Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR 999077, China.
School of Biological Sciences, The University of Hong Kong, Hong Kong SAR 999077, China.
ACS Appl Mater Interfaces. 2021 Feb 17;13(6):7539-7545. doi: 10.1021/acsami.0c21148. Epub 2021 Feb 3.
Recent research on conductive hydrogels has revealed their potential for building advanced soft bioelectronic devices. Their mechanical flexibility, water content, and porosity approach those of biological tissues, providing a compliant interface between the human body and electronic hardware. Conductive hydrogels could be utilized in many soft tools such as neural electrodes, tactile interfaces, soft actuators, and other electroactive devices. However, most of the available conductive hydrogels exhibit weak mechanical properties, which hinders their application in durable biointegrated systems. Here, we report aramid nanofiber-based hydrogels providing a combination of high elasticity, strength, and electrical conductivity. Highly branched aramid nanofibers (ANFs) provide a robust three-dimensional (3D) framework resembling those in load-bearing soft tissues. When interlaced with poly(vinyl alcohol) (PVA) and cross-linked with both noncovalent and covalent interactions, the nanofiber composites exhibit a high water content of ∼76.4 wt %, strength of ∼7.5 MPa, ductility of ∼407%, and shape recovery of ∼99.5% under cyclic tensile stress of 0.3 MPa. Mobile ions impart a conductivity of ∼2 S/m to the hydrogels, enabling large-strain sensors with stable operation. In addition, the embedded silver nanoparticles afford broad-spectrum antimicrobial activities, which is favorable for medical devices. The versatility of aramid nanofiber-based composites suggests their further possibilities for functionalization and scalable fabrication toward sophisticated bioelectronic systems.
最近对导电水凝胶的研究揭示了它们在构建先进的软生物电子设备方面的潜力。它们的机械灵活性、含水量和多孔性与生物组织相近，为人体和电子硬件之间提供了一个顺应性的接口。导电水凝胶可用于许多软工具，如神经电极、触觉接口、软致动器和其他电活性器件。然而，大多数现有的导电水凝胶表现出较弱的机械性能，这阻碍了它们在耐用的生物集成系统中的应用。在这里，我们报告了基于芳纶纳米纤维的水凝胶，它提供了高弹性、高强度和导电性的结合。高度支化的芳纶纳米纤维（ANF）提供了类似于承重软组织的坚固的三维（3D）框架。当与聚乙烯醇（PVA）交织并通过非共价和共价相互作用交联时，纳米纤维复合材料表现出高含水量约为 76.4wt%、强度约为 7.5MPa、延展性约为 407%和在 0.3MPa 的循环拉伸应力下的形状恢复约为 99.5%。可移动离子赋予水凝胶约 2S/m 的电导率，使大应变传感器能够稳定运行。此外，嵌入的银纳米粒子赋予了广谱的抗菌活性，这有利于医疗器械。芳纶纳米纤维基复合材料的多功能性表明，它们在功能化和可扩展制造方面具有进一步的可能性，以实现复杂的生物电子系统。
