Sequestration of CO2 using Cu nanoparticles supported on spherical and rod-shape mesoporous silica

The CO₂ sequestration is one of the most promising solutions to tackle global warming. In this study, spherical mesoporous silica particles (MPS-S) and rod-shaped mesoporous silica particles (MPS-R) loaded with Cu nanoparticles were selectively prepared and employed for CO₂ adsorption. For the first time uniform Cu nanoparticles were incorporated into the rod-shaped mesoporous silica particles by post-synthesis modification using both N-[3-(trimethoxysilyl)propyl]ethylenediamine (PEDA) and ethylenediamine (EDA) as coupling agents. The physiochemical properties of the mesoporous and copper grifted silica composites were investigated by CHN elemental analysis, FTIR spectroscopy, thermogravimetric analysis, X-ray diffraction, energy dispersive X-ray spectroscopy (EDX), surface area analysis, scanning, transmission electron microscopy and gas analysis system (GSD 320, TERMO). The mesoporous silica shows highly ordered mesoporous structures, with the rod-shaped particles having a higher surface area than the spherical ones. Copper nanoparticles with an average diameter of 6.0 nm were uniformly incorporated into the MPS-S and MPS-R. Moreover, Cu-loaded mesoporous silica exhibits up to 40% higher CO₂ adsorption capacity than the bare MPS. The MPS-R modified with Cu nanoparticles showed a maximum CO₂ adsorption capacity of 0.62 mmol/g and the humidity showed a slight negative effect on CO₂ uptake process. The enhancement of CO₂ adsorption onto transition metal/mesoporous substrates provides basis for imminent CO₂ sequestration.     

Synthesis of hierarchical sieve-like mesoporous silica nanoparticle aggregates via centrifugal method for drug delivery system

A facile approach towards the scaled-up synthesis of a novel hierarchical sieve-like structure of mesoporous silica nanoparticle aggregates (hsMSNA) with high drug encapsulation efficiency and sustained release behaviors acting as a drug delivery system in the field of nanomedicine.     

Facile assembly of mesoporous silica nanoparticles with hierarchical pore structure for CO2 capture

A facile one-pot hydrothermal approach has been developed for the preparation of mesoporous silica nanoparticles (MSNs) with hierarchical pore structure. The PEI-modified MSNs exhibit an improved adsorption capacity for CO₂ capture.     

Dual pH and glucose sensitive gel gated mesoporous silica nanoparticles for drug delivery

A low-molecular-weight gel with dual pH and glucose sensitivity was designed as the gate controller for mesoporous silica nanoparticles (MSNs) to fabricate a smart drug delivery system. The smart gel caped MSNs could control the antidiabetic drug release via the detection of glucose and pH levels.     

Facile assembly of mesoporous silica nanoparticles with hierarchical pore structure for CO2 capture

In the work, we propose an efficient one-pot approach for synthesis of a new type of mesoporous silica nanoparticles (MSNs). That can be successfully realized by using tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) as the silica precursors and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent through a facile assembly process. The as-synthesized MSNs possess a spherical morphology with about 230 nm, a relatively high surface area of 133 m²/g, and a hierarchical pore size distribution. When applied as the sorbents, the amine-functioned MSNs demonstrate the enhanced adsorption capacity for CO₂ capture (at 1 bar, 15 vol% CO₂, up to 80.5 mg/g at 75 °C), high selectivity, and good cycling durability, benefiting from the suitable modification of polyethyleneimine.     

Functionalized mesoporous silica nanoparticles templated by pyridinium ionic liquid for hydrophilic and hydrophobic drug release application

Chemotherapy is the most common treatment for all cancer patients but this treatment poses many side effects due to lack of drug’s selectivity. To overcome this problem, utilizing a better and more effective delivery agent is the solution. Mesoporous silica nanoparticles (MSNs) emerged as a promising platform in development of drug delivery agent. This is due to its desirable properties such as tunable pores, large surface area, good biocompatibility and easy functionalization. Furthermore, these properties can be tuned through the utilization of alternative template such as pyridinium ionic liquid. Besides, by employing surface functionalization, the effectiveness of MSNs as drug delivery agent may also increase. This work reported the usage of 1-hexadecylpyridinium bromide ionic liquid as template for MSNs production and the surface of MSNs was then further functionalized via post – grafting method in order to obtain MSN – NH₂, MSN – SH and MSN – COOH as drug carrier, respectively. These functionalized MSNs were then used to study the drug loading and drug release of hydrophilic drug, gemcitabine and hydrophobic drug, quercetin. For quercetin, MSN-NH₂ had the highest drug loading percentage (72%) and slowest release (14%) in 48 h while for gemcitabine, it was found that MSN-COOH had the highest drug loading percentage (45%) and slowest release (15%) in 48 h. Based on the results, it is suggested that mesoporous silica nanoparticle with surface functionalization has suitable properties for controlled drug release which gives constant release behavior over a period of time to avoid repeated administration of drug where the drug is administered at a fixed dosage and regular time interval.     

新型SiO2/SiO2核壳型固定相的制备与评价

采用层层自组装的方法,以微米多孔硅胶小球为核,将硅胶纳米粒子多层包覆,制备了核壳型SiO2/SiO2硅胶小球.透射电子显微镜表明这种硅胶小球具有明显的核壳结构,氮气吸附实验证明该硅胶小球是典型的介孔材料,具有良好的介孔结构和窄的孔径分布.将其作为基质制备碳十八键合核壳型SiO2/SiO2色谱固定相,该固定相的碳含量与未...     

Construction of a pH-responsive drug delivery platform based on the hybrid of mesoporous silica and chitosan

Mesoporous silica nanoparticles (MSN) have been widely used for drug delivery due to their large specific surface area and excellent biocompatibility. However, the mesoporous structure of MSN would lead to the inevitable “premature release” of the drugs, and therefore the modification of MSN for controlled delivery seems to be a necessary step. Herein, chitosan (CS) was used for the surface functionalization of MSN via amidation reaction, and the introduced CS could function as a “gatekeeper” and the drug of methotrexate (MTX) might be encapsulated in the mesopores of MSN. As a result, the “premature release” of the encapsulated MTX could be effectively circumvented with the aid of the CS cap. More importantly, the drug delivery from the hybrid of MSN and CS (MSN/CS) can be endowed with pH-sensitivity by the introduction of CS because the amide bonding between CS and MSN is highly pH-sensitive. The cumulative release of MTX from the MSN/CS is more pronounced at pH 5.0 (80.86%) than those at pH 6.8 (40.46%) and pH 7.4 (18.25%).     

Preparation of mesoporous silica nanoparticle with tunable pore diameters for encapsulating and slowly releasing eugenol

Fragrances are frequently added to a variety of products, including food, cosmetics and health products. However, the high volatility and instability of essence limit its application in some fields. In this study, mesoporous silica nanoparticles (MSNs) were prepared to encapsulate eugenol, which could reduce the volatilization of the fragrance molecules. A facile approach was presented to synthesize MSNs with three different pore diameters for encapsulating eugenol. In addition, the properties of MSNs including mean particle size, morphology, encapsulating efficiency and release tendency were characterized. Results showed that the larger the pore diameters of MSNs, the more aromatic molecules were adsorbed. Furthermore, the release mechanism was described as the smaller the pore diameters of MSNs, the slower the release of eugenol.     

Synthesis of sulfated titania supported on mesoporous silica using direct impregnation and its application in esterification of acetic acid and n-butanol

A new method has been developed for the preparation of sulfated titania (S-TiO₂) supported on mesoporous silica. The use of direct exchange of metal containing precursors for the surfactants in the as-synthesized MCM-41 substrate produced a product with high sulfur content without serious blockage of the pore structure of MCM-41. The pore sizes and volumes of the resultant S-TiO₂/MCM-41 composites were found to vary markedly with the loading of TiO₂. The strong acidic character of the composites obtained was examined by using them as catalysts for the esterification of acetic acid and n-butanol.     

以伯胺为模板剂合成含铁介孔分子筛FeHMS

以非离子型表面活性剂伯胺为模板剂合成了含铁介孔分子筛FeHMS,并对其结构和形态进行了表征。发现FeHMS的颗粒比SiHMS小,粒子表面更为光滑。除了2.5nm的介孔外,FeHMS还原10nm左右的孔。FeHMS介孔分子筛在脱除模板剂之前,铁主要处于四面体配位状态的骨架位,经焙烧脱除模板剂之后,部分铁由骨架位迁移到孔壁表面。用酸化的乙醇溶液抽提脱除模板剂,能更有效地让铁保留在四面体配位状态的骨架位上。高温脱除模板剂后,孔壁表面的铁物种处于一种高分散的状态。此外还研究了HMS类介孔分子筛材料的水热稳定性,发现铁的引入可改善介孔分子筛材料的水热稳定性。     

Preparation of luminescent Cy5 doped core-shell SFNPs and its application as a near-infrared fluorescent marker

Cy5 dye is widely used as a biomarker in the research fields of life science because of its excitation at wavelengths above 600 nm where autofluorescence of bio-matter is much reduced. However, Cy5 dye could not be encapsulate into silica directly to form stable nanoparticles by using of the traditional methods. In this paper, an improved method had been developed to prepare Cy5 dye doped core-shell silica fluorescent nanoparticles (SFNPs), employing biomolecules conjugated Cy5 as the core material and silica coating produced from the hydrolysis TEOS (tetraethyl orthosilicate) in the water-in-oil microemulsion. To obtain stable Cy5 dye doped SFNPs with core-shell structure, five kinds of biomolecules with different iso-electric point (pI) have been selected to conjugate Cy5 for preparation of core-shell SFNPs. Results demonstrated that very bright and photostable Cy5 doped core-shell SFNPs could be both prepared by use of positive polysine conjugated Cy5 or IgG conjugated Cy5 as the core material, respectively. IgG conjugated Cy5 doped core-shell SFNPs was selected as a demonstration to be characterized and applied as a near-infrared fluorescent marker in cell recognition. The results showed that Cy5 doped core-shell SFNPs prepared by conjugating with a positive biomolecules IgG as the core material were luminescent and stable. About 110 Cy5 dye molecules could be doped in one nanoparticle with size of 42 ± 5 nm. The breast cancer cells had been selectively recognized by use of the near-infrared fluorescent marker based on the Cy5-IgG doped core-shell SFNPs. And the results demonstrated that this Cy5 doped core-shell SFNPs fluorescence marker was superior to the pure Cy5 dye marker for cell recognition in photostability and detection sensitivity.     

利用Triton X-100合成介孔二氧化硅及其形貌研究

以非离子型表面活性剂Triton X-100为模板剂,正硅酸乙酯为硅源,合成了介孔二氧化硅分子筛.利用XRD、N2吸附—脱附、SEM、以及TG-DTA对样品进行了表征,结果表明合成的材料具有有序介孔结构、高比表面积及高孔容。同时比较了不同条件下所得产物的形貌结构,并分析了它们的形成机理。     

Peroxidase-like activity of mesoporous silica encapsulated Pt nanoparticle and its application in colorimetric immunoassay

Nanomaterial-based artificial enzymes have received great attention in recent year due to their potential application in immunoassay techniques. However, such potential is usually limited by poor dispersion stability or low catalytic activity induced by the capping agent essentially required in the synthesis. In an attempt to address these challenges, here, we studied the novel Pt nanoparticles (NPs) based peroxidase-like mimic by encapsulating Pt NP in mesoporous silica (Pt@mSiO₂ NPs). Compared with other nanomaterial-based artificial enzymes, the obtained Pt@mSiO₂ NPs not only exhibit high peroxidase-like activity but also have good dispersion stability in buffer saline solution when grafted with spacer PEG. Results show that when the thickness of silica shell is about 9 nm the resulting Pt@mSiO₂ NPs exhibit the catalytic activity similar to that of Pt NPs, which is approximately 26 times higher than that of Fe₃O₄ NPs (in terms of K_cat for H₂O₂). Due to the protection of silica shell, the subsequent surface modification with antibody has little effect on their catalytic activity. The analytical performance of this system in detecting hCG shows that after 5 min incubation the limit of detection can reach 10 ng mL⁻¹ and dynamic linear working range is 5–200 ng mL⁻¹. Our findings pave the way for design and development of novel artificial enzyme labeling.     

Synthesis of SiO2@SiO2 core-shell microspheres using urea-formaldehyde polymers as the templates for fast separation of small solutes and proteins

The monodisperse superficially porous core-shell silica microspheres (CSSMs) with controllable shell thickness and pore size were synthesized by an improved polymerization-induced colloid aggregation (PICA) approach for fast separation of small solutes and proteins.     

Preparation of functional ordered mesoporous carbons and their application as the QCM sensor with ultra-low humidity

Ordered mesoporous carbon (OMCs) FDU-15 was synthesized through an EISA (Evaporation-Induced Self-Assembly) method, and the oxidized OMCs (FDU-15-COOH) were obtained by subsequent oxidation treatments in liquid phase to introduce functional groups. The samples were characterized by XRD, TEM, FT-IR and nitrogen adsorption-desorption test. The low humidity sensing performances of FDU-15 and FDU-15-COOH thin films were investigated by using a quartz crystal microbalance (QCM) transducer. The responses of FDU-15-COOH is higher than that of the pristine FDU-15 at very low humidity (< 729 ppm_v) with high long-term stability, implying that FDU-15-COOH is a good candidate for low humidity QCM sensor.     

Periodic mesoporous organosilicas with co-existence of diurea and sulfanilamide as an effective drug delivery carrier

In this article we report the synthesis of new periodic mesoporous organosilicas (PMOs) with the co-existence of diurea and sulfanilamide-bridged organosilica that are potentially useful for controlled drug release system. The materials possess hexagonal pores with a high degree of uniformity and show long-range order as confirmed by the measurements of small-angle X-ray scattering (SAXS), N₂ adsorption isotherms, and transmission electron microscopy(TEM). FT-IR and solid state ²⁹Si MAS and ¹³C CP MAS NMR spectroscopic analyses proved that the bridging groups in the framework are not cleaved and covalently attached in the walls of the PMOs. It was found that the organic functionality could be introduced in a maximum of 10 mol% with respect to the total silicon content and be thermally stable up to 230 °C. The synthesized materials were shown to be particularly suitable for adsorption and desorption of hydrophilic/hydrophobic drugs from a phosphate buffer solution at pH 7.4.     

High-temperature synthesis of highly hydrothermal stable mesoporous silica and Fe-SiO2 using ionic liquid as a template

Mesoporous silicas and Fe-SiO₂ with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150-190 °C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 °C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 °C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe-SiO₂ has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 °C for 12 d or steam-treated at 600 °C for 6 h.     

有序介孔石墨相氮化碳的合成及催化Knoevenagel缩合研究

以二氰二胺为前驱体,不同晶化温度的SBA-15为硬模板,用纳米浇铸法合成了一系列比表面和孔体积可调的介孔石墨相氮化碳(CND-SBA15)。通过N2吸-脱附、TEM、小角XRD、XPS、FT IR、CO2-TPD等手段研究了材料的织构、微观形貌、孔结构的有序性、化学组成和碱性质等。在以苯甲醛和丙二腈为底物的Knoevenagel缩合反应中,CND-SBA15材料表现出了很好的催化活性和稳定性。