原位自组装形成二氧化硅/十六烷基三甲基溴化铵纳米网络粒子

提出了以具有纳米尺寸孔径及孔壁厚度的MCM 48作为无机基体、以无机 有机原位自组装的方法形成纳米网络粒子 .研究结果表明 ,在一定实验条件下 ,有机相可进入无机相的三维孔道自组装形成立方有序结构的纳米网络复合粒子 .通过研究纳米网络粒子在极性介质和非极性介质中的分散发现 ,有机相的存在有利于纳米网络粒子的分散     

Optical Chemical Sensors Based on Sol-Gel Materials: Recent Advances and Critical Issues

The use of the sol-gel process to produce materials for optical chemical sensors and biosensors is attracting considerable interest. This interest derives mainly from the design flexibility of the sol-gel process and the ease of fabrication. In most applications the sol-gel material is used to provide a microporous support matrix in which analyte-sensitive species are entrapped and into which smaller analyte molecules may diffuse. Sensors based on entrapped organic and inorganic dyes, enzymes and other biomolecules have been reported. A range of sensor configurations has been employed, including monoliths, thin films, as well as more elaborate structures. In this paper a selection is presented of recent significant developments in optical chemical sensors which employ solgel-derived materials. These developments include the tailoring of sol-gel materials to optimise sensor response, advanced waveguide structures and novel probe-tip sensors. Those issues which remain critical to the eventual deployment of sol-gel sensors are examined. In particular, the problems of leaching, microstructural stability, diffusion-limited response time, and susceptibility to interferents are discussed and some solutions proposed.     

A MgO Nanoparticles Composite Matrix‐Based Electrochemical Biosensor for Hydrogen Peroxide with High Sensitivity

A novel horseradish peroxidase (HRP) electrochemical biosensor based on a MgO nanoparticles (nano‐MgO)‐chitosan (chit) composite matrix was developed. The morphology of nano‐MgO‐chit nanocomposite was examined by scanning electron microscopy (SEM). The interaction between nano‐MgO‐chit nanocomposite matrix and enzyme was characterized with UV‐vis spectra. This proposed composite material combined the advantages of inorganic nanoparticles and organic polymer chit. The HRP immobilized in the nanocomposite matrix displayed excellent electrocatalytic activity to the reduction of H₂O₂ in the presence of hydroquinone as a mediator. The effects of the experimental variables such as solution pH and the working potential were investigated using steady‐state amperometry. The present biosensor (HRP‐modified electrode) had a fast response towards H₂O₂ (less than 10 s), and excellent linear relationships were obtained in the concentration range of 0.1–1300 μM, with a detection limit of 0.05 μM (S/N=3). Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.     

Stabilizing structure-switching signaling RNA aptamers by entrapment in sol-gel derived materials for solid-phase assays

Structure-switching, fluorescence-signaling DNA and RNA aptamers have been reported as highly versatile molecular recognition elements for biosensor development. While structure-switching DNA aptamers have been utilized for solid-phase sensing, equivalent RNA aptamers have yet to be successfully utilized in solid-phase sensors due to their lack of chemical stability and susceptibility to nuclease attack. In this study, we examined entrapment into sol-gel derived organic-inorganic composite materials as a platform for immobilization of structure-switching fluorescence-signaling RNA aptamer reporters, using both the synthetic theophylline- and naturally occurring thiamine pyrophosphate-binding RNA aptamers as test cases. Structure-switching versions of both aptamers were entrapped into a series of sol-gel derived composites, ranging from highly polar silica to hydrophobic methylsilsesquioxane-based materials, and the target-binding and signaling capabilities of these immobilized aptamers were assessed relative to solution. Both immobilized aptamers demonstrated sensitivity and selectivity similar to that of free aptamers when entrapped in a composite material derived from 40% (v/v) methyltrimethoxysilane/tetramethoxysilane. Importantly, this material also conferred protection from nuclease degradation and imparted long-term chemical stability to the RNA reporter systems. Given the versatility of sol-gel entrapment for development of biosensors, microarrays, bioaffinity columns, and other devices, this entrapment method should provide a useful platform for numerous solid-phase RNA aptamer-based devices.     

Analytical applications of organically modified silicates

Inorganic-organic hybrid materials prepared by the sol-gel process have become an attractive field of study due to the immense versatility associated with this method of composite material preparation. The blending of inorganic precursors with organosilicon reagents enables unique materials to be fabricated with the desired chemical and physical characteristics. The ability to control the interfacial polarity, the degree of porosity, and the chemical functionality in the matrix has been shown to be a powerful tool in the design of materials for sensor, optical, chromatographic, and catalytic applications. In this review, the preparation of the organically modified silicates (ORMOSILs) where the individual precursors are covalently bound to each other is discussed and selected examples of their potential usefulness in analytical applications is presented.     

Properties and applications of proteins encapsulated within sol-gel derived materials

The last decade has seen a revolution in the area of sol-gel-derived materials since the demonstration that these materials can be used to encapsulate biological species such as enzymes, antibodies and other proteins in a functional state. The interactions between the biomolecule and the inorganic, organic or hybrid nanocomposite material determines the degree to which the biomolecule retains its native properties, and such interactions can be tuned to provide optimised biomaterials that are suitable for a variety of applications. Typical applications of sol-gel derived biomaterials include selective coatings for optical and electrochemical biosensors, stationary phases for affinity chromatography, immunoadsorbent and solid-phase extraction materials, controlled release agents, solid-phase biosynthesis, and unique matrices for biophysical studies. Through careful selection of precursors and additives, these materials can be designed for specific applications, and can produce useful, robust devices with good analytical parameters of merit. Indeed, current advances in the development of nanocomposite and mesostructured materials suggest that major improvements in bioimmobilisation are on the horizon, and should result in substantial improvements in bioanalytical devices over the next decade.     

Optical biosensors based on Prussian Blue films

Optical biosensing schemes based on enzymatically modified inorganic/organic transparent films predominately composed of Prussian Blue are demonstrated. The composite film, which is non-electrochemically deposited on a non-conducting support. is used as an optical transducer for flow-through biosensors based on hydrolases and oxidases. Urease and glucose oxidase are utilized as model enzymes. Action of the urea biosensor is based on optical pH sensitivity of Prussian Blue indicator. The glucose biosensor is acting as first-generation optical biosensor based on in situ generated Prussian White transducer for hydrogen peroxide. These simple, single-pass transmission optical biosensors exhibit sensitivity in the millimolar range of concentration. The biosensors are very stable owing to presence of a poly(pyrrolylbenzoic acid) network in the composite material. This organic polymer plays a dual role as a binding agent for inorganic material and as a functionalized support for strong covalent immobilization of enzyme molecules.     

An H2O2 Biosensor Based on Immobilization of Horseradish Peroxidase Labeled Nano‐Au in Silica Sol‐Gel/Alginate Composite Film

Abstract

A novel approach to assemble an H₂O₂ amperometric biosensor was introduced. The biosensor was constructed by entrapping horseradish peroxidase (HRP) labeled nano‐scaled particulate gold (nano‐Au) (HRP‐nano‐Au electrostatic composite) in a new silica sol‐gel/alginate hybrid film using glassy carbon electrode as based electrode. This suggested strategy fully merged the merits of sol‐gel derived inorganic‐organic composite film and the nano‐Au intermediator. The silica sol‐gel/alginate hybrid material can improve the properties of conventional sol‐gel material and effectively prevent cracking of film. The entrapment of HRP in the form of HRP‐nano‐Au can not only factually prevent the leaking of enzyme out of the film but also provide a favorable microenvironment for HRP. With hydroquinone as an electron mediator, the proposed HRP electrode exhibited good catalytic activity for the reduction of H₂O₂. The parameters affecting both the qualities of sol‐gel/alginate hybrid film and the biosensor response were optimized. The biosensor exhibited high sensitivity of 0.40 Al mol^?1 cm^?2 for H₂O₂ over a wide linear range of concentration from 1.22×10^?5 to 1.46×10^?3 mol L^?1, rapid response of <5 s and a detection limit of 0.61×10^?6 mol L^?1. The enzyme electrode has remarkable stability and retained 86% of its initial activity after 45 days of storage in 0.1 mol L^?1 Tris‐HCl buffer solutions at pH 7.     

Gold nanoparticles-induced enhancement of the analytical response of an electrochemical biosensor based on an organic-inorganic hybrid composite material

The design and characterization of a new organic-inorganic hybrid composite material for glucose electrochemical sensing are described. This material is based on the entrapment of both gold nanoparticles (AuNPs) and glucose oxidase, which was chosen as a model, into a sol-gel matrix. The addition of spectroscopic grade graphite to this system, which confers conductivity, leads to the development of a material particularly attractive for electrochemical biosensor fabrication. The characterization of the hybrid composite material was performed using atomic force microscopy and scanning electron microscopy techniques. This composite material was applied to the determination of glucose in presence of hydroxymethylferrocene as a redox mediator. The system exhibits a clear electrocatalytic activity towards glucose, allowing its determination at 250 mV vs Ag/AgCl. The performance of the resulting enzyme biosensor was evaluated in terms of sensitivity, detection limit, linear response range, stability and accuracy. Finally, the enhancement of the analytical response of the resulting biosensor induced by the presence of gold nanoparticles was evaluated by comparison with a similar organic-inorganic hybrid composite material without AuNPs.     

无机-无机复合电致变色材料的研究进展

在外加电压的作用下,电致变色材料的光学性能（颜色、透光率等）能够可控制、可逆地变化,在节能减排领域有重要应用前景。随着相关研究的不断创新、深入和拓展,单一组分的电致变色材料因受到其自身结构和性能的限制,不能表现出人们所期望的电致变色性能,并且在结构和性能上不具有可设计和调控性,因而越来越无法满足实际应用的需求。与非复合电致变色材料相比较,复合型材料在这方面具有明显的优势,其优势体现在通过合理的材料设计,借助复合材料各组分的协调作用,充分激发各组分的优点,克服各自的缺点,可以获得结构和性能优异的电致变色材料。因此,近年来越来越多的研究聚焦于复合型电致变色材料。目前已开展研究的复合型电致变色材料的种类很多,根据复合组分是无机材料还是有机材料来对复合型电致变色材料分类的话主要可分为无机-无机复合、无机-有机复合和有机-有机复合3大类。相比有机电致变色材料,无机电致变色材料在材料成分控制、机械性能、光调制、使用稳定性、寿命等方面优势显著,因此,单一组分的和复合型的无机电致变色材料始终是本领域研究的重要方向。因此,本文致力于近年来无机-无机复合电致变色材料、器件和电解质的研究现状和未来的发展动态,对其研究进展、所存在的问题和发展趋势进行了归纳总结,为复合型电致变色材料的进一步研发和应用提供依据。     

有机-无机纳米复合材料光谱与电子性质研究进展

有机-无机纳米复合材料的研究在当前纳米科学技术的发展中占有重要地位，开创了材料与催化科学研究的新纪元。自从10年前首次合成纳米孔无机材料MCM-41至今，该领域研究不断深入，已展现出广阔的应用前景。当客体有机分子分散于纳米孔道内部时，其分子性质将产生明显变化。本文结合作者近期研究成果，力图从实验与理论两方面阐明在纳米复合体系中客体分子性质变化的原因。     

Proteins in Countryclub-Like Jails:Encapsulation of Enzymes in Nanoporous Materials

A popular method for enzyme immobilization is formation of covalent bonds between enzymes and a solid support, which often alters the enzymatic activities. Recently, various enzymes have been entrapped in inorganic oxides such as silica for biocatalysis and biosensor applications through conventional sol-gel process. However, because of the microporous nature (i.e. pore diameter of 1.5-2 nm or less) of conventional sol-gels, the activities of enzymes are hindered by low diffusion rates of substrate molecules and poor accessibility of enzymes inside the materials.     

Surface modification of natural cellulose substances:toward functional materials and applications

Combining various synthetic chemical processes and biological assemblies provides a promising strategy for the design and fabrication of functional materials with tailored structures and properties.The unique multilevel structures and morphologies of natural cellulose substances such as ordinary commercial laboratory filter paper make them ideal platforms for the self-assemblies of various functional guest molecules that are to be deposited on the surfaces of their fine structures,and the resulting composite matters show significant potentials for various applications.The surface sol-gel process was employed to deposit ultrathin metal-oxide(e.g.,titania and zirconia)gel films to coat the cellulose nanofibers in bulk filter papers;thereafter,monolayers of specific guest substrates were immobilized onto the surfaces of the metal-oxide gel films.Highly selective,sensitive,and reversible chemosensors based on the surface modification of filter paper were obtained toward the fluorescence and colorimetric detection of various analytes such as heavy-metal ions,inorganic anions,amino acids,and gases.Cellulosebased composite materials with superhydrophobic,antibacterial,or luminescent properties were fabricated by self-assembly approaches toward practical applications.     

溶胶-凝胶法制备纳米WO_3气致变色材料

本文主要阐述了纳米WO3气致变色材料的溶胶-凝胶制备方法、气致变色机理及其应用的研究新进展,重点评述了溶胶-凝胶法中各种制备条件诸如掺杂、模板剂、溶剂、热处理温度等对这种材料的结构和性能的影响,最后展望了纳米WO3气致变色材料的研究和应用前景。我们认为,在未来的溶胶-凝胶法制备纳米WO3气致变色材料领域,如何进行最优化的掺杂设计和选择高效模板剂、如何降低气体检测温度以及气致变色机理等将是该项研究的重点。     

Study of the fire resistant behavior of unfilled and carbon nanofibers reinforced polybenzimidazole coating for structural applications

With increasing interest in epoxy‐based carbon fiber composites for structural applications, it is important to improve the fire resistant properties of these materials. The fire resistant performance of these materials can be improved either by using high performance epoxy resin for manufacturing carbon fiber composite or by protecting the previously used epoxy‐based composite with some fire resistant coating. In this context, work is carried out to evaluate the fire resistance performance of recently emerged high performance polybenzimidazole (PBI) when used as a coating material. Furthermore, the effect of carbon nanofibers (CNFs) on fire resistant properties of inherently flame retardant PBI coating was studied. Thermogravimetric analysis of carbon/epoxy composite, unfilled PBI and nano‐filled PBI shows that the carbon/epoxy composite maintained its thermal stability up to a temperature of 400°C and afterwards showed a large decrease in mass, while both unfilled PBI and nano‐filled PBI have shown thermal stability up to a temperature of 575°C corresponding to only 11% weight loss. Cone calorimeter test results show that unfilled PBI coating did not improve the fire retardant performance of carbon/epoxy composite. Conversely, nano‐filled PBI coating has shown a significant improvement in fire retardant performance of the carbon/epoxy composite in terms of increased ignition time, reduced average and peak heat release rate and reduced smoke and carbon monoxide emission. These results indicate that addition of carbon nanofibers to inherently flame retardant coating can significantly be helpful for improving the fire resistance performance of composite materials even with low coating thickness. Copyright © 2013 John Wiley & Sons, Ltd.     

Highly responsive biosensors based on organic field-effect transistors under light irradiation

High responsivity and sensitivity play essential roles in the development of organic field-effect transistors (OFETs)-based biosensors with regard to biological detections, particularly for disease diagnosis. Nonetheless, how to design a biosensor which improves these two outstanding properties while achieving low cost, easy processing, and time saving is a daunting challenge. Herein, a novel biosensor based on OFET with copolymer thin film, whose surface is illuminated with a suitable light beam is reported. This film can be used as both an organic semiconductor material and as a photoelectric active material. Due to amplification of signals as a result of the film’s strong response to light, the biosensor possesses higher responsivity and sensitivity compared to dark condition and even realizes a maximum responsivity of up to 10³ for alpha-fetoprotein (AFP) detection. The simple combination of light and transistor builds a bridge between photoelectric effect and biological system. In addition, the emergence of more excellent photoelectric active materials is expected to pave a way for ultrasensitive bio-chemical diagnostic tools.     

Advances in Template Prepared Nano‐Oxides and their Applications: Polluted Water Treatment,Energy, Sensing and Biomedical Drug Delivery

The nano‐oxide materials with special structures prepared by template methods have a good dispersion, regular structures and high specific surface areas. Therefore, in some areas, improved properties are observed than conventional bulk oxide materials. For example, in the treatment of dye wastewater, the treatment efficiency of adsorbents and catalytic materials prepared by template method was about 30 % or even higher than that of conventional samples. This review mainly focuses on the progress of inorganic, organic and biological templates in the preparation of micro‐ and nano‐ oxide materials with special morphologies, and the roles of the prepared materials as adsorbents and photocatalysts in dye wastewater treatment. The characteristics and advantages of inorganic, organic and biological template are also summarized. In addition, the applications of template method prepared oxides in the field of sensors, drug carrier, energy materials and other fields are briefly discussed with detailed examples.     

仿生矿化的机理和应用研究进展

碳酸钙、磷酸钙为代表的生物矿物广泛分布于自然界中,经过不同的矿化过程,在生物体内呈现出多样的结构、形貌和功能,构成生物体多种组织和器官.在人工材料合成领域,仿生矿化通过调控碳酸钙、磷酸钙等矿物的成核与生长,获得具有复杂高级结构和特殊生物功能的无机或无机/有机复合材料.本文重点介绍仿生矿化机理和应用的最近研究进展,包括仿...     

Fullerenes in Sol-Gel Materials

The family of fullerene molecules is composed of a large variety of compounds that have been synthesized following the discovery of C₆₀ in 1985. The chemistry of fullerenes, developed in these last years, has allowed designing the properties of this family of molecules for specific applications in materials science. One of the main tasks to build up solid state devices based on fullerenes is the synthesis of materials doped with a highly dispersed and homogeneous distribution of fullerenes. Many of the peculiar photophysical properties, such as the reverse saturable absorption used to obtain a solid state optical limiter, are in fact lost in the aggregates of fullerenes. Sol-gel processing allows preparing inorganic oxides and hybrid organic-inorganic materials at low temperatures and presents an interesting alternative to organic polymers to entrap molecules of the fullerene family in a solid matrix. Porous inorganic solids and aerogels are also important classes of materials that can be synthesized via sol-gel and can act as hosts of fullerenes. In the present article we have reviewed the main achievements of sol-gel processing of fullerene based nanocomposite materials.     

氧化铝/聚乙二醇溶胶凝胶对酪氨酸酶的固定及应用研究

氧化铝/聚乙二醇(Al2O3/PEG)溶胶凝胶复合材料对酪氨酸酶具有较好的生物相容性和较高的稳定性。将生物酶固定于其中制备成的生物传感器具有良好的反应活性。实验证明这种生物传感器具有好的稳定性和灵敏度高的特点。