SiO2气凝胶/壳聚糖复合药物载体材料的制备和表征

采用常压干燥法制备了SiO2气凝胶,所得气凝胶为介孔结构,比表面积618.8m2/g,孔径分布5～20nm.以SiO2气凝胶为原料,通过静电吸附法制备了SiO2气凝胶/壳聚糖复合药物载体材料,采用扫描电镜(SEM)、红外光谱(FTIR)等对复合材料的结构形貌进行了分析,研究了复合材料对硫酸庆大霉素药物的担载和释放性能.结果表明,所得SiO2气凝胶/壳聚糖复合材料为多孔网络结构,其中,由450℃处理的SiO2气凝胶制得的气凝胶/壳聚糖复合材料对硫酸庆大霉素具有较好的药物担载和缓释性能.     

染料敏化太阳电池有序介孔SiO2/离子液体凝胶电解质的研究

以P123为模板剂,采用溶胶-凝胶法制备有序介孔SiO2,用N2吸附、扫描电镜及透射电镜对样品进行分析.结果表明,制备的介孔SiO2呈短棒状,具有有序柱状孔结构,平均孔径为5.75nm.有序介孔SiO2固化二元离子液体(1-甲基-丙基咪唑碘/1-甲基-己基咪唑碘)形成凝胶电解质.由于凝胶电解质中离子液体在介孔SiO2的孔道中有序排列,使凝胶电解质I3-的扩散系数增大,从而降低了电解质的内阻,抑制了染料敏化纳晶多孔膜-凝胶电解质界面的复合反应,使凝胶电解质染料敏化太阳电池具有较大的开路电压和填充因子,光电转换效率达到5.22%.     

新型SiO_2基微/介孔材料的合成及其对集成电路生产中VOCs废气的吸附研究

采用新型SiO2基微/介孔材料为吸附剂,针对集成电路(Integrated Ciruit,IC)产业中废气排放的特点,以丙酮、苯、甲苯为挥发性有机化合物(VOCs)的典型,进行了一系列吸附实验.用气相色谱定时测取VOCs获得动态穿透曲线,就各VOCs分别在SiO2基微/介孔材料、疏水沸石、活性炭3种吸附荆上的吸附以及SiO2基微/介孔材料对3种不同VOCs的吸附进行了研究,同时考察了水蒸汽脱附对该材料吸附性能的影响.实验结果显示,该吸附剂在对VOCs的吸附中较疏水沸石FX-I和活性炭有着明显的优势,主要表现在透过时间的延迟和传质区长度的缩短.     

高比表面积Ag掺杂SiO2气凝胶的制备及表征

以正硅酸乙酯（TEOS）为前驱体,硝酸银为掺杂剂,采用酸碱两步催化sol—gel方法,获得掺杂纳米Ag微晶的SiO2气凝胶,其中银的掺入量在1％-30％wt范围内可控。用红外光谱（IR）、透射电子显微镜（TEM）、X射线荧光（XRF）、X射线衍射（XRD）和比表面积仪（BET）技术分析了气凝胶的结构组成和掺杂物质的存在形式。测量显示,Ag—SiO2气凝胶平均孔径在15nm左右,比表面积在500m^2／g以上;掺杂物以单质银微晶形式存在,微晶大小在50nm左右。     

可降解聚酯PBS/接枝有序介孔SiO2纳米复合材料的制备及其表征

为了研究有序介孔SiO2对可降解聚酯PBS(聚丁二酸丁二醇酯)力学性能的影响,采用经过修饰后的有序介孔SiO2与PBS熔融共混挤出造粒制备复合材料,通过FTIR、TG、SEM和力学性能分析,有效地表征了复合材料,分析研究了修饰后有序介孔SiO2不同添加比例对材料力学性能的影响.结果表明,有序介孔SiO2的加入可以改善材料的韧性、刚性和强度,添加质量分别为1%时效果最好;而且,明显改善了颗粒在基体中的分散性及基体与颗粒之间界面的相容性,使复合材料的性能得到提高.     

纳米多孔SiO2气凝胶的常压制备及应用

采用多聚硅(E-40)为前驱体摸索了用溶胶-凝胶方法制备SiO2气凝胶的不同反应条件,探索和采用了常压干燥技术.在免除了昂贵繁琐的超临界干燥过程之后,气凝胶的制备成本下降,生产效率提高,并能成规模批量生产多种规格的SiO2气凝胶.采用适当的方法将SiO2气凝胶与聚酰亚氨和无纺布等材料进行复合,制成能耐高温的柔性隔热保温薄膜和高效吸附材料.     

Ni/SiO2介孔复合体的组装与光吸收性质研究

采用溶胶-凝胶方法制备二氧化硅介孔固体,通过镍的硝酸盐溶液浸泡、干燥和随后氢热还原法,形成Ni/SiO2介孔复合体.根据DSC,XRD,TEM表征结果,纳米Ni颗粒尺寸为7～9nm,均匀地分布于SiO2介孔基体中.随着热处理温度提高,纳米颗粒尺寸增大,Ni/SiO2介孔复合体光吸收边明显发生红移.     

双介孔SiO2的制备及表征

以正硅酸乙酯(TEOS)为硅源,十六烷基三甲基溴化铵(CTAB)为模板剂,采用溶胶-凝胶法制备了具有双介孔独立分布的SiO2,并用FT-IR、HRTEM、BET等方法对SiO2进行了表征.结果表明,双介孔SiO2中存在大量无序排列的2～3nm的小介孔和18nm左右的大介孔,具有高比表面积(716.4～968.6m2/g)和大孔(1.03～1.63mL/g):通过改变氨水及模板剂的用量可以实现对孔分布的调控.     

双介孔SiO_2的原位合成及表征

以富含大孔或大介孔结构的硅胶为原料,在其上通过原位晶化合成具有小介孔-大介孔双孔分布的复合SiO2,并利用N2吸附-脱附、X射线衍射、扫描电镜、透射电子显微镜等手段对SiO2的物化性能和孔分布进行了表征。结果表明,所制备的样品具有双孔分布,孔径分别在3和45nm左右;小介孔的孔结构与MCM-41介孔类似,负载于硅胶表面及大孔孔壁上;大介孔的孔径较硅胶孔径有所减小,但未被完全填充堵塞。通过改变TEOS/大孔硅胶及CTAB/TEOS的配比可以实现对双介孔SiO2孔分布的调控。     

m-PH-SiO2/Nafion复合膜的质子导电性

为提高Nafion膜在中温段的质子导电性,用溶胶-凝胶法制备比表面积为386 m2/g掺磷中孔SiO2 (m-PH- SiO2),并与Nafion的N,N二甲基甲酰胺溶液混合,重铸法制备不同m-PH-SiO2含量的m- PH- SiO2/Nafion复合膜.用N2-吸附脱附和TEM表征m-PH- SiO2的介孔结构,S...     

介孔二氧化硅纳米复合材料的研究进展

介绍了近年来介孔二氧化硅复合材料的研究趋势与发展方向。介孔二氧化硅材料作为研究时间最长、技术最成熟的介孔材料,对整个介观材料的理论和材料设计具有重要意义。阐述了介孔二氧化硅材料的主要合成方法及其原理,着重从材料复合方式以及相应材料的特点、相关应用等方面的研究进展进行了综述,探讨了现有的问题,并且对未来介孔材料的发展趋势进行了展望。     

Study of mesoporous silica/magnetite systems in drug controlled release

Ordered mesoporous materials like SBA-15 have a network of channels and pores with well-defined size in the nanoscale range. This particular silica matrix pore architecture makes them suitable for hosting a broad variety of compounds in very promising materials in a range of applications, including drug release magnetic carriers. In this work, magnetic nanoparticles embedded into mesoporous silica were prepared in two steps: first, magnetite was synthesized by oxidation-precipitation method, and next, the magnetic nanoparticles were coated with mesoporous silica by using nonionic block copolymer surfactants as structure-directing agents. The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N(2) adsorption, and scanning electron microscopy (SEM). The influence of magnetic nanoparticles on drug release kinetics was studied with cisplatin, carboplatin, and atenolol under in vitro conditions in the absence and in the presence of an external magnetic field (0.25 T) by using NdFeB permanent magnet. The constant external magnetic field did not affect drug release significantly. The low-frequency alternating magnetic field had a large influence on the cisplatin release profile.     

Sol-gel synthesis, microstructure and adsorption properties of hollow silica spheres

Spherical colloidal particles with a hollow interior and a mesoporous shell are particularly useful for drug delivery and release because such spheres combine the unique properties of hollow interior (for storing the drug) with mesoporous shell (for controlled release). Hollow silica spheres (HSS) with a mesoporous shell were prepared via a sol-gel process in the presence of dual templates polystyrene spheres and cetyltrimethylammonium bromide for creating the hollow core and mesopore shell. The effect of the ratio of silica precursor over polystyrene spheres on particle morphology and pore structure of the HSS was investigated. The adsorption kinetics of methyl blue on the HSS was evaluated and correlated with the mesoporous shell structure.     

Controlled release of phenytoin for epilepsy treatment from titania and silica based materials

Template technique was used to obtain well ordered nanostructured materials: mesoporous silica and nanostructured titania tubes. This technique permits the synthesis of solids with controlled mesoporosity, where a large variety of molecules that have therapeutic activity can be hosted and further released to specific sites. In this work phenytoin (PH), a drug used in epilepsy treatment, was loaded in ordered mesoporous silica (SBA 15) and nanostructured titania tubes (TiO₂). The pure materials and those containing PH were characterized by X-ray diffraction, FTIR spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N₂ adsorption–desorption at 77 K. In order to determine the loading capacity of the antiepileptic drug on these silica- and titania-based materials, the loading and release of PH was investigated using UV–vis spectroscopy. Tubular structures were found for the titania samples, for which the X-ray diffractograms showed to be formed by anatase and rutile phases. On the other hand, an amorphous phase was found in the silica sample. A highly ordered hexagonal structure of 1D cylindrical channels was also observed for this material. Loaded PH showed a good stability inside the used materials as observed by spectroscopy analysis. The adsorption and desorption of PH are faster in nanostructured TiO₂ tubes than in mesoporous silica matrix.     

Structure and functionalization of mesoporous bioceramics for bone tissue regeneration and local drug delivery

This review article describes the importance of structure and functionalization in the performance of mesoporous silica bioceramics for bone tissue regeneration and local drug delivery purposes. Herein, we summarize the pivotal features of mesoporous bioactive glasses, also known as 'templated glasses' (TGs), which present chemical compositions similar to those of conventional bioactive sol-gel glasses and the added value of an ordered mesopore arrangement. An in-depth study concerning the possibility of tailoring the structural and textural characteristics of TGs at the nanometric scale and their influence on bioactive behaviour is discussed. The highly ordered mesoporous arrangement of cavities allows these materials to confine drugs to be subsequently released, acting as drug delivery devices. The functionalization of mesoporous silica walls has been revealed as the cornerstone in the performance of these materials as controlled release systems. The synergy between the improved bioactive behaviour and local sustained drug release capability of mesostructured materials makes them suitable to manufacture three-dimensional macroporous scaffolds for bone tissue engineering. Finally, this review tackles the possibility of covalently grafting different osteoinductive agents to the scaffold surface that act as attracting signals for bone cells to promote the bone regeneration process.     

Observation of quantum confinement effect on ZnO embedded mesoporous silica

Nonionic surfactant as liquid organic template and tetraethoxysilane as silica precursor were used for the synthesis of mesoporous silica with ordered arrangement of nanopores (diameters are about 1-6 nm). The synthesized mesoporous silica was used as the template for the synthesis of ZnO nanoparticles using zinc acetylacetonate as ZnO precursor. The as synthesized ZnO incorporated in the mesoporous silica nanocomposite were analyzed using X-ray diffraction, TEM and Photoluminescent spectrum. ZnO introduction has no extensive influence on the mesoporous structure of silica. Quantum confinement effects are observed in the case of ZnO nanoparticles embedded in mesoporous silica. The particle size of ZnO is about 3.2 nm. The band gap is broadening to 3.47 eV.     

Tuning mesoporous silica dissolution in physiological environments: a review

Matrix degradation has a major impact on the release kinetics of drug delivery systems. Regarding ordered mesoporous silica materials for biomedical applications, their dissolution is an important parameter that should be taken into consideration. In this paper, we review the main factors that govern the mesoporous silica dissolution in physiological environments. We also provide the necessary knowledge to researchers in the area for tuning the dissolution rate of those matrices, so the degradation could be controlled and the material behaviour optimised.     

Mesoporous Silica Nanoparticles for Intracellular Controlled Drug Delivery

The application of nanotechnology in the field of drug delivery has attracted much attention in the latest decades. Recent breakthroughs on the morphology control and surface functionalization of inorganic‐based delivery vehicles, such as mesoporous silica nanoparticles (MSNs), have brought new possibilities to this burgeoning area of research. The ability to functionalize the surface of mesoporous‐silica‐based nanocarriers with stimuli‐responsive groups, nanoparticles, polymers, and proteins that work as caps and gatekeepers for controlled release of various cargos is just one of the exciting results reported in the literature that highlights MSNs as a promising platform for various biotechnological and biomedical applications. This review focuses on the most recent progresses in the application of MSNs for intracellular drug delivery. The latest research on the pathways of entry into live mammalian and plant cells together with intracellular trafficking are described. One of the main areas of interest in this field is the development of site‐specific drug delivery vehicles; the contribution of MSNs toward this topic is also summarized. In addition, the current research progress on the biocompatibility of this material in vitro and in vivo is discussed. Finally, the latest breakthroughs for intracellular controlled drug release using stimuli‐responsive mesoporous‐silica‐based systems are described.     

Preparation and characterisation of silica‐based nanoparticles for cisplatin release on cancer brain cells

In the present work, the preparation, characterisation, and efficiency of two different silica nanostructures as release vehicles of Cisplatin are reported. The 1‐hexadeciltrimethyl‐ammonium bromide templating agent was used to obtain mesoporous silica nanoparticles which were later loaded with Cisplatin. While sol–gel silica was very fast prepared using an excess of acetic acid during the hydrolysis–condensation reactions of tetraethylorthosilicate and at the same time the Cisplatin was added. Several physicochemical techniques including spectroscopies, electronic microscopy, X‐ray diffraction, N₂ adsorption–desorption were used to characterise the silica nanostructures. An in vitro Cisplatin release test was carried out using artificial cerebrospinal fluid. Finally, the toxicity of all silica nanostructures was tested using the C6 cancer cell line. The spectroscopic results showed the suitable stabilisation of Cisplatin into the two different silica nanostructures. A large surface area was obtained for the mesoporous silica nanoparticles, while low areas were obtained in the silica nanoparticles. Cisplatin was released faster from mesoporous silica channels than from inside of aggregates nanoparticles silica. Cisplatin alone, as well as, cisplatin released from both silica nanostructures exerted a toxic effect on cancer cells. In contrast, both silica structures without the drug did not exert any toxic effect.Inspec keywords: cellular biophysics, desorption, adsorption, biomedical materials, sol‐gel processing, silicon compounds, cancer, toxicology, nanofabrication, brain, condensation, mesoporous materials, nanoparticles, X‐ray diffraction, nanomedicine, drugs, aggregates (materials)Other keywords: mesoporous silica channels, silica‐based nanoparticles, cancer brain cells, silica nanostructures, 1‐hexadeciltrimethyl‐ammonium bromide, mesoporous silica nanoparticles, sol‐gel silica, C6 cancer cell line, in vitro cisplatin release test, C6 cancer cell line, acetic acid, hydrolysis‐condensation reactions, tetraethylorthosilicate, physicochemical techniques, electronic microscopy, X‐ray diffraction, N₂ adsorption‐desorption, artificial cerebrospinal fluid, toxicity, toxic effect, N₂ , SiO₂      

Ultra-small MoS2nanodots-incorporated mesoporous silica nanospheres for pH-sensitive drug delivery and CT imaging

Functionalization of mesoporous silica spheres with well-dispersed and ultra-small nanodots to exert their synergistic effects for biomedical applications has been considered to be an urgent challenge.Herein,homogeneously incorporation of ultra-small and monodispersed MoS₂ nanodots in the mesoporous silica nanospheres(MSN)was achieved by a facile one-step solvothermal reaction.The as-synthesized UsMSND@MSN possessed uniform size(~115 nm)and favorable biocompatibility inherited from MSN.The dispersed UsMSND within MSN could act as anchoring sites for aromatic anti-cancer drug DOX loading,and consequently achieved pH-responsive release based on the specialπ-π/electrostatic interactions with the DOX molecules.More importantly,the well-dispersed UsMSND in MSN could function as the non-toxic contrast agent for the sensitive in vivo CT imaging in various tumors including breast cancer and glioma with different sections.This work promises a good strategy for dispersed incorporation of UsMSND into MSN as an excellent pH-responsive platform for simultaneous cancer imaging and therapy.