Objective: To investigate chronic durability of transparent graphene electrodes fabricated on polyethylene terephthalate (PET) and SU-8 substrates for chronic in vivo studies. Methods: We perform systematic accelerated aging tests to understand the chronic reliability and failure modes of transparent graphene microelectrode arrays built on PET and SU-8 substrates. We employ graphene microelectrodes fabricated on PET substrate in chronic in vivo experiments with transgenic mice. Results: Our results show that graphene microelectrodes fabricated on PET substrate work reliably after 30 days accelerated aging test performed at 87 °C, equivalent to 960 days in vivo lifetime. We demonstrate stable chronic recordings of cortical potentials in multimodal imaging/recording experiments using transparent graphene microelectrodes fabricated on PET substrate. On the other hand, graphene microelectrode arrays built on SU-8 substrate exhibit extensive crack formation across microelectrode sites and wires after one to two weeks, resulting in total failure of recording capability for chronic studies. Conclusion: PET shows superior reliability as a substrate for graphene microelectrode arrays for chronic in vivo experiments. Significance: Graphene is a unique neural interface material enabling cross-talk free integration of electrical and optical recording and stimulation techniques in the same experiment. To date, graphene-based microelectrode arrays have been demonstrated in various multi-modal acute experiments involving electrophysiological sensing or stimulation, optical imaging and optogenetics stimulation. Understanding chronic reliability of graphene-based transparent interfaces is very important to expand the use of this technology for long-term behavioral studies with animal models.

中文翻译：

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不同柔性基材上制造的透明石墨烯电极用于慢性体内实验的耐久性评估

目的：研究在聚对苯二甲酸乙二醇酯 (PET) 和 SU-8 基材上制造的透明石墨烯电极的长期耐久性，用于长期体内研究。方法：我们进行系统的加速老化测试，以了解构建在 PET 和 SU-8 基板上的透明石墨烯微电极阵列的长期可靠性和失效模式。我们在转基因小鼠的长期体内实验中采用了在 PET 基底上制造的石墨烯微电极。结果：我们的结果表明，在 PET 基底上制造的石墨烯微电极在 87 °C 下进行 30 天的加速老化测试后可以可靠地工作，相当于 960 天的体内寿命。我们使用在 PET 基底上制造的透明石墨烯微电极在多模态成像/记录实验中展示了皮层电位的稳定长期记录。另一方面，在一到两周后，建立在 SU-8 基底上的石墨烯微电极阵列在微电极位点和导线上表现出广泛的裂纹形成，导致长期研究的记录能力完全失效。结论：PET 作为石墨烯微电极阵列基材在长期体内实验中表现出卓越的可靠性。意义：石墨烯是一种独特的神经接口材料，可以在同一实验中实现电学和光学记录以及刺激技术的无串扰集成。迄今为止，基于石墨烯的微电极阵列已在涉及电生理传感或刺激、光学成像和光遗传学刺激的各种多模式急性实验中得到证明。了解基于石墨烯的透明界面的长期可靠性对于扩大该技术在动物模型长期行为研究中的使用非常重要。