Surface-Confined Winding Assembly of Mesoporous Nanorods.

Bending and folding are important stereoscopic geometry parameters of one-dimensional (1D) nanomaterials, yet the precise control of them has remained a great challenge. Herein, a surface-confined winding assembly strategy is demonstrated to regulate the stereoscopic architecture of uniform 1D mesoporous SiO2 (mSiO2) nanorods. Based on this brand-new strategy, the 1D mSiO2 nanorods can wind on the surface of 3D premade nanoparticles (sphere, cube, hexagon disk, spindle, rod, etc.) and inherit their surface topological structures. Therefore, the mSiO2 nanorods with a diameter of ∼50 nm and a variable length can be bent into arc shapes with variable radii and radians, as well as folded into 60, 90, 120, and 180° angular convex corners with controllable folding times. Additionally, in contrast to conventional core@shell structures, this winding structure induces partial exposure and accessibility of the premade nanoparticles. The functional nanoparticles can exhibit large accessible surface and efficient energy exchanges with the surroundings. As a proof of concept, winding-structured CuS&mSiO2 nanocomposites are fabricated, which are made up of a 100 nm CuS nanosphere and the 1D mSiO2 nanorods with a diameter of ∼50 nm winding the nanosphere in the perimeter. The winding structured nanocomposites are demonstrated to have fourfold photoacoustic imaging intensity compared with the conventional core@shell nanostructure with an inaccessible core because of the greatly enhanced photothermal conversion efficiency (increased by ∼30%). Overall, our work paves the way to the design and synthesis of 1D nanomaterials with controllable bending and folding, as well as the formation of high-performance complex nanocomposites.

Efficacy of two actinomycete extracts in the amelioration of carbon tetrachloride-induced oxidative stress and nephrotoxicity in experimental rats.

Actinomycetes are a group of the Gram-positive bacteria famous for their antimicrobial, anticancer, anti-parasitic, and anti-inflammatory activities. This study aimed to investigate the efficacy of two bacterial extracts derived from two soil actinomycete strains (S19 and G30) against carbon tetrachloride (CCl4)-induced nephrotoxicity in experimental rats. Sixty-four male rats were assigned to four groups of 16 rats in each group. The 1st group was kept as a normal (control) group and given corn oil combined with the used production medium, while the 2nd group received only CCl4 (CCl4 group). On the other hand, the 3rd group (CCl4+S19) was administered CCl4 and the extract of the actinomycete strain S19 and the 4th group (CCl4+G30) received CCl4 and the extract of the actinomycete strain G30, both treatments for 8 weeks. The results revealed that the two actinomycete extracts S19 and G30 could significantly (p < 0.01) lower the elevated levels of serum creatinine, urea, and uric acid caused by the CCl4 administration. Additionally, the two actinomycete extracts improved the decreased serum total protein. Interestingly, treatment of the CCl4-intoxicated rats with S19 and G30 extracts remarkably reversed the lowered renal glutathione (GSH), glutathione peroxidase (GSH-Px), peroxidase (Px) and superoxide dismutase (SOD) activities, and the elevated lipid peroxidation (LPO) levels. The histopathological examination of the treated kidney revealed that the two actinomycete extracts improved rats against CCl4-induced kidney lesions. The present results suggested that the protective effect of the two actinomycete extracts may rely on its effect on reducing the oxidative stress and improving the antioxidant defense system.

The potential protective effect of two actinomycete extracts against carbon tetrachloride-induced hepatotoxicity in rats.

The aim of this study was to investigate the potential protective effect of two extracts derived from two soil actinomycete strains, designated S19 and G30, against CCl4-induced hepatotoxicity in male rats. Sixty-four male rats were divided into four groups of 16 rats per group. The first group was a control group given corn oil and the nutritive medium which is composed of a mixture of the two used media. The second group received CCl4 only, the third group was administered CCl4 and the extract S19, and the fourth group was administered CCl4 and the extract G30. The results were taken after a treatment period of 8 weeks. Our data demonstrated that the two actinomycete extracts significantly (P < 0.01) lowered the CCl4-induced elevation of serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) after 8 weeks of treatment. The extract S19 had no effect on serum lactate dehydrogenase (LDH) and total bilirubin, whereas the extract G30 significantly decreased (P < 0.01) the elevated levels of these parameters in the serum, especially after 4 weeks of treatment. The levels of hepatic glutathione (GSH), glutathione peroxidase (GSH-Px), peroxidase (Px), catalase (CAT), and superoxide dismutase (SOD) significantly increased (P < 0.01), while those of malondialdehyde (MDA) markedly decreased in rats treated with the two extracts. Furthermore, histopathological lesions in the liver, including necrosis, inflammatory cell infiltration, hydropic degeneration, and congestion of the central vein, were partially reversed by treatment with the two microbial extracts. Our results provided evidence for the protective effect of the two used actinomycete extracts against CCl4-induced liver damage occurred through the reduction of oxidative stress and improvement of antioxidant defense markers.

A vesicle-aggregation-assembly approach to highly ordered mesoporous γ-alumina microspheres with shifted double-diamond networks.

Alumina materials have widely been used in industrial fields, such as catalysis and adsorption. However, due to the fast sol-gel process and complicated crystalline-phase transformation, the synthesis of alumina materials with both highly ordered mesostructures and crystallized frameworks remains a great challenge. Herein, we report a novel vesicle-aggregation-assembly strategy to prepare highly ordered mesoporous γ-alumina microspheres with unique shifted double-diamond networks for the first time, by using diblock copolymer poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA) as a template and aluminum isopropoxide as a precursor in a tetrahydrofuran (THF)/hydrochloric acid binary solvent. During the gradual evaporation of THF and H2O, the as-made Al3+-based gel/PEO-b-PMMA composites can be obtained through a co-assembly process based on the hydrogen bonding interaction between hydroxyl groups of alumina oligomers and PEO segments of the diblock copolymers. The formed composites exhibit a spherical morphology with a wide size distribution (diameter size 1-12 µm). Furthermore, these composite microspheres possess an inverse bicontinuous cubic mesostructure (double diamond, Pn3[combining macron]m) with Al3+-based gel buried in the PEO-b-PMMA matrix in the form of two intertwined but disconnected networks. After a simple calcination at 900 °C in air, the structure of the resultant mesoporous alumina changes to a relatively low symmetry (shifted double diamond, Fd3[combining macron]m), ascribed to the shifting of the two alumina networks due to loss of the templates. Meanwhile, the unit cell size of the alumina mesostructure decreases from ∼131 to ∼95 nm. The obtained ordered mesoporous alumina products retain the spherical morphology and possess ultra-large mesopores (∼72.8 nm), columnar frameworks composed of γ-alumina nanocrystalline particles (crystal size of ∼15 nm) and high thermal stability (up to 900 °C). As a support of Au nanoparticles, the formed Au/mesoporous γ-alumina composite catalysts have been used in the catalytic reduction of 4-nitrophenol with a high kinetic constant k of 0.0888 min-1, implying promising potential as a catalyst support.

Spatial Isolation of Carbon and Silica in a Single Janus Mesoporous Nanoparticle with Tunable Amphiphilicity.

Like surfactants with tunable hydrocarbon chain length, Janus nanoparticles also possess the ability to stabilize emulsions. The volume ratio between the hydrophilic and hydrophobic domains in a single Janus nanoparticle is very important for the stabilization of emulsions, which is still a great challenge. Herein, dual-mesoporous Fe3O4@mC&mSiO2 Janus nanoparticles with spatial isolation of hydrophobic carbon and hydrophilic silica at the single-particle level have successfully been synthesized for the first time by using a novel surface-charge-mediated selective encapsulation approach. The obtained dual-mesoporous Fe3O4@mC&mSiO2 Janus nanoparticles are made up of a pure one-dimensional mesoporous SiO2 nanorod with tunable length (50-400 nm), ∼100 nm wide and ∼2.7 nm mesopores and a closely connected mesoporous Fe3O4@mC magnetic nanosphere (∼150 nm diameter, ∼10 nm mesopores). As a magnetic "solid amphiphilic surfactant", the hydrophilic/hydrophobic ratio can be precisely adjusted by varying the volume ratio between silica and carbon domains, endowing the Janus nanoparticles surfactant-like emulsion stabilization ability and recyclability under a magnetic field. Owing to the total spatial separation of carbon and silica, the Janus nanoparticles with an optimized hydrophilic/hydrophobic ratio show spectacular emulsion stabilizing ability, which is crucial for improving the biphasic catalysis efficiency. By selectively anchoring catalytic active sites into different domains, the fabricated Janus nanoparticles show outstanding performances in biphasic reduction of 4-nitroanisole with 100% conversion efficiency and 700 h-1 high turnover frequency for biphasic cascade synthesis of cinnamic acid.

Near-Infrared Triggered Decomposition of Nanocapsules with High Tumor Accumulation and Stimuli Responsive Fast Elimination.

A near-infrared (NIR) induced decomposable polymer nanocapsule is demonstrated. The nanocapsules are fabricated based on layer-by-layer co-assembly of azobenzene functionalized polymers and up/downconversion nanoparticles (U/DCNPs). When the nanocapsules are exposed to 980 nm light, ultraviolet/visible photons emitted by the U/DCNPs can trigger the photoisomerization of azobenzene groups in the framework. The nanocapsules could decompose from large-sized nanocapsule to small U/DCNPs. Owing to their optimized original size (ca. 180 nm), the nanocapsules can effectively avoid biological barriers, provide a long blood circulation (ca. 5 h, half-life time) and achieve four-fold tumor accumulation. It can fast eliminate from tumor within one hour and release the loaded drugs for chemotherapy after NIR-induced dissociation from initial 180 nm capsules to small 20 nm U/DCNPs.