The need for implant replacement after battery depletion is a major drawback for recipients of pacemakers and other medical electronic devices.

Swiss researchers are experimenting with the use of subcutaneous solar cells to continuously recharge such devices and avoid the need for surgical replacement.

Measurement device affixed on the upper arm. Credit: Lukas BereuterScientists from Bern University Hospital and the University of Bern report the first real-life validation data of energy harvesting by 3.6 square cm subcutaneous solar cells. Each of 10 devices was covered by optical filters to simulate how properties of the skin would influence how well the sun penetrates the skin. These were worn on the arm of 32 volunteers in Switzerland for one week during summer, autumn, and winter.

The solar cells generated more than the 5-10 microwatts of power that a typical cardiac pacemaker uses, regardless of season. The participant with the lowest power output still obtained 12 microwatts on average.

Use of solar cells to power implants may also result in further device miniaturization.