Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA; Center for Polymer-based Protein Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
Center for Polymer-based Protein Engineering, Carnegie Mellon University, Pittsburgh, PA, USA; Disruptive Health Technology Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
Biosens Bioelectron. 2016 Dec 15;86:446-453. doi: 10.1016/j.bios.2016.06.078. Epub 2016 Jun 29.
Enzymatic biofuel cells (EBFCs) are capable of generating electricity from physiologically present fuels making them promising power sources for the future of implantable devices. The potential application of such systems is limited, however, by inefficient current generation. Polymer-based protein engineering (PBPE) offers a unique method to tailor enzyme function through tunable modification of the enzyme surface with functional polymers. In this study, we report on the modification of glucose oxidase (GOX) with ferrocene-containing redox polymers to increase current generation efficiency in an enzyme-modified anode. Poly(N-(3-dimethyl(ferrocenyl)methylammonium bromide)propyl acrylamide) (pFcAc) was grown from covalently attached, water-soluble initiator molecules on the surface of GOX in a "grafting-from" approach using atom transfer radical polymerization (ATRP). The covalently-coupled ferrocene-containing polymers on the enzyme surface promoted the effective "wiring" of the GOX active site to an external electrode. The resulting GOX-pFcAc conjugates generated over an order of magnitude increase in current generation efficiency and a 4-fold increase in maximum EBFC power density (≈1.7µWcm(-2)) with similar open circuit voltage (0.27V) compared to native GOX when physically adsorbed onto paddle-shaped electrodes made up of electrospun polyacrylonitrile fibers coated with gold nanoparticles and multi-wall carbon nanotubes. The formation of electroactive enzyme-redox polymer conjugates using PBPE represents a powerful new tool for the improvement of mediated enzyme-based bioelectronics without the need for free redox mediators or anode/cathode compartmentalization.
酶生物燃料电池 (EBFC) 能够从生理上存在的燃料中产生电能，因此它们是植入式设备未来有前途的电源。然而，此类系统的潜在应用受到低效电流产生的限制。基于聚合物的蛋白质工程 (PBPE) 通过用功能聚合物对酶表面进行可调修饰，提供了一种独特的方法来定制酶的功能。在这项研究中，我们报告了用含二茂铁的氧化还原聚合物修饰葡萄糖氧化酶 (GOX)，以提高酶修饰阳极中的电流产生效率。聚（N-(3-二甲基（二茂铁基）甲基铵溴）丙基丙烯酰胺）（pFcAc）通过原子转移自由基聚合 (ATRP) 以“从接枝”方式从共价附着的水溶性引发剂分子在 GOX 表面生长。在酶表面上共价偶联的含二茂铁聚合物促进了 GOX 活性位点与外部电极的有效“布线”。与天然 GOX 相比，所得的 GOX-pFcAc 缀合物在物理吸附到由涂有金纳米颗粒和多壁碳纳米管的电纺聚丙烯腈纤维制成的桨形电极上时，电流产生效率提高了一个数量级，最大 EBFC 功率密度（≈1.7µWcm(-2)) 增加了 4 倍（0.27V）。使用 PBPE 形成电活性酶-氧化还原聚合物缀合物代表了一种改进基于酶的生物电子学的强大新工具，而无需游离氧化还原介体或阳极/阴极分隔。
