Xenobots, named after the African clawed frog (Xenopus laevis),[1] are synthetic lifeforms that are designed by computers to perform some desired function and built by combining together different biological tissues.[1][2][3][4][5][6] Whether xenobots are robots, organisms, or something else entirely remains a subject of debate among scientists.
Existing xenobots
The first xenobots were built by Douglas Blackiston according to blueprints generated by an AI program, which was developed by Sam Kriegman.[3]
Xenobots built to date have been less than 1 millimeter (0.04 inches) wide and composed of just two things: skin cells and heart muscle cells, both of which are derived from stem cells harvested from early (blastula stage) frog embryos.[7] The skin cells provide rigid support and the heart cells act as small motors, contracting and expanding in volume to propel the xenobot forward. The shape of a xenobot's body, and its distribution of skin and heart cells, are automatically designed in simulation to perform a specific task, using a process of trial and error (an evolutionary algorithm). Xenobots have been designed to walk, swim, push pellets, carry payloads, and work together in a swarm to aggregate debris scattered along the surface of their dish into neat piles. They can survive for weeks without food and heal themselves after lacerations.[2]
Other kinds of motors and sensors have been incorporated into xenobots. Instead of heart muscle, xenobots can grow patches of cilia and use them as small oars for swimming.[8] However, cilia-driven xenobot locomotion is currently less controllable than cardiac-driven xenobot locomotion.[9] An RNA molecule can also be introduced to xenobots to give them molecular memory: if exposed to specific kind of light during behavior, they will glow a prespecified color when viewed under a fluorescence microscope.[9]
Xenobots can also self-replicate. Xenobots can gather loose cells in their environment, forming them into new xenobots with the same capability
Existing xenobots The first xenobots were built by Douglas Blackiston according to blueprints generated by an AI program, which was developed by Sam Kriegman.[3]
Xenobots built to date have been less than 1 millimeter (0.04 inches) wide and composed of just two things: skin cells and heart muscle cells, both of which are derived from stem cells harvested from early (blastula stage) frog embryos.[7] The skin cells provide rigid support and the heart cells act as small motors, contracting and expanding in volume to propel the xenobot forward. The shape of a xenobot's body, and its distribution of skin and heart cells, are automatically designed in simulation to perform a specific task, using a process of trial and error (an evolutionary algorithm). Xenobots have been designed to walk, swim, push pellets, carry payloads, and work together in a swarm to aggregate debris scattered along the surface of their dish into neat piles. They can survive for weeks without food and heal themselves after lacerations.[2]
Other kinds of motors and sensors have been incorporated into xenobots. Instead of heart muscle, xenobots can grow patches of cilia and use them as small oars for swimming.[8] However, cilia-driven xenobot locomotion is currently less controllable than cardiac-driven xenobot locomotion.[9] An RNA molecule can also be introduced to xenobots to give them molecular memory: if exposed to specific kind of light during behavior, they will glow a prespecified color when viewed under a fluorescence microscope.[9]
Xenobots can also self-replicate. Xenobots can gather loose cells in their environment, forming them into new xenobots with the same capability