When heartbeats slip into an irregular, life-threatening rhythm, a pacemaker or defibrillator can jolt the heart back into rhythm. But because electricity can cause pain, tissue damage, and other side-effects, a research team lead by scientists at Johns Hopkins, Baltimore, MD, say that there is a kinder, gentler option—light.

The “optrode” (left) delivers blue light to the heart via fiber optics, while (right) a red heart cell contains an implanted light-sensitive blue opsin protein that works with (yellow) heart proteins. (Credit: Patrick M. Boyle)

In a paper published in the online journal, Nature Communications, five biomedical engineers from Johns Hopkins and Stony Brook universities describe their plan to use biological lab data and an intricate computer model to use low-energy light to solve serious heart problems such as arrhythmia.

To achieve this, the team is working with optogenetics, which refers to inserting light-responsive proteins called opsins into cells. When exposed to light, these proteins become tiny portals within the target cells, allowing a stream of ions—an electric charge—to pass through.

They have already successfully tested this technique on a computer model of a heart, incorporating biological data from the Stony Brook lab. The Stony Brook collaborators are working on techniques to make heart tissue light-sensitive by inserting opsins into some cells, and will test how these cells respond when illuminated.

The Hopkins team members will use this model to conduct virtual experiments to determine how to position and control the light-sensitive cells to help the heart maintain a healthy rhythm and pumping activity. They will also attempt to gauge how much light is needed to activate the healing process. They say that after the technology is honed through the computer modeling tests, it could be incorporated into light-based pacemakers and defibrillators.