In Vivo Imaging MicroRNA with Bright Fluorescent RNA Aptamer Through Target-Mediated Entropy-Driven Toehold Exchange

Abstract

MicroRNAs (miRNAs) play vital roles in biological activities, but their in vivo imaging is still challenging due to the low abundance and the lack of efficient fluorescent tools. RNA aptamers with high affinity and low background emerge for bioimaging yet suffering from low brightness. We introduce a rational design based on target-mediated entropy-driven toehold exchange (EDTE) to induce the release of RNA aptamer and subsequently light up corresponding fluorophore, which achieves selective imaging of miRNAs with good stability in both living cells and tumor-bearing mouse. Through tailoring recognition unit of the EDTE probes, highly sensitive imaging of different miRNAs including miRNA-125b and miRNA-21 is achieved, confirming its universal bioimaging applications. In comparison with the reported "one-to-one" model, the EDTE strategy shows a remarkable 4.6-time improvement in signal/noise ratio for intracellular imaging of the same miRNA. Particularly, it realizes sensitive imaging of miRNA in vivo, providing a promising tool in investigating functions and interactions of disease-associated miRNAs.

Synergy of Target-Induced Magnetic Network and Single-Drop Chromogenic System for Ultrasensitive “All-in-Tube” Detection of miRNA in Whole Blood

“…To meet the urgent need for ultrasensitivity in miRNA detection strategies, researchers have developed various miRNA detection methods based on isothermal amplification technologies. − Thereinto, enzyme-free isothermal amplification strategies, such as hybridization chain reaction, strand displacement reaction, entropy-driven reaction, and catalytic hairpin assembly (CHA), , are easier to apply in biomolecular analysis. As a powerful DNA amplification technique, CHA can induce the binding of two DNA hairpins to produce a large quantity of double-stranded DNA structures through the catalytic action of a primer strand.…”