Staff member

Biohybrid actuators leveraging living muscle tissue offer the potential to replicate natural motion for biomedical and robotic applications. However, challenges such as limited force output and inefficient force transfer at tissue interfaces persist. The myotendinous junction, a specialized interface connecting muscle to the tendon, plays a critical role in efficient force transmission for movement. Engineering muscle-tendon units in vitro is essential for replicating native musculoskeletal functions in biohybrid actuators. Here, we present a three-dimensionally bioprinted system integrating skeletal muscle tissue with tendon-mimicking anchors containing fibroblasts, forming a biomimetic interdigitated myotendinous junction. Using computational models, we optimized muscle geometries to enhance deformation and force generation. The engineered system improved mechanical stability, myofiber maturation, and force transmission, generating contractile forces of up to 350 micronewtons over a 3-month period. This work highlights how biomimetic designs and mechanical optimization can advance bioactuator technologies for applications in medicine and robotics.

JTD

Soft and flexible robotics is an emerging field that attracts a huge interest due to its ability to produce bioinspired devices that are easily adaptable to the environment. Biohybrid Machines (BHM) represent a category of soft robots that integrate biological tissues, such as engineered muscle tissues, as actuating systems. Although these devices present several advantages in some applications, their proper actuation still represents a challenge for researchers. This paper focuses on the development of a portable and programmable electrical stimulator designed to control muscle fiber-based biohybrid actuators. The stimulator, made using off-the-shelf components, was designed as a stacking of three independent printed circuit boards (PCBs), connected vertically in order to result in a final device with compact dimensions of 59 mm 28 mm 25 mm. The stimulation circuit is capable of delivering currents up to 18 mA with a voltage compliance of ± 90 V, and a power consumption of approximately 1.3 W. The device’s ability to induce twitch and tetanic contractions in a biohybrid actuator is demonstrated in different stimulation conditions. A practical application was also explored through a test case involving a flexible catheter prototype controlled by a biohybrid actuator, demonstrating its potential utility in a BHMs.

JTD

3D printing has emerged as a transformative technology in several manufacturing processes, being of particular interest in biomedical research for allowing the creation of 3D structures that mimic native tissues. The process of tissue 3D printing entails the construction of functional, 3D tissue structures. In this article, the integration of ferrofluid consisting of iron oxide nanoparticles into muscle cell-laden bioink is presented to obtain a 3D printed magnetically responsive muscle tissue, i.e., the ferromuscle. Using extrusion-based methods, the seamless integration of biocompatible ferrofluids are achieved to cell-laden hydrogels. The resulting ferromuscle tissue exhibits improved tissue differentiation demonstrated by the increased force output upon electrical stimulation compared to muscle tissue prepared without ferrofluid. Moreover, the magnetic component originating from the iron oxide nanoparticles allows magnetic guidance, as well as good cytocompatibility and biodegradability in cell culture. These findings offer a new versatile fabrication approach to integrate magnetic components into living constructs, with potential applications as bioactuators and for future integration in smart, functional muscle implants.

JTD Keywords: 3d printing, Ferrofluid, Magnetic bioink, Muscle actuators, Muscle tissu

Biofabrication of three-dimensional (3D) cultures through the 3D Bioprinting technique opens new perspectives and applications of cell-laden hydrogels. However, to continue with the progress, new BioInks with specific properties must be carefully designed. In this study, we report the synthesis and 3D Bioprinting of an electroconductive BioInk made of gelatin/fibrinogen hydrogel, C2C12 mouse myoblast and 5% w/w of conductive poly (3,4-ethylenedioxythiophene) nanoparticles (PEDOT NPs). The influence of PEDOT NPs, incorporated in the cellladen BioInk, not only showed a positive effect in cells viability, differentiation and myotube functionalities, also allowed the printed constructs to behaved as BioCapacitors. Such devices were able to electrochemically store a significant amount of energy (0.5 mF/cm2), enough to self-stimulate as BioActuator, with typical contractions ranging from 27 to 38 mu N, during nearly 50 min. The biofabrication of 3D constructs with the proposed electroconductive BioInk could lead to new devices for tissue engineering, biohybrid robotics or bioelectronics.

JTD Keywords: 3d bioprinting, Animal, Animals, Bioactuator, Bioactuators, Biocapacitor, Biofabrication, Bioprinting, Biosensing techniques, C2c12 myoblasts, Cells, Chemistry, Electric conductivity, Electroconductive, Electroconductive bioink, Ethylenedioxythiophenes, Genetic procedures, Hydrogel, Hydrogels, Mice, Mouse, Pedot nps, Pedot nps,3d bioprinting,electroconductive bioink,bioactuator,biocapacito, Poly (3,4-ethylenedioxythiophene) nanoparticle, Printing, three-dimensional, Procedures, Skeletal-muscle,cytotoxicity,polymer, Synthesis (chemical), Three dimensional printing, Tissue engineering, Tissue scaffolds