Preparation of Three‐Dimensional Ordered Macroporous Prussian Blue Film Electrode for Glucose Biosensor Application

Ordered 3D interconnected macroporous Prussian blue (PB) films were electrochemically fabricated by using colloidal crystals of polystyrene beads as sacrificial templates. The prepared PB film electrodes have excellent catalytic activity towards the reduction of hydrogen peroxide. The PB structure was further used as functional interface for fabricating an enzyme‐based glucose sensor by using surface modification technique based on the electrostatic interactions. The resulted sensor has higher functional density, and larger surface area. The interconnected macroporous structure allows enhanced mass transport. These characteristics of the sensor enable us to detect glucose with high sensitivity. Therefore, the present 3D ordered macroporous film sensor exhibits wide linear detection range towards glucose, acceptable reproducibility and operational and storage stability. The present approach is promising for the generation of high‐enzyme‐content thin films with tailored bioactivity.     

A glucose/oxygen enzymatic fuel cell based on redox polymer and enzyme immobilisation at highly-ordered macroporous gold electrodes

Highly ordered macroporous electrodes are prepared by electro-deposition of gold through a polystyrene sphere template. Drop-coating redox polymer and either glucose oxidase, for the anode, or Melanocarpus albomyces laccase, for the cathode on the macroporous gold provides film-coated electrodes for assembly of membrane-less glucose/oxygen enzymatic fuel cells (EFC) in pH 7.4 buffer containing 10 mM glucose and 0.15 M NaCl. Under these conditions the maximum power density of 17 μW cm(-2) for EFCs using films adsorbed to planar gold electrodes increased to 38 μW cm(-2) for films adsorbed to 2? sphere gold macroporous electrodes.     

Glucose biosensor based on three dimensional ordered macroporous self-doped polyaniline/Prussian blue bicomponent film

In this paper, a three dimensional ordered macroporous self-doped polyaniline/Prussian blue (3DOM SPAN/PB) bicomponent film was fabricated via the inverted crystal template technique using step-by-step electrodeposition. In this bicomponent film, PB not only acted as a redox mediator, but also presented increased stability in neutral or weak alkaline solution by the protection of SPAN layer on the top. A novel glucose biosensor was fabricated based on the large active surface area and excellent conductivity possessed by the 3DOM SPAN/PB film. The applying experimental conditions of the glucose biosensor have been optimized. Under the optimal conditions, the biosensor showed a wide linear range over three orders of magnitude in glucose concentrations (from 2 to 1600 μM) and a low detection limit of 0.4 μM. Moreover, the biosensor exhibited short response time, high selectivity and excellent operation stability, which can be applied to detect the blood sugar in real samples without any pretreatment.     

Amperometric glucose-responding property of enzyme electrodes fabricated by covalent immobilization of glucose oxidase on conducting polymer films with macroporous structure

Macroporous conducting polymer films were prepared by the electrochemical copolymerization of 3-methylthiophene and thiophene-3-acetic acid on the ITO-coated glass plates bearing different sizes of polystyrene template particles, and enzyme electrodes were fabricated by covalent immobilization of glucose oxidase on the macroporous copolymer films. It was found that the doping level and conductivity of the copolymer films was significantly affected by the treatment with solvent to remove the polystyrene particles, which was considered to result in deterioration in amperometric glucose-responding property of the enzyme electrodes fabricated with the copolymer films. Three-dimensionally ordered macroporous structure on the copolymer films led to enhancement of amperometric response of the enzyme electrodes, and this effect was attributed to the geometry of the interconnected channel structure formed by the linkage of macropores. It was suggested that the amperometric response of the enzyme electrodes was determined by whether the interconnected channel structure on the copolymer films had long distance regularity and a proper size to allow the enzyme and electron-mediator molecules to penetrate into the interior pores of the copolymer film. In particular, the interconnected channel structure seemed to play an important role in the electron-transfer reaction between the mediator molecules and the surface of electrodes.     

Direct electrochemistry of cytochrome c immobilized on a novel macroporous gold film coated with a self-assembled 11-mercaptoundecanoic acid monolayer

We have successfully constructed a novel gold film with open interconnected macroporous walls of nanoparticles by combining the hydrogen bubble dynamic template synthesis with galvanic replacement reaction. After modified by a self-assembled monolayer (SAM) of 11-mercaptoundecanoic acid (MUA), the three-dimensionally (3D) interconnected macroporous Au film has been used as a biocompatible substrate for the immobilization of cytochrome c. The morphology, structure and electrochemical features of the modified and unmodified macroporous Au films were characterized by field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results reveal that the resultant films had a large electroactive surface area for high protein loading, enhanced electron transfer of cytochrome c, retained electrochemical activity, good stability and repeatability. And the excellent electrochemical behaviors could be attributed to the hierarchical structure of the macroporous Au film constructed by nanoparticles.     

Colloidal crystal-derived nanoporous electrode materials of Cut SWNTs-assembly and TiO2/SWNTs nanocomposite

Relatively ordered macroporous films of a cut single-walled carbon nanotubes (c-SWNTs) assembly and a TiO 2/c-SWNTs nanocomposite were successfully fabricated by colloidal crystal template processes using polystyrene particles. The macroporous TiO2/c-SWNTs nanocomposite film showed excellent rate capability of Li-insertion/extraction. The rate-dependent Li-insertion/extraction capacities were close to theoretical values expected from Li-diffusion in anatase--TiO2 thin layer without blocking electrolyte-ion and electron access.     

Improvement of the Selectivity of Amperometric Biosensors by Using a Permselective Electropolymerized Film

Abstract

Dichlorophenolindophenol (DCPIP) was electrochemically deposited onto the surface of glassy carbon and platinum electrodes to form a permselective film. Cyclic voltammetry of the DCPIP coated electrode exhibited a reversible oxidation/reduction current at +0.14 V, behavior similar to monomeric DCPIP. However, such an electrode did not mediate glucose oxidase in the presence of β-D-glucose. For operation at +0.7 V vs Ag/AgCl, the DCPIP electrodeposited film behaved like a permselective membrane and virtually eliminated oxidative interference currents resulting from 0.2 mM acetaminophen, uric acid and glutathione. For ascorbic acid, interfering current due to 0.2 mM ascorbate was decreased by 80%. Improvement of the selectivity due to ascorbic acid was achieved using an electrodeposited film prepared from a mixture of DCPIP with diaminobenzene or resorcinol.     

Improved Electrochromic Performance of Poly(3,4‐ethylenedioxythiophene) by Incorporating a Three‐Dimensionally Ordered Macroporous Structure

In this paper, three‐dimensionally ordered macroporous (3DOM) poly(3,4‐ethylenedioxythiophene) (PEDOT) films were electropolymerized from an ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([Bmim]PF₆). The electrochromic performances of the 3DOM PEDOT films were studied. The 3DOM films exhibited high transmittance modulation (41.2 % at λ=580 nm), high ionic fast switching speeds (0.7 and 0.7 s for coloration and bleaching, respectively), and enhanced cycling stability relative to that exhibited by the dense PEDOT film. The relationship between the declining behavior of the transmittance modulation and the nanostructure of the film was investigated. A three‐period decay process was proposed to understand the declining behavior. The 3D interconnected macroporous nanostructure is beneficial for fast ion and electron transportation, high ion accessibility, and maintenance of structure integrity, which result in enhanced cycling stability and fast switching speeds.     

A Glucose Biosensor Based on Immobilization of Glucose Oxidase into 3D Macroporous TiO2

3D macroporous TiO₂ inverse opals have been derived from a sol‐gel procedure using polystyrene colloidal crystals as templates. EDS and SEM showed a face‐centered cubic (FCC) structure TiO₂ inverse opal was obtained. Glucose oxidase (GOx) was successfully immobilized on the surface of indium‐tin oxide (ITO) electrode modified by TiO₂ inverse opal (TiO_2(IO)). Electrochemical properties of GOx/TiO_2(IO)/ITO electrode were characterized by using the three electrodes system. The result of cyclic voltammetry showed that a couple of stable and well‐defined redox peaks for the direct electron transfer of GOx in absence of glucose, and the redox peak height enhanced in presence of 0.1 μM glucose. Compare with the ordinary structured GOx/TiO₂/ITO electrode, inverse opal structured GOx/TiO_2(IO)/ITO electrode has a better respond to the glucose concentration change. Under optimized experimental conditions of solution pH 6.8 and detection potential at 0.30 V versus saturated calomel electrode (SCE), amperometric measurements were performed. The sensitivity and the detection limit of glucose detection was 151 μA cm^?2 mM^?1 and 0.02 μM at a signal‐to‐noise ratio of 3, respectively. The good response was due to the good biocompatibility of TiO₂ and the large effective surface of the three‐dimensionally ordered macroporous structure.     

Properties of glucose sensors prepared by the electropolymerization of a positively charged pyrrole derivative

Amperometric glucose sensors were prepared by electropolymerization of a pyrrole derivative having the positively charged group, 3-(1-pyrrolyl)propyltrimethylammonium bromide, in the presence of glucose oxidase on bare and Nafion-coated platinum electrodes. Linear relationships between the glucose concentration and the response current for the electrode with and without Nafion inner film were up to 10.0 and 6.0 mmol dm⁻³, respectively. The introduction of Nafion inner film lowered the influence of electroactive compounds, such as ascorbic acid, uric acid, and acetoaminophen, on the sensor response, but was not able to eliminate the influence of these compounds sufficiently. However, Nafion inner film was effective in increasing the electrode stability. The response current of the electrode with Nafion film remained stable for more than 50 days, while that without Nafion film was significantly reduced after 20 days of use.     

三维有序大孔CdS/TiO2薄膜的制备及其可见光催化性能

采用胶体晶体模板辅助溶胶-凝胶法以及S2-离子交换法合成了三维有序大孔CdS/TiO₂膜.结果表明,该薄膜材料在可见光催化降解污染水中罗丹明B和对氯苯酚的反应中表现出高活性.这可归因于修饰剂CdS的光敏化作用实现可见光催化,CdS-TiO₂之间形成了异质结,促进了电子和空穴的分离; 另一方面,有序大孔结构有利于光的利用以及反应物的扩散和吸附.     

磺化聚苯乙烯有序孔水凝胶的制备及其模板效应

有序大孔聚苯乙烯材料通过胶体晶模板技术合成, 再经过磺化处理制备得到有序大孔水凝胶体系. 研究了其化学组成和形态. 以溶胶/凝胶制备有序无机材料如二氧化钛对凝胶进行复型, 证明了有序大孔凝胶的形态特征, 同时显示了有序大孔水凝胶作为新型模板制备形态可控的介观尺度有序无机材料的潜力.     

Uniform hierarchical silica film with perpendicular macroporous channels and accessible ordered mesopores for biomolecule separation

Herein, we demonstrate that silica films with perpendicular macroporous channels and accessible ordered mesopores can be conveniently prepared. The hierarchical macroporous–mesoporous silica films are synthesized by using zinc oxide nanorod array as macroporous template and CTAB surfactant as mesoporous template. In basic surfactant-containing solution, ordered mesoporous silica shells homogeneously grow on the zinc oxide nanorod array. The growth of the mesostructures do not require any chemical modification for the zinc oxide nanorod, which opens a new way for preparing hierarchical silica films with perpendicular mesochannels. The prepared hierarchical macroporous–mesoporous silica films possess a uniform thickness of 2 mm, large perpendicular macropores with a length of 1.8 mm and a width of 80 nm, and accessible ordered mesopores. Separation experiment demonstrates that this macroporous–mesoporous film can effectively separate biomolecules with different sizes.     

基于室温离子液体的有序多孔金膜葡萄糖传感器

将1-丁基-3-甲基咪唑四氟硼酸盐（[BMIm][BF4]）、N,N-二甲基甲酰胺（DMF）与葡萄糖氧化酶（GOD）的混合物修饰于三维有序大孔（3DOM）金膜电极上,构建了一种新型的葡萄糖传感器．固定的GOD在pH7．0的磷酸缓冲液（PBS）中展现出一对可逆性好的氧化还原峰,这归因于GOD的活性中心黄素腺嘌呤二核苷酸（FAD）的直接电化学行为．研究表明,离子液体（IL）、DMF以及3DOM金膜对GOD的直接电化学都起到了重要的作用．3DOM金膜修饰电极作为基底提高了酶的负载量,加速了GOD与电极表面的电子传递;IL的应用增加了固定GOD的电化学活性;DMF与IL、GOD的协同作用更好地保持了GOD的生物活性．固定在电极表面的GOD对葡萄糖显示出良好的催化性能,其检测线性范围为10～125nmol／L,检测限为3．3nmol／L（S／N=3）,酶催化反应的表观米氏常数Km为0．018mmol／L．     

Enhancement of response by incorporation of platinum microparticles into a polypyrrole-glucose oxidase electrode

Platinum was incorporated into a polypyrrole/glucose oxidase electrode by immersion in a hexachloroplatinate(IV) solution after electrochemical oxidation of the polypyrrole film; dispersed platinum was then formed by electrochemical reduction. The platinized electrode reproducibly yielded a response to glucose (20 mM) which was typically about 40% higher than that obtained in the absence of platinum microparticles in the polypyrrole/glucose oxidase film.     

聚苯乙烯胶晶膜及三维有序大孔SiO2膜的制备及表征

采用垂直沉积法组装了三维聚苯乙烯胶晶膜,并用其为模板制备了三维有序大孔（3DOM）SiO2膜．SEM观察表明,制备的胶晶膜和3DOMSiO2膜具有fcc结构,有序性很好．考察乳液浓度对胶晶膜结构的影响表明,浓度越高,胶晶膜越厚,有序性也越高,膜在30层内都能很好的粘附在载玻片上．通过调整前驱物溶液的浓度和滴加方式,可得到表面为球形或孔状的3DOM SiO2膜．     

The effect of platinum oxide films on reaction kinetics at platinum electrodes

It has been known for some time that the pre-treatment of platinum electrodes often effects subsequent electrochemical reactions. Part of the effect of pre-treatment is due to the fact that anodized or chemically oxidized platinum electrodes become coated to some degree with a film of platinum oxide. This work was concerned with quantitative measurement of kinetic parameters as a function of the extent of oxide film formation. Whenever possible, variations in reaction mechanisms are proposed.

Most of the experimental evidence has been taken from current-potential curves but the techniques of chronopotentiometry and microscopy were also used.

The reduction of vanadium^V chromium^VI, arsenic^V, iodate and oxygen were investigated as well as the oxidation of vanadium^IV, arsenic^III, oxalic acid, and formic acid. The presence of the platinum oxide film effected the reactions studied in a variety of ways but in every case some variation in the kinetic parameters of the reactions studied was recorded. For a number of cases, a modified oxygen bridge theory was found useful.     

三维有序大孔Al2O3制备的新方法及表征

以聚苯乙烯胶晶为模板,用Al(NO3)3•9H2O为前驱物,使用柠檬酸为配体,成功地制备了孔径为250～350 nm的三维有序大孔Al2O3材料.SEM观察表明,所得大孔材料孔结构规则排列,孔与孔之间通过小孔相连,形成了一个三维有序排列的蜂窝状结构.实验发现,以Al(NO3)3•9H2O为前驱物,加入柠檬酸可以防止团聚粒子的产生,有利于三维有序结构的形成.前驱物浓度在0.5～0.8 mol•L－1范围内均能得到较好的三维有序大孔结构.在1 100 ℃焙烧2 h后,Al2O3大孔材料仍能保持完整的规则孔结构特征,表现出较高的热稳定性.     

ADSORPTION DYNAMICS OF MACROPOROUS POLYMERIC ADSORBENT Ⅱ. The Studies on the Film Diffusion Mass-Transfer Process

1 INTRODUCTIONAt present time, most of the studies for the adsorption dynamics of macroporous adsorbent,.especially for the film diffusion mass-transfer process, were based on the conclusions for theBoyd ion-exchange dynamics equationl'l. The structure of gel-type ion-exchange resin andmacroporous polystyrene resin is different. Because of having the hydrophilic group, both of theirmer and outer of the ion-exchange resin can swell to the reticulation struCture in the aqueous.Based on the…     

三维有序大孔尖晶石型Li1.6Mn1.6O4的制备及锂离子筛吸附特性

用LiNO3、Mn(Ac)2•4H2O和柠檬酸的混合溶液填充聚甲基丙烯酸甲酯胶体晶体模板, 在空气中氧化焙烧, 制备出三维有序大孔尖晶石型锂锰氧化物Li1.6Mn1.6O4. 前驱体经过0.1 mol/L盐酸脱锂后获得相应的三维有序大孔锂离子筛, 其大孔直径和孔壁厚度分别为240 nm和50 nm左右. XRD测试结果表明, Li1.6Mn1.6O4、锂离子筛和吸锂后的样品均保持尖晶石结构. 三维有序大孔材料呈现彼此连通的孔道空间, 缩短了Li+的平衡吸附时间, 前驱体脱锂率在80 ℃时达到95%, 而锰的溶损率在低于60 ℃时小于2.5%. 溶液温度对Li+的交换能力影响很大, 升高温度, Li+与H+的可逆交换程度增大, Li+的最大吸附容量为56.7 mg/g, 但处于锰16d八面体缺陷位置的氢难于被交换. pH滴定和分配系数(Kd)分析表明, 该固体酸在Li+, Na+和K+共存溶液中对Li+的吸附具有较高的选择性.