World’s smallest radio may cure blindness, detect harmful chemicals

Illustration: Claus Lunau

Nanoradios work by using physical vibrations. They won’t change how we listen to music, but they could have a significant impact on the world of medicine.

When the radio was invented in the 1890s, no one dreamed that 120 years later there would be a version small enough to fit inside a living cell. The first “nanoradio” was built at the University of California at Berkeley in the US in 2007, when physicists at the Centre of Integrated Nanomechanical Systems (COINS) realised that the mechanical properties of a single carbon nanotube meant that it could function as a radio.

Although nanoradios don’t have tremendous potential for consumer gadgets — who needs a music player smaller than the width of a human hair? — the technology might have profound medical and environmental applications.

It could restore vision, for example. For some types of blindness, doctors can bring back sight by electrically stimulating specific areas of the brain. In current therapies, wires connect electrodes implanted in the brain to an external power source. But the wires can cause infections. In 10 years, an array of implanted nanoradios could be stimulating the brain wirelessly, says COINS physicist Alex Zettl, whose team invented the tiny radio.

Zettl also predicts that the radios, coupled with similarly small transmitters in development at COINS, will one day be built into remote-controlled nanodevices that communicate with each other. The nanoradios and transmitters could be used to monitor thermal or chemical conditions, including the air quality in a city or the toxic chemicals in a factory, without the tangle of wires required by existing systems. “But the real advantage in going nano,” Zettl says, “is that the power requirements are much smaller.” In environmental applications, a smaller power source means lower costs. In medicine, it means that a single living cell could power sensors inside the body.

Four-part harmony
For all their futuristic practical applications, the world’s smallest radios play music as well. One of the first songs Zettl and his colleagues played to prove that their nanoradio worked was “Good Vibrations” by the Beach Boys. It’s a bit of lab humour — vibrations are the secret behind nanoradios.

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