National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China.
Department of Biomedical Engineering, Tufts University, Medford, MA 02155.
Proc Natl Acad Sci U S A. 2023 Aug 15;120(33):e2305704120. doi: 10.1073/pnas.2305704120. Epub 2023 Aug 7.
Biocompatible and morphable hydrogels capable of multimode reprogrammable, and adaptive shape changes are potentially useful for diverse biomedical applications. However, existing morphable systems often rely on complicated structural designs involving cumbersome and energy-intensive fabrication processes. Here, we report a simple electric-field-activated protein network migration strategy to reversibly program silk-protein hydrogels with controllable and reprogrammable complex shape transformations. The application of a low electric field enables the convergence of net negatively charged protein cross-linking networks toward the anode (isoelectric point plane) due to the pH gradient generated in the process, facilitating the formation of a gradient network structure and systems suitable for three-dimensional shape change. These tunable protein networks can be reprogrammed or permanently fixed by control of the polymorphic transitions. We show that these morphing hydrogels are capable of conformally interfacing with biological tissues by programming the shape changes and a bimorph structure consisting of aligned carbon nanotube multilayers and the silk hydrogels was assembled to illustrate utility as an implantable bioelectronic device for localized low-voltage electrical stimulation of the sciatic nerve in a rabbit.
具有生物相容性和可变形的水凝胶能够实现多模式可重编程和自适应形状变化，对于各种生物医学应用具有潜在的用途。然而，现有的可变形系统通常依赖于涉及繁琐和能源密集型制造工艺的复杂结构设计。在这里，我们报告了一种简单的电场激活蛋白网络迁移策略，用于可逆地对丝蛋白水凝胶进行可编程控制和可重编程的复杂形状转变。施加低电场会导致净负电荷蛋白交联网络由于在该过程中产生的 pH 梯度而向阳极（等电点平面）收敛，从而有利于形成梯度网络结构和适合三维形状变化的系统。这些可调蛋白网络可以通过控制多态转变来进行重新编程或永久固定。我们表明，这些变形水凝胶能够通过编程形状变化和双折射结构来与生物组织贴合，该双折射结构由对齐的碳纳米管多层和丝蛋白水凝胶组成，用于说明作为一种可植入的生物电子设备的实用性，可用于在兔子的坐骨神经上进行局部低压电刺激。
