ITHome News on October 28: ETH Zurich published a blog post on October 22,showcasing a biohybrid microrobot made of mouse skeletal muscle cells and hydrogel scaffolds, which can jump, run, swim and grasp.
ITHome attaches the related demonstration video below:
This achievement is the first to integrate living skeletal muscle tissue with a flexible hydrogel scaffold, co-designed in a computer to create a "bio-actuator" about 1.5 centimeters long. When stimulated by electrical pulses, it produces bending movements visible to the naked eye and drives the microrobot to perform actions such as jumping, swimming, crawling and grasping.
The team from ETH pointed out that lab-cultured muscle has in the past been able to contract, but the amplitude was often so tiny that it required a microscope to observe, making it difficult to actually drive a robot. The breakthrough in the new research redesigned the interaction between muscle and scaffold: an algorithm simultaneously optimizes the distribution and volume of the muscle tissue as well as the shape and mechanical properties of the hydrogel scaffold, so that muscle contractions are converted into overall deformation as efficiently as possible.
For manufacturing, the team used a light-based 3D printing technique called Xolography, which uses light to cure the hydrogel; printing a single scaffold takes about one minute.
The results show that with a similar amount of muscle, the new actuator's range of motion can reach up to 11 times that of previous systems. A single contraction lets the device spring up about 5 millimeters from the bottom of the culture dish, equivalent to one-third of its body length; the walking version reached a speed of 6.2 millimeters per second, about 0.4 body lengths per second, which the study says is the highest speed reported to date for a walking biohybrid robot.
However, such robots are still far from real-world applications. Their muscle tissue must be soaked in nutrient solution to survive and cannot work outside the laboratory; to scale up in size, a system resembling "artificial blood circulation" might also be needed to continuously deliver oxygen and nutrients and remove metabolic waste.