Characterizing and mitigating the role of oxidative damage in microelectrode failure

Capadona研究小组已经确定了炎症介导的氧化应激产物在 微电极引发的神经炎症是导致贫困的最全面的来源 电极可靠性。为了实现使用皮质内微电极的任何应用的潜力， 我们必须最大限度地减少氧化应激产物造成的降解性副作用，而不是抑制 有利于伤口愈合的炎症方面。 我们已经使用了各种抗氧化剂治疗来证明皮质内的 微电极介导的氧化应激和保存神经元活性。我们最有希望的战略是 提高皮质内记录可靠性的日期是我们的仿生抗氧化涂层。我们最初的 努力集中在平面硅衬底，以便于表征，成本和它们最近的流行 在文学作品中。我们的初步数据表明，我们的新型抗氧化剂涂层微电极可以减少 初始炎症反应，保存神经元数量，提高初始记录质量。 最初的模拟涂层并不是一个全面的抗氧化策略。氧化应激可以是 由损伤相关分子模式(DAMPS)或病原体相关分子启动 模式(PAMP)途径。在拟议的研究中，我们将具体调查 涂有抗氧化剂的微电极对刺激和神经记录的稳定性有影响。我们的 电极上将涂有针对PAMP、DAMP或同时针对PAMP和DAMP的抗氧化剂 路径，以便制定一种全面的、但不过度压制的方法。 为了适用于正在进行的临床试验，我们的涂层还必须可翻译为仅 美国FDA批准的穿透式记录微电极。因此，我们已经证明了这些 抗氧化剂可以附着在对二甲苯C上。这一建议的创新之处在于应用了一种 平台方法表面改性对二甲苯C涂层黑岩阵列，有效地减少两个 皮质内微电极失效的主要原因：材料损伤和生物损伤。 在更基本的层面上，这项工作还将研究如何改变大脑皮质内的维度 微电极同时影响ROS和组织反应。超薄的设备，无论 材料固有的杨氏模数，变得非常灵活。由于它的高度断裂 电阻，我们将利用非晶态碳化硅制造具有小尺寸的微电极探头 厚度。这样的探针将使我们能够测试氧化应激和 神经炎症与装置的尺寸和由此产生的僵硬成正比。我们将进一步 证明相关的氧化应激和神经炎症是由更大更僵硬的 通过在植入物上涂上抗氧化剂，可以使设备变得柔和。

The Capadona group has identified the role of inflammation-mediated oxidative stress products in microelectrode-initiated neuroinflammation to be the most comprehensive source contributing to poor electrode reliability. In order to realize the potential of any application using intracortical microelectrodes, we must minimize the degradative side effects caused by oxidative stress products, without inhibiting the beneficial wound healing aspects of inflammation. We have used a variety of antioxidant treatments to demonstrate a reduction in intracortical microelectrode-mediated oxidative stress and preserve neuron viability. Our most promising strategy to date for improving intracortical recording reliability is our biomimetic antioxidative coating. Our initial efforts focused on planar silicon substrates for ease of characterization, cost, and their recent popularity in the literature. Our preliminary data suggest that our novel antioxidative-coated microelectrodes reduce the initial inflammatory response, preserve neuron populations, and improve initial recording quality. The initial mimetic coating is not a comprehensive antioxidative strategy. Oxidative stress can be initiated by either a damage-associated molecular patterns (DAMPs) or pathogen-associated molecular patterns (PAMPs) pathway. In the proposed study, we will specifically investigate the effect that antioxidant-coated microelectrodes have on the stability of stimulation and neural recordings. Our electrodes will be coated with antioxidants that target either PAMP, DAMP, or both PAMP and DAMP pathways, in order to develop a comprehensive, but not overly suppressive approach. In order to be applicable to on-going clinical trials, our coating must also be translatable to the only penetrating recording microelectrode approved by the US FDA. Therefore, we have shown that these antioxidants can be attached to Parylene C. The innovation of this proposal is in the application of a platform approach to surface modify Parylene C coated Blackrock Arrays, to effectively minimize two of the leading causes of intracortical microelectrode failure: materials damage and biological damage. On a more fundamental level, this work will also examine how varying the dimensions of intracortical microelectrodes impacts both ROS and the tissue response. Extremely thin devices, regardless of inherent Young's modulus of the constituent material, become very flexible. Due to its high fracture resistance, we will leverage amorphous silicon carbide to create microelectrode probes with small thicknesses. Such probes will enable us to test the hypothesis that oxidative stress and neuroinflammation are proportional to the device dimension and resulting rigidity. We will further demonstrate that the associated oxidative stress and neuroinflammation generated from larger more rigid devices can be subdued by coating the implant with antioxidants.