Materials Science and Engineering Program, University of California at Riverside, 900 University Avenue, Riverside, California, 92521.
Department of Bioengineering, University of California at Riverside, 900 University Avenue, Riverside, California, 92521.
J Biomed Mater Res A. 2018 Jul;106(7):1887-1895. doi: 10.1002/jbm.a.36385. Epub 2018 Apr 2.
Metals are widely used in electrode design for recording neural activities because of their excellent electrical conductivity and mechanical strength. However, there are still serious problems related to these currently used metallic electrodes, including tissue damage due to the mechanical mismatch between metals and neural tissues, fibrosis, and electrode fouling and encapsulation that lead to the loss of signal and eventual failure. In this study, a biocompatible, biodegradable, and conductive electrode was created. Specifically, pure magnesium (Mg) microwire with a diameter of 127 µm was used as the electrode substrate and the conductive polymer, that is, poly(3,4-ethylenedioxythiophene) (PEDOT), was electrochemically deposited onto Mg microwires to decrease corrosion rate and improve biocompatibility of the electrodes for potential neural electrode applications. Both chronopotentiometry and cyclic voltammetry (CV) methods and the associated parameters for electrochemical deposition of PEDOT onto Mg microwires were investigated, such as deposition current, deposition temperature, voltage, sweep rate, cycle number, and duration. The CV method from -2.0 to 1.25 V for 1 cycle at a cycle duration of 600 s with a sweep rate of 5 mV/s at 65°C led to a consistent, uniform, and complete PEDOT coating on Mg microwires. The surface conditions of Mg microwires also affected the quality of PEDOT coating. The corrosion rate of PEDOT-coated Mg microwire was 0.75 mm/year, much slower than the noncoated Mg microwire that showed a corrosion rate of 1.78 mm/year. The optimal Mg microwires with PEDOT coating could potentially serve as biodegradable electrodes for neural recording and stimulation applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1887-1895, 2018.
金属由于其优异的导电性和机械强度，被广泛应用于电极设计以记录神经活动。然而，目前使用的金属电极仍然存在严重的问题，包括金属与神经组织之间的机械不匹配导致的组织损伤、纤维化以及电极污染和封装，这些都会导致信号丢失，最终导致电极失效。在本研究中，我们制备了一种具有生物相容性、可生物降解和导电性的电极。具体来说，我们使用直径为 127 µm 的纯镁（Mg）微米线作为电极基底，并通过电化学沉积导电聚合物，即聚（3,4-亚乙基二氧噻吩）（PEDOT），来降低镁微米线的腐蚀速率并提高电极的生物相容性，使其适用于潜在的神经电极应用。我们研究了电化学沉积 PEDOT 到 Mg 微米线的恒电流电位法和循环伏安法（CV）及其相关参数，如沉积电流、沉积温度、电压、扫速、循环次数和时间。CV 方法在 65°C 下以 5 mV/s 的扫速进行 1 个循环，持续时间为 600 s，在 -2.0 到 1.25 V 的范围内进行，导致在 Mg 微米线上形成了一致、均匀和完整的 PEDOT 涂层。Mg 微米线的表面状态也影响 PEDOT 涂层的质量。涂有 PEDOT 的 Mg 微米线的腐蚀速率为 0.75 mm/年，远低于非涂层 Mg 微米线的 1.78 mm/年。具有 PEDOT 涂层的最佳 Mg 微米线有可能作为神经记录和刺激应用的可生物降解电极。© 2018 Wiley Periodicals, Inc. J 生物材料研究杂志 A 部分：106A：1887-1895，2018。
