Fine‐Tuning Mesochannel Orientation of Organically Functionalized Mesoporous Silica Nanoparticles

Three orientations to choose from : 2D hexagonal organically functionalized mesoporous silica nanoparticles with tunable mesochannel orientation (straight, helical, and radial mesochannels) were synthesized through a simple addition of various amounts of ureidopropyltrimethoxylsilane (UDPTMS) in the condensation of tetraorthosilicate (TEOS) in aqueous solution.

     

Facile Synthesis of Boronic Acid‐Functionalized Magnetic Mesoporous Silica Nanocomposites for Highly Specific Enrichment of Glycopeptides

In the work, aminophenylboronic acid (APB)‐functionalized magnetic mesoporous silica, which holds the attractive features of high magnetic responsivity and large surface area, was developed to enrich glycopeptides. At first, magnetic mesoporous silica nanocomposites were prepared. And then, the nanocomposites were functioned with glycidoxypropyltrimethoxysilane (GLYMO) for boronic acid immobilization. Due to that the boronic acid group on the surface of magnetic mesoporous silica nanocomposites can form tight yet reversible covalent bond with glycopeptides containing cis‐1,2‐diols groups, the magnetic mesoporous silica nanocomposites were successfully applied to selective enrichment of glycopeptides. APB functionalized magnetic mesoporous silica was also demonstrated to have high selectivity for the glycopeptides in the presence of a 10‐fold excess bovine serum albumin (BSA) over horseradish peroxidase (HRP) in the tryptic digest. We also find that magnetic mesoporous silica has better sensitivity in HRP digest compared with that of commercial aminophenylboronic acid‐functionalized magnetic nanoparticles beads. The limit of detection for glycopeptides from glycoprotein HRP is about 0.01 ng/µL.     

苯基磺酸官能化中孔硅基材料的制备及催化性能研究

通过溶胶-凝胶法制得了苯基聚硅氧烷, 进一步磺化制备了苯基磺酸官能化的中孔硅基催化材料, 并通过BET, SEM和固体核磁技术对其进行了表征. BET结果表明, 该催化剂比表面积为722 m²/g, 平均孔径为9.06 nm, 孔容0.59 mL/g. ¹³C CPMAS NMR和²⁹Si CPMAS NMR表征显示磺酸基键合于苯环间位, 苯基以共价方式进入无机-有机杂化硅基材料的内部结构. 该固体酸的活性中心磺酸基在表面呈均匀分布, 在芳族羧酸和取代酚的直接酯化反应中表现出优异的催化性能.     

Tuning Single‐Molecule Dynamics in Functionalized Mesoporous Silica

Diffusion of single molecules of a substituted terrylene diimide dye in functionalized mesoporous silica films was monitored by single‐molecule fluorescence microscopy. By varying the chemical nature and density of the functional groups, the diffusion dynamics of the dye molecules can be controlled precisely. The picture shows a sketch of a dye molecule in a pore, diffusion data for different phenyl functionalization densities, and the trajectory of one molecule in a cyanopropyl‐functionalized film.

     

Oxygen‐Assisted Synthesis of Mesoporous Palladium Nanoparticles as Highly Active Electrocatalysts

Mesoporous Pd nanoparticles (MPNs) enclosed by high‐index facets have been successfully prepared by taking advantage of successive oxygen adsorption and desorption caused by the oxidative etching effect. The as‐prepared MPNs exhibit excellent performance toward formic acid electro‐oxidation, which is due to the synergetic effect between the diffusion‐feasible tubular mesochannels and the high index facets.     

Tartardiamide‐Functionalized Chiral Organosilicas with Highly Ordered Mesoporous Structure

A novel chiral mesoporous organosilica with L ‐tartardiamide moieties integrated in the backbone has been synthesized for the first time by a mild synthetic approach with block copolymer P123 as a template. The materials have highly ordered 2D hexagonal mesostructure and uniform pore size in the range of 7.6 to 5.5 nm. NMR, IR, and TG analyses confirm that the tartardiamide group was successfully incorporated into the framework. The intrinsic chirality of L ‐tartardiamide endows the materials with unique optical activities and chiral‐recognition properties. By dissolving the materials into NaOH, the solutions show rotation of polarized light by +8.42° to +15.53°, depending on the amount of the chiral moieties in the materials. Owing to the chirality of L ‐tartardiamide, the materials exhibited chiral‐induction ability in the epoxidation of allyl alcohol, thus further demonstrating the chirality of the materials.     

表面含磺酸基的介孔分子筛SBA-15-SO3H的直接合成

 采用水热法直接合成了含磺酸基的介孔分子筛SBA－15－SO3H．XRD表征结果表明，该分子筛具有规则的、六方立柱形的中孔结构，通过酸碱滴定和XRD确定了正硅酸乙酯／有机硅的最佳合成配比为9（α＝0．1）．29SiMASNMR固体核磁结果表明，含磺酸基的有机基团Si－（CH2）3－SO3H中的硅与SBA－15骨架上的氧通过Si－O键结合，形成稳定的有机／无机组成，FT－IR谱表明：在SBA－15－SO3H表面含有质子酸中心－SO3H．N2吸附－脱附和TEM结果表明，SBA－15－SO3H具有较大的比表面积、孔容和孔径，孔大小是单一的，孔分布是高度有序的．酯化反应结果表明，与后合成法相比，直接法合成的催化剂既具有较高的稳定性，又具有简便、快捷和高效的优点．     

Boronic Acids as Bioorthogonal Probes for Site‐Selective Labeling of Proteins

Over the past two decades, bioorthogonal chemistry has become a preferred tool to achieve site‐selective modifications of proteins. However, there are only a handful of commonly applied bioorthogonal reactions and they display some limitations, such as slow rates, use of unstable or cytotoxic reagents, and side reactions. Hence, there is significant interest in expanding the bioorthogonal chemistry toolbox. In this regard, boronic acids have recently been introduced in bioorthogonal chemistry and are exploited in three different strategies: 1) boronic ester formation between a boronic acid and a 1,2‐cis diol; 2) iminoboronate formation between 2‐acetyl/formyl‐arylboronic acids and hydrazine/hydroxylamine/semicarbazide derivatives; 3) use of boronic acids as transient groups in a Suzuki–Miyaura cross‐coupling or other reactions that leave the boronyl group off the conjugation product. In this Review, we summarize progress made in the use of boronic acids in bioorthogonal chemistry to enable site‐selective labeling of proteins and compare these methods with the most commonly utilized bioorthogonal reactions.     

SBA-15介孔分子筛表面的磺酸基改性及其催化性能

 采用后合成方法，将含有巯基的化合物3－巯丙基三甲氧基硅烷（MPTMS）键合在大孔径、厚孔壁的新型纯硅介孔分子筛SBA－15表面上，经氧化和酸化后得到含有强酸性的磺酸基团的固体酸催化剂SBA－15－SO3H．用X射线衍射、红外光谱、固体核磁共振及热失重等方法对改性前后的SBA－15样品进行了表征．结果表明，改性后SBA－15分子筛的结构未发生变化，MPTMS键合于分子筛的表面，改性后的分子筛具有质子酸中心．SBA－15－SO3H催化剂对十八碳烯酸与甲醇的酯化反应具有较高的活性，催化剂上的磺酸基团在反应过程中具有较好的稳定性．     

Ligand Conformation Dictates Membrane and Endosomal Trafficking of Arginine‐Glycine‐Aspartate (RGD)‐Functionalized Mesoporous Silica Nanoparticles

Recent breakthrough research on mesoporous silica nanoparticle (MSN) materials has illustrated their significant potential in biological applications due to their excellent drug delivery and endocytotic behavior. We set out to determine if MSN, covalently functionalized with conformation specific bioactive molecules (either linear or cyclic RGD ligands), behave towards mammalian cells in a similar manner as the free ligands. We discovered that RGD immobilized on the MSN surface did not influence the integrity of the porous matrix and improved the endocytosis efficiency of the MSN materials. Through competition experiments with free RGD ligands, we also discovered a conformation specific receptor–integrin association. The interaction between RGD immobilized on the MSN surface and integrins plays an important role in endosome trafficking, specifically dictating the kinetics of endosomal escape. Thus, covalent functionalization of biomolecules on MSN assists in the design of a system for controlling the interface with cancer cells.     

In Situ Synthesis of Porous Carbons by Using Room‐Temperature,Atmospheric‐Pressure Dielectric Barrier Discharge Plasma as High‐Performance Adsorbents for Solid‐Phase Microextraction

A one‐step, template‐free method is described to synthesize porous carbons (PCs) in situ on a metal surface by using a room‐temperature, atmospheric‐pressure dielectric barrier discharge (DBD) plasma. This method not only features high efficiency, environmentally friendliness, and low cost and simple equipment, but also can conveniently realize large‐area synthesis of PCs by only changing the design of the DBD reactor. The synthesized PCs have a regulated nestlike morphology, and thus, provide a high specific surface area and high pore volume, which result in excellent adsorption properties. Its applicability was demonstrated by using a PC‐coated stainless‐steel fiber as a solid‐phase microextraction (SPME) fiber to preconcentrate polycyclic aromatic hydrocarbons (PAHs) prior to analysis by gas chromatography with flame ionization detection (GC‐FID). The results showed that the fiber exhibited excellent enrichment factors (4.1×10⁴ to 3.1×10⁵) toward all tested PAHs. Thus, the PC‐based SPME‐GC‐FID provides low limits of detection (2 to 20 ng L ^?1), good precision (<7.8 %), and good recoveries (80–115 %) for ultra‐sensitive determination of PAHs in real water samples. In addition, the PC‐coated fiber could be stable enough for more than 500 replicate extraction cycles.     

Redox‐ and Temperature‐Controlled Drug Release from Hollow Mesoporous Silica Nanoparticles

A controlled drug‐delivery system has been developed based on mesoporous silica nanoparticles that deliver anticancer drugs into cancer cells with minimized side effects. The copolymer of two oligo(ethylene glycol) macromonomers cross‐linked by the disulfide linker N,N′‐bis(acryloyl)cystamine is used to cap hollow mesoporous silica nanoparticles (HMSNs) to form a core/shell structure. The HMSN core is applied as a drug storage unit for its high drug loading capability, whereas the polymer shell is employed as a switch owing to its redox/temperature dual responses. The release behavior in vitro of doxorubicin demonstrated that the loaded drugs could be released rapidly at higher temperature or in the presence of glutathione (GSH). Thus, the dual‐stimulus polymer shell exhibiting a volume phase transition temperature higher than 37 °C can effectively avoid drug leakage in the bloodstream owing to the swollen state of the shell. Once internalized into cells, the carriers shed the polymer shell because of cleavage of the disulfide bonds by GSH, which results in the release of the loaded drugs in cytosol. This work may prove to be a significant development in on‐demand drug release systems for cancer therapy.