The sun is responsible for all life on Earth, and now it can even be responsible for powering electronic implant devices that keep many people alive.
In a new study, researchers from Bern University Hospital and the University of Bern in Switzerland found that using solar cells to power devices, like deep brain stimulators and pacemakers, is possible. Lead author Lukas Bereuter said he believes wearing power-generating solar cells under the skin could eliminate the need for future procedures to change the batteries of current life-saving devices.
“The overall mean power obtained is enough to completely power for example a pacemaker or at least extend the lifespan of any other active implant,” Bereuter told Science Daily. “By using energy-harvesting devices such as solar cells to power an implant, device replacements may be avoided and the device size may be reduced dramatically.”
Common electronic implants are battery powered, with their battery capacity determining their size. The batteries must be changed like any other electronic device, but this involves costly surgery and the risk of medical complications.
Research groups have presented prototypes of small electronic solar cells to carry under the skin that can recharge medical devices. The sun’s light penetrates the skin and is converted into energy by the cells.
Bereuter and his team developed specially designed solar measurement devices to determine the possibility of the rechargeable energy generators. The devices are able to measure the output of power that is generated.
Study participants wore a device that measured the solar cell’s power output and stored data on a memory card. Each individual wore the device during a period of one week per season in summer, autumn and winter.
Most participants wore the devices uncovered, on the upper arm during the day from morning to bedtime. Volunteers were instructed to cover the device when wearing a neck covering in order to stimulate a neck implant.
Activity and weather were registered using a daily questionnaire, and all data was registered anonymously. Ten devices were tested with each covered by optical filters in order to mimic the properties of the skin.
By using the optical filters, the researchers determined how the properties of the skin influence the sun’s penetration. The cells generated significantly more power than the five to ten microwatts that a typical cardiac pacemaker uses.
The cells generated an average of 12 microwatts by participants with the lowest power outputs. The study suggested that future implants should be covered by a translucent, biocompatible material and should have an alarm to warn the patient if the accumulator charge falls below a certain limit.
Bereuter said he believes the results of the study can be applied to any other solar-powered mobile application for humans, if it’s to scale. Before this can happen, the efficiency and catchment area of a solar cell and the thickness of a patient’s skin needs to be considered, he said.
The study was published in the Annals of Biomedical Engineering. It is not considered a clinical trial by Swiss law, because no health-related data was recorded.