Fluorescent Nanocrystals for Biomedical Applications.

We report on fluorescence quenching experiments of CdSe quantum dots, which were encapsulated for biocompatibility using different strategies. Since their fluorescence is very sensitive against water and other quenching molecules reaching their surface, quenching experiments allow conclusions on particle shielding towards the surrounding medium. It turns out that best shielded particles with comparable chemical composition of their ligand shell have also outstanding properties in respect of undesired unspecific cellular uptake. [ABSTRACT FROM AUTHOR]