( ther a peptide sequence measuring only...)'Smart' nanoprobes light up disease

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.

Ultimately, the researchers hope to pair a series of quantum dots, each with a unique NIR optical signature, to an index of linker proteases.

"There is currently a critical need for methods to simultaneously image the activity of multiple proteases in vivo," said Drezek. "This is important not only for early detection of several diseases, but perhaps more significantly, in understanding and monitoring the efficacy of therapeutic interventions, including the growing class of drugs that act as protease inhibitors. What is particularly powerful about the protease imaging probes described in this study is the combination of the contrast enhancement achievable through an activateable probe with the imaging advantages provided by the brightness, photostability, and tunability of quantum dots."