In vivo imaging of quantum dots.

Noninvasive whole-body near-infrared fluorescence imaging is now acknowledged as a powerful method for the molecular mapping of biological events in live small animals such as mouse models. With outstanding optical properties such as high fluorescence quantum yields and low photobleaching rates, quantum dots (QDs) are labels of choice in the near-infrared domain. The main applications described in the literature for in vivo imaging of mice after injection of QDs encompass imaging of lymph nodes and tumors and cell tracking. Standard methods for the preparation, the purification, and the in vivo fluorescence whole-body imaging of QDs in the live mouse are described. Nanoparticles coated by PEG chains of different sizes and terminal groups are prepared using 705-nm-emitting commercial QDs. Their biodistribution after intravenous or intradermal injections in tumor-bearing mice is reported here.