Lanthanide-based tools for the investigation of cellular environments.

Biological probes constructed from lanthanides can provide a variety of readout signals, such as the luminescence of Eu(iii), Tb(iii), Yb(iii), Sm(iii) and Dy(iii), and the proton relaxation enhancement of Gd(iii) and Eu(ii). For numerous applications the intracellular delivery of the lanthanide probe is essential. Here, we review the methods for the intracellular delivery of non-targeted complexes (i.