Researchers create a soft robotic arm that tastes using bacteria

Scientists at the University of California, Davis (UC Davis) and Carnegie Mellon University (CMU) have designed a soft robotic gripping arm that uses engineered bacteria to "taste" for a specific chemical. The robotic gripper arm is a proof-of-concept for biologically-based soft robots.

Researcher Cheemeng Tan from UC Davis says that the long term goal of the researchers is to build a synthetic microbiota for soft robots that can help with repair, energy generation, or biosensing. Soft robotics is an area of significant research and aim to create machines that match the versatility of living things, and soft robot designs are inspired by nature.

The team says that combining work in flexible electronics and robotic skin with synthetic biology puts them closer to breakthroughs in biohybrid robots. The new robot that the team has created uses a biosensing module that is based on the E. coli bacteria engineered to respond to the chemical IPTG. When exposed to the chemical, the robot produces a fluorescent protein.

The bacterial cells are in wells with a flexible and porous membrane that allows chemicals to enter while keeping the cells inside. The biosensing module is built into the surface of the flexible gripper on a robotic arm allowing the gripper to "taste" the environment through its fingers.

When the IPTG chemical crosses the membrane into the chamber, the cells fluoresce, and the electronic circuits inside can detect the light. Those signals then travel to the gripper control unit and decide whether to pick something up or release it. In tests, the gripper was able to check a laboratory water bath for IPTG and decide whether or not to place an object into the bath. The team says that the bacteria can be engineered for a different function like detecting chemicals, making polymers for repairs, or generating energy.