Gutruf et al. Nat. Commun. 10, 5742 (2019)

At the heart of it, the heart is controlled by electrical activity. Manipulating those patterns with pacemakers can reveal important details about cardiac diseases. However, such manipulations in small animals, such as rodents, have been hindered by the animals’ small size—powering cardiac pacemakers has previously required bulky batteries, external tethering, or removal for recharging—details not conducive to studies with freely moving rodents.

A new, wirelessly powered device cuts the cord and loses the battery to provide optical and electrical cardiac stimulation in small animals. With all the electronics required, the device weighs just 110 mg and is about the size of dime. In the publication in Nature Communications, the team uses the device in vivo with rats and ex vivo with mouse hearts.