Intracellular Transport Studies of Picolinate Macrocyclic Copper and Lanthanide Complexes
Abstract
In vivo molecular imaging involves different techniques to image cellular biochemical processes. Metal complexes can be used as cell-permeable medical imaging agents. In this work we studied the cytotoxicity and the cellular incorporation kinetics of two recently synthesized picolinate macrocyclic complexes, [Eu(do2pa)]+ and [Cu(te1pa)]+. Both complexes are able to enter inside the cells. The intracellular concentration (Ci) of [Eu(do2pa)]+ is ∼5 times the extracellular concentration (Ce). In the case of [Cu(te1pa)]+, the ratio Ci/Ce is approximately 1.4. Furthermore, the results suggest that these complexes are not substrates of P-gp, an efflux transport protein involved in the mechanisms of multidrug resistance in cancer cells and in the low permeability of blood-brain barrier. The results obtained here, added to their physicochemical properties, let us propose that the complexes studied could be suitable platforms for the synthesis of cell-permeable MRI contrast agents or PET tracers.