A group of researchers consisting of Patrick Mercier (principal investigator of the Energy-Efficient Microsystems Group), Andrew Lysaght, Saurav Bandyopadhyay, Anantha Chandrakasan, and Konstantina Stankovic have discovered how to extract power from the biologic battery that occurs naturally within the inner-ear of mammals. The results, featured in the journal Nature Biotechnology this week, show for the first time that it is not only possible to extract energy from the ear, but that it is also possible to use this energy to power useful electronic devices – in this case a miniaturized radio transmitter and sensor.
One of the main engineering challanges of building such a bioelectronics and energy harvesting system is that the extractable power from the inner-ear is extremely small – on the order of a few nanowatts. By employing innovative near-zero-leakage power electronics, the researchers were able to boost the voltage of the biologic battery from approximately 80 mV to 1 V, which was then used to operated a 2.4 GHz radio transmitter. The resulting chip design, implemented in a 180nm CMOS technology, employed an extremely duty-cycled energy-buffering architecture, where the radio transmitted a single packet approximately once per minute.
More detailed information regarding chip implementation results, clinical experiments, and future directions can be found in the paper here. Meanwhile, the results have generated interest in the press, featuring coverage by many news and social media organizations, including the journal Nature, IEEE Spectrum, Popular Science, the front page of MIT’s website, Discovery News, the Los Angeles Times, the Wall Street Journal, etc. In particular, MIT News has a recommended article about the work, and can be found here.