Harvard Program in Biophysics, Harvard University, Cambridge, MA, USA.
Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA.
Nat Nanotechnol. 2021 Sep;16(9):1019-1029. doi: 10.1038/s41565-021-00926-z. Epub 2021 Jun 17.
Living tissues are non-linearly elastic materials that exhibit viscoelasticity and plasticity. Man-made, implantable bioelectronic arrays mainly rely on rigid or elastic encapsulation materials and stiff films of ductile metals that can be manipulated with microscopic precision to offer reliable electrical properties. In this study, we have engineered a surface microelectrode array that replaces the traditional encapsulation and conductive components with viscoelastic materials. Our array overcomes previous limitations in matching the stiffness and relaxation behaviour of soft biological tissues by using hydrogels as the outer layers. We have introduced a hydrogel-based conductor made from an ionically conductive alginate matrix enhanced with carbon nanomaterials, which provide electrical percolation even at low loading fractions. Our combination of conducting and insulating viscoelastic materials, with top-down manufacturing, allows for the fabrication of electrode arrays compatible with standard electrophysiology platforms. Our arrays intimately conform to the convoluted surface of the heart or brain cortex and offer promising bioengineering applications for recording and stimulation.
活体组织是非线性弹性材料，具有粘弹性和塑性。人造的、可植入的生物电子阵列主要依赖于刚性或弹性封装材料和延展性金属的刚性薄膜，这些材料可以通过微观精度进行操纵，以提供可靠的电气性能。在这项研究中，我们设计了一种表面微电极阵列，用粘弹性材料替代了传统的封装和导电组件。我们的阵列克服了以前在匹配软生物组织的刚度和松弛行为方面的限制，方法是将水凝胶用作外层。我们引入了一种基于水凝胶的导体，它由离子导电的海藻酸钠基质增强的碳纳米材料制成，即使在低负载分数下也能提供电渗流。我们的导电和绝缘粘弹性材料的组合，以及自上而下的制造方法，允许制造与标准电生理学平台兼容的电极阵列。我们的阵列与心脏或大脑皮层的凹凸不平的表面紧密贴合，并为记录和刺激提供了有前途的生物工程应用。
