Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan.
Small. 2020 Aug;16(34):e2001849. doi: 10.1002/smll.202001849. Epub 2020 Jul 30.
Microbial electrochemical systems in which metabolic electrons in living microbes have been extracted to or injected from an extracellular electrical circuit have attracted considerable attention as environmentally-friendly energy conversion systems. Since general microbes cannot exchange electrons with extracellular solids, electron mediators are needed to connect living cells to an extracellular electrode. Although hydrophobic small molecules that can penetrate cell membranes are commonly used as electron mediators, they cannot be dissolved at high concentrations in aqueous media. The use of hydrophobic mediators in combination with small hydrophilic redox molecules can substantially increase the efficiency of the extracellular electron transfer process, but this method has side effects, in some cases, such as cytotoxicity and environmental pollution. In this Review, recently-developed redox-active polymers are highlighted as a new type of electron mediator that has less cytotoxicity than many conventional electron mediators. Owing to the design flexibility of polymer structures, important parameters that affect electron transport properties, such as redox potential, the balance of hydrophobicity and hydrophilicity, and electron conductivity, can be systematically regulated.
微生物电化学系统中，从微生物的代谢电子中提取或注入到细胞外电路中，作为环保的能量转换系统已经引起了广泛的关注。由于普通微生物不能与细胞外的固体交换电子，因此需要电子媒介物将活细胞与细胞外电极连接起来。虽然可以穿透细胞膜的疏水分子通常被用作电子媒介物，但它们在水介质中不能高浓度溶解。将疏水分子与小的亲水性氧化还原分子一起使用，可以显著提高细胞外电子转移过程的效率，但这种方法有副作用，例如在某些情况下的细胞毒性和环境污染。在这篇综述中，强调了最近开发的氧化还原活性聚合物作为一种新型电子媒介物，其细胞毒性比许多传统电子媒介物要小。由于聚合物结构的设计灵活性，可以系统地调节影响电子传输性质的重要参数，如氧化还原电位、疏水性和亲水性的平衡以及电子导电性。
