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https://www.readbyqxmd.com/read/28449545/structural-variety-and-adsorptive-properties-of-mesoporous-silicas-with-immobilized-oligosaccharide-groups
#1
Iryna Trofymchuk, Nadiia Roik, Lyudmila Belyakova
In this research, we report on the synthesis of mesoporous silicas with various quantities of immobilized oligosaccharide groups and different pore ordering degree. The hydrothermal co-condensation of tetraethyl orthosilicate and β-cyclodextrin-containing organosilane in the presence of cetyltrimethylammonium bromide template was employed. The purpose of this investigation was to show the opportunity of increasing β-cyclodextrin content in silica matrix by changing the molar ratio of initial reagents during organosilane synthesis and to determine whether the enhancing of immobilized groups on the surface influences on model aromatic compound adsorption from water...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28449264/macroscopically-oriented-porous-materials-with-periodic-ordered-structures-from-zeolites-and-metal-organic-frameworks-to-liquid-crystal-templated-mesoporous-materials
#2
REVIEW
Joonil Cho, Yasuhiro Ishida
Porous materials with molecular-sized periodic structures, as exemplified by zeolites, metal-organic frameworks, or mesoporous silica, have attracted increasing attention due to their range of applications in storage, sensing, separation, and transformation of small molecules. Although the components of such porous materials have a tendency to pack in unidirectionally oriented periodic structures, such ideal types of packing cannot continue indefinitely, generally ceasing when they reach a micrometer scale...
April 27, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28448441/characterization-of-compounds-with-tumor-cell-proliferation-inhibition-activity-from-mushroom-phellinus-baumii-mycelia-produced-by-solid-state-fermentation
#3
Henan Zhang, Qian Shao, Wenhan Wang, Jingsong Zhang, Zhong Zhang, Yanfang Liu, Yan Yang
The inhibition of tumor-cell proliferationbyan organicsolvent extract from the solid-state fermentation of Phellinus baumii mycelia inoculated in rice medium was investigated in vitro. The active compounds inhibiting tumor-cell proliferation were characterized. Results revealed that all (petroleum ether, chloroform, ethyl acetate, and butanol) fractions inhibited tumor-cell proliferation in a dose-dependent fashion. The ethyl acetate extract had the highest inhibitory effecton tumor-cell proliferation, and the butanol fraction had the lowest...
April 27, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28447768/bio-inspired-bright-structurally-colored-colloidal-amorphous-array-enhanced-by-controlling-thickness-and-black-background
#4
Masanori Iwata, Midori Teshima, Takahiro Seki, Shinya Yoshioka, Yukikazu Takeoka
Inspired by Steller's jay, which displays angle-independent structural colors, angle-independent structurally colored materials are created, which are composed of amorphous arrays of submicrometer-sized fine spherical silica colloidal particles. When the colloidal amorphous arrays are thick, they do not appear colorful but almost white. However, the saturation of the structural color can be increased by (i) appropriately controlling the thickness of the array and (ii) placing the black background substrate...
April 26, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28447683/self-assembled-hybrid-elastin-like-polypeptide-silica-nanoparticles-enable-triggered-drug-release
#5
Wei Han, Ashutosh Chilkoti, Gabriel P López
The discovery of biomimetic polypeptides that enable the biomineralization of synthetic and biosynthetic materials has resulted in the development of hybrid materials that incorporate inorganic components for potential application in drug delivery, enzyme immobilization, and surface modification. Here, we describe an approach that uses micellar assemblies of an elastin-like polypeptide (ELP) modified with silica-promoting sequences and drug conjugates that are subsequently encapsulated within a silica matrix...
April 27, 2017: Nanoscale
https://www.readbyqxmd.com/read/28447548/preparation-of-wormlike-polymeric-nanoparticles-coated-with-silica-for-delivery-of-methotrexate-and-evaluation-of-anticancer-activity-against-mcf7-cells
#6
Farhad Gharebaghi, Naser Dalali, Ebrahim Ahmadi, Hossein Danafar
Methotrexate is one of the most effective drugs that is commonly used in the treatment of cancer. However, its application is limited due to low solubility, high toxicity and rapid metabolism. Therefore, in the present study, worm-like polymeric nanoparticles as carrier of methotrexate were prepared using biodegradable copolymers (mPEG-PCL). The impact of nanoparticles' geometry on the loading, delivery and drug's anti-cancer activity was investigated. The di-block copolymer mPEG-PCL was being synthesized by a ring opening polymerization of ɛ-caprolactone in the presence of mPEG as the initiator and Sn(oct)2 as the catalyst...
April 2017: Journal of Biomaterials Applications
https://www.readbyqxmd.com/read/28446331/mechanistic-investigations-of-c-h-activations-on-silica-supported-co-ii-sites-in-catalytic-propane-dehydrogenation
#7
Deven P Estes
Catalytic reactions involving C-H bond activations are central to the chemical industry. One such example, alkane dehydrogenation, has recently become very important due to shortfalls in propene production and a large supply of cheap propane. However, current technologies are inefficient and have only moderate selectivity. In order to understand how to improve currently used catalysts, we must know more about the mechanism by which propane is dehydrogenated. We show here that Co(<small>ii</small>) sites on silica are good catalysts for the dehydrogenation of propane, having high activity and selectivity that is reasonably stable over the course of 10 h...
April 26, 2017: Chimia
https://www.readbyqxmd.com/read/28446021/evaporation-of-drops-containing-silica-nanoparticles-of-varying-hydrophobicity-exploiting-particle-particle-interactions-for-additive-free-tunable-deposit-morphology
#8
Manos Anyfantakis, Damien Baigl, Bernard P Binks
We describe the systematic and quantitative investigation of a large number of patterns that emerge after the evaporation of aqueous drops containing fumed silica nanoparticles of varying wettability, for an extended particle concentration range. We show that for a chosen system, the dry pattern morphology is mainly determined by particle-particle interactions (Coulomb repulsion and hydrophobic attraction) in the bulk. These depend on both particle hydrophobicity as well as particle concentration within the drop...
April 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28445998/infrared-raman-and-magnetic-resonance-spectroscopic-study-of-sio2-c-nanopowders
#9
Dariya Savchenko, Vladimir Vorliček, Ekaterina Kalabukhova, Aleksandr Sitnikov, Andrii Vasin, Dmytro Kysil, Stanislav Sevostianov, Valentyn Tertykh, Alexei Nazarov
Optical and magnetic properties of SiO2:C nanopowders obtained by chemical and thermal modification of fumed silica were studied by Fourier transform infrared spectroscopy, Raman, continuous wave (CW) electron paramagnetic resonance (EPR), echo-detected EPR and pulsed electron nuclear double resonance (ENDOR) spectroscopy. Two overlapping signals of Lorentzian lineshape were detected in CW EPR spectra of the initial SiO2:C. The EPR signal at g = 2.0055(3) is due to the silicon dangling bonds, which vanishes after thermal annealing, and the second EPR signal at g = 2...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28445169/continuous-size-and-shape-control-synthesis-of-hollow-silica-nanoparticles-enabled-by-a-microreactor-assisted-rapid-mixing-process
#10
Yujuan He, Ki-Joong Kim, Chih-Hung Alex Chang
Hollow silica nanoparticles (HSNPs) were synthesized using a microreactor-assisted system with a hydrodynamic focusing micromixer (HFM). Due to the fast mixing of each precursor in the system, the PAA thermodynamic-locked (TML) conformations were protected from their random aggregations by the immediately initiated growth of silica shells. When altering the mixing time through varying flow rates and flow rate ratios, the different degrees of the aggregation of PAA TML conformations were observed. The globular and necklace-like TML conformations were successfully captured by modifying the PAA concentration at the optimized mixing condition...
April 26, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28444786/targeted-photodynamic-therapy-with-a-folate-sensitizer-assembly-produced-from-mesoporous-silica
#11
Salvatore Sortino, Chunfang Zhou, Damien Afonso, Sabrina Valetti, Adam Feiler, Venera Cardile, Adriana Graziano, Sabrina Conoci
A mesoporous silica material prepared by using folic acid (FA) as a template enables the effective encapsulation of meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in its interior. Combination of steady-state and time-resolved absorption and emission spectroscopy demonstrate that FA and TCPP are released from the silica material to aqueous phase in the form of a non-covalent assembly. This assembly does not form by simple mixing of the two components in the absence of silica, suggesting the key role of the material in the assembling process...
April 26, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28444018/effect-of-nanotechnology-in-self-etch-bonding-systems-on-the-shear-bond-strength-of-stainless-steel-orthodontic-brackets
#12
Shaza M Hammad, Noha El-Wassefy, Ahmed Maher, Shafik M Fawakerji
OBJECTIVE: To evaluate the effect of silica dioxide (SiO2) nanofillers in different bonding systems on shear bond strength (SBS) and mode of failure of orthodontic brackets at two experimental times. METHODS: Ninety-six intact premolars were divided into four groups: A) Conventional acid-etch and primer Transbond XT; B) Transbond Plus self-etch primer; and two self-etch bonding systems reinforced with silica dioxide nanofiller at different concentrations: C) Futurabond DC at 1%; D) Optibond All-in-One at 7%...
February 2017: Dental Press Journal of Orthodontics
https://www.readbyqxmd.com/read/28443913/the-effect-of-surface-roughness-and-viscoelasticity-on-rubber-adhesion
#13
A Tiwari, L Dorogin, A I Bennett, K D Schulze, W G Sawyer, M Tahir, G Heinrich, B N J Persson
Adhesion between silica glass or acrylic balls and silicone elastomers and various industrial rubbers is investigated. The work of adhesion during pull-off is found to strongly vary depending on the system, which we attribute to the two opposite effects: (1) viscoelastic energy dissipation close to an opening crack tip and (2) surface roughness. Introducing surface roughness on the glass ball is found to increase the work of adhesion for soft elastomers, while for the stiffer elastomers it results in a strong reduction in the work of adhesion...
April 26, 2017: Soft Matter
https://www.readbyqxmd.com/read/28443896/an-msn-peg-ip-drug-delivery-system-and-il13r%C3%AE-2-as-targeted-therapy-for-glioma
#14
Jinlong Shi, Shiqiang Hou, Jianfei Huang, Shanshan Wang, Wei Huan, Chuanjun Huang, Xiaojiang Liu, Rui Jiang, Wenbo Qian, Jingjing Lu, Xiubing Wang, Wei Shi, Rongqin Huang, Jian Chen
A combination of gene therapy and chemotherapy has recently received interest as a targeted therapy for glioma. A mesoporous silica nanoparticle (MSN)-based vehicle coated with IL13Rα2-targeted peptide (IP) using polyethylene glycol (PEG), MSN-PEG-IP (MPI), was constructed and confirmed as a potential glioma-targeted drug delivery system in vitro. In this work, tissue microarray (TMA) results revealed that IL13Rα2 was over-expressed in human glioma tissues and that high expression of IL13Rα2 in patients was associated with poor survival...
April 26, 2017: Nanoscale
https://www.readbyqxmd.com/read/28443884/monolithic-porous-magnesium-silicide
#15
N Hayati-Roodbari, R J F Berger, J Bernardi, S Kinge, N Hüsing, M S Elsaesser
Macroporous magnesium silicide monoliths were successfully prepared by a two-step synthesis procedure. The reaction of gaseous magnesium vapor with macro-/mesoporous silicon, which was generated from hierarchically organized meso-/macroporous silica by a magnesiothermic reduction reaction, resulted in monolithic magnesium silicide with a cellular, open macroporous structure. By adjusting the reaction conditions, such as experimental set-up, temperature and time, challenges namely loss of porosity or phase purity of Mg2Si were addressed and monolithic magnesium silicide with a cellular network builtup was obtained...
April 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28443528/understanding-medusahead-low-intake-and-palatability-through-in-vitro-digestibility-and-fermentation-kinetics
#16
J J Montes-Sánchez, J J Villalba
The low intake of medusahead grass (Taeniatherum caput-medusae ssp. asperum) by sheep is attributed to the high silica content of the plant and its negative impact on digestibility, making this weed a successful competitor in grazed plant communities. The goals of this study were to determine the influence of (1) plant maturity stage (from late vegetative stage to beginning of senescence and thatch), (2) particle size (1, 5, 10 and 20 mm), and (3) high-quality feeds (alfalfa hay and a high-energy concentrate) on fermentation kinetics and apparent digestibility of medusahead relative to palatable feeds (alfalfa and tall fescue hays, and high-energy concentrates)...
April 26, 2017: Animal: An International Journal of Animal Bioscience
https://www.readbyqxmd.com/read/28443502/fe3o4-sio2-kit-6-as-an-efficient-and-reusable-catalyst-for-the-synthesis-of-novel-derivatives-of-3-3-aryl-1-phenyl-1h-pyrazol-4-yl-methylene-bis-1h-indole
#17
Mohammad Nikpassand, Leila Zare Fekri, Mozhdeh Nabatzadeh
Korea advanced institute of science and technology cubic ordered mesoporous silica (KIT-6 mesoporous) silica coated magnetite nanoparticles, is an effective, eco-benign and recyclable catalyst for the electrophilic substitution reactions of indoles with various synthetized aldehydes to afford the corresponding novel diindolylmethanes in high yields and short reaction times. The catalyst can be recovered and reused without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification...
April 25, 2017: Combinatorial Chemistry & High Throughput Screening
https://www.readbyqxmd.com/read/28443326/ionic-liquid-silica-precursors-via-solvent-free-sol-gel-process-and-their-application-in-epoxy-amine-network-a-theoretical-experimental-study
#18
Magdalena Perchacz, Ricardo Keitel Donato, Leandro Seixas, Alexander Zhigunov, Rafal Konefal, Magdalena Serkis-Rodzeń, Hynek Benes
This work describes the solvent-free sol-gel synthesis of epoxy-functionalized silica-based precursors, in the presence of 1-butyl-3-methylimidazolium-based ionic liquids (ILs) containing different anions - chloride (Cl(-)) and methanesulfonate (MeSO3(-)). The IL-driven sol-gel mechanisms were investigated in details using experimental characterizations ((29)Si NMR and ATR FTIR spectroscopy) and a theoretical computational method based on density functional theory (DFT). We observed a complex IL's influence on both hydrolysis and condensation steps, involving especially H-bonding and Coulomb coupling stabilization of the process intermediates...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28442903/magnetic-and-ph-dual-responsive-mesoporous-silica-nanocomposites-for-effective-and-low-toxic-photodynamic-therapy
#19
Jieqiong Zhan, Zhiqiang Ma, Dan Wang, Xinfang Li, Xiangui Li, Lijing Le, Anfeng Kang, Pengwei Hu, Lan She, Feng Yang
Nonspecific targeting, large doses and phototoxicity severely hamper the clinical effect of photodynamic therapy (PDT). In this work, superparamagnetic Fe3O4 mesoporous silica nanoparticles grafted by pH-responsive block polymer polyethylene glycol-b-poly(aspartic acid) (PEG-b-PAsp) were fabricated to load the model photosensitizer rose bengal (RB) in the aim of enhancing the efficiency of PDT. Compared to free RB, the nanocomposites (polyethylene glycol-b-polyaspartate-modified rose bengal-loaded magnetic mesoporous silica [RB-MMSNs]) could greatly enhance the cellular uptake due to their effective endocytosis by mouse melanoma B16 cell and exhibited higher induced apoptosis although with little dark toxicity...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28441616/core-shell-hierarchical-mesostructured-silica-nanoparticles-for-gene-chemo-synergetic-stepwise-therapy-of-multidrug-resistant-cancer
#20
Lijun Sun, Dangge Wang, Yu Chen, Liying Wang, Ping Huang, Yaping Li, Ziwei Liu, Heliang Yao, Jianlin Shi
The design and synthesis of hierarchically nanoporous structures for the co-encapsulation and sequential releases of different cargos are still great challenges in biomedical applications. In this work, we report on the elaborate design and controlled synthesis of a unique core-shell hierarchical mesoporous silica/organosilica nanosystem, in which there are large and small mesopores separately present in the shell and core, facilitating the independent encapsulations of large (siRNA) and small (doxorubicin) molecules, respectively...
April 18, 2017: Biomaterials
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