硅酸铝纤维和玻璃纤维复合二氧化硅气凝胶材料的制备与性能

分别以硅酸铝纤维和玻璃纤维为骨架材料,采用溶胶-凝胶、常压干燥制得纤维复合二氧化硅气凝胶材料,并对材料进行了结构和性能的测试分析。结果表明,二氧化硅气凝胶附着于纤维表面,提高了材料力学强度。硅酸铝纤维复合二氧化硅气凝胶材料的隔音性能优于玻璃纤维复合二氧化硅气凝胶材料。两种纤维复合二氧化硅气凝胶材料耐高温、燃烧性能均达到A级。硅酸铝纤维复合二氧化硅气凝胶材料和玻璃纤维复合二氧化硅气凝胶材料的产烟毒性分别为AQ₁级和AQ₂级,导热系数分别为0.034 W/（m·K）和0.033 W/（m·K）。     

介孔二氧化硅花球的制备及药物缓释性能研究

采用溶胶-凝胶法,以正硅酸乙酯为硅源、十六烷基三甲基溴化铵(CTAB)为模板,在碱性条件下合成了尺寸均匀、形状规则的花状形貌的介孔状二氧化硅微球。基于二氧化硅花球特殊的表面褶皱和内部的介孔孔道,将其作为载体负载模型药物布洛芬,探究其药物缓释性能。结果表明,所制备的介孔二氧化硅花球对布洛芬模型药物的负载量为701.63 mg·g~(-1),明显高于传统药物载体材料。此外,对介孔二氧化硅/布洛芬复合粒子进行缓释实验研究,发现10 h后布洛芬的释放量为74.60%,表明其具有较好的药物缓释性能。     

氨基改性壳聚糖复合二氧化硅气凝胶的制备及其对Cu(Ⅱ)、Cd(Ⅱ)、Pb(Ⅱ)离子的吸附性能研究

以溶胶-凝胶法在常压条件下制得壳聚糖-二氧化硅复合气凝胶,经扫描电镜(SEM)、小角X射线散射(SAXS)、氮气吸附-脱附、傅里叶变化红外光谱(FTrIR)、元素分析等表征结果表明,所制复合气凝胶材料保留了硅气凝胶典型的介孔结构,氨基改性后的复合二氧化硅气凝胶对Cu(Ⅱ)、Cd(Ⅱ)、Pb(Ⅱ)离子的吸附效果明显增强,其中对Pb(Ⅱ)离子的饱和吸附量由改性前的10.3 mg/g提高到42.5 mg/g.     

介孔二氧化硅在布洛芬的装载及控释系统中的研究进展

介孔二氧化硅材料因具有规则的孔道结构和形貌、可控的孔道形状和孔径以及很好的生物相容性,成为药物装载及控释系统的研究热点。本文总结了介孔二氧化硅在布洛芬(IBU)的装载及控释系统中的研究进展,系统阐述了介孔材料的孔径孔容、表面官能化及载药、释药方法等因素,对介孔二氧化硅装载IBU及控释效率的影响,并介绍了酶响应性、温度响应性等刺激响应性的装载及控释系统。     

壳聚糖原位合成复合炭材料及表征

以壳聚糖、导电剂(PbO)为原料,利用原位合成方法,制备了复合炭材料。利用X射线粉末衍射仪、扫描电子显微镜和电子能谱仪、比表面仪、拉曼光谱仪等对复合炭材料的组成、结构和形貌进行表征。结果表明,壳聚糖为碳源的复合炭材料具有非晶态结构,活性炭与导电剂相容性良好,孔径分布集中在5~10 nm,,比表面积高达487.4 m~2/g。壳聚糖比炭黑更适合作炭材料的碳源。     

定向生物质多孔碳复合相变材料的制备及其热性能研究

针对石蜡热导率低以及易泄漏等问题,以生物质木头多孔碳作为导热填料骨架,利用壳聚糖改性木头多孔碳在其竖向孔道中生长碳薄片形成分级多孔网络结构,并与石蜡复合制成定形复合相变材料（PCC）。结果表明,由于分级多孔网络骨架的引入,PCC的定形效果好,无明显泄漏,其相变焓值为126.9 J/g,经100次熔化凝固循环测试,其相变温度和焓值均无明显变化,具有良好的循环稳定性。PCC的导热性能具有较大提高,且呈现明显的各向导热异性,平面外和平面内热导率分别为0.67和0.41 W/(m·K)。此外,通过模拟太阳光进行光热实验,发现PCC具有良好的光热转换性能。本复合相变材料在储热以及热管理领域具有应用前景。     

壳聚糖改性空心多巴胺纳米复合载体的制备及其性能研究

将多巴胺负载于二氧化硅表面,再用氢氟酸刻蚀二氧化硅得到空心多巴胺纳米粒子,该方法简单易操作。再引入壳聚糖对空心多巴胺进行表面改性,提高复合纳米载体的黏附性和生物相容性。红外谱图分析证明材料中具备多巴胺和壳聚糖的特征峰,扫描电镜图显示纳米粒子粒径为100 nm左右,这种壳聚糖改性多巴胺纳米复合载体结合了高药物包载率和优异的缓释性能,将在生物医药领域应用更广阔。     

壳聚糖-二氧化硅纳米多孔材料的制备及pH敏感性

这篇文章制备了壳聚糖-二氧化硅复合材料(CS-Si),SEM显示该材料呈现出有序纳米多孔结构,BET比表面积较高为102.80 m2/g,壳聚糖和二氧化硅两组分之间存在较强的相互作用力。CS-Si材料在pH=1.2的溶液中有较高的溶胀度且伴随溶蚀,pH=6.8溶液中的溶胀度明显高于pH=4.5溶液。在pH=1.2和pH=4.5介质中,药物从CS-Si载体材料的释放速率明显慢于pH=6.8,壳聚糖的润湿作用能够提高药物的溶出速率。     

茴拉西坦/MCM-48载体的制备及释药性能研究

为了提高难溶性药物的口服生物利用度,采用水热合成法制备了MCM-48介孔二氧化硅载体材料,利用浸渍法将水难溶性药物茴拉西坦负载于MCM-48载体上。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、激光粒度仪、小角X射线衍射(XRD)、N_2吸附-脱附、红外光谱(IR)、差热-热重(DTA-TG)对载药前后MCM-48的表面形貌、粒径、孔径、孔容、比表面积、晶胞参数等进行测试,结果表明,MCM-48外形为球形颗粒,介孔结构为三维立方结构,孔径3.55 nm,孔容及比表面积分别为0.86 cm³/g和764 m3/g和764 m²/g;MCM-48负载茴拉西坦的载药量为16%,载药后药物以非晶态装载于介孔孔道中或吸附于载体表面,没有影响MCM-48的骨架结构,但使孔径、孔容及比表面积下降。通过在不同pH溶液中载药MCM-48与茴拉西坦原料药的溶出度比较发现,MCM-48载体能够提高茴拉西坦的溶出速率。     

介孔二氧化硅-壳聚糖复合粒子的合成

以十六烷基三甲基溴化铵(CTAB)为模板,通过正硅酸乙酯(TEOS)的水解获得二氧化硅粒子,通过冻干、灼烧,制得介孔二氧化硅纳米粒子(MSNs);以巯丙基三甲氧基硅烷为巯基化的硅烷化试剂,制得巯基化的介孔二氧化硅纳米粒子(MSNs-SH);弱酸性条件下,以N-(3-二甲氨基丙基)-N′-乙基碳二亚胺盐酸盐(EDCI)为缩合剂,将巯基乙酸与壳聚糖结构中的氨基缩合,获得巯基化的壳聚糖(CS-SH);最后通过MSNs-SH与CS-SH巯基连接制得纳米介孔二氧化硅-壳聚糖复合粒子(MSNs-SS-CS),并实现了对阿霉素(DOX)、布地奈德2种药物的包载。实验通过FTIR、紫外可见分光光度计、荧光分光光度计、马尔文激光粒度仪等对粒子的结构、粒径、Zeta电位、载药等性能进行表征。     

Preparation of macroporous chitosan patch using co-solvent as a transdermal drug-delivery system

As a simple method, bio-patches of band type have been widely used in various medical areas for more than 70 years. Despite their numerous advantages, drawbacks such as a lack of adhesive strength and low efficiency of transdermal drug delivery have limited their application. To improve the convenience of use, a 3D porous chitosan patch was prepared simply by phase separation of a solvent (acidic water)/co-solvent [dimethyl carbonate (DMC)]. As a tackifìer of low cytotoxicity, allyl 2-cyanoacrylate bio-glue was prepolymerized and coated onto the porous chitosan patch. Various properties were examined, such as mechanical strength, efficiency of drug-delivery, morphology, cytotoxicity and degradability. We ascertained that the optimal ratio of co-solvent for achieving a highly porous chitosan patch was DMC at a ratio of 5 %. The resultant drug release by the optimal highly porous chitosan patch was approximately twofold faster than that of the untreated control. The porous patch showed improved efficiency of cell adhesion after culturing in cells for 4 h. After 72 h, the cultured cells showed increased cell proliferation on the porous patches. These results strongly suggest that the chitosan-based porous patches covered with modified cyanoacrylate can be widely used as good adhesive patches in various incidents.     

Adsorption of indomethacin onto chemically modified chitosan beads

Macroporous chitosan beads used for the immobilization of an anti-inflammatory drug were prepared by the wet phase-inversion method. There are two stages of phase-inversion observed from the cast of chitosan droplet in tripolyphosphate (TPP) aqueous solution. The first stage of phase-inversion is dominated by liquid-liquid demixing and the morphology of the freeze-dried chitosan bead shows a bundle-like porous structure. The following stage of phase-inversion is attributed to the solid-liquid demixing and the morphology of the freeze-dried chitosan bead changes to an interconnected porous structure comprising particulates around the pores. The pore size and porosity of the bead can be varied by altering synthesis conditions, such as initial polymer concentration, and the pH value and concentration of the casting agent (TPP aqueous solution). Quaternary ammonium, and aliphatic and aromatic acyl groups were introduced into the porous chitosan beads to interact with an anti-inflammatory drug, indomethacin, through the electrostatic interaction and hydrophobic interaction. The results indicated that chemical modification of the porous chitosan beads have obvious effect on the adsorption of indomethacin.     

Preparation of silica nanospheres and porous polymer membranes with controlled morphologies via nanophase separation

ABSTRACT: We successfully synthesized two different structures, silica nanospheres and porous polymer membranes, via nanophase separation between silica sol and polymer. Silica sol, which was in-situ polymerized from tetraorthosilicate, was used as a precursor. Subsequently, it was mixed with a polymer that was used as a matrix component. It was observed that nanophase separation occurred after the mixing of polymer with silica sol and subsequent evaporation of solvents, resulting in organizing various structures, from random network silica structures to silica spheres. In particular, silica nanospheres were produced by manipulating the mixing ratio of polymer to silica sol. The size of silica beads was gradually changed from micro- to nanoscale, depending on the polymer content. At the same time, porous polymer membranes were generated by removing the silica component with hydrofluoric acid. Furthermore, porous carbon membranes were produced by using carbon source polymer through the carbonization process.     

Preparation of enhanced three-dimensional porous chitosan scaffolds by acetylation and aqueous extraction

We have devised a method to prepare a 3-dimensional (3D) porous acetylated chitosan scaffold for use as a cell adhesion matrix in tissue engineering applications. The scaffold was prepared by molding a mixture of chitosan and gelatin (as porogen), then removing the uncomplexed porogen by aqueous extraction from the freeze-dried material prior to acetylation. The extent of chitosan acetylation according to the reaction time was observed by X-ray diffraction (XRD) analysis. The differences between the aqueous-extracted and control phase-separated chitosan scaffolds in terms of pore morphology and interconnectivity were examined by scanning electron microscopy (SEM), enzymatic degradation, and surface roughness tests. The fibroblast cell line NIH-3T3 was used to test relative cell affinities for the acetylated versus untreated (control) chitosan scaffolds. The acetylated 3D porous scaffolds showed high interconnectivity and improved biocompatibility properties. Thus, these scaffolds may be very useful for a variety of tissue engineering applications.     

Swelling degree prediction of polyhydroxybutyrate/chitosan matrices loaded with “Arnica-do-Brasil”

Polyhydroxybutyrate and chitosan have been studied as materials for drug delivery systems (DDSs) due to their biodegradability and biocompatibility. The aim of this work was to produce amphiphilic polyhydroxybutyrate/chitosan matrices that form porous structures (scaffolds) after swelling in water and arnica extract. The matrices were analyzed by TGA, SEM, XDR, DSC, and FTIR. Thin plate spline interpolation method (TPSIM) was used to predict the swelling of the matrices generating three-dimensional data fitted, showing the influence of time and concentration variables on both fluids absorption. Polyhydroxybutyrate/chitosan samples containing 60 wt % (weight percent) of chitosan formed a porous structure as they were submitted to arnica loading, and the obtained device was able to deliver arnica in physiological medium. Thus, the produced matrices have a strong potential to perform both as scaffolds and DDS © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47838.     

Synthesis of High Surface Area Silica Gels Using Porous Carbon Matrices

Porous silica was prepared using the sol-gel synthesis with porous carbon matrices as a pore-forming support. Tetraethoxysilane (TEOS) was hydrolyzed in an acid medium in the presence of a substoichiometric amount of water. Various carbon materials were used, among them Sibunit and catalytic filamentous carbon. Carbon matrices were impregnated with hydrolyzed TEOS and dried, then carbon was removed by burning out in air at 873 K. The obtained porous silica samples were studied by adsorption and electron microscopic methods. The specific surface area as high as 1267 m²g and pore volume as high as 5.7 cm³/g were determined for some silica samples. Thus deposited SiO₂ was found to cover the carbon surface copying its surface. With CFC used as carbon matrix, silica nanotubes were obtained. Thermostability of such silica is significantly greater as compared to silica gels reported earlier.     

多孔壳聚糖膜的制备表征及其吸附性能研究

以琼胶固体颗粒为致孔剂,通过热致相转移法制备了的多孔壳聚糖膜,并通过FT-IR和SEM对其进行了表征,也考察了其对有机染料二甲苯蓝FF的吸附性能。结果表明,以琼胶作为制孔剂可以制备出性能良好的多孔壳聚糖膜,在吸附有机染料方面,多孔壳聚糖膜PCS-2对二甲苯蓝FF的吸附量是壳聚糖膜的1.3倍。另外,作为对比,本文也制备和表征了琼胶-壳聚糖共混薄膜。     

Porous Silica Matrix Obtained from Pyrex Glass by Hydrothermal Treatment: Characterization and Nature of the Porosity

A novel porous silica matrix has been prepared from Pyrex glass, using hydrothermal treatment under saturated-steam condition. This process makes it possible to obtain, in one step, a silica support formed of a homogeneously distributed and interconnected macropore microstructure. The new matrix contains silanol groups that can be used in reactions of surface modification to provide a hybrid material and a selective macrofiltration membrane, and also it can improve chemical inertness. The porous matrix is noncrystalline as obtained and, after thermal treatment at temperatures higher than 950°C, exhibits an X-ray pattern characteristic of α-cristobalite and low volume contraction. The present samples were characterized by scanning electron microscopy, mercury intrusion porosimetry, nitrogen adsorption-desorption isotherms, infrared spectroscopy, X-ray powder diffractometry, atomic absorption, and high-resolution solid-state nuclear magnetic resonance. The results present a new way of producing a macroporous silica matrix.     

Microporous Composites Prepared by Coagulation of a CS/PEG Solution in NaOH

Novel biodegradable three-dimensional composites with a porous structure have been prepared by coagulation of a chitosan (CS)/poly ethylene glycol (PEG) solution in NaOH. It is confirmed that PEG acts not only as a modifier to improve the mechanical properties, but also as a porogen for the CS matrix to induce porous structure. The porous structure and mechanical properties of the composites can be tailored with the amount of PEG and glutaraldehyde (GA). The addition of GA can improve the interaction strength and compatibility between the PEG phase and CS matrix. The resulting composites have smaller pore size, lower porosity, and better mechanical properties.     

Preparation of methylene blue-doped silica nanoparticle and its application to electroanalysis heme proteins

In this paper, methylene blue (MB)-doped silica nanoparticles (NPs) were prepared in a reverse microemulsion and used as a novel matrix for biochemical application. By controlling the experiment conditions, MB was successfully captured in a three-dimensional cage of the silica network. The silica matrix, with hydrophilic groups, provides a biocompatible microenvironment for heme proteins retaining their native conformation and biological activity. The chemical and electrochemical stability of MB-doped silica NPs makes the organic–inorganic nanocomposite be a promising platform for bioelectrochemical analysis. Conjugated with chitosan, the MB-doped silica NPs were modified on the surface of glassy carbon (GC) electrode. The developed electrode exhibited the remarkable catalytic activity for the reduction of hemoglobin (Hb) and cytochrome c (Cyt c). The catalytic reduction peak currents for chitosan/MB-doped silica NPs were linearly proportional to the concentrations of Hb and Cyt c. The calculated detection limits (S/N = 3) were 4.5 × 10⁻⁹ mol/L for Hb and 5.0 × 10⁻⁸ mol/L for Cyt c, respectively.