Robots are everywhere. They build cars, they clean up nuclear accidents clean up nuclear accidents, and they even help people with disabilities work help people with disabilities work. But there are challenges where they simply can't be applied. That's where the concept of the biobot comes in: a robot made from living tissue. A group of specialists at Tufts University, the University of Vermont, and the Wyss Institute at Harvard has just introduced the "xenobots", machines less than a millimeter in diameter, built from a hybrid of frog heart and skin cells. These tiny creations could one day neutralize chemicals and absorb microplastics, but the fact that they're "alive" raises some doubts.
What Is a Robot, Anyway?
The basic definition of a robot is a programmable machine with the ability to repeat and automate complex actions. It's so flexible that it doesn't even place restrictions on the material of construction. The traditional "vision" of a robot includes metal, cables, motors, and power sources, but how about a "soft" robot? I'm not referring to designs that try to imitate animals and insects, but to a robot made of tissue. Cells, to be precise.
The Science Behind Xenobots
The latest developments come from Tufts University, the University of Vermont, and the Wyss Institute at Harvard. A team of scientists — biologists Michael Levin and Douglas Blackiston, and roboticists Josh Bongard and Sam Kriegman — recently published a paper in the PNAS based on what the press calls xenobots, tiny living machines no more than a millimeter in diameter, built around a hybrid design.
How Xenobots Are Built
So what does "hybrid" mean? It means the robot combines cells from a frog, specifically from the heart and skin. Heart cells act as pistons, while skin cells provide structural rigidity. The formation of these xenobots begins with an evolutionary algorithm. In essence, it mimics natural selection by generating solutions, selecting the most interesting ones, and mutating them. In a virtual environment, the algorithm combines thousands of configurations, using between 500 and 1,000 heart and skin cells.
The configurations that show superior performance — whether in movement or in moving microscopic objects, parameters defined during the algorithmic phase — are chosen as the starting point for the next generation. After about a hundred iterations, the result is a set of biobots that largely follow the original instructions set by the researchers.
Potential Applications and Open Questions
One of the most interesting aspects of this study is that it doesn't go down to the DNA level; everything happens at the cellular scale. For now, xenobots "live" for about a week, as they only carry the energy they were created with and have no digestive system. In the future, similar designs could deliver drugs to specific parts of the body, remove ocean microplastics, and neutralize chemicals.
But there are also doubts and risks. On one hand, what would happen if a designer added something like a nervous system in the future? How well would the public receive the idea of a "microscopic Frankenstein"? And on the other hand, what stops xenobot designers from transferring other types of substances? Injecting medicine into a tumor is an excellent strategy, but someone — not necessarily a person — could have darker intentions...
Source: Smithsonian Magazine
