How did scientists create a robot made of liquid metal?

The answer

In January 2023, researchers at Carnegie Mellon University and the Chinese University of Hong Kong published a study in Matter demonstrating a miniature robot made from gallium embedded with magnetic neodymium-iron-boron microparticles. By applying alternating magnetic fields, the robot could transition between solid and liquid states. The gallium alloy melts at just 29.8°C, close to body temperature. In demonstrations, the robot liquefied to escape a cage, then resolidified outside. Potential medical applications include removing foreign objects from the body, delivering drugs to specific locations, and acting as smart soldering material for circuit assembly. The research was inspired by the T-1000 character from the Terminator franchise, though practical medical deployment requires significant further development.