(The Economist) – Its components dissolve once it has done its job

DEVICES THAT peer into the human body from the outside, like X-ray scanners and MRI machines, have transformed medicine. A new generation of ingestible sensors could do the same from the inside. But these require power, and as standard batteries contain harmful chemicals, swallowing them is generally inadvisable.

To get around this problem, ingestible sensors—most commonly small, pill-like cameras—are often designed so their batteries do not contact the body and the entire unit is eventually excreted. Sometimes their protective casing fails, however, or they get stuck inside the body. A better solution would be batteries made of materials that are not toxic in the first place. Ideally, those that could safely degrade inside the body. (Read More)