Here,
a dual-wavelength ratiometric electrochemiluminescence (ECL)
approach is reported based on resonance energy transfer (RET) from
graphite-like carbon nitride nanosheet (g-C3N4 NS) to Ru(bpy)3
2+ for sensitive detection
of microRNA (miRNA). In this approach, Au nanoparticles (Au NPs) functionalized
g-C3N4 NS nanohybrid (Au-g-C3N4 NH) coated on glassy carbon electrode (GCE) could exhibit
strong and stable ECL emissions with emission peak centered at 460
nm. The ECL emission at such wavelength matched well with the absorption
peak of Ru(bpy)3
2+ as well as impeccably stimulating
the emission of Ru(bpy)3
2+ at the wavelength
of 620 nm, producing ECL-RET with high efficiency. Thus, based on
the ECL signals quenching at 460 nm and increasing at 620 nm, a dual-wavelength
ratiometric ECL-RET system was achieved. This system was then utilized
for determination of target miRNA. With the attachment of thiol-modified
molecular beacon on Au-g-C3N4 NH, target miRNA
hybridized with the molecular beacon to form a DNA-RNA duplex. The
obtained DNA-RNA duplex could be cleaved by duplex-specific nuclease
to release target miRNA which would take part in the next cycle for
further hybridization. Finally, the introducing of Ru(bpy)3
2+ was through the probe DNA-Ru(bpy)3
2+ complementary with the rest single-strand DNA on electrode. By measuring
the ratio of ECL460 nm/ECL620 nm,
we could accurately quantify the concentration of miRNA-21 in a wide
range from 1.0 fM to 1.0 nM. This work provides an important reference
for the study of dual-wavelength ECL ratiometry and also exhibits
potential capability in the detection of nucleic acids.
Multifunctional theranostic nanoplatforms (NPs) in response to environment stimulations for ondemand drug release are highly desirable. Herein, the nearinfrared (NIR)-absorbing dye, indocyanine green (ICG), and the antitumor drug, doxorubicin (DOX), were efficiently coencapsulated into the thermosensitive liposomes based on natural phase-change material. Folate and conjugated gadolinium (Gd) chelate-modified liposome shells enhance active targeting and magnetic resonance performance of the NPs while maintaining the size of the NPs. The ICG/DOXloaded and gadolinium chelate conjugated temperaturesensitive liposome nanoplatforms (ID@TSL-Gd NPs) exhibited NIR-triggered drug release and prominent chemo-, photothermal, and photodynamic therapy properties. With the coencapsulated ICG, DOX, and the conjugated gadolinium chelates, the ID@TSL-Gd NPs can be used for triple-modal imaging (fluorescence/photoacoustic/magnetic resonance imaging)-guided combination tumor therapy (chemotherapy, photothermotherapy, and photodynamic therapy). After tail vein injection, the ID@TSL-Gd NPs accumulated effectively in subcutaneous HeLa tumor of mice. The tumor was effectively suppressed by accurate imaging-guided NIR-triggered phototherapy and chemotherapy, and no tumor regression and side effects were observed. In summary, the prepared ID@TSL-Gd NPs achieved multimodal imaging-guided cancer combination therapy, providing a promising platform for improving diagnosis and treatment of cancer.
DNA/RNA strand displacement is one of the most fundamental reactions in DNA and RNA circuits and nanomachines. In this work, we reported an exploration of the dynamic process of the toehold-mediated strand displacement via core-satellite plasmon rulers at the single-molecule level. Applying plasmon rulers with unlimited lifetime, single-strand displacement triggered by the invader that resulted in stepwise leaving of satellite from the core was continuously monitored by changes of scattering signal for hours. The kinetics of strand displacement in vitro with three different toehold lengths have been investigated. Also, the study revealed the difference in the kinetics of strand displacement between DNA/RNA and DNA/DNA duplexes. For the kinetics study in vivo, influence from the surrounding medium has been evaluated using both phosphate buffer and cell lysate. Applying core-satellite plasmon rulers with high signal/noise ratio, kinetics study in living cells proceeded for the first time, which was not possible by conventional methods with a fluorescent reporter. The plasmon rulers, which are flexible, easily constructed, and robust, have proven to be effective tools in exploring the dynamical behaviors of biochemical reactions in vivo.
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.