Huang Sizhe, Xiao Ruobai, Lin Shaoting, Wu Zuer, Lin Chen, Jang Geunho, Hong Eunji, Gupta Shovit, Lu Fake, Chen Bo, Liu Xinyue, Sahasrabudhe Atharva, Zhang Zicong, He Zhigang, Crosby Alfred J, Sumaria Kaushal, Liu Tingyi, Wang Qianbin, Rao Siyuan
Department of Biomedical Engineering, State University of New York at Binghamton, Binghamton, NY, 13902, USA.
Department of Mechanical Engineering, Michigan State University, East Lansing, MI, 48824, USA.
Nat Commun. 2025 Jan 28;16(1):1127. doi: 10.1038/s41467-025-56450-4.
Creating durable, motion-compliant neural interfaces is crucial for accessing dynamic tissues under in vivo conditions and linking neural activity with behaviors. Utilizing the self-alignment of nano-fillers in a polymeric matrix under repetitive tension, here, we introduce conductive carbon nanotubes with high aspect ratios into semi-crystalline polyvinyl alcohol hydrogels, and create electrically anisotropic percolation pathways through cyclic stretching. The resulting anisotropic hydrogel fibers (diameter of 187 ± 13 µm) exhibit fatigue resistance (up to 20,000 cycles at 20% strain) with a stretchability of 64.5 ± 7.9% and low electrochemical impedance (33.20 ± 9.27 kΩ @ 1 kHz in 1 cm length). We observe the reconstructed nanofillers' axial alignment and a corresponding anisotropic impedance decrease along the direction of cyclic stretching. We fabricate fiber-shaped hydrogels into bioelectronic devices and implant them into wild-type and transgenic Thy1::ChR2-EYFP mice to record electromyographic signals from muscles in anesthetized and freely moving conditions. These hydrogel fibers effectively enable the simultaneous recording of electrical signals from ventral spinal cord neurons and the tibialis anterior muscles during optogenetic stimulation. Importantly, the devices maintain functionality in intraspinal electrophysiology recordings over eight months after implantation, demonstrating their durability and potential for long-term monitoring in neurophysiological studies.
创建耐用、顺应运动的神经接口对于在体内条件下接触动态组织以及将神经活动与行为联系起来至关重要。在此，我们利用纳米填料在聚合物基质中在重复拉伸下的自排列，将高纵横比的导电碳纳米管引入半结晶聚乙烯醇水凝胶中，并通过循环拉伸创建电各向异性的渗流路径。由此产生的各向异性水凝胶纤维（直径为187±13μm）表现出抗疲劳性（在20%应变下可达20,000次循环），拉伸性为64.5±7.9%，且电化学阻抗低（在1cm长度下，1kHz时为33.20±9.27kΩ）。我们观察到重建的纳米填料轴向排列以及沿循环拉伸方向相应的各向异性阻抗降低。我们将纤维状水凝胶制成生物电子器件，并将其植入野生型和转基因Thy1::ChR2-EYFP小鼠体内，以在麻醉和自由活动条件下记录肌肉的肌电信号。这些水凝胶纤维能够在光遗传学刺激期间有效地同时记录来自腹侧脊髓神经元和胫前肌的电信号。重要的是，这些器件在植入后八个多月的脊髓内电生理记录中保持功能，证明了它们在神经生理学研究中的耐用性和长期监测潜力。
