A Near‐Infrared‐Fluorescence‐Quenched Gold‐Nanoparticle Imaging Probe for In Vivo Drug Screening and Protease Activity Determination

Nanodiagnosis: A matrix-metalloproteinase (MMP) sensitive gold-nanoparticle (AuNP) imaging probe quenches conjugated near-infrared (NIR) dyes with high efficiency and is specifically activated by the target MMPs (see picture, left). With this system, nanomolar amounts of protease can be detected—both in vitro and in vivo. Experiments disclose an apparent positive contrast in MMPs-positive tumor-bearing mice (right).