Zwitterionic bottlebrush elastomers for bioelectronics

植入式生物电子学的进步正在改变我们对神经系统疾病的理解和治疗。例如，像Neuralink和Kernel这样的商业企业正在利用纤维状的柔性探针实现超高带宽脑机接口。因为慢性植入是终身疾病所需要的，所以考虑减轻导致设备失效的免疫反应的策略是很重要的。改善组织相容性的一种方法是通过使用低弯曲刚度结构或低模量材料来降低设备的机械刚度，但这些努力与柔软生物组织的模量不匹配。把你嘴唇的柔软度和手机里的电子元件相比较——你可以直观地分辨出柔软度和拉伸度的巨大差异。在制造与生物组织具有良好机械匹配的电子材料方面取得了进展；一类叫做水凝胶的材料就是一个例子。然而，水凝胶含有大量的水，这使电子性能和设备制造变得复杂（例如，很难将湿层粘附在一起）。此外，在制造材料方面也取得了进展，这些材料可以通过精确的化学功能，延缓和避免设备故障，有效地隐身于我们的免疫系统。这些材料无污染或有效地模拟自然环境，避免了导致纤维化胶囊形成和设备故障的免疫事件级联。然而，化学策略本身不足以长期植入设备。目前，利用机械和化学方法的集成材料平台还不存在，这是延长植入时间的潜在解决方案。本文所描述的工作是化学家和物理学家之间的合作努力，以合成无污垢的超软材料，并随后表征其机械性能，以设计用于植入式设备的下一代涂层。

Advances in implantable bioelectronics are changing our understanding and treatment of neurological disorders. For example, commercial ventures like Neuralink and Kernel are realizing ultra-high-bandwidth brain-machine interfaces with fiber-like flexible probes. Because chronic implantation is needed for lifelong disorders, it is important to consider strategies to mitigate the immunological responses that lead to device failure. One approach to improving tissue compatibility is to reduce the mechanical rigidity of devices by using low bending stiffness architectures or lower-modulus materials, but these efforts have not matched the moduli of soft biological tissue. Consider the softness of your lips to the electronics in your mobile phones-- you can intuitively discern a large difference in softness and stretchability. There have been advances in making electronic materials with a good mechanical match to biological tissue; one example is a class of material called hydrogels. However, hydrogels contain substantial water, which complicates electronic performance and device fabrication (e.g., it is difficult to adhere wet layers together). Also, there have been advances in making materials that are effectively stealth to our immune system through precise chemical functionalities, delaying and avoiding device failure. These materials are non-fouling or effectively mimic the natural milieu, avoiding the cascade of immunological events that leads to fibrotic capsule formation and device failure. However, chemical strategies alone are insufficient for long-term implantation of devices. Currently, an integrated materials platform that exploits both mechanical and chemical approaches does not exist and poses as a potential solution for extending implantation time. There work described herein is a collaborative effort between a chemist and physicist to synthesize ultrasoft materials that are non-fouling and subsequently characterize their mechanical properties to design the next generation of coatings for implantable devices.