Versatile Surfactant/Swelling-Agent Template for Synthesis of Large-Pore Ordered Mesoporous Silicas and Related Hollow Nanoparticles

A surfactant/swelling-agent pair suitable for templating a variety of well-defined large-pore nanoporous silicas was identified. The pair includes a poly­(ethylene oxide)-poly­(propylene oxide)-poly­(ethylene oxide), PEO-PPO-PEO, block copolymer surfactant (Pluronic F127, EO₁₀₆PO₇₀EO₁₀₆) with a large fraction of long hydrophilic PEO blocks and a swelling agent (toluene) that strongly solubilizes in micelles of the PEO-PPO-PEO surfactant family. Such a combination affords micellar templates for both spherical and cylindrical mesopores with potential to hinder cross-linking of micelle-templated nanostructures due to stabilization of nanoparticles by long PEO chains. Under low-temperature conditions (11–12 °C), the Pluronic F127/toluene pair affords ultralarge-pore FDU-12 (ULP-FDU-12) silica with face-centered cubic structure of spherical mesopores and related hollow nanospheres, as well as large-pore SBA-15 (LP-SBA-15) with two-dimensional hexagonal structure of cylindrical mesopores and related silica nanotubes. ULP-FDU-12 reaches the unit-cell parameter of 69 nm, which is very large. LP-SBA-15 has a unit-cell parameter up to 26 nm and pore diameter up to ∼20 nm and is exceptionally well ordered. The hollow nanospheres and nanotubes are attainable through lowering of the silica-precursor/surfactant ratio. The materials templated by spherical micelles form when the surfactant/swelling-agent solution is kept under stirring for extended periods of time before the addition of the silica precursor. The sizes of entrances to the hollow nanospheres can be continuously tuned by adjusting the hydrothermal treatment temperature. The ordered mesoporous silicas can be converted from open-pore to closed-pore materials through the thermally induced pore closing. The diversity in morphology, pore size, and pore connectivity makes the proposed surfactant/swelling-agent templating system unprecedented in the large mesopore domain

Graphene-Based Membranes for Molecular Separation

In comparison with traditional chemical separation processes, membrane separation is much simpler and more efficient. An ideal membrane for molecular separation should be as thin as possible to maximize its solvent flux, be mechanically robust to prevent it from fracture, and have well-defined pore sizes to guarantee its selectivity. Graphene is an excellent platform for developing size-selective membranes because of its atomic thickness, high mechanical strength, and chemical inertness. In this Perspective, we review the recent advancements on the fabrication of nanoporous graphene membranes and graphene oxide membranes (GOMs) for molecular separation. The methods of fabricating these membranes are summarized, and the mechanisms of molecular separation based on these two types of graphene membranes are compared. The challenges of synthesizing and transferring large-area nanoporous graphene membranes and engineering the performances of GOMs are discussed

Ultrasensitive and Selective Nitrogen Dioxide Sensor Based on Self-Assembled Graphene/Polymer Composite Nanofibers

Reduced graphene oxide (rGO) sheets were self-assembled onto the surfaces of electrospun polymer nanofibers to form an ultrathin coating. These rGO/polymer composite nanofibers were used to fabricate nitrogen dioxide (NO₂) sensor. This sensor can be performed at room temperature, and it exhibited a high sensitivity of 1.03 ppm^–1 with excellent selectivity and good reversibility. Furthermore, the limit of detection was experimentally measured to be as low as 150 ppb, and this value is much lower than the threshold exposure limit proposed by American Conference of Governmental Industrial Hygienists (200 ppb)

Biocompatible and Highly Luminescent Near-Infrared CuInS₂/ZnS Quantum Dots Embedded Silica Beads for Cancer Cell Imaging

Bright and stable CuInS₂/ZnS@SiO₂ nanoparticles with near-infrared (NIR) emission were competently prepared by incorporating the as-prepared hydrophobic CuInS₂/ZnS quantum dots (QDs) directly into lipophilic silane micelles and subsequently an exterior silica shell was formed. The obtained CuInS₂/ZnS@SiO₂ nanoparticles homogeneously comprised both single-core and multicore remarkable CuInS₂/ZnS QDs, while the silica shell thickness could be controlled to within 5–10 nm and their overall size was 17–25 nm. Also, the functionalized CuInS₂/ZnS QDs encapsulated in the silica spheres, expedited their bioconjugation with holo-Transferrin (Tf) for further cancer cell imaging. The CuInS₂/ZnS@SiO₂ nanoparticles not only showed a dominant NIR band-edge luminescence at 650–720 nm with a quantum yield (QY) between 30 and 50%, without a recognized photoluminescence (PL) red shift, but also exhibited excellent PL and colloidal stability in aqueous media. Impressively, the cytotoxicity studies revealed minor suppression on cell viability under both CuInS₂/ZnS@SiO₂ and CuInS₂/ZnS@SiO₂@Tf concentrations up to 1 mg/mL. The application in live-cell imaging revealed that the potential of CuInS₂/ZnS QDs as biocompatible, robust, cadmium-free, and brilliant NIR emitters is considered promising for fluorescent labels

One-Pot Synthesis of Fe₃O₄ Nanoparticle Loaded 3D Porous Graphene Nanocomposites with Enhanced Nanozyme Activity for Glucose Detection

A novel one-pot strategy is proposed to fabricate 3D porous graphene (3D GN) decorated with Fe₃O₄ nanoparticles (Fe₃O₄ NPs) by using hemin as iron source. During the process, graphene oxide was simultaneously reduced and self-assembled to form 3D graphene hydrogel while Fe₃O₄ NPs synthesized from hemin distributed uniformly on 3D GN. The preparation process is simple, facile, economical, and green. The obtained freeze-dried product (3D GH-5) exhibits outstanding peroxidase-like activity. Compared to the traditional 2D graphene-based nanocomposites, the introduced 3D porous structure dramatically improved the catalytic activity, as well as the catalysis velocity and its affinity for substrate. The high catalytic activity could be ascribed to the formation of Fe₃O₄ NPs and 3D porous graphene structures. Based on its peroxidase-like activity, 3D GH-5 was used for colorimetric determination of glucose with a low detection limit of 0.8 μM

Secondary study outcomes.

<p>Secondary study outcomes.</p

Additional file 1: Figure S1. of Synthesis of Si-Sb-ZnO Composites as High-Performance Anodes for Lithium-ion Batteries

Cycling performance of ZnO, Si-Sb, Si-Sb-(ZnO)0.3 anode materials

Cost of drugs and hospitalization in the two groups.

<p>Cost of drugs and hospitalization in the two groups.</p

Coefficients.

<p>Coefficients.</p

Kaplan-Meier curves for DFS (A) and OS (B) of TNBC patients in the training set according to the prognostic model.

<p>Kaplan-Meier curves for DFS (C) and OS (D) in the validation set.</p