Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, the Chinese Academy of Sciences (CAS), Beijing, P R China.
J Phys Chem B. 2012 May 3;116(17):5185-91. doi: 10.1021/jp3006475. Epub 2012 Apr 23.
Laccase enzyme has been widely used as the catalyst of the biocathodes in enzymatic biofuel cells (BFCs); the poor biocompatibility of this enzyme (e.g., poor catalytic activity in neutral media and low tolerance against chloride ion) and the lack of selectivity for oxygen reduction at the laccase-based biocathode against ascorbic acid, unfortunately, offer a great limitation to future biological applications of laccase-based BFCs. This study demonstrates a facial yet effective solution to these limitations with the assistance of hydrophobic room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (Bmim(+)PF(6)(-)). With the Bmim(+)PF(6)(-) overcoating, the laccase-based biocathodes possess a good bioelectrocatalytic activity toward O(2) reduction in neutral media and a high tolerance against Cl(-). Moreover, the Bmim(+)PF(6)(-) overcoating applied to the laccase-based biocathodes also well suppresses the oxidation of ascorbic acid (AA) at the biocathodes and thereby avoids the AA-induced decrease in the power output of the laccase-based BFCs. The mechanisms underlying the excellent properties of the Bmim(+)PF(6)(-) overcoating are proposed based on the intrinsic features of ionic liquid Bmim(+)PF(6)(-). To demonstrate the applications of the BFCs with the as-prepared biocathodes in biologically relevant systems, an AA/O(2) BFC is assembled with single-walled carbon nanotubes (SWNTs) as electrode materials both for accelerating AA oxidation at the bioanode and for promoting direct electron transfer of laccase at the biocathode. With the presence of 0.50 mM AA in 0.10 M quiescent phosphate buffer (pH 7.2), the assembled BFC has an open circuit voltage of 0.73 V and a maximum power output of 24 μW cm(-2) at 0.40 V under ambient air and room temperature. This study essentially offers a new strategy for the development of enzymatic BFCs with a high biocompatibility.
漆酶酶已被广泛用作酶生物燃料电池 (BFCs) 中的生物阴极催化剂；该酶的生物相容性差（例如，在中性介质中的催化活性差，以及对氯离子的容忍度低），并且在基于漆酶的生物阴极对抗坏血酸的氧气还原反应中缺乏选择性，不幸的是，这为基于漆酶的 BFC 的未来生物应用提供了极大的限制。本研究通过疏水性室温离子液体 1-丁基-3-甲基咪唑六氟磷酸盐（Bmim(+)PF(6)(-)）提供了一种简单而有效的解决方案。通过 Bmim(+)PF(6)(-)覆盖，基于漆酶的生物阴极在中性介质中对 O(2)还原具有良好的生物电催化活性，并且对 Cl(-)具有高容忍度。此外，应用于基于漆酶的生物阴极的 Bmim(+)PF(6)(-)覆盖物还很好地抑制了生物阴极处抗坏血酸 (AA)的氧化，从而避免了 AA 降低基于漆酶的 BFC 的功率输出。基于离子液体 Bmim(+)PF(6)(-)的固有特性，提出了 Bmim(+)PF(6)(-)覆盖的优异性能的机制。为了展示具有预制备生物阴极的 BFC 在生物学相关系统中的应用，组装了一个 AA/O(2)BFC，其中单壁碳纳米管 (SWNTs) 用作电极材料，以加速生物阳极处的 AA 氧化，并促进漆酶在生物阴极处的直接电子转移。在 0.10 M 静止磷酸盐缓冲液（pH 7.2）中存在 0.50 mM AA 的情况下，在环境空气中和室温下，组装的 BFC 在 0.40 V 时具有 0.73 V 的开路电压和 24 μW cm(-2) 的最大功率输出。这项研究为开发具有高生物相容性的酶 BFC 提供了新的策略。
