溶胶-凝胶技术在电化学和生物传感器制备中的应用近况

对溶胶-凝胶技术在制备电化学和生物传感器中的应用近况(涉及年份主要在1992-2006年间)作了评述,内容主要集中在应用此技术包埋某些电化学活性物质或生物化学活性分子于其中而制备相关传感器的方法及其原理,在制备传感器过程中的影响因素以及此类传感器的分析应用。此外,对其发展趋势也作了简单的讨论(引用参考文献51篇)。     

基于溶胶-凝胶壳聚糖／SiO2杂化材料的安培型葡萄糖生物传感器

近年来，基于溶胶-凝胶技术的有机/无机杂化复合材料由于具有有机物的柔性和易修饰性，以及无机物的刚性和稳定性等，因此有利于保持生物分子的活性和生物传感器的研制．壳聚糖(CS)具有易成膜性和生物相容性，其在生物传感器中的研究已受到重视．本文通过原位溶胶-凝胶(Sol-gel)技术，     

DNA水凝胶在生物传感中的应用和发展

脱氧核糖核酸(DNA)是一种重要的生物分子,具有许多独特的性质如:信息传递、分子识别、可编辑等。DNA水凝胶同时具有DNA分子和水凝胶材料的优势,并且可以引入其他纳米材料获得多功能杂化水凝胶。相比于传统水凝胶,DNA水凝胶具有良好的特异识别能力以及可以按需设计的性质,从而被广泛应用于生物传感领域。本文围绕DNA水凝胶的合成、响应机制以及在传感领域的应用进行综述。按照不同的合成方法可分为线性DNA链缠绕水凝胶、枝状DNA自组装水凝胶、杂合DNA水凝胶。根据传感机制的不同又可以分为包埋封装法和非包埋封装法,包埋封装发法又分为:酶的包埋释放、抗原-抗体的包埋释放、纳米材料的包埋释放。本文总结了近几年DNA水凝胶在重金属离子检测、核酸检测、葡萄糖检测、蛋白质和代谢小分子检测,以及细胞检测等热门领域的研究情况,最后对其未来的发展进行了展望。     

新型固定化方法－－环氧胺树脂及硅树脂生物包埋

在生物包埋技术的研究过程中，人们发现生物功能可以融合并保存于聚合物基 质中，继溶胶凝胶生物包埋法以后，目前以发展了许多非溶胶凝胶聚合物用于蛋白 质的固定化，此类聚合物包括环氧胺树脂，硅树脂，聚乙烯塑料和聚氨酯泡沫材料 等。迄今为止，人们已成功地将多种酶包埋其中，加上原有的溶胶凝胶包埋物。这 些生物复合体为生物物质的固定化及在生物传感器和生物催化剂中的应用提供了一 个强有力的工具，此外，作为具有生物活性且防污染的聚合物，它们还有望应用于 环境，食品以及医药行业，尽管尚处于发展阶段，但是这些生物复合体将为高效生 物固定化提供一种新的手段，将具体介绍其中最受关注的环氧胺树脂和硅树脂。     

基于溶胶-凝壳聚糖/SiO2杂化材料的安培型葡萄糖生物传感器

近年来 ,基于溶胶 -凝胶技术的有机 /无机杂化复合材料由于具有有机物的柔性和易修饰性 ,以及无机物的刚性和稳定性等 ,因此有利于保持生物分子的活性和生物传感器的研制 [1] .壳聚糖 ( CS)具有易成膜性和生物相容性 ,其在生物传感器中的研究已受到重视 [2 ] .本文通过原位溶胶 -凝胶 ( Sol- gel)技术 ,用 CS和甲基三甲氧基硅烷 ( MTOS)制备了 CS/Si O2 有机 /无机杂化材料 ,并将其用于对葡萄糖氧化酶 ( GOD)的固定 ,研制出葡萄糖生物传感器 .采用人工过氧化物酶普鲁士蓝 ( PB) [3]作为电子传递的媒介体 ,并外加一层 Nafion膜以增强…     

溶胶-凝胶包埋法制备银离子选择电极的研究

研制了一种用溶胶 凝胶技术包埋电活性物质的银离子选择电极。研究了包埋过程的变量参数及电极的响应机理。电极Nernst响应范围为 1.0× 10 - 1～ 1.0× 10 - 5mol·L- 1,斜率为5 5 .5mV·pc- 1,检出限为 3.1× 10 - 6mol·L- 1。该电极响应快 ,体积小 ,制作简单 ,使用方便 ,具有坚固耐磨 ,可在严酷条件下使用的特点。此研究对进一步研制溶胶 凝胶ISFET化学传感器和生物传感器具有探索意义     

界面活化的溶胶凝胶包埋Candida rugosa脂肪酶催化合成维生素E琥珀酸酯

采用界面活化的溶胶凝胶包埋Candida rugosa脂肪酶(CRL)催化合成了维生素E琥珀酸酯.考察了影响溶胶凝胶包埋固定化CRL的因素,获得的最佳固定化条件为:丙基三甲氧基硅烷/正硅酸四乙酯摩尔比为1/1,水与硅烷前体摩尔比为15,酶的添加量为0.5mg/ml,PEG400的添加量为12μl/ml溶胶. 溶胶凝胶包埋的CRL在50℃,18h后其活性仍然保持了70.58%,是游离酶的2.6倍,且稳定性得到了明显的改善.基于CRL的界面特性,采用五种表面活性剂对其进行界面活化.结果表明,采用橄榄油活化的溶胶凝胶包埋的CRL合成维生素E琥珀酸酯的酯化活力最高,相比原酶和未界面活化的溶胶凝胶包埋酶分别提高了6.7和1.43倍.     

溶胶-凝胶法设计与制备金属及合金纳米材料的研究进展

溶胶-凝胶法是常见的制备金属氧化物的方法之一。在溶胶-凝胶法中,各种反应物能达到分子级的均匀混合,因此能制备成份复杂的氧化物材料。目前,溶胶-凝胶法也应用于设计与制备金属纳米材料,特别是合金纳米颗粒。例如,溶胶-凝胶法能应用于制备CoPt、FePt等磁性纳米合金材料以及CoCrCuNiAl高熵合金纳米材料,以及物相结构为有序相的Cu3Pt合金纳米材料。本文综述溶胶-凝胶法设计制备金属纳米材料的研究进展,包括溶胶-凝胶法实施的基本步骤、该方法在制备金属纳米材料方面的具体应用,并着重论述采用热力学计算设计金属及化合物的基本原理。该基本原理包括计算金属氧化物与还原性气体如氢气的还原反应的吉布斯自由能的变化量、金属氧化物的标准电极电位(不同于金属离子的标准电极电位)。最后探讨溶胶-凝胶法设计制备金属纳米材料存在的问题以及后续可能的发展方向。     

制备方法对CuO—Ce0．7Zr0．3O2催化剂的氧缺位和CO氧化活性的影响

采用溶胶-凝胶法和溶胶-凝胶 浸渍法两种方法制备了CuO-Ce0.7Zr0.3O2催化剂,并对催化剂进行了XRD、Raman等表征,考察了催化剂的CO氧化性能.研究结果表明,溶胶-凝胶法制备的CuO-Ce0.7Zr0.3O2催化剂的CO氧化活性明显高于溶胶-凝胶 浸渍法制备的CuO/Ce0.7Zr0.3O2催化剂,CuO-Ce0.7Zr0.3O2催化剂容易形成氧缺位和表面高分散CuO的颗粒较大,从而提高催化活性.     

介孔纳米 MoPO-AlPO4 的制备及其对异丁烯选择氧化的催化性能

 分别采用溶胶-凝胶法和等体积浸渍法制备了 MoPO-AlPO4 催化剂, 考察了钼物种存在状态对催化剂晶格氧活性以及异丁烯选择氧化反应性能的影响. N2 吸附-脱附、X 射线衍射、高分辨透射电镜、X 射线光电子能谱、傅里叶变换红外光谱、程序升温还原和微反实验结果表明, 与浸渍法制备的催化剂相比, 溶胶-凝胶法制备的 MoPO-AlPO4 催化剂为介孔纳米材料, 其比表面积和孔数量均有较大程度的提高. 在浸渍法制备的催化剂中, 钼物种以四面体 MoO42− 和八表面体 MoO66− 形式存在; 而在溶胶-凝胶法制备的催化剂中钼物种主要以四面体 MoO42− 的形式存在, 并有部分钼物种嵌入到了 AlPO4 骨架中. 钼物种的种类对异丁烯选择氧化反应的活性和选择性有较大影响, 溶胶-凝胶法制备的催化剂由于嵌入 AlPO4 骨架中钼物种的存在, 异丁烯选择氧化反应性能得到较大提高.     

Phycobiliproteins encapsulated in sol-gel glass

Light transducing phycobiliproteins are encapsulated in optically transparent sol-gel matrices. Absorption and fluorescence spectroscopies are used to characterize the effect of the sol-gel encapsulation on the conformation and aggregation states of the three major phycobiliproteins present in phycobilisomes: phycoerythrin, phycocyanin, and allophycocyanin. It is found that the effects of sol-gel entrapment on the spectroscopic properties are significantly different for the three phycobiliproteins. The results indicate that phycoerythrin undergoes only minor change in its native structure when entrapped in sol-gel. However, significant changes in conformation and aggregation state occur when phycocyanin and allophycocyanin are entrapped in sol-gel matrices. A thin film of sol-gel encapsulated phycoerythrin is also coated on an optical fiber surface and strong fluorescence from the evanescent wave excitation is detected. The potential applications of sol-gel encapsulated phycobiliproteins in biosensors are discussed.     

Oxidation of dibenzothiophene catalyzed by heme-containing enzymes encapsulated in sol-gel glass

We have encapsulated several hemoproteins in the sol-gel glass to catalyze the oxidation reaction of dibenzothiophene (model for organic sulfur compounds in coal) with hydrogen peroxide. In addition to cytochrome c and myoglobin, which have previously been encapsulated in sol-gel glasses, two other hemoproteins, horseradish peroxidase and bovine blood hemoglobin, have now been successfully immobilized in sol-gel media with the retention of their spectroscopic properties. All four hemoproteins studied also demonstrate similar catalytic activities toward the oxidation of dibenzothiophene as compared with the results obtained with the proteins in solution. In the case of encapsulated cytochrome c, the more water-soluble S-oxide was obtained with much higher selectivity over the less water-soluble sulfone (S-oxide/sulfone = 7.1) as compared to what was obtained in the aqueous/organic medium (S-oxide/sulfone = 2.3). Because of the advantage of easy separation of the encapsulated proteins from the liquid reaction mixture, it is clear from these studies that the immobilization of active hemoproteins in the solid glass media could serve as more practical biocatalysts.     

基于酚藏花红掺杂有机改性溶胶-凝胶膜的亚硝酸盐光学传感器

利用溶胶-凝胶法,研制出基于有机改性溶胶-凝胶膜的亚硝酸盐光学传感器.以甲基三乙氧基硅烷为有机交联剂,与正硅酸乙酯进行水解和缩聚,制备了酚藏花红包埋的有机-无机硅酸盐杂化材料,并采用旋涂法将其涂抹在显微镜载玻片上,形成薄膜.在酸性条件下,NO<'-><,2>与酚藏花红掺杂的溶胶-凝胶膜发生作用,使溶胶-凝胶膜从红色变为...     

Supported ionic liquid phase rhodium nanoparticle hydrogenation catalysts

Rh(0) nanoparticles (ca. 4 nm) dispersed in an ionic liquid (1-n-butyl-3-methylimidazolium tetrafluoroborate) were immobilized within a silica network, prepared by the sol-gel method. The effect of the sol-gel catalyst (acid or base) on the encapsulated ionic liquid and Rh(0) content, on the silica morphology and texture, and on the catalyst alkene hydrogenation activity was investigated. The Rh(0) content in the resulting xerogels (ca. 0.1 wt% Rh/SiO(2)) was shown to be independent of the sol-gel process. However, acidic conditions afforded higher contents of encapsulated ionic liquid and xerogels with larger pore diameters, which in turn might be responsible for the higher catalyst activity in hydrogenation of the alkenes.     

Trapping specific quaternary states of the allosteric enzyme aspartate transcarbamoylase in silica matrix sol-gels

The extreme T and R quaternary structures of the allosteric enzyme aspartate transcarbamoylase have been trapped by encapsulation in a silica sol-gel matrix. Detection of the specific quaternary structure present in the sol-gel was accomplished using a pyrene-labeled version of the enzyme that exhibited monomer fluorescence in the T quaternary structure and excimer fluorescence in the R quaternary structure. Using thin films of the encapsulated enzyme, kinetics of the T and R states could be determined without interconversion of the states. Using a monolith form of the encapsulated enzyme, the transition from the T or the R structure was monitored. Within the sol-gel matrix, the rate of the transition was slowed approximately 105 over that observed in solution.     

SYNTHESIS AND BIOTECHNOLOGICAL APPLICATIONS OF VINYL POLYMERINORGANIC HYBRID AND MESOPOROUS MATERIALS

We describe the sol-gel synthesis of a new family of organic-inorganic hybrid materials, in which various vinylpolymers are covalently bonded to and uniformly distributed in inorganic oxide matrices. The materials can be tailored tohave both good toughness and hardness while maintaining excellent optical transparency. Doping the sol-gel metal oxideswith optically active compounds such as D-glucose results in new optical rotatory composite materials. Removal of thedopant compounds from the composites affords mesoporous oxide materials, which represents a new, nonsurfactant-templated route to mesoporous molecular sieves. We have successfully immobilized a series of enzymes and other bioactiveagents in mesoporous materials. Catalytical activities of the enzyme encapsulated in mesoporous materials were found to bemuch higher than those encapsulated in microporous materials.     

Sol-gel encapsulated horseradish peroxidase: a catalytic material for peroxidation

This study addresses the viability of sol-gel encapsulated HRP (HRP:sol-gel) as a recyclable solid-state catalytic material. Ferric, ferric-CN, ferrous, and ferrous-CO forms of HRP:sol-gel were investigated by resonance Raman and UV-visible methods. Electronic and vibrational spectroscopic changes associated with changes in spin state, oxidation state, and ligation of the heme in HRP:sol-gel were shown to correlate with those of HRP in solution, showing that the heme remains a viable ligand-binding complex. Furthermore, the high-valent HRP:sol-gel intermediates, compound I and compound II, were generated and identified by time-resolved UV-visible spectroscopy. Catalytic activity of the HRP:sol-gel material was demonstrated by enzymatic assays by using I(-), guaiacol, and ABTS as substrates. Encapsulated HRP was shown to be homogeneously distributed throughout the sol-gel host. Differences in turnover rates between guaiacol and I(-) implicate mass transport of substrate through the silicate matrix as a defining parameter in the peroxidase activity of HRP:sol-gel. HRP:sol-gel was reused as a peroxidation catalyst for multiple reaction cycles without loss of activity, indicating that such materials show promise as reusable catalytic materials.     

溶胶-凝胶法固定生物活性物质的研究进展

综述了近年来溶胶一凝胶(Sol-gel)技术在生物活性物质固定化方面的应用和进展。蛋白质、酶、抗体(抗原)、细胞及微生物均可被包埋于Sol-gel玻璃中。包埋后,这些生物活性物质仍保持其生物活性和光谱性质,有望成为实用的生物催化剂和生物传感器。     

Molecular state and distribution of fullerenes entrapped in sol-gel samples

A novel synthetic method that can encapsulate fullerene molecules (pure C60, pure C70, or their mixture) over a wide range of concentrations ranging from micromolar to millimolar in hybrid glass by a sol-gel method without any time-consuming, complicated, and unwanted extra steps (e.g., addition of a surfactant or derivatization of the fullerenes) has been successfully developed. The molecular state and distribution of encapsulated fullerene molecules in these sol-gel samples were unequivocally characterized using newly developed multispectral imaging techniques. The high sensitivity (single-pixel resolution) and ability of these instruments to record multispectral images at different spatial resolutions (approximately 10 microm with the macroscopic instrument and approximately 0.8 microm with the microscopic instrument) make them uniquely suited for this task. Specifically, the imaging instruments can be used to simultaneously measure multispectral images of sol-gel-encapsulated C60 and C70 molecules at many different positions within a sol-gel sample in an area either as large as 3 mm x 4 mm (with the macroscopic imaging instrument) or as small as 0.8 microm x 0.8 microm (with the microscopic instrument). The absorption spectrum of the fullerene molecule at each position can then be calculated either by averaging the intensity of a 15 x 15 square of pixels (which corresponds to an area of 3 mm x 4 mm) or from the intensity of a single pixel (i.e., an area of about 0.8 microm x 0.8 microm), respectively. The molecular state and distribution of fullerene molecules within sol-gel samples can then be determined from the calculated spectra. It was found that spectra of encapsulated C60 and C70 measured at five different positions within a sol-gel sample were similar not only to one another but also to spectra measured at six different times during the sol-gel reaction process (from t = 0 to 10 days). Furthermore, these spectra are similar to the corresponding spectra of monomeric C60 or C70 molecules in solution. Similarly, spectra of sol-gel samples containing a mixture of C60 and C70 were found to be the same at five different positions, as well as similar to spectra calculated from an average of the spectra of C60 and C70 either encapsulated in a sol-gel or in solution. It is evident from these results that C60 and C70 molecules do not undergo aggregation upon encapsulation into a sol-gel but rather remain in their monomeric state. Furthermore, entrapped C60 and C70 molecules in their monomeric state were distributed homogeneously throughout the entire sol-gel samples. Such a conclusion can be readily, quickly, and easily obtained, not with traditional spectroscopic techniques based on the use of a single-channel detector (absorption, fluorescence, infrared, Raman) but rather with the newly developed multispectral imaging technique. More importantly, the novel synthetic method reported here makes it possible, for the first time, to homogenously entrap monomeric fullerene molecules (C60, C70, or their mixture) in a sol-gel at various concentrations ranging from as low as 2.2 mM C60 (or 190 microM C70) to as high as 4.2 mM C60 (or 360 microM C70).