Millions of people around the world are medicated with heparin, a blood thinner used for the treatment and prevention of blood clots. One of the ways in which doctors monitor the effectiveness of heparin is to look for a blood protein known as factor Xa in a patient’s bloodstream – the less factor Xa activity that is occurring, the better. Now, thanks to an enzyme obtained from fireflies, that protein may be easier than ever to detect.

The firefly enzyme is called luciferase, which sounds like something that could be used to thwart Superman. It’s what allows the insects’ abdomens to glow.

Scientists from Connecticut College have combined a protein obtained from the enzyme with special fluorescent dyes, which cause the protein to emit near-infrared light. This is particularly valuable to doctors, as near-infrared rays travel through tissue better than other types of light, allowing medical practitioners to see deeper into the body.

In laboratory tests, the luciferase derivative allowed scientists to detect the presence of factor Xa in blood samples.

Luciferase is said to be relatively inexpensive to obtain, and to be more stable than other protein-imaging agents. Scientists from Missouri’s Washington University School of Medicine have also recently had success using bismuth-containing nanoparticles to image blood clots.

The luciferase research was recently published in the journal Bioconjugate Chemistry.