title: Sensitive electrochemical determination of miRNAs based on a sandwich assay onto magnetic microcarriers and hybridization chain reaction amplification.
abstract: A novel electrochemical approach for determination of miRNAs involving a sandwich hybridization assay onto streptavidin-magnetic beads (Strep-MBs), hybridization chain reaction (HCR) amplification and amperometric detection at disposable screen-printed carbon electrodes is reported. Using miRNA-21 as the target analyte, a dynamic linear range from 0.2 to 5.0nM with a 60pM (1.5fmol in 25μL) detection limit was obtained. The achieved sensitivity is 24-fold higher than a non-HCR amplification approach involving conventional sandwich type assay onto MBs. Moreover, the whole assay time lasted 1h 45min which is remarkably shorter than other reported methodologies. The methodology exhibited full selectivity against other non-complementary miRNAs as well as an acceptable discrimination between homologous miRNA family members. The applicability of this novel approach was demonstrated by determining mature miRNA-21 in total RNA (RNAt) extracted from tumor cells and human tissues.
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain.
authors.forename: R M
authors.initials: RM
authors.lastname: Torrente-Rodríguez
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Campuzano
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain.
authors.forename: V Ruiz-Valdepeñas
authors.initials: VR
authors.lastname: Montiel
authors.affiliation: Canaan RI & Facultad Medicina, Universidad Alfonso X el Sabio, E-28691 Madrid, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Montoya
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Pingarrón
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics; D045744:Cell Line, Tumor; D055664:Electrochemical Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008280:Magnetics / Q000379:methods; D059346:Magnets / Q000737:chemistry*; D035683:MicroRNAs / Q000032:analysis* / Q000302:isolation & purification; D009693:Nucleic Acid Hybridization / Q000379:methods*
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs
keywords: Human tissues; Hybridization chain reaction; Magnetic beads; SPCEs; Tumor cell; miRNA-21