A biofuel cell with enhanced performance by multilayer biocatalyst immobilized on highly ordered macroporous electrode

A one-compartment glucose/O-2. biofuel cell based on an electrostatic layer-by-layer (LbL) technique on three-dimensional ordered macroporous (3DOM) gold electrode was described. A 3DOM gold electrode was synthesized electrochemically by an inverted colloidal crystal template technique. Then the macroporous gold electrodes were functionalized with Au nanoparticles (AuNPs) and enzyme, glucose dehydrogenase (GDH) or laccase.

Multilayer structured carbon nanotubes/poly-L-lysine/laccase composite cathode for glucose/O-2 biofuel cell

Multilayer film of laccase, poly-L-lysine (PLL) and multi-walled carbon nanotubes (MWNTs) were prepared by a layer-by-layer self-assembly technique. The results of the UV-vis spectroscopy and scanning electron microscopy studies demonstrated a uniform growth of the multilayer. The catalytic behavior of the modified electrode was investigated. The (MWNTs/PLL/laccase)(n) multilayer modified electrode catalyzed four-electron reduction of O-2 to water, without any mediator.

Highly ordered mesoporous carbons-based glucose/O-2 biofuel cell

This study demonstrates a novel compartment-less glucose/O-2 biofuel cell (BFC) based on highly ordered mesoporous carbons (OMCs) with three-dimensionally (3D) interconnected and ordered pore structures. OMCs are used as supports for both stably confining the electrocatalyst (i.e., meldola's blue, MDB) for NADH oxidation and the anodic biocatalyst (i.e., NAD(+)-dependent glucose dehydrogenase, GDH) for glucose oxidation, and for facilitating direct electrochemistry of the cathodic biocatalyst (i.e., laccase, LAC) for O-2 electroreduction. In 0.10 M pH 6.0 PBS containing 20 mM NAD(+) and 60 mM glucose under the air-saturated atmosphere, the open circuit voltage (0.82 V) and the maximum power output (38.7 mu W cm(-2) (at 0.54V)) of the assembled compartment-less OMCs-based BFC are both higher than those of carbon nanotubes (CNTs)-based BFC (0.75 V and 2.1 mu W cm(-2) (at 0.46 V)).

A biofuel cell harvesting energy from glucose-air and fruit juice-air

The membraneless biofuel cell (BFC) is facile prepared based on glucose oxidase and laccase as anodic and cathodic catalyst, respectively, by using 1,1'-dicarboxyferrocene as the mediators of both anode and cathode. The BFC can work by taking glucose as fuel in air-saturated solution, in which air serves as the oxidizer of the cathode. More interestingly, the fruit juice containing glucose, e.g. grape, banana or orange juice as the fuels substituting for glucose can make the BFC work. The BFC shows several advantages which have not been reported to our knowledge: (1) it is membraneless BFC which can work with same mediator on both anode and cathode; (2) fruit juice can act as fuels of BFCs substituting for usually used glucose; (3) especially, the orange juice can greatly enhance the power output rather than that of glucose, grape or banana juice. Besides, the facile and simple preparation procedure and easy accessibility of fruit juice as well as air being whenever and everywhere imply that our system has promising potential for the development and practical application of BFCs.

A biofuel cell with enhanced power output by grape juice

Glucose oxidase and laccase immobilized at multiwalled carbon nanotubes-ionic liquid gel modified electrodes are used as the catalysts of anode and cathode of biofuel cells (BFCs), respectively. The BFC based on glucose and air is proposed. When ferrocene monocarboxylic acid is adopted as the mediator of anode, the power output of the BFC is ca. 4.1 mu W (power density ca. 10.0 mu W cm(-2)), which is higher than the value of 2.7 mu W (power density ca. 6.6 mu W cm(-2)) by taking ferrocene dicarboxylic acid as the mediator. This implies that the mediator with formal potential closing to that of the enzyme does improve the power output. Furthermore, the power output of the BFC is greatly improved by taking grape juice as the fuel of anode rather than glucose. This system also indicates that grape juice as a fuel of the BFC not only is feasible and can also enhances the power output of the BFCs. Besides, it greatly lowers the cost and simplifies the preparation procedure of the BFCs, making the BFC towards "green" bioenergy.

A high throughput Nile red method for quantitative measurement of neutral lipids in microalgae

Isolation of high neutral lipid-containing microalgae is key to the commercial success of microalgae-based biofuel production. The Nile red fluorescence method has been successfully applied to the determination of lipids in certain microalgae, but has been unsuccessful in many others, particularly those with thick, rigid cell walls that prevent the penetration of the fluorescence dye. The conventional "one sample at a time" method was also time-consuming. In this study, the solvent dimethyl sulfoxide (DMSO) was introduced to microalgal samples as the stain carrier at an elevated temperature. The cellular neutral lipids were determined and quantified using a 96-well plate on a fluorescence spectrophotometer with an excitation wavelength of 530 nm and an emission wavelength of 575 run. An optimized procedure yielded a high correlation coefficient (R-2 = 0.998) with the lipid standard triolein and repeated measurements of replicates. Application of the improved method to several green algal strains gave very reproducible results with relative standard errors of 8.5%, 3.9% and 8.6%, 4.5% for repeatability and reproducibility at two concentration levels (2.0 mu g/mL and 20 mu g/mL), respectively. Moreover, the detection and quantification limits of the improved Nile red staining method were 0.8 mu g/mL and 2.0 mu g/mL for the neutral lipid standard triolein, respectively. The modified method and a conventional gravimetric determination method provided similar results on replicate samples. The 96-well plate-based Nile red method can be used as a high throughput technique for rapid screening of a broader spectrum of naturally-occurring and genetically-modified algal strains and mutants for high neutral lipid/oil production. (C) 2009 Published by Elsevier B.V.

Low potential detection of glutamate based on the electrocatalytic oxidation of NADH at thionine/single-walled carbon nanotubes composite modified electrode

A glutamate biosensor based on the electrocatalytic oxidation of reduced nicotinamide adenine dinucleotide (NADH), which was generated by the enzymatic reaction, was developed via employing a single-walled carbon nanotubes/thionine (Th-SWNTs) nanocomposite as a mediator and an enzyme immobilization matrix. The biosensor, which was fabricated by immobilizing glutamate dehydrogenase (GIDH) on the surface of Th-SWNTs, exhibited a rapid response (ca. 5 s), a low detection limit (0.1 mu M), a wide and useful linear range (0.5-400 mu M), high sensitivity (137.3 +/- 15.7) mu A mM(-1) cm(-2), higher biological affinity, as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, uric acid, and 4-acetamidophenol, did not cause any interference due to the use of a low operating potential (190 mV vs. NHE). The biosensor can be used to quantify the concentration of glutamate in the physiological level. The Th-SWNTs system represents a simple and effective approach to the integration of dehydrogenase and electrodes, which can provide analytical access to a large group of enzymes for wide range of bioelectrochemical applications including biosensors and biofuel cells.

酶生物燃料电池载体选择及其应用基础研究

酶生物燃料电池（EBFC）是利用酶作为催化剂将化学能转化为电能的装置。由于氧化还原蛋白质和酶通常具有复杂的空间结构，活性中心深埋在它们的肽链中，很难与基底电极进行直接电子传递，从而影响了电池的性能。但使用适当的载体对电极表面进行修饰，可以实现直接的、快速的电子传递。因此，开发稳定性好、成本低、能够有效促进氧化还原蛋白质或酶与基底电极进行直接电子传递的载体成为EBFC发展中的重要课题之一。 本论文主要集中于EBFC中蛋白质或酶载体的选择方面的研究。探讨不同性质的载体，包括半导体电物质、生物相容性物质和导电物质对氧化还原蛋白质或酶的直接电子传递的影响。同时以SiO2纳米粒子为例，探讨了载体促进氧化还原蛋白质直接电子传递的作用机理。通过对不同载体的考察，最终选择了一种合适的材料组装成葡萄糖/O2 EBFC，并考察了EBFC的性能。主要结果如下： 1．将SiO2纳米粒子固定在GC电极上，成功实现了细胞色素c（Cyt c）的准可逆的直接电化学反应，并在这基础上提出双功能机理模型，说明了半导体对氧化还原蛋白质和电极之间的直接电子迁移的影响。 2．发现Cyt c能够在SBA-15膜修饰的电极上实现准可逆的直接电化学反应，并能够对H2O2产生较好的电催化还原效果。 3．以生物相容性物质壳聚糖为载体，分别研究了Cyt c、微过氧化物酶（MP-11）和葡萄糖氧化酶（GOD）的准可逆的直接电化学反应。并发现固载在壳聚糖上的Cyt c和MP-11对H2O2和O2还原有很好的电催化活性，而固载在壳聚糖上的GOD对葡萄糖氧化有很好的电催化活性。 4．以碳纳米管（CNT）为载体，实现了GOD的准可逆的直接电化学反应。并在氧化还原媒介体的作用下实现了其对葡萄糖的电催化氧化。 5．将筛选出的最佳载体组装成葡萄糖/O2 EBFC，分别以葡萄糖氧化酶和漆酶作为阳极和阴极的催化剂，制得有隔膜和无隔膜的EBFC。

直接型生物燃料电池酶催化剂的研究

生物燃料电池作为一种真正意义上的理想绿色环保电源，由于可作为小功率长寿命的体内植入电源，已成为人们研究的热点课题之一。目前对生物燃料电池的研究主要集中在间接型生物燃料电池，已取得一定进展。但是间接型生物燃料电池具有电子传递链长、效率低等弱点，而直接型生物燃料电池有望克服以上缺点，成为更具研究潜力的新一代生物燃料电池。本文从探索简单、有效的酶固定方法入手，制备炭载辣根过氧化物酶（HRP）、漆酶（Lac）、酪氨酸酶（Tyr）作直接型生物燃料电池的阴极催化剂和炭载葡萄糖氧化酶（GoD）作阳极催化剂。用多种谱学方法表征了炭载酶催化剂的结构特征和用电化学方法研究了炭载酶的直接电化学及电催化性能。得到的主要结果和结论如下：1．以比活性高、稳定、结构清楚、有纯的商品化试剂且价廉的HRP为模型分子来探索用平衡吸附法将HRP固定到活性炭表面，用Nofion膜加固并修饰到玻碳（GC）电极上，以期制备得到炭载HRP修饰的Gc电极（HRP-C／GC）。实验结果表明，炭载HRP能进行准可逆的直接电化学反应，式电位（0）在50-700mv／s的范围内几乎不随扫速变化，平均值为C0．362±0．001）v，表观速率常数（ks）为（3．4±0．69）s-1HRP-C/GC电极对HZoZ还原有很好和稳定的电催化活性，表明固定在活性炭上的HRP能保持其生物活性，而且能稳定数月时间。因此，固定在活性炭上的HRP有可能用作直接型生物燃料电池的阴极催化剂。由上述结果可见，用平衡吸附法把HRP固载到活性炭上，并用Nofion膜加固的酶电极的制备方法具有简单且有效的特点，有可能作为直接型生物燃料电池酶催化剂的制备方法。2．用平衡吸附法将Lac和Tyr分别固定到活性炭上，发现炭载Lac和Tyr都能进行准可逆的直接电化学反应，其0，在10-150mv／s的范围内几乎不随扫速而变化，分别为-0．166和-0．139v。另外，还发现炭载Lac和Tyr对02的还原有明显的电催化作用，表明炭载Lac和Tyr仍能保持它们的生物活性，因而能作直接型生物燃料电池的阴极催化剂。3．用平衡吸附法将葡萄糖氧化酶（GOD）固定到活性炭表面，发现炭载GOD能进行准可逆的直接电化学反应，其0，在10-200mv／s的范围内几乎不随扫速而变化，平均值为C0．467±0．002）v；ks值为（1．18±0．59）5-1；且其直接电化学反应是2e＋ZH＋的过程。另外，还发现炭载GOD对p-D（＋）葡萄糖的氧化有明显的电催化作用，表明炭载GOD没有发生变性，仍保持其生物活性，所以能用作直接型生物燃料电池的阳极催化剂。

聚合物锂离子电池和生物燃料电池的相关研究

本论文分为两个部分研究了铿离子电池和生物燃料电池中的关键材料，主要的创新点和结论如下。采用聚合物电解质是提高铿二次电池性能的有效方法之一。聚合物电解质良好电导率、高铿离子迁移数、宽电化学窗口以及好的机械性能是其应用于铿二次电池中的关键。论文的第一部分主要讨论了聚合物、增塑剂和无机纳米粒子等对复合电解质体系的化学和物理性质的影响。我们采用溶液浇注一浸渍法制备了各种纳米复合聚合物电解质，例如开发出基于PVDFHFP或梳状聚合物基体的全固态以及聚合物和碳酸醋形成的胶体聚合物电解质体系。首次制备了具有较高离子电导率的单离子聚合物电解质。考察了两类纳米粒子填充物对体系的影响：一种是“惰性”发烟硅；另一种是“活性”蒙脱土。比较了全固态和胶体聚合物电解质体系电化学性质的不同之处。采用电化学交流阻抗，示差扫描量热法，X衍射，拉曼光谱，红外光谱，扫描电镜，循环伏安等方法详细研究了聚合物电解质中各组分对体系离子电导率和机械性能的影响。研究结果表明，纳米复合物为开发具有特定电化学和机械性能的电解质提供了一种有效的途径，它对聚合物电解质的物理性质影响明显。纳米粒子的加入增强了体系的机械性能，同时也使体系对溶剂的吸附能力增加。在全固态聚合物电解质中加入增塑剂，形成胶体态聚合物电解质，体系的电导率大大增加。所制备的胶体复合物电解质的室温电导率可以达到10-3s cm-1的数量级，机械强度好，阳离子迁移数高。指出选择合适的添加剂及复合方法，控制界面的结构和形态，形成尽可能多的高导电的界面，是获得电导率高和机械性能良好的聚合物电解质的有效途径。并讨论了聚合物电解质在铿离子电池中的应用。 近年来，针对生物燃料电池的研究得到了广泛关注，其中实现蛋白质酶分子和电极之间的直接电子传递是研究中的热点。论文的第二部分主要研究了生物燃料电池中的酶电极。通过对碳纳米管（MWNTs）进行预处理，使其表面带有功能性官能团，从而可以实现酶分子在碳纳米管表面的固定，同时还保持了其生物活性。采用吸附法将微过氧化物酶-11（MP-11）或葡萄糖氧化酶（GOx）等生物分子固定到MWNTs上制成酶修饰电极，研究MWNTs对酶和电极之间电子传递的促进作用。当酶分子（MP-11，GOX）固定到MWNTs表面后，循环伏安结果显示出一对可逆的氧化还原峰，对应酶分子的直接电子转移。研究结果表明这种方法可以扩展到固定其他生物酶分子以及实现蛋白质酶分子和电极之间的直接电化学，可以获得一系列氧化还原酶分子的电化学参数，如反应速率常数等。同时，我们还研究了酶修饰电极对其底物的电催化反应。研究结果表明，该修饰电极对底物的电化学反应表现出较好的催化活性。我们还研究了酶分子在MWNTs修饰铂微电极上的电化学行为。这些研究为研制生物燃料电池提供了一种固定酶以及制备电极材料较好的方法。

Electrochemical characteristics of mediated laccase-catalysis and electrochemical detection of environmental pollutants

Laccase has been immobilized on the carbon nanotubes modified glassy carbon electrode surface by adsorption. As-prepared laccase retains good electrocatalytic activity to oxygen reduction by using 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) as the mediator. It can be used as a biosensor for the determination of catechol with broad linear range.