This Strange Robot Arm Can “Taste” with Special Bacteria

When you think of a robot, you probably picture a machine built from hard, inorganic material, such as metal. And you have good reason to, because that’s what the vast majority of robots are constructed from. But there isn’t a rule that says they have to be. In many instances, it could be beneficial for them not to be. We’ve seen that already in the burgeoning field of soft robotics with robots that are made or actuated with soft, flexible materials. Now a team of engineers from the University of California, Davis and Carnegie Mellon University are pushing the envelop even further with a robot that can “taste” using living bacteria.

The idea of using bacteria as part of a symbiotic, mutually-beneficial relationship isn’t new. Every animal on the planet has a biome flourishing with a variety of bacteria. Your gut, for example, is teaming with bacteria that help your digestion. They, in return, receive nutrients so they can thrive. But the idea of creating a symbiotic relationship between robots and bacteria is one that has barely been explored until now. As a proof of concept, the team behind this robot are using bacteria as a means of detecting a chemical called IPTG.

IPTG itself isn’t something that we have much of a need to detect, but it does have unique properties that make it ideal for this kind of testing. To take advantage of it, the team engineered a special kind of E. coli bacteria that produces a fluorescent protein in the presence of IPTG. They put that bacteria inside special pods on the robot’s soft gripper. Those pods have a flexible membrane that is only permeable enough to allow IPTG to pass through. If the robot touches something with IPTG on it, it will react with the bacteria and produce the fluorescent protein.

Inside of the bacteria pods there is electronic circuitry that can detect that fluorescence. That gives the robot the ability to “taste” the IPTG without using conventional electronic sensors. There isn’t a practical use for this exact technology, but it does prove that bacteria could be useful in robotics. It may even be possible to eventually use bacteria within a robot to make polymers or generate energy.