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.

Nanomotor-Enabled pH-Responsive Intracellular Delivery of Caspase-3: Toward Rapid Cell Apoptosis

“…Considerable progress has been made recently towards the development of synthetic nano/micromachines with attractive capabilities for diverse biomedical applications, 1–3 including biosensing, 4–6 cargo delivery, 7–9 nanosurgery, 10,11 and detoxification. 12,13 The attractive movement, cargo-towing, and navigation functions of different self-propelled and externally-powered nano/micromotors 1,14–18 have led to their growing use for active transport and delivery of therapeutic payloads, compared to common diffusion-based passive approaches.…”

“…12,13 The attractive movement, cargo-towing, and navigation functions of different self-propelled and externally-powered nano/micromotors 1,14–18 have led to their growing use for active transport and delivery of therapeutic payloads, compared to common diffusion-based passive approaches. 19–23 Nano/microscale machines have thus demonstrated promise for improving the diagnosis and treatment of cancer by delivering anticancer drugs to specific target sites, 7,20,24,25 isolating circulating tumor cells, 26 monitoring intracellular miRNA expression, 6 or silencing specific genes inside cancer cells. 27 …”

MnO2 Nanotube-Based NanoSearchlight for Imaging of Multiple MicroRNAs in Live Cells

“…Recently, optical imaging assay based on the strategy of Förster resonance energy transfer (FRET) becomes an appealing method for monitoring miRNAs in living cells. 19 In order to achieve high FRET efficiency, some nanomaterials, particularly 0D and 2D nanomaterials, have been fabricated as nanoquenchers for miRNA detection, including gold nanoparticles, 20 quantum dots, 21 carbon nanoparticles, 22 graphene oxide, 23 WS 2 nanosheets, 24 and metal-organic frameworks. 25 It is worth noting that few 1D nanotubes beyond carbon nanotubes 26–28 have been reported for such applications.…”

Graphene oxide-quenching-based fluorescencein situhybridization (G-FISH) to detect RNA in tissue: simple and fast tissue RNA diagnostics

“…The structural organization of individual pyramidal neurons was observed clearly in the mouse brain. GO can penetrate cells easily through the cell membrane, and thus G-FISH could be applied to live cells with intact membranes in culture [11,15,16] . The CLARITY technique allowed antBC1-GO to penetrate to a depth of 100 µm, so that 3D volume imaging of thick brain tissues became possible.…”