Light Makes Right

Gunjan Sinha Popular Science

Light-emitting diodes developed by NASA to grow plants in outer space, it turns out, can generate a lot more than a little green. Scientists have also discovered that the diodes speed up wound healing.

In a small study, a portable flat array of LEDs placed on the outside of a patient’s cheek for about 1 minute a day helped heal mouth ulcers caused by cancer therapies. Now, as part of a nationwide clinical trial, scientists are investigating the therapy to treat such hard-to-heal wounds as diabetic skin ulcers, burns, and oral sores.

While laser light and pressurized oxygen are known to speed healing, their use in a clinical setting is problematic, explains lead researcher Harry Whelan. "They don’t emit the appropriate wavelengths, and the machines are the size of refrigerators." LEDs emit infrared light at up to 880 nanometers — wavelengths that are long enough to penetrate deep into bodily tissues. And because they can deliver light without heat, they are safer than most lasers.

Normally, cells get their energy from the food we eat, but cells can also use light to generate energy. In the laboratory, skin and muscle cells exposed to the infrared light grow 150 to 200 percent faster. Whelan is also investigating whether LEDs can heal muscle and bone injuries that have not healed through traditional physical therapy.