000148287 001__ 148287 000148287 005__ 20250115160155.0 000148287 0247_ $$2doi$$a10.1126/scirobotics.abe7577 000148287 0248_ $$2sideral$$a135318 000148287 037__ $$aART-2021-135318 000148287 041__ $$aeng 000148287 100__ $$aGuix, Maria 000148287 245__ $$aBiohybrid soft robots with self-stimulating skeletons 000148287 260__ $$c2021 000148287 5060_ $$aAccess copy available to the general public$$fUnrestricted 000148287 5203_ $$aBioinspired 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. 000148287 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000148287 590__ $$a27.541$$b2021 000148287 591__ $$aROBOTICS$$b1 / 30 = 0.033$$c2021$$dQ1$$eT1 000148287 592__ $$a6.569$$b2021 000148287 593__ $$aArtificial Intelligence$$c2021$$dQ1 000148287 593__ $$aMechanical Engineering$$c2021$$dQ1 000148287 593__ $$aComputer Science Applications$$c2021$$dQ1 000148287 594__ $$a32.6$$b2021 000148287 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/acceptedVersion 000148287 700__ $$aMestre, Rafael 000148287 700__ $$aPatiño, Tania 000148287 700__ $$0(orcid)0000-0002-9361-4794$$aDe Corato, Marco$$uUniversidad de Zaragoza 000148287 700__ $$aFuentes, Judith 000148287 700__ $$aZarpellon, Giulia 000148287 700__ $$aSánchez, Samuel 000148287 7102_ $$15001$$2600$$aUniversidad de Zaragoza$$bDpto. Ciencia Tecnol.Mater.Fl.$$cÁrea Mecánica de Fluidos 000148287 773__ $$g6, 53 (2021), eabe7577 [13 pp.]$$pSci. robotics$$tScience robotics$$x2470-9476 000148287 8564_ $$s2565451$$uhttps://zaguan.unizar.es/record/148287/files/texto_completo.pdf$$yPostprint 000148287 8564_ $$s1331741$$uhttps://zaguan.unizar.es/record/148287/files/texto_completo.jpg?subformat=icon$$xicon$$yPostprint 000148287 909CO $$ooai:zaguan.unizar.es:148287$$particulos$$pdriver 000148287 951__ $$a2025-01-15-15:06:34 000148287 980__ $$aARTICLE