Synthesis of Nanospheres-on-Microsphere Silica with Tunable Shell Morphology and Mesoporosity for Improved HPLC

Core–shell particles have a wide range of applications. Most of the core–shell particles are prepared in two or multiple steps. Core–shell silica microspheres, with solid core and porous shell, have been used as novel packing materials in recent years for highly efficient liquid chromatography separation with relatively low back-pressure. These core–shell silica microspheres are usually prepared by the time-consuming layer-by-layer technique. Built on our previous report of one-pot synthesis of core–shell nanospheres-on-microspheres (termed as SOS particles for “spheres-on-spheres”), we describe here a two-stage synthesis for the introduction of shell mesoporosity into SOS particles with tunable shell morphology by co-condensation of tetraethyl orthosilicate (TEOS) with 3-mercaptopropyltrimethoxysilane (MPTMS) in the presence of surfactant in the second stage. With MPTMS as the primary precursor at the first stage, some other silica precursors (apart from TEOS) are also employed at the second stage. Expansion of the surfactant-templated mesopores with swelling agents during the reaction and by hydrothermal postsynthesis treatment is then performed to allow the pore sizes (> 6 nm) suitable for separation of small molecules in liquid chromatography. Compared to the standard SOS silica (both the nanospheres and microspheres contain nearly no mesopores), the introduction of mesoporosity into the nanosphere shell increases the separation efficiency of small molecule mixtures by 4 times as judged by the height equivalent plate number, while the separation of protein mixtures is not negatively affected

Polydopamine-Coated Polymer Nanofibers for In Situ Protein Loading and Controlled Release

Nanofibrous polymeric materials, combined with protein therapeutics, play a significant role in biomedical and pharmaceutical applications. However, the upload of proteins into nanofibers with a high yield and controlled release has been a challenging issue. Here, we report the in situ loading of a model protein (bovine serum albumin) into hydrophilic poly(vinyl alcohol) nanofibers via ice-templating, with a 100% protein drug loading efficiency. These protein-loaded nanofibers were further coated by polydopamine in order to improve the nanofiber stability and achieve a controlled protein release. The mass ratio between poly(vinyl alcohol) and bovine serum albumin influenced the percentage of proteins in composite nanofibers and fiber morphology. More particles and less nanofibers were formed with an increasing percentage of bovine serum albumin. By varying the coating conditions, it was possible to produce a uniform polydopamine coating with tunable thickness, which acted as an additional barrier to reduce burst release and achieve a more sustained release profile

Reduction-Controlled Release of Organic Nanoparticles from Disulfide Cross-linked Porous Polymer

Reduction-controlled release is favored for many applications. The cleavage of disulfide bonds is known to be sensitive to reducing agents. Here, a cross-linker containing a disulfide bond is prepared and then used to prepare cross-linked porous polymer via an emulsion templating approach. Oil-in-water (O/W) emulsions are first formed where an organic dye is dissolved in the oil droplet phase and monomer/cross-linker/surfactant are added into the continuous aqueous phase. By polymerizing the O/W emulsion followed by freeze-drying, organic nanoparticles are formed <i>in situ</i> within the disulfide-cross-linked porous polymer. The release of organic nanoparticles in water is demonstrated and can be tuned by the presence of reducing agents such as dithiothreitol and tris­(2-carboxyethyl)­phospine. This approach has the potential to be used for the reduction-controlled release of poorly water-soluble drug nanoparticles from porous polymers or hydrogels

Microwave-assisted NaHSO₄-catalyzed synthesis of ricinoleic glycol ether esters

<p>The synthesis of several ricinoleic acid glycol ether esters by high-pressure microwave radiation is described. Ricinoleic acid which is from castor oil reacted fastly with glycol ethers in the presence of NaHSO₄ · H₂O and dichloromethane (DCM) in special microwave reactor. The influences of reaction factors such as catalyst and solvent type, reaction temperature, and time were investigated and the optimal reaction conditions were obtained. The activity of catalyst had a higher performance up to the 10th cycle and the excellent values of turnover numbers and turnover frequency were obtained. Compared with the traditional esterification in reflux heating systems., the microwave-assisted process has many advantages such as shorter reaction time, less side effects, higher yield, which is a great potential for the development of green chemistry.</p

Tuning Morphology of Nanostructured ZIF‑8 on Silica Microspheres and Applications in Liquid Chromatography and Dye Degradation

Zeolitic imidazolate framework-8 (ZIF-8) is one type of metal–organic framework (MOF) with excellent thermal and solvent stability and has been used extensively in separation, catalysis, and gas storage. Supported ZIF-8 structures can offer additional advantages beyond the MOF-only materials. Here, spheres-on-spheres (SOS) silica microspheres are used as support for the nucleation and growth of ZIF-8 nanocrystals. The surface functionalities (−SH, −COOH, and −NH₂) of silica and reaction conditions are investigated for their effects on the ZIF-8 morphology. The use of SOS microspheres results in the formation of highly crystalline ZIF-8 nanostructured shell with varied sizes and shapes, ranging from spherical to cubic and to needle crystals. The SOS@ZIF-8 microspheres are packed into a column and utilized for separation of aromatic molecules on the basis of π–π interaction in high-performance liquid chromatography (HPLC). Furthermore, by thermal treatment in air, ZIF-8 nanocrystals can be transformed into ZnO coating on SOS silica microspheres. The SOS@ZnO microspheres show excellent photocatalytic activity, as measured by degradation of methyl orange in water, when compared to ZnO nanoparticles. This study has demonstrated the facile way of using SOS microspheres to prepare core–shell microspheres and their applications

Characteristics of six libraries.

<p>Characteristics of six libraries.</p

Transcriptome Profiling of Watermelon Root in Response to Short-Term Osmotic Stress

<div><p>Osmotic stress adversely affects the growth, fruit quality and yield of watermelon (<i>Citrullus lanatus</i> (Thunb.) Matsum. & Nakai). Increasing the tolerance of watermelon to osmotic stress caused by factors such as high salt and water deficit is an effective way to improve crop survival in osmotic stress environments. Roots are important organs in water absorption and are involved in the initial response to osmosis stress; however, few studies have examined the underlying mechanism of tolerance to osmotic stress in watermelon roots. For better understanding of this mechanism, the inbred watermelon accession M08, which exhibits relatively high tolerance to water deficits, was treated with 20% polyethylene glycol (PEG) 6000. The root samples were harvested at 6 h after PEG treatment and untreated samples were used as controls. Transcriptome analyses were carried out by Illumina RNA sequencing. A total of 5246 differentially expressed genes were identified. Gene ontology enrichment and biochemical pathway analyses of these 5246 genes showed that short-term osmotic stress affected osmotic adjustment, signal transduction, hormone responses, cell division, cell cycle and ribosome, and M08 may repress root growth to adapt osmotic stress. The results of this study describe the watermelon root transcriptome under osmotic stress and propose new insight into watermelon root responses to osmotic stress at the transcriptome level. Accordingly, these results allow us to better understand the molecular mechanisms of watermelon in response to drought stress and will facilitate watermelon breeding projects to improve drought tolerance.</p></div

Spatiotemporal Trends of Heavy Metals in Indo-Pacific Humpback Dolphins (<i>Sousa chinensis</i>) from the Western Pearl River Estuary, China

We assessed the spatiotemporal trends of the concentrations of 11 heavy metals (HMs) in the liver and kidney of Indo-Pacific humpback dolphins (<i>Sousa chinensis</i>) from western Pearl River Estuary (PRE) during 2004–2015. The hepatic levels of Cr, As, and Cu in these dolphins were among the highest reported for cetaceans globally, and the levels of Zn, Cu, and Hg were sufficiently high to cause toxicological effects in some of the animals. Between same age-sex groups, dolphins from Lingdingyang were significantly more contaminated with Hg, Se, and V than those from the West-four region, while the opposite was true for Cd. Generalized additive mixed models showed that most metals had significant but dissimilar temporal trends over a 10-year period. The concentrations of Cu and Zn increased significantly in recent years, corresponding to the high input of these metals in the region. Body-length-adjusted Cd levels peaked in 2012, accompanied by the highest annual number of dolphin stranding events. In contrast to the significant decrease in HM levels in the dolphins in Hong Kong waters (the eastern reaches of the PRE), the elevated metal exposure in the western PRE raises serious concerns

GO Classification.

<p>The DEGs were assigned into biological process, cellular components and molecular function. The x-axis represents the categories of GO, the left y-axis represents the percentages of the DEGs in each category and the right y-axis represents the number of DEGs in each category.</p

Forest plot- work status.

<p>Forest plot- work status.</p