Staff member

Abstract The integration of biological systems into robotic devices might provide them with capabilities acquired from natural systems and significantly boost their performance. These abilities include real-time bio-sensing, self-organization, adaptability, or self-healing. As many muscle-based bio-hybrid robots and bio-actuators arise in the literature, the question of whether these features can live up to their expectations becomes increasingly substantial. Herein, the force generation and adaptability of skeletal-muscle-based bio-actuators undergoing long-term training protocols are analyzed. The 3D-bioprinting technique is used to fabricate bio-actuators that are functional, responsive, and have highly aligned myotubes. The bio-actuators are 3D-bioprinted together with two artificial posts, allowing to use it as a force measuring platform. In addition, the force output evolution and dynamic gene expression of the bio-actuators are studied to evaluate their degree of adaptability according to training protocols of different frequencies and mechanical stiffness, finding that their force generation could be modulated to different requirements. These results shed some light into the fundamental mechanisms behind the adaptability of muscle-based bio-actuators and highlight the potential of using 3D bioprinting as a rapid and cost-effective tool for the fabrication of custom-designed soft bio-robots.

JTD

The field of bio-hybrid robotics aims at the integration of biological components with artificial materials in order to take advantage of many unique features occurring in nature, such as adaptability, self-healing or resilience. In particular, skeletal muscle tissue has been used to fabricate bio-actuators or bio-robots that can perform simple actions. In this paper, we present 3D bioprinting as a versatile technique to develop these kinds of actuators and we focus on the importance of optimizing the designs and properly characterizing their performance. For that, we introduce a method to calculate the force generated by the bio-actuators based on the deflection of two posts included in the bio-actuator design by means of image processing algorithms. Finally, we present some results related to the adaptation, controllability and force modulation of our bio-actuators, paving the way towards a design- and optimization-driven development of more complex 3D-bioprinted bio-actuators.

JTD Keywords: 3D bioprinting, Bio-hybrid robotics, Muscle-based bio-actuators

The integration of biological tissue and artificial materials plays a fundamental role in the development of biohybrid soft robotics, a subfield in the field of soft robotics trying to achieve a higher degree of complexity by taking advantage of the exceptional capabilities of biological systems, like self-healing or responsiveness to external stimuli. In this work, we present a proof-of-concept 3D bioprinted bio-actuator made of skeletal muscle tissue and PDMS, which can act as a force measuring platform. The 3D bioprinting technique, which has not been used for the development of bio-actuators, offers unique versatility by allowing a simple, biocompatible and fast fabrication of hybrid multi-component systems. Furthermore, we prove controllability of contractions and functionality of the bio-actuator after applying electric pulses by measuring the exerted forces. We observe an increased force output in time, suggesting improved maturation of the tissue, opening up possibilities for force adaptability or modulation due to prolonged electrical stimuli.

JTD