A complementary metal-based compilation of the complexes discussed is also provided in a concise tabular form.Rapid screening monofluoroacetic acid (FAcOH) is responsible for preventing chemical poisoning and food safety events. Whereas surface enhanced Raman scattering (SERS) spectra is an effective tool for detecting forbidden chemicals, it is difficult to directly detect FAcOH due to its small Raman scattering cross section as well as weak adsorption on SERS substrates. https://www.selleckchem.com/products/cc-92480.html In this work, the metal phenolic supramolecular networks (MPNs, i.e., the tannic acid and Fe3+ complex) were fabricated on the commercial nanoanodic aluminum oxide film (NAAO) for assisting in situ chemical deposition highly uniform Ag nanostructure over large areas (the NAAO@AgNS). The low cost and simple fabrication process made the NAAO@AgNS a single-use consumable. For FAcOH detection, a specific derivative reaction between FAcOH and thiosalicylic acid (TSA) was introduced. By taking TSA as the Raman probe, its SERS signal attenuated constantly with the increasing amount of FAcOH. For improving quantitative accuracy, thiocyanate (SCN-) was introduced on the NAAO@AgNS as an internal standard; thus, the characteristic peak intensity ratios associated with TSA and SCN- (I1035/I2125) were fitted to the concentration of FAcOH. It was demonstrated that the SERS assay achieved good sensitivity and selection toward FAcOH with the limit of quantitation (LOD) as low as 50 nmol L-1. The NAAO@AgNS featured with highly sensitive, uniform, and consistent SERS performances could easily extend to wide SERS applications.Surface-modified mesoporous silica nanoparticles (MSNs) have attracted more and more attention as promising materials for biomolecule delivery. However, the lack of detailed evaluation relevant to the potential cytotoxicity of these MSNs is still a major obstacle for their applications. Unlike the bare MSNs and amino- or liposome-modified MSNs, we found that polyethylenimine-modified MSNs (MSNs-PEI) had no obvious toxicity to human umbilical vein endothelial cells (HUVECs) at the concentrations up to 100 μg/mL. However, MSNs-PEI induced autophagosomes accumulation by blocking their fusion with lysosomes, an essential mechanism for the cytotoxicity of many nanoparticles (NPs). Thus, we predicted that an alternative pathway for autophagosome clearance exists in HUVECs to relieve autophagic stress induced by MSNs-PEI. We found that MSNs-PEI prevented STX17 loading onto autophagosomes instead of influencing lysosomal pH or proteolytic activity. MSNs-PEI induced the structural alternation of the cytoskeleton but did not cause endoplasmic reticulum stress. The accumulated autophagosomes were released to the extracellular space via microvesicles (MVs) when the autophagic degradation was blocked by MSNs-PEI. More importantly, blockade of either autophagosome formation or release caused the accumulation of damaged mitochondria and excessive ROS production in the MSNs-PEI-treated HUVECs, which in turn led to cell death. Thus, we propose here that the MV-mediated autophagosome release, a compensation mechanism, allows the vascular endothelial cell survival when the degradation of autophagosomes is blocked by MSNs-PEI. Accordingly, promoting the release of accumulated autophagosomes may be a protective strategy against the endothelial toxicity of NPs.For the most part, enzymes contain one active site wherein they catalyze in a serial manner chemical reactions between substrates both efficiently and rapidly. Imagine if a situation could be created within a chiral porous crystal containing trillions of active sites where substrates can reside in vast numbers before being converted in parallel into products. Here, we report how it is possible to incorporate 1-anthracenecarboxylate (1-AC-) as a substrate into a γ-cyclodextrin-containing metal-organic framework (CD-MOF-1), where the metals are K+ cations, prior to carrying out [4+4] photodimerizations between pairs of substrate molecules, affording selectively one of four possible regioisomers. One of the high-yielding regioisomers exhibits optical activity as a result of the presence of an 81 ratio of the two enantiomers following separation by high-performance liquid chromatography. The solid-state superstructure of 1-anthracenecarboxylate potassium salt (1-ACK), which is co-crystallized with γ-cyclodextrin, reveals that pairs of substrate molecules are not only packed inside tunnels between spherical cavities present in CD-MOF-1, but also stabilized-in addition to hydrogen-bonding to the C-2 and C-3 hydroxyl groups on the d-glucopyranosyl residues present in the γ-cyclodextrin tori-by combinations of hydrophobic and electrostatic interactions between the carboxyl groups in 1-AC- and four K+ cations on the waistline between the two γ-cyclodextrin tori in the tunnels. These non-covalent bonding interactions result in preferred co-conformations that account for the highly regio- and enantioselective [4+4] cycloaddition during photoirradiation. Theoretical calculations, in conjunction with crystallography, support the regio- and stereochemical outcome of the photodimerization.Gas solubility can go beyond classical bulk-liquid Henry's law saturation under the nanoconfinement of a liquid phase. This concept establishes the foundation of the current study for developing a novel catalytic system for transformation of carbon dioxide to cyclic carbonates at mild conditions with major emphasis on application for CO2 capture and utilization. A series of mesoporous silica-based supports of various pore sizes and shapes grafted with a quaternary ammonium salt is synthesized and characterized. CO2 sorption in styrene oxide, either in bulk or nanoconfined state, as well as catalytic reactivity for CO2 transformation into styrene carbonate, are experimentally evaluated. The family of mesoporous catalysts with aligned cylindrical pores (MCM-41 and SBA-15) with pore sizes ranging from 3.5 to 9 nm exhibit enhanced sorption of CO2 in nanoconfined styrene oxide with maximum sorption capacity taking place in MCM-41 with the smallest pore size. The catalysts with interconnected cylindrical pores (KIT-6) with pore sizes ranging from 4.
A complementary metal-based compilation of the complexes discussed is also provided in a concise tabular form.Rapid screening monofluoroacetic acid (FAcOH) is responsible for preventing chemical poisoning and food safety events. Whereas surface enhanced Raman scattering (SERS) spectra is an effective tool for detecting forbidden chemicals, it is difficult to directly detect FAcOH due to its small Raman scattering cross section as well as weak adsorption on SERS substrates. https://www.selleckchem.com/products/cc-92480.html In this work, the metal phenolic supramolecular networks (MPNs, i.e., the tannic acid and Fe3+ complex) were fabricated on the commercial nanoanodic aluminum oxide film (NAAO) for assisting in situ chemical deposition highly uniform Ag nanostructure over large areas (the NAAO@AgNS). The low cost and simple fabrication process made the NAAO@AgNS a single-use consumable. For FAcOH detection, a specific derivative reaction between FAcOH and thiosalicylic acid (TSA) was introduced. By taking TSA as the Raman probe, its SERS signal attenuated constantly with the increasing amount of FAcOH. For improving quantitative accuracy, thiocyanate (SCN-) was introduced on the NAAO@AgNS as an internal standard; thus, the characteristic peak intensity ratios associated with TSA and SCN- (I1035/I2125) were fitted to the concentration of FAcOH. It was demonstrated that the SERS assay achieved good sensitivity and selection toward FAcOH with the limit of quantitation (LOD) as low as 50 nmol L-1. The NAAO@AgNS featured with highly sensitive, uniform, and consistent SERS performances could easily extend to wide SERS applications.Surface-modified mesoporous silica nanoparticles (MSNs) have attracted more and more attention as promising materials for biomolecule delivery. However, the lack of detailed evaluation relevant to the potential cytotoxicity of these MSNs is still a major obstacle for their applications. Unlike the bare MSNs and amino- or liposome-modified MSNs, we found that polyethylenimine-modified MSNs (MSNs-PEI) had no obvious toxicity to human umbilical vein endothelial cells (HUVECs) at the concentrations up to 100 μg/mL. However, MSNs-PEI induced autophagosomes accumulation by blocking their fusion with lysosomes, an essential mechanism for the cytotoxicity of many nanoparticles (NPs). Thus, we predicted that an alternative pathway for autophagosome clearance exists in HUVECs to relieve autophagic stress induced by MSNs-PEI. We found that MSNs-PEI prevented STX17 loading onto autophagosomes instead of influencing lysosomal pH or proteolytic activity. MSNs-PEI induced the structural alternation of the cytoskeleton but did not cause endoplasmic reticulum stress. The accumulated autophagosomes were released to the extracellular space via microvesicles (MVs) when the autophagic degradation was blocked by MSNs-PEI. More importantly, blockade of either autophagosome formation or release caused the accumulation of damaged mitochondria and excessive ROS production in the MSNs-PEI-treated HUVECs, which in turn led to cell death. Thus, we propose here that the MV-mediated autophagosome release, a compensation mechanism, allows the vascular endothelial cell survival when the degradation of autophagosomes is blocked by MSNs-PEI. Accordingly, promoting the release of accumulated autophagosomes may be a protective strategy against the endothelial toxicity of NPs.For the most part, enzymes contain one active site wherein they catalyze in a serial manner chemical reactions between substrates both efficiently and rapidly. Imagine if a situation could be created within a chiral porous crystal containing trillions of active sites where substrates can reside in vast numbers before being converted in parallel into products. Here, we report how it is possible to incorporate 1-anthracenecarboxylate (1-AC-) as a substrate into a γ-cyclodextrin-containing metal-organic framework (CD-MOF-1), where the metals are K+ cations, prior to carrying out [4+4] photodimerizations between pairs of substrate molecules, affording selectively one of four possible regioisomers. One of the high-yielding regioisomers exhibits optical activity as a result of the presence of an 81 ratio of the two enantiomers following separation by high-performance liquid chromatography. The solid-state superstructure of 1-anthracenecarboxylate potassium salt (1-ACK), which is co-crystallized with γ-cyclodextrin, reveals that pairs of substrate molecules are not only packed inside tunnels between spherical cavities present in CD-MOF-1, but also stabilized-in addition to hydrogen-bonding to the C-2 and C-3 hydroxyl groups on the d-glucopyranosyl residues present in the γ-cyclodextrin tori-by combinations of hydrophobic and electrostatic interactions between the carboxyl groups in 1-AC- and four K+ cations on the waistline between the two γ-cyclodextrin tori in the tunnels. These non-covalent bonding interactions result in preferred co-conformations that account for the highly regio- and enantioselective [4+4] cycloaddition during photoirradiation. Theoretical calculations, in conjunction with crystallography, support the regio- and stereochemical outcome of the photodimerization.Gas solubility can go beyond classical bulk-liquid Henry's law saturation under the nanoconfinement of a liquid phase. This concept establishes the foundation of the current study for developing a novel catalytic system for transformation of carbon dioxide to cyclic carbonates at mild conditions with major emphasis on application for CO2 capture and utilization. A series of mesoporous silica-based supports of various pore sizes and shapes grafted with a quaternary ammonium salt is synthesized and characterized. CO2 sorption in styrene oxide, either in bulk or nanoconfined state, as well as catalytic reactivity for CO2 transformation into styrene carbonate, are experimentally evaluated. The family of mesoporous catalysts with aligned cylindrical pores (MCM-41 and SBA-15) with pore sizes ranging from 3.5 to 9 nm exhibit enhanced sorption of CO2 in nanoconfined styrene oxide with maximum sorption capacity taking place in MCM-41 with the smallest pore size. The catalysts with interconnected cylindrical pores (KIT-6) with pore sizes ranging from 4.
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