In the swim

The concept of tiny robots capable of use in microsurgery or continuously monitoring water supplies for biological toxins is one step closer to being a reality thanks to a recent development by researchers from two US universities and the

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The transatlantic team devised a method to supply microscopic devices with sufficient energy to propel themselves through liquid, an impressive feat in the world of microfluidics. The micro-devices are powered and controlled with external energy from electric fields but there is also the potential to power them by radio waves.

The researchers took various types of millimetre-sized diodes, or electronic devices containing two electrodes, and put them in a dish of liquid with two external electrodes placed on the outer edges of the dish. They then applied alternating electric currents to the electrodes at the outer edges of the dish, which provided energy for the diodes to move on their own. The diodes absorb the external field energy and convert it into motion in a process called electro-osmosis.