Near-Infrared Quantum Dot and Zr Dual-Labeled Nanoparticles for in Vivo Cerenkov Imaging.

Cerenkov luminescence (CL) is an emerging imaging modality that utilizes the light generated during the radioactive decay of many clinical used isotopes. Although it is increasingly used for background-free imaging and deep tissue photodynamic therapy, in vivo applications of CL suffer from limited tissue penetration. Here, we propose to use quantum dots (QDs) as spectral converters that can transfer the CL UV-blue emissions to near-infrared light that is less scattered or absorbed in vivo. Experiments on tissue phantoms showed enhanced penetration depth and increased transmitted intensity for CL in the presence of near-infrared (NIR) QDs. To realize this concept for in vivo imaging applications, we developed three types of NIR QDs and Zr dual-labeled nanoparticles based on lipid micelles, nanoemulsions, and polymeric nanoplatforms, which enable codelivery of the radionuclide and the QDs for maximized spectral conversion efficiency. We finally demonstrated the application of these self-illuminating nanoparticles for imaging of lymph nodes and tumors in a prostate cancer mouse model.