Ionic Liquid-Assisted Preparation of Laccase-Based Biocathodes with Improved Biocompatibility

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• 作者：Qin Qian ; Lei Su ; Ping Yu ; Hanjun Cheng ; Yuqing Lin ; Xiaoyong Jin ; Lanqun Mao
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：May 3, 2012
• 年：2012
• 卷：116
• 期：17
• 页码：5185-5191
• 全文大小：303K
• 年卷期：v.116,no.17(May 3, 2012)
• ISSN：1520-5207

文摘

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⁺PF₆^{鈥?/sup>). With the Bmim+PF₆鈥?/sup> overcoating, the laccase-based biocathodes possess a good bioelectrocatalytic activity toward O₂ reduction in neutral media and a high tolerance against Cl鈥?/sup>. Moreover, the Bmim+PF₆鈥?/sup> 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+PF₆鈥?/sup> overcoating are proposed based on the intrinsic features of ionic liquid Bmim+PF₆鈥?/sup>. To demonstrate the applications of the BFCs with the as-prepared biocathodes in biologically relevant systems, an AA/O₂ 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 渭W cm鈥? 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.}