Sleuthing out signs of disease is particularly difficult when those signs are only visible at the molecular scale. That’s why scientists developed a way to use the molecule that makes fireflies’ glow to lead the way.
Using a modified form of this molecule, known as luciferase, they can flag molecular signs of disease with light that’s visible to the naked eye. The researchers enabled luciferase to perform this task by attaching a synthetic molecule — a process known as tagging — that they specifically engineered to detect a particular molecular target.
“You can think of the tagged luciferase as a cyborg molecule … half bio, half synthetic,” senior study author Kai Johnsson said in a statement.
In this luciferase-based system, described in a paper published in the journal Nature Communications, the synthetic “tag” molecule acts like a switch. If the tag has not yet come across its target — which would consist of a particular protein indicative of disease — it prevents luciferase from producing light. When the tag identifies the target protein, it turns on luciferase, causing it to emit light.
This system could allow doctors to test for a disease by simply sending in the tagged luciferase to scout out disease indicators and then looking to see if the luciferase is lighting up. Since the light that luciferase produces is visible to the naked eye, this method does not require complex and often expensive devices to read the test results.
“This is a generalized design,” Johnsson said in a statement. “It shows how you can exploit synthetic chemistry to create sophisticated biosensor proteins.”
The potential applications of this method extend far beyond disease diagnosis. Scientists can adapt this system to target essentially any protein. Considering that proteins are the primary type of molecule found in living things, the future for this new luciferase system looks pretty bright.
The photo below shows tagged luciferase that is “off” on the left, and “on” on the right.