title: A highly sensitive microRNA biosensor based on hybridized microRNA-guided deposition of polyaniline.
abstract: On the basis of hybridized microRNA (miRNA)-guided deposition of polyaniline (PAn), a highly sensitive impedimetric miRNA biosensor is developed in this report. Briefly, a gold electrode coated with charge neutral peptide nucleic acid (PNA) capture probes (CPs) is first hybridized to a target miRNA. After a very brief rinsing the hybridized electrode is incubated in pH 3.0 of 0.10 M potassium phosphate buffer-based cocktail containing aniline, H2O2, and a G-qudraplex-hemin DNAzyme. The DNAzyme catalyzes the polymerization of aniline and the hybridized miRNA strands guide the deposition of PAn, thus resulting in the formation of a thin PAn film on the biosensor surface. Electron-transfer impeding power of the PAn film in alkaline medium is utilized to determine the concentration of the target miRNA. Under optimized experimental conditions, 0.50 fM target miRNA is successfully detected. Excellent mismatch discrimination capability of the biosensor was observed largely due to the excellent hybridization selectivity of the PNA CPs. Attempts were made in profiling miRNAs in total RNA samples extracted from cancer cells and blood.
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore.
authors.forename: Huimin
authors.initials: H
authors.lastname: Deng
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore.
authors.forename: Yuqian
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore. Electronic address: chmgaoz@nus.edu.sg.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Gao
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D035683:MicroRNAs / Q000032:analysis / Q000235:genetics*; D054802:Molecular Imprinting / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017423:Sequence Analysis, RNA / Q000295:instrumentation*; D013499:Surface Properties
chemical_list: D000814:Aniline Compounds; D035683:MicroRNAs; C416807:polyaniline
keywords: DNAzyme; Electrochemical impedance; Gold electrode; Microrna; Polyaniline