Rice University’s Center for Biological and Environmental Nanotechnology (CBEN) researchers have developed a quantum dot that is programmed to light up only when activated by specific proteases.

Altered expression of particular proteases is a common hallmark of cancer, atherosclerosis, and many other diseases.

The probe’s design makes use of a technique called “quenching” that involves tethering a gold nanoparticle to the quantum dot to inhibit luminescence. The tether, a peptide sequence measuring only a few nanometers, holds the gold close enough to prevent the quantum dot from giving off its light.

In their test system, the Rice team used a peptide tether that is cleaved by the enzyme collagenase. The researchers first showed that luminescence of the quantum dots was cut by more than 70 percent when they were attached to the gold particles. They remained dark until the nanostructures were exposed to collagenase after which the luminescence steadily returned.

Rice University news release