Bioinspired hybrid soft robots that combine living and synthetic components are an emerging field in the development of advanced actuators and other robotic platforms (i.e., swimmers, crawlers, and walkers). The integration of biological components offers unique characteristics that artificial materials cannot precisely replicate, such as adaptability and response to external stimuli. Here, we present a skeletal muscle–based swimming biobot with a three-dimensional (3D)–printed serpentine spring skeleton that provides mechanical integrity and self-stimulation during the cell maturation process. The restoring force inherent to the spring system allows a dynamic skeleton compliance upon spontaneous muscle contraction, leading to a cyclic mechanical stimulation process that improves the muscle force output without external stimuli. Optimization of the 3D-printed skeletons is carried out by studying the geometrical stiffnesses of different designs via finite element analysis. Upon electrical actuation of the muscle tissue, two types of motion mechanisms are experimentally observed: directional swimming when the biobot is at the liquid-air interface and coasting motion when it is near the bottom surface. The integrated compliant skeleton provides both the mechanical self-stimulation and the required asymmetry for directional motion, displaying its maximum velocity at 5 hertz (800 micrometers per second, 3 body lengths per second). This skeletal muscle–based biohybrid swimmer attains speeds comparable with those of cardiac-based biohybrid robots and outperforms other muscle-based swimmers. The integration of serpentine-like structures in hybrid robotic systems allows self-stimulation processes that could lead to higher force outputs in current and future biomimetic robotic platforms.

结合生物和合成组件的仿生混合软机器人是高级执行器和其他机器人平台（即游泳者、爬行者和步行者）开发的新兴领域。生物成分的整合提供了人工材料无法精确复制的独特特性，例如对外部刺激的适应性和反应。在这里，我们展示了一种基于骨骼肌的游泳生物机器人，具有 3D 打印的蛇形弹簧骨架，可在细胞成熟过程中提供机械完整性和自我刺激。弹簧系统固有的恢复力允许在自发肌肉收缩时动态骨骼顺应性，导致循环机械刺激过程，在没有外部刺激的情况下提高肌肉力输出。3D 打印骨架的优化是通过有限元分析研究不同设计的几何刚度来进行的。在肌肉组织的电驱动下，通过实验观察到两种运动机制：生物机器人在液-气界面时的定向游泳和靠近底面时的滑行运动。集成的柔顺骨架提供机械自刺激和定向运动所需的不对称性，显示其最大速度为 5 赫兹（每秒 800 微米，每秒 3 个身体长度）。这种基于骨骼肌的生物混合游泳运动员的速度可与基于心脏的生物混合机器人相媲美，并且优于其他基于肌肉的游泳运动员。