Multiply Guaranteed Catalytic DNA Circuit for Cancer-Cell-Selective Imaging of miRNA and Robust Evaluation of Drug Resistance.

Catalytic DNA circuits are desirable for sensitive bioimaging in living cells; yet, it remains a challenge to monitor these intricate signal communications because of the uncontrolled circuitry leakage and insufficient cell selectivity. Herein, a simple yet powerful DNA-repairing enzyme (APE1) activation strategy is introduced to achieve the site-specific exposure of a catalytic DNA circuit for realizing the selectively amplified imaging of intracellular microRNA and robust evaluation of the APE1-involved drug resistance. Specifically, the circuitry reactants are firmly blocked by the enzyme recognition/cleavage site to prevent undesirable off-site circuitry leakage. The caged DNA circuit has no target-sensing activity until its circuitry components are activated via the enzyme-mediated structural reconstitution and finally transduces the amplified fluorescence signal within the miRNA stimulation. The designed DNA circuit demonstrates an enhanced signal-to-background ratio of miRNA assay as compared with the conventional DNA circuit and enables the cancer-cell-selective imaging of miRNA. In addition, it shows robust sensing performance in visualizing the APE1-mediated chemoresistance in living cells, which is anticipated to achieve in-depth clinical diagnosis and chemotherapy research.

Efficient Intracellular MicroRNA Imaging Based on the Localized and Self-Sustainable Catalytic DNA Assembly Circuit.

Building dynamic biological networks, especially DNA circuits, has provided a powerful prospect for exploring the intrinsic regulation processes of live cells. Nevertheless, for efficient intracellular microRNA analysis, the available multi-component circuits are constrained by their limited operating speed and efficiency due to the free diffusion of reactants. Herein, we developed an accelerated Y-shaped DNA catalytic (YDC) circuit for high-efficiency intracellular imaging of microRNA. By grafting the catalytic hairpin assembly (CHA) reactants into an integrated Y-shaped scaffold, the CHA probes were concentrated in a compact space, thus achieving high signal amplification. Profiting from the spatially confined reaction and the self-sustainably assembled DNA products, the YDC system facilitated reliable and in situ microRNA imaging in live cells. Compared with the homogeneously dispersed CHA reactants, the integrated YDC system could efficiently promote the reaction kinetics as well as the uniform delivery of CHA probes, thus providing a robust and reliable analytical tool for disease diagnosis and monitoring.

Non-thermal plasma-enhanced low-temperature catalytic desulfurization of electrolytic aluminum flue gas by CuO-ZrSnO4: experimental and numerical analysis.

Catalytic desulfurization is favored for its ability to desulfurize low concentrations of SO2 by generating sulfur without the need for flue gas conditioning or additives. Maintaining reaction efficiency at a low temperature would justify the industrial scale use of this method. To that end, in this study, we modified a previously reported highly efficient CuO-ZrSnO4 catalyst and investigated its desulfurization performance. The non-thermal plasma (NTP) method was used to enhance the low-temperature efficiency of the catalyst. The desulfurization rate was significantly improved without generating excess heat or by-products in the low-output mode of post-plasma-catalysis-type (PPC-type) dielectric barrier discharge (DBD). In addition, we studied the physicochemical properties of the catalyst (pore structure, physical structure, morphology, electronic properties, and chemical state) under plasma enhancement conditions. The catalyst loaded with 20 wt% Cu and aged at 40 °C exhibited optimum desulfurization performance. This study provides a theoretical foundation for the analysis of plasma-enhanced catalytic desulfurization under low-temperature conditions. Graphical abstract.