Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, SE 41296, Sweden.
Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 201, 79110, Freiburg, Germany.
Adv Sci (Weinh). 2024 Jul;11(27):e2306244. doi: 10.1002/advs.202306244. Epub 2024 Mar 9.
Many biological processes rely on endogenous electric fields (EFs), including tissue regeneration, cell development, wound healing, and cancer metastasis. Mimicking these biological EFs by applying external direct current stimulation (DCS) is therefore the key to many new therapeutic strategies. During DCS, the charge transfer from electrode to tissue relies on a combination of reversible and irreversible electrochemical processes, which may generate toxic or bio-altering substances, including metal ions and reactive oxygen species (ROS). Poly(3,4-ethylenedioxythiophene) (PEDOT) based electrodes are emerging as suitable candidates for DCS to improve biocompatibility compared to metals. This work addresses whether PEDOT electrodes can be tailored to favor reversible biocompatible charge transfer. To this end, different PEDOT formulations and their respective back electrodes are studied using cyclic voltammetry, chronopotentiometry, and direct measurements of HO and O. This combination of electrochemical methods sheds light on the time dynamics of reversible and irreversible charge transfer and the relationship between capacitance and ROS generation. The results presented here show that although all electrode materials investigated generate ROS, the onset of ROS can be delayed by increasing the electrode's capacitance via PEDOT coating, which has implications for future bioelectronic devices that allow longer reversibly driven pulse durations during DCS.
许多生物过程依赖于内源性电场 (EFs)，包括组织再生、细胞发育、伤口愈合和癌症转移。因此，通过施加外部直流刺激 (DCS) 来模拟这些生物 EF 是许多新治疗策略的关键。在 DCS 过程中，从电极到组织的电荷转移依赖于可逆和不可逆电化学过程的组合，这可能会产生有毒或改变生物的物质，包括金属离子和活性氧物种 (ROS)。与金属相比，基于聚(3,4-亚乙基二氧噻吩) (PEDOT) 的电极作为 DCS 的合适候选材料，具有改善生物相容性的优势。这项工作旨在探讨是否可以对 PEDOT 电极进行定制，以有利于可逆的生物相容性电荷转移。为此，使用循环伏安法、恒电流计时法和 HO 和 O 的直接测量研究了不同的 PEDOT 配方及其各自的背电极。电化学方法的这种组合揭示了可逆和不可逆电荷转移的时间动态以及电容与 ROS 生成之间的关系。这里呈现的结果表明，尽管所有研究的电极材料都会产生 ROS，但通过增加 PEDOT 涂层来增加电极的电容可以延迟 ROS 的产生，这对未来允许在 DCS 期间进行更长时间可逆驱动脉冲持续时间的生物电子设备具有重要意义。
