UC Berkeley physicist Alex Zettl and his colleagues have devised a working nanoradio, building a receiver whose key components are a single carbon nanotube between two electrodes. Nanoradios have the potential to make mobile devices smaller, and by using less energy extend their battery life. Tiny devices with nanoradios could even be injected into the bloodstream, delivering radio-controlled dosages of medications. Reducing the size and power consumption of radios has been a major electronic engineering goal since RCA introduced the first pocket sized transistor radios in 1955. Progress in microminiaturization has permitted new applications such as radio frequency identification (RFID) tags. The effort to push radio engineering down to the molecular scale appeared stalled until Zettl and his students had a key insight: a single nanotube could do the job. Within days they were listening to vintage rock music on a prototype nanoradio. The nanoradio consists of a nanotube projecting from an electrode, with another electrode not quite touching the other end. A voltage is passed through the nanotube, sending electrons streaming to the other electrode. Any radio-frequency signal causes the nanotube to vibrate, changing the current flow. The resulting current duplicates the radio signal, and can be fed into an amplifier and speakers. So far the nanoradios only work as receivers, but developing a transmitter should not be difficult, since it is essentially just a receiver working in reverse.