4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶/漆酶基燃料电池性能

以4-巯基苯甲酸修饰纳米金粒子作为固酶载体和导电基体构建了新型纳米结构固酶葡萄糖/O₂燃料电池,其制备简单,长期使用性能稳定。利用纳米金粒子通过表面修饰基团和酶分子活性中心附近疏水结合位之间的相互作用固定葡萄糖氧化酶(GO_x)和漆酶(Lac)分子,分别制备了固酶阳极-4-巯基苯甲酸功能化纳米金粒子固定葡萄糖氧化酶修饰金盘电极GO_x/4-MBA@GNP/Au和固酶阴极-4-巯基苯甲酸功能化纳米金粒子固定漆酶修饰金盘电极Lac/4-MBA@GNP/Au。电化学实验结果表明,两种电极在不引入任何外加电子中介的条件下,均可以实现酶活性中心-纳米金粒子之间的直接电子迁移,而且具有较快的催化反应能力(固酶阳极和阴极的转化速率分别为1.3和0.5 s^-1;催化葡萄糖氧化和氧气还原的起始电位分别为-0.23和0.76 V)。评估了固酶阳极和阴极组装成的纳米结构固酶葡萄糖/O₂燃料电池的能量输出性能。该燃料电池在没有Nafion薄膜和阳极无N₂气保护下,开路电压和最大输出能量密度分别可达0.56 V和760.0 μW/cm²,使用一周后输出能量密度仍然可以达到最初值的~88%。进一步测试结果显示,该燃料电池呈现出与游离漆酶类似的pH依赖关系和热稳定性,这些实验结果均暗示:影响整个酶燃料电池性能的关键在于漆酶基阴极催化氧还原的过程。此外,这种燃料电池的性能虽然受到共存干扰物抗坏血酸的影响,但在人类血清中测试结果显示其仍然具有较高的输出能量密度(132.0 μW/cm²,开路电压0.40 V)。本文研究结果给出了设计高性能葡萄糖/O₂燃料电池的新思路,同时也为研究固酶燃料电池的构效关系提供了实验依据和有价值的启示。

Performance of Biofuel Cell Based on 4-Mercaptobenzoic Acid Functionalized Nanoparticles Tethered with Glucose Oxidase and Laccase

A novel prototype of nano-structure glucose/O₂ biofuel cell was constructed with immobilized enzyme on 4-mercapto benzoic acid(4-MBA) modified gold nanoparticles as electrical medium and enzyme carrier. It features with simple fabrication and favorable long-term usability. Glucose oxidase(GO_x) and Laccase(Lac) molecules are tethered steadily to the surface of gold nanoparticles via interaction between modified group of gold nanoparticles and hydrophobic binding-sites in the vicinity of cofactor within enzyme. The as-prepared bioanode and biocathode are fabricated and denoted as GO_x/4-MBA@GNP/Au and Lac/4-MBA@GNP/Au, respectively. Electrochemical results indicate that the direct electron transfer occurs between enzyme active sites and gold nanoparticles for both biocathode and bioanode in the absence of any mediator achieves with fast catalytic activity(turn-over frequency of bioanode and biocathode:1.3 and 0.5 s^-1, onset potential according to the glucose catalytic oxidation and catalytic reduction of oxygen:-0.23 and 0.76 V). The power out-put performance of nano-structure with entrapped enzyme glucose/O₂ biofuel cell was further evaluated after the constitution of cell via connection bioanode and biocathode on the basis of previous results. The results of test show that the open-circuit voltage and the maximum out-put energy density of this biocell amount to 0.56 V and 760.0 μW/cm² in the absence of Nafion ion-exchange membrane and anode protection gas of N₂, respectively. The out-put density of biofuel cell after storage in refrigerator for one week can still retain ~88%of the initial value. Furthermore, this fuel cell shares the similar characteristics of pH dependence and thermal stability to those of free laccase. The key factor contributed to the performance of biofuel cell should be related to the catalytic oxygen reduction process at biocahode. Despite of the apparent influence of concomitant interferent-ascorbic acid on cell performance, this cell still shows superior out-put energy density(132.0 μW/cm², open circuit voltage:0.40 V) recorded in the circumstance of the human serum. This study may afford a new route to design in high performance glucose/O₂ fuel cell and provide experimental basis and valuable enlightenment for the study of relationship between the structure of enzyme based cell and its performance.