Enzymes are promising electrocatalysts for electron transfer (ET) in many biological processes. Strategies to enhance ET between enzymes and electroactive surfaces include orientation and immobilization of the enzymes and electron mediation. Here, we develop a strategy to couple orientation and electron mediation on electrodes based on carbon nanotubes. This is achieved by the synthesis of a redox mediator that contains an enzyme-orientation site (pyrene), an electron-carrier redox mediator (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS)) and an electropolymerizable monomer (pyrrole). The coupling of an enzymatic orientation and a mediated ET in the same chemical structure (pyrrole–ABTS–pyrene (pyrr–ABTS–pyr)) provides a much-improved performance in the bioelectrocatalysis. We demonstrate two fuel cells for the synthesized redox mediator. In a proton-exchange membrane hydrogen/air fuel cell and in a membraneless fuel cell, the pyrr–ABTS–pyr biocathode provides a power density of 1.07 mW cm⁻² and 7.9 mW cm⁻², respectively. The principle of coupling an enzyme orientation and a redox mediator allows a great variety of mediators to be engineered and provides vast possibilities for the development of fuel cells.

在许多生物过程中，酶都是用于电子转移（ET）的有前途的电催化剂。增强酶和电活性表面之间的ET的策略包括酶的定向和固定化以及电子介导。在这里，我们开发了一种策略，可以在基于碳纳米管的电极上耦合取向和电子介导。这是通过合成包含酶定向位点（py）的氧化还原介体，电子载体氧化还原介体（2,2'-叠氮基-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS））来实现的和可电聚合的单体（吡咯）。在相同的化学结构（吡咯-ABTS-py（pyrr-ABTS-pyr））中酶方向和介导的ET的耦合在生物电催化中提供了大大改善的性能。我们演示了用于合成氧化还原介体的两个燃料电池。在质子交换膜氢/空气燃料电池和无膜燃料电池中，pyr–ABTS–pyr生物阴极提供的功率密度为1.07 mW cm^-2和7.9 mW cm ^-2。将酶方向和氧化还原介体耦合的原理允许设计多种介体，并为燃料电池的开发提供了广阔的可能性。