Two Scientists Have Invented Tiny Robots Made from Living Cells
A report in the Proceedings of the National Academy of Sciences states that Joshua Bongard (University of Vermont) and Michael Levin (Tufts University) and their colleagues have designed organic robots from cellular components. The result is close to matching the biological definition of an organism, in that it can behave autonomously and contains cell types that are specialized to perform different roles. Though only a millimeter or so across, the artificial organisms Dr. Bongard and Dr Levin have invented, which they call xenobots, can move and perform simple tasks, such as pushing pellets along in a dish.
These accomplishments may not sound like much, but the process could be scaled up and made to do useful things. Bots derived from a person’s own cells could theoretically be injected into the bloodstream to remove plaque from artery walls or to identify cancer. On a bigger level, swarms of them could be built to seek out and digest toxic waste in the environment, including microscopic bits of plastic in the sea.
To design their bots Dr Bongard and Dr Levin employed a computer program called an evolutionary algorithm. This worked by creating virtual representations of thousands of arrangements of cells that might achieve a particular task.
The demonstration bots Dr Bongard and Dr Levin have made use two types of stem cell. Some called pluripotent cells taken from early-stage embryos. These embryonic cells retain wide powers to turn into other cell types. The others are cardiac progenitor cells, a more specialized type of stem cell already destined to generate heart muscle. Besides pushing single pellets, groups of lots put into a dish together were able to work collectively, moving around in circles and gathering the pellets into neat piles.
“It is possible”, says Dr Bongard, “that the cells are signaling to one another in a way we’re not aware of.” That possibility, and many other questions, will be the subject of further research. The team are also trying to work out how cells can be motivated to build complex, functioning bodies. Such knowledge, says Dr Levin, would be immensely useful in regenerative medicine, which seeks to repair organs and build body parts for transplant.