
keywords: Cancer cells; Electronic sensor; Strand displacement; Target recycling; microRNA detection