Tiny Microelectronic Robot Is Powered By Jets Of Bubbles

Researchers have created tiny microbots that they claim to be the world's smallest microelectronic robot. The minuscule robots are powered by shooting out dual jets of bubbles behind them, a propulsion system first conceived about a decade ago. The tiny robots were developed by an international team led by Professor Oliver G. Schmidt from the Chemnitz University of Technology in Germany.The robots are flat and measure 0.8 mm long by 0.8 mm wide by 0.14 mm tall. The robots are steered wirelessly using an external transmitter. When the bots receive a signal from the transmitter, an induction coil in the center heats one of two polymer tubes that run lengthwise across both sides and the top of the tiny robot. Both tubes continuously draw in a solution of hydrogen peroxide and water that the robots are immersed in.

Inside the robots is a tiny amount of platinum that causes a catalytic reaction producing oxygen bubbles that are expelled out of the rear of the tubes to produce thrust. The robot can be steered through the aqueous solution using remote control by heating only one of the tubes to varying degrees. The team designed the microbot to swim in circles if no heat is applied at all.

If some heat is applied, turning is compensated for, and the robot moves in a straight line. With more heat applied robot turns in the other direction. The team also created a manipulator arm for the robot in the form of an actuator composed of a thermoresponsive polymer that opens and closes when heat is applied. The tiny robots can also be fitted with a small LED light source.

The team foresees a future where these tiny robots could be used to deliver medications to specific parts of the human body. One challenge before that can happen is designing the robots to operate on a fuel that is more biocompatible than hydrogen peroxide. Finding a different sort of fuel will be the team's focus in the next phase of research.