Silver nanoparticles (Ag-NPs) exhibit the highest efficiency of localized surface plasmon resonance (LSPR) excitation that can be tuned to any wave length in the visible spectrum. Its performance depends to a large extent on its physicochemical characteristics such as size and shape; which, in turn, can be modulated by the selective growth of their crystalline facets. We used a simple direct chemical reduction method with a precise manipulation of seed-mediated growth control through an automated single-phase continuous flow-batch system to induce customized geometries on Ag-NPs. Optimization of the experimental design was carried out from a multivariate analysis, where the height / width ratio of LSPR band was used as response signal. Proposed methodology controls the critical steps in the synthesis of Ag-NPs that modulate their morphology to attain customized surface plasmon resonance in an interval of 380 nm (spherical-shaped nanoparticles) to 925 nm ({111}- faceted prism-shaped nanoplates) absorptions, leading to a versatile platform to extend their potential applications. Although the present work focused on silver nanoparticles, we believe that this methodology can be extended to any free-electron metals.
H2O2‐Inducible DNA Cross‐linking Agents Capable of Releasing Multiple DNA Alkylators as Anticancer Prodrugs
Three novel arylboronate analogues have been developed and characterized as H2O2-activated anticancer prodrugs. These nontoxic molecules selectively react with H2O2 to release multiple DNA cross-linkers leading to highly efficient DNA interstrand cross-link (ICL) formation. They showed potent cytotoxicity towards a few cancer cell lines.
Abstract
Three compounds with arylboronate esters conjugated with two equivalent nitrogen mustards [bis(2-chloroethyl)methylamine, HN2] have been synthesized and characterized. These inactive small molecules selectively react with H2O2 to produce multiple DNA cross-linkers, such as two HN2 molecules alongside a bisquinone methide (bisQM), leading to efficient DNA ICL formation. In comparison to other amine functional groups, using HN2 as a leaving group greatly improves the DNA cross-linking efficiency of these arylboronate esters as well as cellular activity. The introduction of HN2 in these arylboronate ester analogues favored the generation of bisQM that can directly cross-link DNA. Two equivalents of HN2 are also generated from these compounds upon treatment with H2O2, which directly produces DNA ICL products. The cumulative effects of HN2 and bisQM on DNA cross-linking makes these molecules highly effective H2O2-inducible DNA ICL agents. The three compounds with HN2 as a leaving group showed greatly enhanced cytotoxicity towards cancer cells in comparison to those containing trimethyl amine as a leaving group. This provides an effective strategy for further design of novel potential ROS-activated anticancer prodrugs.
Evaluation of the drinking water quality and potential health risks of nitrate and fluoride in Southwest Delhi, India
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Efficient aerobic oxidation of alcohols and sulfides using an M-doped (M: Mn and Ni) zinc oxide nanostructure
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Electroanalytical sensors-based biogenic synthesized metal oxide nanoparticles for potentiometric assay of pantoprazole sodium
Recent Development in Fluorescent Probes for the Detection of Hg2+ Ions
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Design of Silica@Au Hybrid Nanostars for Enhanced SERS and Photothermal Effect
Core-shell nanostructures of silicon oxide@noble metal have drawn a lot of interest due to their distinctive characteristics and minimal toxicity with remarkable biocompatibility. Due to the unique property of localized surface plasmon resonance (LSPR), plasmonic nanoparticles are being used as surface-enhanced Raman scattering (SERS) based detection of pollutants and photothermal (PT) agents in cancer therapy. Herein we demonstrate the synthesis of multifunctional silica core - Au nanostars shell (SiO2@Au NSs) nanostructures using surfactant free aqueous phase method. The SERS performance of the as-synthesized anisotropic core-shell NSs was examined using Rhodamine B (RhB) dye as a Raman probe and resulted in strong enhancement factor of 1.37 × 106. Furthermore, SiO2@Au NSs were also employed for PT killing of breast cancer cells and they exhibited a concentration-dependent increase in the photothermal effect. The SiO2@Au NSs show remarkable photothermal conversion efficiency of up to 72% which is unprecedented. As an outcome, our synthesized NIR active SiO2@Au NSs are of pivotal importance to have their dual applications in SERS enhancement and PT effect.
Thermodynamics and spectroscopic properties of N-methylpiperazine with propan-1-ol, 2-propen-1-ol, 2-propyn-1-ol
All‐Organic Battery Based on Deep Eutectic Solvent and Redox‐Active Polymers
Sustainable battery concepts are of great importance for the energy storage demands of the future. Organic batteries based on redox-active polymers are one class of promising storage systems to meet these demands, in particular when combined with environmentally friendly and safe electrolytes. Deep Eutectic Solvents (DESs) represent a class of electrolytes that can be produced from sustainable sources and exhibit in most cases no or only a small environmental impact. Because of their non-flammability, DESs are safe, while providing an electrochemical stability window almost comparable to established battery electrolytes and much broader than typical aqueous electrolytes. Here, we report the first all-organic battery cell based on a DES electrolyte composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and N-methylacetamide (NMA) alongside the electrode active materials poly(2,2,6,6-tetramethylpiperidin-1-yl-oxyl methacrylate) (PTMA) and crosslinked poly(vinylbenzylviologen) (X-PVBV2+). The resulting cell shows two voltage plateaus at 1.07 V and 1.58 V and achieves Coulombic efficiencies of 98%. Surprisingly, the X-PVBV/X-PVBV+ redox couple turned out to be much more stable in NaTFSI:NMA 1:6 than the X-PVBV+/X-PVBV2+ couple, leading to asymmetric capacity fading during cycling tests.
Insights into the Application of Ultrasound Tomography in the Precipitation of Calcium Carbonate
An ultrasound tomography (UST) system was employed as a non-invasive and non-intrusive measurement tool to investigate the liquid phase precipitation of calcium carbonate and to detect the onset of the precipitation process. UST-based tomographic reconstructions also offered useful insights into the reagent feeding visualization in the stirred-tank reactor.
Abstract
The application of an ultrasound tomography (UST) system in a liquid-phase reactive crystallization process is reported. The measurement system was applied to precipitated calcium carbonate processing where liquid Na2CO3 was added to a CaCl2 solution. Analysis of the measured sound velocity signals from the experiments demonstrated a clear change in the average time-of-flight (TOF) delay signals, indicating the detection of the onset of the precipitation and the formation of the microcrystalline stable phase of calcite. Moreover, spatial-centric TOF signals from the tomographic images were associated with an increase in the overall suspension density. These findings highlight the potential of the UST measurement system for studying the solidification phenomenon during CaCO3 precipitation.