Accurate and sensitive fluorescence imaging of intracellular miRNA is essential for understanding the mechanism underlying some physiological and pathological events, as well as the prevention and diagnosis of diseases. Herein, a highly sensitive ratiometric fluorescent nanoprobe for intracellular miRNA imaging was fabricated by integrating a Ru-SiO 2 @polydopamine (Ru-SiO 2 @PDA) nanoplatform with a near-infrared light (NIR)-assisted DNA strand displacement signal amplification strategy. The Ru-SiO 2 @PDA spheres have excellent biosafety, high photothermal effect, and unique photophysical properties that can both emit a stable red fluorescence and well quench the fluorophores getting closer to them. So, when the fuel DNA and carboxyfluorescein (FAM)-labeled signal DNA are co-assembled on their outer surfaces, the FAM's green fluorescence is quenched, and a low ratiometric signal is obtained. However, in the presence of miRNA, the target displaces the signal DNA from the capture DNA, releasing the signal DNA far away from the Ru-SiO 2 @PDA. Then, the green fluorescence recovers and leads to an enhanced I green / I red value. Under NIR light irradiation, the Ru-SiO 2 @PDA increases the local temperature around the probe and triggers the release of fuel DNA, which thus recycles the target miRNA and effectively amplifies the ratiometric signal. Using A549 cells as a model, the nanoprobe realizes the highly sensitive ratiometric fluorescence imaging of miRNA let-7a, as well as its in vivo up-and downregulation expressions. It provides a facile tool for highly sensitive and accurate intracellular miRNA detection through one-step incubation and may pave a new avenue for single-cell analysis.
A smart deoxyribose nucleic acid nanogel coated polydopamine nanosphere hybrid was designed for chemo-photothermal therapy of cancer. The nanohybrid showed good colloid stability, narrow size distribution, high drug loading, good biocompatibility, and high photothermal conversion efficiency, and could release the drug on desired tumor sites.
Dopamine and polyethyleneimine (PEI) copolymerized nanodots (PDA–PEI nanodots) with both fluorescence emission and quenching features were synthesized by a simple one-step reaction at room temperature. By adjusting the dopamine and PEI ratio as well as the chain length of PEI, the fluorescence emission and quenching properties of PDA–PEI nanodots can be controlled well. Under optimal conditions, the nanodots showed strong green fluorescence emission with an absolute quantum yield of 1–2% and a quenching efficiency of more than 99% to several fluorophores with emission wavelengths ranging from blue to red light regions. The nanodots with a large number of functional groups also showed strong affinity to nucleic acid strands, excellent solubility in aqueous solution, long-term stability, and uniform size distribution. Integrating these attractive features with the specific enzymatic digestion reaction of the DSN enzyme, a highly sensitive ratiometric fluorescence nanoprobe for miRNA analysis was developed. Aminomethylcoumarin acetate (AMCA), which possesses the same excitation wavelength but a well-resolved blue fluorescence emission with PDA–PEI nanodots, was selected as the signal-reporting unit for capture probe labeling, while the inherent green fluorescence of PDA–PEI nanodots served as the reference. According to the ratiometric fluorescence signal, the ratiometric fluorescence nanoprobes showed high sensitivity and good accuracy for the miRNA assay. Because of the high and universal quenching efficiency, stable fluorescence emission, easily assembled interface, and uniform morphology, the nanodots may have great application prospects to serve as a universal nanoplatform for the fabrication of ratiometric fluorescence nanoprobes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.