Development of responsive lanthanide probes for cellular applications

Useful probes of the intracellular environment are required for a wide range of bioactive species including metal ions, oxyanions and pH. These probes need to be targeted to specific organelles (mitochondria, nucleus and lysosomes) in order to allow direct observation of the changes in these regions. Critical probe design features for luminescent lanthanide complexes are defined, together with a review of published sub-cellular localisation profiles. Cell uptake by macropinocytosis has been demonstrated for a wide range of probes and the importance of minimising perturbation of cellular homeostasis emphasised, so that cell viability, proliferation and membrane permeability are not compromised.