Quintero-Jaime Andrés Felipe, Cazorla-Amorós Diego, Morallón Emilia
Departamento de Química Física and Instituto Universitario de Materiales de Alicante (IUMA), University of Alicante, Ap. 99, 03080 Alicante, Spain.
Bernal Institute and Department of Chemical Sciences, School of Natural Sciences, University of Limerick (UL), V94 T9PX Limerick, Ireland.
Nanomaterials (Basel). 2025 May 11;15(10):722. doi: 10.3390/nano15100722.
The development of efficient electron transfer between enzymatic elements and the electrode is considered an important issue in the synthesis and design of bioelectrochemical devices. In this regard, the modification of the surface properties is an effective route to obtain a high-performance electrode using enzymatic elements. As we present here, understanding the role of surface functional groups generated by the electrochemical functionalization of graphene-based materials facilitates the design and optimization of effective electroactive bioelectrodes. In this sense, the surface chemistry directly influences the inherent electrocatalytic activity of cytochrome c (Cyt C) toward the electrochemical reduction of HO. Although the surface oxygen groups provide an immobilization matrix for the Cyt C in the pristine graphene oxide, the electrochemical functionalization with N and P species in one step significantly improves the electrocatalytic activity, since they may facilitate an optimal electrostatic interaction and orientation between the electrode material and the redox heme cofactor in the Cyt C, enhancing the electron transfer process. On the other hand, the lack of surface functional groups in the reduced graphene oxide does not favor the electron transfer with the Cyt C immobilized on the surface being completely inactive. Thus, the incorporation of surface groups using electrochemical functionalization with N and P species provokes a remarkable enhancement of the electrocatalytic activity of cytochrome c, up to four times more than the HO reduction reaction. This demonstrated the effectiveness of the functionalization process and the impact in the electrochemical performance of Cyt C immobilized in graphene-based electrodes.
酶元件与电极之间高效电子转移的发展被认为是生物电化学装置合成与设计中的一个重要问题。在这方面，改变表面性质是使用酶元件获得高性能电极的有效途径。正如我们在此所展示的，了解基于石墨烯材料的电化学功能化所产生的表面官能团的作用有助于有效电活性生物电极的设计与优化。从这个意义上讲，表面化学直接影响细胞色素c（Cyt C）对HO电化学还原的固有电催化活性。尽管表面氧基团为原始氧化石墨烯中的Cyt C提供了固定基质，但一步法用N和P物种进行电化学功能化可显著提高电催化活性，因为它们可能促进电极材料与Cyt C中氧化还原血红素辅因子之间的最佳静电相互作用和取向，增强电子转移过程。另一方面，还原氧化石墨烯中缺乏表面官能团不利于与固定在表面的Cyt C进行电子转移，导致其完全无活性。因此，通过用N和P物种进行电化学功能化引入表面基团可显著提高细胞色素c的电催化活性，比HO还原反应高出四倍之多。这证明了功能化过程的有效性以及对固定在基于石墨烯电极中的Cyt C电化学性能的影响。
