Gadolinium‐Conjugated Dendrimer Nanoclusters as a Tumor‐Targeted T 1 Magnetic Resonance Imaging Contrast Agent

A sensitive quenched electrochemiluminescent DNA sensor based on the catalytic activity of gold nanoparticle functionalized MoS2

A simple sandwich-type ECL sensor for DNA detection based on MoS₂–Au quenching the ECL signal of CdS/ZnS QDs.

Specific detection and imaging of enzyme activity by signal-amplifiable self-assembling (19)F MRI probes

Specific turn-on detection of enzyme activities is of fundamental importance in drug discovery research, as well as medical diagnostics. Although magnetic resonance imaging (MRI) is one of the most powerful techniques for noninvasive visualization of enzyme activity, both in vivo and ex vivo, promising strategies for imaging specific enzymes with high contrast have been very limited to date. We report herein a novel signal-amplifiable self-assembling (19) F NMR/MRI probe for turn-on detection and imaging of specific enzymatic activity. In NMR spectroscopy, these designed probes are "silent" when aggregated, but exhibit a disassembly driven turn-on signal change upon cleavage of the substrate part by the catalytic enzyme. Using these (19) F probes, nanomolar levels of two different target enzymes, nitroreductase (NTR) and matrix metalloproteinase (MMP), could be detected and visualized by (19) F NMR spectroscopy and MRI. Furthermore, we have succeeded in imaging the activity of endogenously secreted MMP in cultured media of tumor cells by (19) F MRI, depending on the cell lines and the cellular conditions. These results clearly demonstrate that our turn-on (19) F probes may serve as a screening platform for the activity of MMPs.