Publications

Skeletal muscle tissue represents an attractive powering component for biohybrid robots, as traditional actuators used in the soft robotic context often rely on complex mechanisms and lack scalability at small dimensions. This article proposes a monolithic biohybrid flexure mechanism actuated by a bioengineered skeletal muscle tissue. The design leverages the contractile properties of a bioengineered skeletal muscle to produce a bending motion in a monolithic, tubular mechanism made of a soft and biocompatible silicone blend. This structure integrates two cylindrical pillars that facilitate force transmission from the bioengineered muscle tissue. Performance assessments reveal excellent contractile and stable behavior upon electrical stimulation, compared to current biohybrid actuation systems, with enhanced performance as the mechanism's internal and external diameters decrease. Finite-element simulations further reveal distinct force-displacement responses in mechanisms with different flexural rigidity. This innovative, scalable, and easy-to-fabricate design represents a significant step forward in the development of novel biohybrid machines.

JTD Keywords: Bioactuator, Biohybrid robotics, Flexible skeleton, Microfabrication, Muscle contraction, Muscle tissue engineering, Soft robotic

© 2021 Wiley Periodicals LLC. Biohybrid robotics is a field in which biological entities are combined with artificial materials in order to obtain improved performance or features that are difficult to mimic with hand-made materials. Three main level of integration can be envisioned depending on the complexity of the biological entity, ranging from the nanoscale to the macroscale. At the nanoscale, enzymes that catalyze biocompatible reactions can be used as power sources for self-propelled nanoparticles of different geometries and compositions, obtaining rather interesting active matter systems that acquire importance in the biomedical field as drug delivery systems. At the microscale, single enzymes are substituted by complete cells, such as bacteria or spermatozoa, whose self-propelling capabilities can be used to transport cargo and can also be used as drug delivery systems, for in vitro fertilization practices or for biofilm removal. Finally, at the macroscale, the combinations of millions of cells forming tissues can be used to power biorobotic devices or bioactuators by using muscle cells. Both cardiac and skeletal muscle tissue have been part of remarkable examples of untethered biorobots that can crawl or swim due to the contractions of the tissue and current developments aim at the integration of several types of tissue to obtain more realistic biomimetic devices, which could lead to the next generation of hybrid robotics. Tethered bioactuators, however, result in excellent candidates for tissue models for drug screening purposes or the study of muscle myopathies due to their three-dimensional architecture. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

JTD Keywords: bacteria-bots, based biorobots, biorobots, bots, enzymatic nanomotors, hybrid robotics, muscle‐, Bacteria‐, Bacteria-bots, Biomimetic materials, Biorobots, Enzymatic nanomotors, Humans, Hybrid robotics, Muscle-based biorobots, Nanoparticles, Nanotechnology, Robotics

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