title: Single Cell Real-Time miRNAs Sensing Based on Nanomotors.
abstract: A nanomotor-based strategy for rapid single-step intracellular biosensing of a target miRNA, expressed in intact cancer cells, at the single cell level is described. The new concept relies on the use of ultrasound (US) propelled dye-labeled single-stranded DNA (ssDNA)/graphene-oxide (GO) coated gold nanowires (AuNWs) capable of penetrating intact cancer cells. Once the nanomotor is internalized into the cell, the quenched fluorescence signal (produced by the π-π interaction between GO and a dye-labeled ssDNA) is recovered due to the displacement of the dye-ssDNA probe from the motor GO-quenching surface upon binding with the target miRNA-21, leading to an attractive intracellular "OFF-ON" fluorescence switching. The faster internalization process of the US-powered nanomotors and their rapid movement into the cells increase the likelihood of probe-target contacts, leading to a highly efficient and rapid hybridization. The ability of the nanomotor-based method to screen cancer cells based on the endogenous content of the target miRNA has been demonstrated by measuring the fluorescence signal in two types of cancer cells (MCF-7 and HeLa) with significantly different miRNA-21 expression levels. This single-step, motor-based miRNAs sensing approach enables rapid "on the move" specific detection of the target miRNA-21, even in single cells with an extremely low endogenous miRNA-21 content, allowing precise and real-time monitoring of intracellular miRNA expression.
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Berta
authors.initials: B
authors.lastname: Esteban-Fernández de Ávila
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.|‡Department of Analytical Chemistry, University of Alcalá de Henares, E-28871 Madrid, Spain.
authors.forename: Aída
authors.initials: A
authors.lastname: Martín
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Fernando
authors.initials: F
authors.lastname: Soto
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Lopez-Ramirez
authors.affiliation: §Department of Analytical Chemistry, Complutense University of Madrid, E-28040 Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Campuzano
authors.forename: Gersson Manuel
authors.initials: GM
authors.lastname: Vásquez-Machado
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Gao
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Liangfang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: †Department of Nanoengineering, University of California, San Diego, La Jolla, California 92093, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D006367:HeLa Cells; D019220:High-Energy Shock Waves; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods; D053770:Nanowires / Q000737:chemistry* / Q000528:radiation effects; D059010:Single-Cell Analysis / Q000379:methods*; D013010:Sonication / Q000379:methods
chemical_list: D004277:DNA, Single-Stranded; D005456:Fluorescent Dyes; D035683:MicroRNAs; D006046:Gold; D006108:Graphite
keywords: graphene oxide; miRNAs; nanomotors; real-time biosensing; single intact cancer cells; ultrasound