Combining viscosity-restricted intramolecular motion and mitochondrial targeting leads to selective tumor visualization.

We report a novel fluorescent molecular conjugate,V-M1,enabling an accurate visualization of tumor tissues. The emission wavelength ofV-M1exceeds 650 nm, which is well within the near-infrared therapeutic window. Tumor accumulation of this cationic dye allows the visualization of cancerous cells as a function of mitochondrial viscosity.