The biohybrid system is capable of mimicking the biological interface between bones and muscles
A biohybrid system, capable of mimicking the biological interface between bones and muscles, has been developed by researchers at the Soft Robotics Lab at ETH Zurich.
This technology is suitable for both robotics and the development of medical implants.
Muscles are powerful, soft, and flexible, possessing a high degree of fine motor control that enables them to grasp delicate objects and even self-repair when faced with minor injuries.
Tendons are the key factor when it comes to the precise and effective transmission of force.
Scientists are researching biohybrid solutions to enable the transfer of these properties to robotics. They have discovered that combining synthetic and biological materials can replicate the structure and function of biological tissue and the movement of living organisms.
The future of biohybrid robots could see the enhancement of human-machine interaction in healthcare, medicine, and assistive robotics. This approach could also advance the development of biohybrid implants for humans.
An interdisciplinary research team led by the Soft Robotics Lab at ETH Zurich, with contributions from researchers at the Institute for Bioengineering of Catalonia (IBEC) and the University of Barcelona, has succeeded in creating a novel muscle-bone interface.
The research led to the creation of a fully functional model made of living biological tissue, replicating the structure of tendons and their transition to muscle, the myotendinous junction, whilst enabling improved integration with technical systems.
Miriam Filippi, lead author of the scientific paper and researcher at the Soft Robotics Lab, which Professor Rober Katzschmann leads, said, “Our solution is based on a 3D bioprinted actuator that structurally and functionally mimics the natural connection between muscle and bone.
The muscle and tendon were both made from biological cell tissue and connected to a bone made from synthetic material.
Katzschmann said, “This study represents a breakthrough in the development of functional muscle-tendon units, laying the foundation for biohybrid systems that bridge biology and robotics. We are taking the next major step towards musculoskeletal robots by investigating how to integrate real muscles and tendons into functional units.”
Based on biology
The main challenge was that forces are often poorly transmitted at the interface between biological and synthetic materials, which leads to energy losses.
In order to solve this issue, the team turned to the natural structure of the musculoskeletal system, where tendons serve as intermediaries between muscles and bones.
Filippi said, “We developed a tendon made from printed cell tissue, with a stiffness level between that of living muscle and a bone-mimicking rigid segment. This enables a stable coupling of soft biological and rigid synthetic components.”
3D bioprinting was used to create the living actuator, which has muscle cells and tendon-like anchors containing connective tissue cells printed onto a platform, and a computer-assisted analysis was utilised to develop the shape and structure of the actuator.
Initial application tests found that the 3D bioprinted actuators demonstrated reliable and long-term stable contraction ability.
Medical applications
Katzschmann said, “The work demonstrates how engineered biological tissue can be harnessed to reproduce the mechanics of natural musculoskeletal systems, thereby advancing both fundamental research and applications in the fields of soft robotics, bioinspired technology, and regenerative medicine.”
A potential medical application is the biomechanical modelling of the middle ear, in particular, the interaction between the stapes and the stapedius muscle.
Other uses include adaptive prosthetics, biologically integrated robotic systems, and lab-grown replacement tissues.
