Photo credit: arstechnica.com
Biohybrid robots represent a fascinating fusion of biological elements, such as muscle tissues, plant components, and fungi, with synthetic materials. Though we have made considerable advancements in the development of the non-biological aspects of these robots, a persistent challenge has been maintaining the vitality of the organic components. This challenge has historically limited the scale and complexity of biohybrid robots, resulting in designs that typically measure only a few centimeters and feature a singular actuating joint.
According to Shoji Takeuchi, a professor at the University of Tokyo, significant hurdles remain in the quest to scale up biohybrid robots. “The weak contractile force of lab-grown muscles, the potential for necrosis in denser muscle tissues, and the difficulties in integrating biological actuators with artificial frameworks contribute to these challenges,” he stated. Takeuchi heads a research team that has successfully developed a full-sized biohybrid hand, measuring 18 centimeters in length, featuring five fingers operated by lab-cultured human muscles.
Addressing the Challenge of Muscle Vitality
Among the many obstacles in creating larger biohybrid robots, necrosis poses one of the most significant difficulties. The conventional process of cultivating muscles in a lab often relies on a liquid medium that provides essential nutrients and oxygen to muscle cells, typically grown on petri dishes or gel scaffolds. During the cultivation of smaller, flatter muscle tissues, nutrients and oxygen can permeate throughout, promoting healthy cell growth.
However, as the goal shifts to generating thicker and more powerful muscle tissues, the cells positioned deeper within these structures become deprived of essential nutrients and oxygen, leading to cell death through necrosis. In natural organisms, this issue is mitigated by a vascular system that distributes nutrients throughout the body. Unfortunately, the ability to create effective artificial vascular networks within lab-grown muscle tissues remains an unsolved problem. Therefore, Takeuchi and his team needed to devise a creative solution to circumvent the issue of necrosis. Their innovative approach involved a technique reminiscent of sushi-making.
The research team initiated their process by cultivating thin, flat muscle fibers on a petri dish, arranging them side by side. This configuration allowed all of the muscle cells to receive adequate nutrients and oxygen, resulting in robust and healthy muscle fibers. Once the fibers were fully developed, Takeuchi and his colleagues employed a rolling technique, assembling them into cylindrical structures they termed MuMuTAs (multiple muscle tissue actuators), akin to preparing sushi rolls. “MuMuTAs were created by culturing thin muscle sheets and rolling them into cylindrical bundles to optimize contractility while maintaining oxygen diffusion,” Takeuchi elaborated.
Source
arstechnica.com