Blasting light through human flesh to power implants

During the past few decades, medical technology has seen advances in scope and efficiency, leading to increased use of electronic implants such as pacemakers to regulate heart rate and cerebrospinal shunts to control the flow of spinal fluid. Most of these medical devices require a constant source of energy, typically batteries, but they have finite lifespans. Replacing an exhausted battery requires invasive surgery, which risks surgical complications such as bruising, infections, and other adverse events.

A research group from South Korea, led by Professor Jongho Lee at the Gwangju Institute of Science and Technology (GIST), has developed a way to recharge the internal battery of devices without invasive surgery or risky penetrative procedures.

“One of the greatest demands in biomedical electronic implants is to provide sustainable electrical power for extended healthy life without battery replacement surgeries,” Lee explains.

Although this is a tricky concept, Lee believes the answer lies in the translucency of living tissue. When you hold your hand up to a powerful light, the edges of your hand glow as light passes through your skin. Taking inspiration from this, Lee and his team developed an active photonic power transfer method that generates electrical power in the body.

The system consists of two parts – a skin-attachable micro-LED source patch, which generates photons that penetrate through tissues, and a photovoltaic device [similar to ones used in solar panels] integrated into a medical implant, which captures photons and generates electrical energy. It provides a sustainable way of supplying the medical implant device with enough power to avoid high-risk replacement methods.

“Currently, a lack of a reliable source of power limits the functionality and performance of implant devices,” Lee says. “If we can secure enough electrical power in our body, new types of medical implants with diverse functions and high performance can be developed.”

When the scientists tested the power system in mice, they found it easy to use, regardless of weather, clothes, and indoor or outdoor conditions. The photons emitted from the source patch successfully penetrated live tissues in mice and wirelessly recharged the device.

“These results enable long-term use of currently available implants, in addition to accelerating emerging electrical implants that require higher power to provide diverse, convenient diagnostic and therapeutic functions in human bodies,” Lee says.

Gwangju Institute of Science and Technology
https://www.gist.ac.kr