Cambridge, MA — In a breakthrough that could change how damaged hearts are treated, researchers from Harvard Medical School and Duke University have developed a new kind of heart tissue that responds to light instead of wires or surgery. This innovation may offer a safer and less invasive way to repair heart damage.
Light Instead of Wires
The human heart relies on electrical signals to pump blood effectively. When these signals are disrupted—often due to injury or disease—the heart may not beat properly. In recent years, scientists have used 3D-printed tissues made from living cells and soft materials to patch damaged areas. While these artificial tissues can help restore structure, they have one major drawback: they cannot send the electrical signals the heart needs to beat in rhythm.
Until now, doctors had to use wires and electrodes to activate these engineered tissues. This required invasive surgery and often carried risks of tissue damage and infection. In many cases, the devices could not remain in the body for long.
The Power of Light
The new study presents a safer alternative. Instead of using wires, the research team designed a 3D-printed scaffold made from gelatin methacryloyl, a gel-like substance. They inserted tiny solar cells—each smaller than a grain of rice—into the soft framework. After that, they added heart muscle cells, known as cardiomyocytes.
This created a living tissue structure that can be activated with light alone. When exposed to light pulses, the solar cells generate enough energy to change how the heart cells beat. The tissue needs no wires, no surgical implants, and causes no physical harm.
Promising Results in Testing
In laboratory tests, heart cells in the scaffold beat over 40% faster when exposed to light. More importantly, the tissue remained healthy. Over 96% of the cells stayed alive during light stimulation, and there were no signs of irregular electrical patterns—an important safety concern in cardiac research.
These results suggest that the new tissue could help restore proper heart function without triggering dangerous side effects like abnormal heart rhythms.
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